Article Bites #46: Influence of Prehospital Physician Presence on Survival after Severe Trauma

Article Summary by Robert Skinner, MD

Knapp, J., Haeske, D., Boettiger, B. W., Limacher, A., Stalder, O., Schmid, A., ... & Bernhard, M. (2019). Influence of prehospital physician presence on survival after severe trauma: systematic review and meta-analysis. Journal of Trauma and Acute Care Surgery, 87(4), 978-989.

Background:

The leading cause of death in the United States for individuals under the age of 40 is trauma, according to the CDC, with an estimated death toll of greater than 160,000 people per year [1].  Because of this, attention has been placed on how to improve trauma outcomes in the prehospital setting.  One area of interest in this field is on the deployment of EMS physicians, and the practicality of their presence in the prehospital field. 

The practice of using prehospital EMS physicians is somewhat routine in many placed in Europe [2], however is still somewhat novel in the United States.  This study points out that little literature had shown a benefit of the presence of EMS physicians in the prehospital setting, despite this being a listed key priority in Emergency and Prehospital Medicine research.  This study performed a systematic literature review and meta-analysis to look at the mortality levels in severely injured patients treated by physicians in the prehospital setting compared to those treated by a paramedic led team.

Methods:

A review of the literature was performed using PubMed and Google scholar, reviewing articles published up to 2018. The authors mention that a hand search of their personal literature was performed as well.  Search criteria included studies reporting mortality or survival of severely injured patients treated either by EMS physicians or by the traditional paramedic led team.  Inclusion criteria included any study discussing patients suffering from an acute traumatic injury. Only those studies with a comparative element were included in this study.  This includes randomized control trials, matched-pairs analysis, before and after design or observation studies with a comparative element. Scores mentioned used to compare characteristics include the Injury Severity Score (ISS), Abbreviated Injury Scale (AIS), and predicted mortality. Included studies were compared using fixed effect and random effects meta-analysis using inverse variance weighting for pooling.  To account for any potential changes in care regarding ground transport vs air ambulance, a subgroup analysis was performed on studies where the effect of helicopter transport could be excluded (i.e studies with no helicopter transport in either the physician group or paramedic group or studies that had helicopter transport in both groups.)

Results:

A total of 2,249 publications were considered for inclusion in this study, and after exclusion criteria was applied, a total of 22 studies were considered eligible for the analysis.  The included studies had a pooled sample size of 54,991 patients suffering from what was considered a severe injury.  13,629 patients were treating by a team including an EMS physician, and 41,362 were treated by a traditional paramedic led team without an on scene physician. The study reports that in the overall analysis of all included studies, the odds ratios for mortality were significantly lower in the EMS physician group (OR of 0.81, 95% CI 0.71-0.92) compared to a team without EMS physician presence. 

When the analysis was subdivided to only include studies that were adjusted or matched for injury severity using one of previously mentioned scores (in other words, where injury scores between the two studies would be comparable), the OR was 0.86 (95% CI 0.73-1.01), making the result not statistically significant.  When only more recent studies (2005-2018) were included, the OR was 0.75 (95% CI 0.64-0.88) for all studies and 0.81 (95% CI 0.67-0.97) in studies adjusted for injury severity.

In the subgroup analysis of studies with comparable modes of transport (to eliminate confounder of helicopter transport), when comparing EMS physician led treatment to paramedic based, the OR for mortality was 0.80 (95% CI 0.65-1.00) in all studies and 0.74 (95% CI, 0.53–1.03) in the more recent studies.  Although not statistically significant, there is a trend towards clinical significance.

What does this study mean for EMS?

This study suggests that there may in fact be a survival benefit for severely injured trauma patients when an EMS physician is on scene and part of the treatment team. The sample size is impressive, with 22 international studies included and a patient population of greater than 54,000 patients.  Although the date of 2005 may seem somewhat arbitrary as a cutoff for “older vs newer” literature, the study does note that training in prehospital trauma management has significantly improved over the past decade, and comparing newer studies to evaluate for changes in standards of care certainly seems to strengthen this study.

Some limitations in the study include the fact that the majority of the studies included were retrospective and observational, and the fact that timing of the mortality benefit varied by study (as most studies measured mortality after 30 days or in hospital, however some measured mortality up to a year.)

EMS clinicians deliver excellent care patient care. When available; EMS physician presence seems to be beneficial as part of a team led effort for those patients who are severely injured. Additional work and research should be pursued in this topic.

References

1. Centers for Disease Control and Prevention. National Center for Health Statistics. Leding Causes of Death. https://www.cdc.gov/nchs/fastats/ leading-causes-of-death.htm. Updated March 17, 2017. Accessed March 22, 2019.

2. Wilson MH, Habig K, Wright C, Hughes A, Davies G, Imray CH. Prehospital emergency medicine. Lancet. 2015;386(10012):2526–2534.

3. Fevang E, Lockey D, Thompson J, Lossius HM, Torpo Research Collabora- tion. The top five research priorities in physician-provided pre-hospital critical care: a consensus report from a European research collaboration. Scand J Trauma Resusc Emerg Med. 2011;19:57.

Website Editing and Layout by EMS MEd Editor James Li MD

Article Bites #45: Characteristics, Prehospital Management, and Outcomes in Patients Assessed for Hypoglycemia: Repeat Access to Prehospital or Emergency Care

Article Summary by James Li, MD

Sinclair, Julie E., et al. "Characteristics, prehospital management, and outcomes in patients assessed for hypoglycemia: repeat access to prehospital or emergency care." Prehospital Emergency Care 23.3 (2019): 364-376.

Background:

Diabetes is a common chronic medical condition. The Centers of Disease Control and Prevention report a total of 37.3 million people with diabetes (11.3% of the US population). Additionally, 96 million people aged 18 and older have prediabetes (38% of the US population). [1] Hypoglycemia events may occur in patients on medications, including insulin and oral medications, to manage diabetes. Diabetes-related calls account for 2.3% of all EMS activations per NEMSIS data in 2015. [2] The NAEMSO National Model EMS Clinical Guidelines does have parameters for a non-transport disposition for hypoglycemic patients treated by prehospital providers.

The current NAEMSO guidelines recommend:

• If hypoglycemia with continued symptoms, transport to closest appropriate facility

• Hypoglycemic patients who have had seizure should be transported to the hospital regardless if their mental status or response to therapy

• If symptoms of hypoglycemia resolve after treatment, release without transport should only be considered if all of the following are true:

  • Repeat glucose greater than 80 mg/dL

  • Patient takes insulin or metformin to control diabetes and does not take long acting oral sulfonylurea agents (e.g., glipizide, glyburide, or others)

  • Patient returns to normal mental status, with no focal neurologic signs/symptoms after receiving glucose/dextrose

  • Patient can promptly obtain and will eat a carbohydrate meal

  • Patient or legal guardian refuses transport and EMS clinicians agree transport not indicated

  • A reliable adult will be staying with patient

  • No major co-morbid symptoms exist like chest pain, shortness of breath, seizures, intoxication

  • A clear cause of hypoglycemia is identified (e.g., missed meal)

However, there is still significant variation in EMS protocols for the treatment of hypoglycemia, and only 49% had specific policy regarding non-transport of patients who were treated. [3]  Please see a prior literature review regarding hypoglycemia treat and release protocols on our blog. 

This study was performed in Ontario, Canada which did not have a prehospital treat-and-release protocol for hypoglycemia at the time of the study. The goal of the study was to determine predictors of repeat access to prehospital or emergency department care within 72 hours of initial paramedic contact. It continues to add to the literature regarding safety of non-transport of patients with hypoglycemia

Methods:

The authors performed a retrospective record review of paramedic reports and emergency department records over a 12-month period. They searched for all adult patients with prehospital glucose less than 72 mg/dl. Repeat access to prehospital care was assessed by searching paramedic databases and repeat access to emergency department care was assessed by searching the databases of the four receiving emergency departments.

Results:

The authors included 791 patients for analysis. The patients received IV D50, IM glucagon, or PO complex carbs for hypoglycemia treatment. 69.4% accepted transport to the hospital. Among those transported, 24.3% were admitted. 43 patients (5.4%) had repeat access to prehospital or emergency department care. 8/43 (18.6%) were related to hypoglycemia. This means that in the entire study population, only 8/791 (1%) of the patients in the study had a need for repeat access to care for hypoglycemia. The authors also found that patients on insulin were less likely to have repeat access to care (adjusted odds ratio 0.4, 95% CI 0.2-0.9) and this was not impacted by initial (or refusal of) transport (adjusted odds ratio 1.1, 95% CI 0.5-2.4).

What does this mean for EMS?

This paper provides additional evidence that treat-and-release strategies may be safe in appropriate patients. EMS leaders consider implementation of treat-and-release into protocols, provide training, and perform QA/QI in their systems to monitor for adverse outcomes. Further research should be conducted to identify high risk factors in hypoglycemic patients.
References:

1.     CDC National Diabetes Statistics Report. https://www.cdc.gov/diabetes/data/statistics-report/index.html

2.     Benoit, Stephen R., et al. "Diabetes-related emergency medical service activations in 23 states, United States 2015." Prehospital Emergency Care 22.6 (2018): 705-712.

3.     Rostykus, Paul, et al. "Variability in the treatment of prehospital hypoglycemia: a structured review of EMS protocols in the United States." Prehospital emergency care20.4 (2016): 524-530.

Article Bites #44: Managing the Out-of-Hospital Extraglottic Airway Device

Article Summary by: Charles Hwang, MD, FAEMS, FACEP

Article: Braude D, Steuerwald M, Wray T, Galgon R. Managing the Out-of-Hospital Extraglottic Airway Device. Ann Emerg Med. 2019 Sep;74(3):416-422. doi: 10.1016/j.annemergmed.2019.03.002. Epub 2019 May 3.

Background

Extraglottic airway devices (commonly referred to as supraglottic airway [SGA] devices) play an integral role in the prehospital airway algorithm as a primary airway device or as a rescue airway after failed intubation.  Recently, two large, randomized controlled trials and a large meta-analysis have demonstrated that, for a variety of medical conditions, SGAs are noninferior to endotracheal intubation with respect to survival-to-discharge, survival with good neurological outcome,[1-3] and first-pass success.  As prehospital SGA use will inevitably become more common, hospital clinicians should be familiar with these devices specifically and the role they serve in airway management generally.  The indiscriminate rapid and reflexive removal of SGAs without a thoughtful strategy can lead to hypoxemia, aspiration, and/or loss of airway in critically ill patients.

Check out our prior post where our readers discuss their preferred SGAs.

Initial Assessment

There are multiple commercially available extraglottic airway devices.  Although they have slightly different features and anatomic positioning, their common attribute is their blind insertion into the oropharynx.

When a patient with an SGA arrives to the emergency department, the ventilation (i.e., waveform capnography, chest rise, lung auscultation) should be assessed, followed by an assessment of oxygenation (i.e., SpO2, PaO2).  As is true for endotracheal intubation, it is important to verify waveform capnography to verify tube placement and ventilation adequacy.  Intrinsic barriers to ventilation include tube positioning (too high or too low in the oropharynx) and cuff issues.  Extrinsic barriers to ventilation are patient factors similar to those experienced while using an endotracheal tube (e.g., pneumothorax, severe bronchospasm, etc.).  Similar to endotracheal intubation, impaired oxygenation can be due to atelectasis, underlying medical conditions, and patient positioning, and can be improved by increasing positive end-expiratory pressure (PEEP) and/or fraction of inspired oxygen (FiO2).

Management

The decision to exchange an SGA should depend on two important questions: (1) whether the SGA is providing adequate oxygenation and ventilation and (2) whether the exchange needs to occur electively or urgently.  Figure 1 demonstrates the decision tree a clinician should follow when considering these important questions.

Once the decision has been made to exchange the SGA for an endotracheal tube, the SGA can be exchanged using several different methods.  The method will depend on patient anatomy, patient stability, anticipated difficulty, and SGA type.

Option 1.  Removal of SGA device and standard laryngoscopy

• Indications: difficult airway not anticipated, favorable physiology, or limited time/equipment.

• Actions: RSI if patient has intact airway reflexes.  Optimize patient positioning and oxygenation.  Use SGA to pre-oxygenate.  May replace SGA if intubation is unexpectedly difficult.

Option 2.  Direct/video laryngoscopy with SGA in place

• Indications: retroglottic device, which obstructs esophagus and prevents esophageal intubation, is in place (e.g., King Laryngeal Tube, Combitube)

• Action: Deflate balloon on retroglottic device, sweep device to left with laryngoscope, attempt intubation with endotracheal tube or bougie.  May remove retroglottic device if there is an adequate view of airway structures but inadequate access.  May reinflate balloon to restore function if unsuccessful intubation.

Option 3. Endoscopic exchange

• Indications: compatible extraglottic device, adequate time, anticipated difficult intubation. 

• Action: Position device with outlet directly at glottic opening.  Pass intubating stylet.  Then pass pre-loaded endotracheal tube over stylet (similar to Seldinger technique).

• An alternative to stylet is the Hennepin double-tube technique which minimizes interruptions in oxygenation and ventilation [4]

Option 4. Blind exchange through extraglottic device

• Indications: LMA Fastrach, Cookgas airQ, iGel

• Action: Pass bougie blindly through device into trachea.  Must have waveform capnography confirmation.  Risks include airway perforation and blind airway technique, which makes this technique less favored.

Option 5.  Surgical airway

• Indications: anticipated difficult airway

• Action: Surgical cricothyrotomy while oxygenating and ventilating through extraglottic device.

References

1.     Benger JR, Kirby K, Black S, Brett SJ, Clout M, Lazaroo MJ, Nolan JP, Reeves BC, Robinson M, Scott LJ, Smartt H, South A, Stokes EA, Taylor J, Thomas M, Voss S, Wordsworth S, Rogers CA. Effect of a Strategy of a Supraglottic Airway Device vs Tracheal Intubation During Out-of-Hospital Cardiac Arrest on Functional Outcome: The AIRWAYS-2 Randomized Clinical Trial. JAMA. 2018 Aug 28;320(8):779-791. doi: 10.1001/jama.2018.11597. PMID: 30167701; PMCID: PMC6142999.

2.     Wang HE, Schmicker RH, Daya MR, Stephens SW, Idris AH, Carlson JN, Colella MR, Herren H, Hansen M, Richmond NJ, Puyana JCJ, Aufderheide TP, Gray RE, Gray PC, Verkest M, Owens PC, Brienza AM, Sternig KJ, May SJ, Sopko GR, Weisfeldt ML, Nichol G. Effect of a Strategy of Initial Laryngeal Tube Insertion vs Endotracheal Intubation on 72-Hour Survival in Adults With Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial. JAMA. 2018 Aug 28;320(8):769-778. doi: 10.1001/jama.2018.7044. PMID: 30167699; PMCID: PMC6583103.

3.     White L, Melhuish T, Holyoak R, Ryan T, Kempton H, Vlok R. Advanced airway management in out of hospital cardiac arrest: A systematic review and meta-analysis. Am J Emerg Med. 2018 Dec;36(12):2298-2306. doi: 10.1016/j.ajem.2018.09.045. Epub 2018 Sep 26. PMID: 30293843.

4.     Lee DH, Paetow G, Prekker ME, Driver BE. THE HENNEPIN DOUBLE-TUBE TECHNIQUE: A MORE EFFICIENT METHOD OF TRACHEAL INTUBATION THROUGH THE LMA FASTRACH. J Emerg Med. 2022 Jul;63(1):88-92. doi: 10.1016/j.jemermed.2022.04.003. Epub 2022 Aug 5. PMID: 35934655.

Editing by James Li MD, EMS MEd Editor

Article Bites #43: Dosing errors made by paramedics during pediatric patient simulations after implementation of a state-wide pediatric drug dosing reference

Article Bites Summary by Kristopher Bianconi, MD

Hoyle Jr, J. D., Ekblad, G., Hover, T., Woodwyk, A., Brandt, R., Fales, B., & Lammers, R. L. (2019). Dosing errors made by paramedics during pediatric patient simulations after implementation of a state-wide pediatric drug dosing reference. Prehospital Emergency Care.

Background

The administration of medications to pediatric patients complex, with some medications having error rates as high as 60% in the prehospital setting. Converting a patient’s weight from pounds to a dose based on mg’s/kg creates a dizzying dance with math made more difficult by the stress of providing prompt and appropriate pediatric critical care. The introduction of physical and electronic portable medication guides work to help ease this burden with the primary goal of reducing medication dosing errors. The NAEMSP has a position statement and resource document regarding medication dosing safety for pediatric patients.

Methods

MI-MEDIC PDR. Image from this study.

This was an observational study of paramedics from 15 EMS agencies throughout the state of Michigan. Using the MI-MEDIC pediatric dosing reference (PDR), paramedics have available an on-scene instruction binder on appropriate medication dose in milliliters based on the patient’s weight. For medications which require dilution prior to administration, the PDR has a step-by-step guide to preform dilution correctly. To test its efficacy, paramedics were run through a series of simulations which were recorded and reviewed by study investigators to evaluate for medication dosing errors. These results were then compared to prior simulation evaluations from the same agencies to evaluate if the PDR reduced the error rate.

The teams participating in the simulations were a mix of two paramedic providers, a paramedic with an EMT-I, or a paramedic with an EMT-B.  In the two paramedic teams, one was elected to calculate, draw up, and administer the medication individually, while in the mixed teams the paramedic is the only practitioner qualified to work with the medications. They were asked to preform four simultaneous pediatric simulation cases; an infant having a hypoglycemic seizure, an 18-month old patient with burns, a 5 year old with anaphylaxis, and an infant in cardiac arrest. Each case was preformed sequentially, simulated guardians were present during the cases, and the PDR was available to all paramedics during each simulation allowing them to reference it as often as needed.

Results

A total of 36 crews participated, allowing for 142 simulations to be evaluated. Overall, paramedics in this study were able to administer medications appropriately to pediatric simulation patients 68.8% of the time. This ranged from a high of correct diphenhydramine dose at 82.8% to a low of correct Midazolam IV dose at 38.9%. Compared to data obtained prior to the implantation of the PDR, correct dose rates increased by at least 30% for IM midazolam, Dextrose, and IM or IV Epinephrine.

Observed errors included both over and under doses, the most common overdoses occurred with IV epinephrine with 13 overdoses, IV fentanyl with 16 overdoses, and IV Midazolam with 8 overdoses. The most common underdoses noted were IV epinephrine with 6 underdoses, IM Midazolam with 9 underdoses, and IV Dextrose with 5 underdoses. Particular to epinephrine IV, there were six 10-fold overdoses with one 10-fold under doses after the medication was erroneously diluted. When examining the effect of dilution, the authors note a decrease in correct dose administration rate of 26.7% when giving IV midazolam, which must be diluted, compared to IM Midazolam, which may be given as is. Finally, in all but three cases the paramedics established the patient’s appropriate weight-based dosing, most often via Broselow tape, followed by asking simulated guardians the patient age and/or the patient’s weight.

Conclusions

In this study the use of a PDR was associated with an increase in the success rate of correct medication dose administered during simulation of critical pediatric patient encounters. Despite its presence, there was still an overall error rate greater than 30% with multiple overdoses of medications well known to depress respiratory drive being noted. The introduction of similar tools in other mobile health systems is likely to be of help in reducing the rate of medication errors for paramedics, however further work needs to be done to get error rates within ranges we can all be more comfortable with.

References

Hoyle JD Jr, Ekblad G, Hover T, Woodwyk A, Brandt R, Fales B, et al. Dosing errors made by paramedics during pediatric patient simulations after implementation of a state-wide pediatric drug dosing reference. Prehosp Emerg Care Mar-Apr 2020;24(2):204-13.

Editing by Jeremy Lacocque, DO and James Li, MD

Article Bites #42: Association of Statewide Implementation of the Prehospital Traumatic Brain Injury Treatment Guidelines with Patient Survival Following Traumatic Brain Injury

Article Summary by James Li, MD

Article:
Spaite, D. W., Bobrow, B. J., Keim, S. M., Barnhart, B., Chikani, V., Gaither, J. B., ... & Hu, C. (2019). Association of statewide implementation of the prehospital traumatic brain injury treatment guidelines with patient survival following traumatic brain injury: the excellence in prehospital injury care (EPIC) study. JAMA surgery, 154(7), e191152-e191152.

Background:

Traumatic brain injury (TBI) is a blunt or penetrating trauma to the head that disrupts normal brain function. The CDC estimated approximately 2.5 million emergency department visits, hospitalizations, and deaths in the United States in 2010 for TBI. TBI has an enormous impact on health and healthcare costs in the United States. (1) Primary prevention of TBI consists of preventing the injury from occurring (helmet use, road safety, fall prevention, etc). The goal of medical treatment for patients who have suffered TBI involves minimizing secondary injury which begins hours to days after the primary injury. Secondary injury can involve pathophysiologic processes such as cerebral edema, metabolic derangements, hypoperfusion, excitotoxicity, and more. (2) This study implemented prehospital TBI guidelines based on Brain Trauma Foundation into the Arizona EMS system and looked at patient outcomes. (3)

Methods:

This study took place in Arizona using a controlled, before-after, multisystem, intention-to-treat design. Every EMS agency in Arizona was invited to participate (included >130 agencies and >11,000 EMS providers). The data was collected from the Arizona State Trauma Registry and information from included patients was linked to EMS data from participating agencies (98.7% linkage). The study included adults and children with trauma who were transported to a trauma center by participating EMS agencies, had hospital diagnosis consistent with TBI, and met definition for major TBI (CDC Barrell Matrix Type 1 and/or Abbreviated Injury Scale-Head of at least 3) between January 1st 2007 to June 30th 2015. The implemented guidelines focused aggressive prevention and treatment of hypoxia, hyperventilation, and hypotension. The primary outcome was survival to hospital discharge and secondary outcome was survival to hospital admission.

Results:

The study enrolled 15,228 patients in the pre-implementation phase and 6624 patients in the post-implementation phase. Implementation was associated with improved treatment to prevent hypoxia, hyperventilation, and hypotension. The overall pre-implementation/post-implementation analysis across all severities (moderate, severe, critical) did not show improved survival to hospital discharge (aOR 1.06, 95% CI 0.93-1.21, P=0.40). Survival to hospital admission did improve (aOR 1.70, 95% CI 1.38-2.09, P<0.001).

Among severity cohorts, for severe TBI patients with a Regional Severity Score - Head 3-4 (not moderate or critical), guideline implementation doubled survival to discharge (aOR 2.03, 95% CI 1.52-2.72, P<0.001). In severe TBI patients who were intubated, guideline implementation tripled survival to discharge (aOR 3.14, 95% CI 1.65-5.98, P<0.001).

What does this mean for EMS?

This study suggests that prehospital guidelines for TBI treatment has the biggest impact on patients with severe TBI. Patients with moderate TBI are likely to survive without implementation of these guidelines. Patients with critical TBI may have such a terrible injury that care targeted towards secondary injury prevention does not change survival.

The targeted treatments in the guidelines are relatively simple and inexpensive. These are treatments that EMS providers do daily, and we know a single episode of hypoxia or hypotension has significant mortality consequences for patients. Secondary brain injury occurs soon after primary injury and early intervention may save neurons. Prevention of the “H-bombs” of hypoxia, hyperventilation, and hypotension has a positive impact on patient outcomes. The increase in survival to hospital admission suggests that the prehospital care provided by EMS is making a difference.

A typical EMS agency participated for three years after implementation of guidelines. The authors noted there was potential for decreased adherence to guidelines over time and assessed changes over time by comparing early and late outcomes. The initial improvement of outcomes faded over time which reflects the need for recurrent education and training to prevent diminishing guideline adherence.

References:

1.     Frieden, T. R., Houry, D., & Baldwin, G. (2015). Traumatic brain injury in the United States: epidemiology and rehabilitation. CDC NIH Rep to Congr, 1-74.

2.     Kaur, P., & Sharma, S. (2018). Recent advances in pathophysiology of traumatic brain injury. Current neuropharmacology, 16(8), 1224-1238.

3.     Badjatia, Neeraj, et al. "Guidelines for prehospital management of traumatic brain injury 2nd edition." Prehospital emergency care 12.sup1 (2008): S1-S52.

Article Bites #41: Consensus Statement - Prehospital Care of Exertional Heat Stroke

Article Summary by Elizabeth Stevens, MD, MA

Article:
Belval, L. N., Casa, D. J., Adams, W. M., Chiampas, G. T., Holschen, J. C., Hosokawa, Y., ... & Stearns, R. L. (2018). Consensus statement-prehospital care of exertional heat stroke. Prehospital Emergency Care, 22(3), 392-397.

Background:

Exertional heat stroke (EHS) is end organ dysfunction due to hyperthermia developed from physical activity. It is characterized by hyperthermia (>40.5 degrees Celsius) with end-organ dysfunction, which typically manifests as central nervous system dysfunction. Gold standard treatment of EHS is cold water immersion, which can be difficult to achieve in prehospital settings. This article summarizes the consensus of best practices for prehospital care of EHS, centering on steps of survival to decrease mortality and morbidity of this condition.

Recognition and Assessment:

Recognition and treatment of exertional heat stroke. Adapted from Belval et al. 2018

The first step in treating any condition is accurate diagnosis. Early recognition of EHS is key in timely treatment. Laypersons, emergency medical responders, and emergency medical dispatchers all play important roles to identify persons developing EHS. The consensus statement provides a flowsheet to help recognize EHS. Often, the initial recognized symptom is collapse during or after physical activity. After stabilization of all other emergency protocols (such as airway management), CNS function should be assessed. If an abnormal finding like unconsciousness, confusion, combative, irrational behavior, or loss of consciousness is present, a rectal temperature should be obtained with other vital signs. If rectal temperature is greater than 40.5 degrees Celsius with CNS dysfunction, a diagnosis of EHS is made. 

Care should be made to consider other causes of CNS depression if the patient’s temperature is not greater than 40.5 degrees Celsius. Additionally, reassessment of the patient’s CNS function should be routinely made as patient’s with EHS often have lucid intervals. Misconceptions about EHS recognition include assertions that a patient with EHS cannot sweat, must have hot skin, and will not be conscious. In reality, patients may be awake, profusely sweating, and feel cool and clammy to the touch. 

Physical activity and hot environments can alter temperature readings of patients. Therefore, diagnosis of EHS requires core temperature evaluation. Oral, axillary, aural, tympanic and temporal measurements of temperature is invalid in patients’ at risk for EHS, most often providing lower temperature readings than the actual core temperature. Even though EHS specifies a core temperature reading of 40.5 degrees Celsius or higher, treatment for EHS should not be delayed if a rectal temperature is unable to be obtained, or if the reading is slightly lower than the definitive cut off of 40.5 C.  

Treatment:

Cold water immersion should be used to cool a patient with EHS to 38.6 C

The motto of EHS treatment in prehospital settings is “cool first, transport second.” Ideal and goal treatment for EHS is cooling the patient to under 104.5 degrees Fahrenheit in under 30 minutes from time of collapse. This goal is to reduce the end organ dysfunction, morbidity and mortality of this severe hyperthermia. Current best practice to achieve this goal is neck-down cold water immersion, which can be a difficult method in prehospital environments. Dispatchers and first responders should initiate any cooling strategies that are immediately available to anyone suspected of having EHS, until EMS responders can arrive. 

The effectiveness of any cooling strategy can be evaluated by its cooling capacity and the body surface area the modality can be applied to. The recommended minimum cooling rate is 0.15 degrees Celsius per minute, yielding 4.5 degrees Celsius in thirty minutes. Cooling should cease when core temperature reaches 38.6 degrees Celsius to decrease the risk of severe hypothermia. Hypothermic overshoot is common; patients should be passively rewarmed to 37 degrees Celsius. 

Cold water immersion in ideal conditions can achieve a rate of cooling of 0.35 degrees Celsius per minute, with a practical rate of 0.22 degrees Celsius per minute, as found in a study of 254 EHS cases. Alternative modalities of cooling include tarp-assisted cooling (rate of 0.14-0.17 degrees Celsius per minute), cold shower, fan, and ice packs (which all have < 0.1 degree Celsius per minute cooling rate). 

At-risk events, including races and athletic programming, should have advance planning to initiate on-site cooling with adequate staffing. Standard of care for situations with on-site medical personnel (such as physicians or certified athletic trainers) writes for completion of on-site cooling prior to transfer to a hospital for continued medical care.
During transport for patients who are unable to be cooled on-site, the most aggressive and effective cooling method should be undertaken until goal core temperature (rectal 38.6 degrees Celsius) is reached. Cold saline infusion alone is not an adequate cooling strategy and should be implored in conjunction with other cooling techniques. 
Additional medical conditions could arise related or unrelated to EHS. Treatment of non-emergent conditions such as emesis should not take priority over initiation and continuation of cooling. Emergent conditions including cardiac arrhythmias and seizures will need to be addressed prior to initiation of cooling with the goal to cool as the priority after stabilization of the patient.  

Advanced Care:

Prehospital notification to the receiving facility allows staff to properly prepare for the patient’s treatment upon arrival. Emergency Departments and hospitals will also be able to evaluate for concurrent diagnoses and sequela of EHS. These conditions include rhabdomyolysis, disseminated intravascular coagulation, and liver failure. 

How does this affect EMS?

This consensus statement provides an actionable outline of recognition, assessment and treatment of EHS patients. Diagnosis of EHS allows for alteration in EMS typical workflow to optimize the treatment of EHS by cooling. Transportation of patients becomes a secondary goal to treatment. 

Bottom Line:

Exertional Heat Stroke is an emergent medical condition that relies on timely treatment in order to reduce morbidity and mortality. EMS is in a unique position to provide rapid recognition, assessment and treatment of these patients. 

For additional reading on this topic, please check out: Feel The Heat: Managing Exertional Heat Stroke

Editing by EMS MEd Editor James Li, MD (@JamesLi_17)

Article Bites #40: Comparative Effectiveness of Analgesics to Reduce Acute Pain in the Prehospital Setting

Article Summary by Emerson Franke, MD, EMT, FAAEM, (@EmersonFrankeMD)

Article:

Sobieraj, D. M., Martinez, B. K., Miao, B., Cicero, M. X., Kamin, R. A., Hernandez, A. V., ... & Baker, W. L. (2020). Comparative effectiveness of analgesics to reduce acute pain in the prehospital setting. Prehospital Emergency Care, 24(2), 163-174.

Background:

Pain control in the prehospital setting varies from agency to agency, and may be limited to advanced prehospital providers. Pain is a common reason for EMS calls and is also common in patients experiencing trauma. Pain in the prehospital setting is known to be inadequately treated, up to 43% of adults and 83% of pediatrics. The reasons for under treating pain in the prehospital setting could be due to several factors including adverse effects and/or abuse potential. Evaluating the pain relief and harm of non-opioid analgesics for severe pain could allow for improved pain management with decreased reliance on opioids.

Methods:

Published studies were reviewed including randomized controlled trials (RCTs), cohort studies, case-control studies of patients with moderate to severe pain. This was determined by study inclusion criteria, baseline pain scores, or a study involving ketamine or opioids. Studies that also evaluated for rescue analgesics were studies separately from the initial treatment. Pain involving labor and delivery, non-zero, or mild pain were excluded.

Studies were also evaluated based on the medication they utilized; including fentanyl, morphine, acetaminophen, ketamine, nitrous oxide, non-steroidal anti-inflammatory drugs (NSAIDs), and ketamine-opioid combinations. The effect of any of these medications were recorded, including time to effect, pain scores, adverse effects, and memory of pain.

Results:

Out of 4907 studies that were found, 65 studies met the inclusion criteria for complete review which included 57 RCTs and 13 observational studies. The majority of patients were adults between the second and fourth decade with varying causes of pain. Due to insufficient prehospital evidence, conclusions for initial analgesia is based on indirect evidence in the emergency department setting. Most medications were administered intravenously, some included intranasal ketamine and fentanyl.

Ketamine versus Opioids

There was not enough prehospital literature to directly determine which treatment was more effective in the prehospital setting. Literature from the Emergency Department was utilized to make an indirect conclusion. At time points after medication administration, 15 minutes, 30 minutes, 60 minutes; there was no clinically significant different in pain scores. Opiates cause fewer total adverse effects and less dizziness than ketamine. Ketamine causes less respiratory depression than opiates. Ketamine may also be quicker than opiates to reduce pain. As a rescue medication, Ketamine may reduce pain more than opiates and allow for a lower total dose of opiates to be given.

Opioids + Ketamine versus Opioids

At time points after medication administration 15 minutes and 30 minutes, the combination of opiates and ketamine may reduce pain more effectively than an opiate alone. However at 60 minutes there was no difference between the combination of ketamine + opioid versus opioids alone. There was not enough data to evaluate for adverse effects in these comparisons.

Opioids versus Acetaminophen

At time points after medication administration, 15 minutes, 30 minutes, 60 minutes; there was no clinically significant different in pain scores. There was also no different in time to analgesic effect when comparing opioids and acetaminophen. Opioids were found to cause more adverse effects, including dizziness, compared to acetaminophen. There was no difference in hypotension between opioids and acetaminophen.

Opioids versus Nitrous Oxide

There was not enough data to make conclusions regarding this comparison as there was only one RCT found.

Opioids versus Nonsteroidal Anti-Inflammatory Drugs

At time points after medication administration 30 minutes and 60 minutes; there was no clinically significant different in pain scores. Opioids cause more adverse events and drowsiness than NSAIDs.

What does this mean for EMS?

This paper reviewed the existing evidence in an attempt to answer the question: what is the most efficacious pain medication in the prehospital setting? Unfortunately, most of the data was insufficient and/or limited to answer the question well.

The EMS clinician or medical director can still extrapolate a few learning points.

• A multimodal approach to pain management should be employed for all patients, with appropriate risks and adverse effects considered.

• Non-opioid medications have fewer immediate adverse effects and can manage pain comparably to opiates.

• The addition of ketamine to opioids may be more effective in reducing pain compared with opioids alone.  

Ultimately each patient population has their unique challenges, and again the use of a multi-modal approach to prehospital pain management should employ opioid and non-opioid analgesics.

Editing by EMS MEd Editor James Li, MD (@JamesLi_17)

Article Bites #39: Prehospital IV bolus nitrogylcerin for pulmonary edema? An evaluation of feasibility, effectiveness and safety

Patrick C, Ward B, Anderson J, Rogers Keene K, Adams E, Cash RE, Panchal AR, Dickson R. Feasibility, Effectiveness and Safety of Prehospital Intravenous Bolus Dose Nitroglycerin in Patients with Acute Pulmonary Edema. Prehosp Emerg Care. 2020 Nov-Dec;24(6):844-850.

An author’s summary by Casey Patrick, MD

Background

The broad teaching of “CHF Exacerbation” as a singular diagnosis is often too broad when applied to undifferentiated dyspneic patients in the emergency setting.  Recently, the term sympathetic crashing acute pulmonary edema (SCAPE) has become more prominent in effort to identify/classify the critically ill faction of CHF exacerbations with hyperdynamic volume shift.  These acute pulmonary edema patients needing emergent vasodilation, which in EMS, has classically been limited to sublingual and topical nitrates.  Levy and Wilson’s ICU and emergency department (ED) data demonstrated a role for IV bolus nitroglycerin (NTG) in severely hypertensive acute pulmonary edema patients with decreased intubation rates, ICU LOS and hospital LOS when compared to nitroglycerin drip. [1,2]  Bolus IV NTG is an attractive EMS option due to ease of use, low cost, and rapid onset with short half-life.

Methods

This was a retrospective chart review of all patients treated with bolus dose IV NTG by the Montgomery County Hospital District (MCHD) EMS service in greater Houston.  Data from the first year following protocol roll out was reviewed.  MCHD is a ground-based, suburban, third-service EMS agency that provides all 911 response coverage for an 1,100 square mile area. 

This was a quality review of a previously implemented protocol for bolus dose IV NTG in acute pulmonary edema patients.  Paramedics were educated on pathophysiology and diagnosis of acute pulmonary edema.  Inclusion parameters included moderate to severe respiratory distress with systolic blood pressure greater than 160mmHg. Upon recognition, a 1mg slow IV NTG bolus was allowed with the option to repeat in 5min (two dose max).  

Initial chart review involved assessment to determine proper protocol application along with EMS and ED chart review to assess final diagnosis via ED imaging, laboratory data and primary impression.

The Results

During the study period 48 total patients were treated with bolus dose IV NTG.  88 patients were determined to have been eligible for treatment with 18 of those having no IV access and the other 22 patients excluded due to paramedic deferral.  Of the 48 treated patients, all were deemed protocol appropriate by reviewers.  These patients were acutely ill with a median EMS initial and ED arrival SBP of 211mmHg and 182mmHg respectively.  This SBP reduction of approximately 15% is consistent with treatment recommendations for hypertensive crisis.  Like in Levy’s hospital data, almost 70% of patients only required a single IV bolus dose.  This is quite appealing from a prehospital efficiency standpoint. 

Additionally, following SCAPE pathophysiology and diagnostic education and training, paramedics were able to accurately recognize decompensated acute pulmonary edema.   45/48 (94%) of treated patients were ultimately determined to have a final ED diagnosis of acute pulmonary edema. 

There was, however, a 2% rate of hypotension (SBP<90) which resolved without treatment or significant clinical event prior to ED arrival which is consistent with Levy and Wilson’s hospital rates of hypotension and subsequent EMS data from Perlmutter et al. as well3.

Conclusions

-       Paramedics can accurately identify acute pulmonary edema with proper education.

-       Bolus IV NTG (1mg x 2 doses) appears safe in the EMS setting.

-       A BP reduction of approximately 15% was obtained.

-       70% of treated patients only required a single 1mg dose.

-       Further randomized, prospective investigation is warranted.

-       Recent European data even suggests a possible long-term mortality benefit from prehospital IV bolus NTG in SCAPE patients

References

1.         Levy P, Compton S, Welch R, et al. Treatment of Severe Decompensated Heart Failure with High-Dose Intravenous Nitroglycerin: A Feasibility and Outcome Analysis. Annals of Emergency Medicine. 2007;50(2):144-152.

2.         Wilson SS, Kwiatkowski GM, Millis SR, et al. Use of nitroglycerin by bolus prevents intensive care unit admission in patients with acute hypertensive heart failure. The American Journal of Emergency Medicine. 2017;35(1):126-131.

3.         Perlmutter MC, Cohen MW, Stratton NS, Conterato M. Prehospital Treatment of Acute Pulmonary Edema with Intravenous Bolus and Infusion Nitroglycerin. Prehosp Disaster Med. 2020 Dec;35(6):663-668. 

4.         Miró Ò, Llorens P, Freund Y, et al.; EAHFE Research Group. Early intravenous nitroglycerin use in prehospital setting and in the emergency department to treat patients with acute heart failure: Insights from the EAHFE Spanish registry. Int J Cardiol. 2021 Dec 1;344:127-134.

Article Bites #38: Outcomes of Prehospital Chemical Sedation with Ketamine Versus Haloperidol and Benzodiazepine or Physical Restraint Only

Article Bites #38: Outcomes of Prehospital Chemical Sedation with Ketamine versus Haloperidol and Benzodiazepine or Physical Restraint Only

Article Summary by Angela Cornelius MD

Article:

O'Connor L, Rebesco M, Robinson C, Gross K, Castellana A, O'Connor MJ, et al. Outcomes of prehospital chemical sedation with ketamine versus haloperidol and benzodiazepine or physical restraint only. Prehosp Emerg Care Mar-Apr 2019;23(2):201-9.

Background:

Transportation of agitated patients is potentially dangerous for both patient and prehospital provider. In 2002 the National Association of EMS Physicians introduced their first position paper on prehospital agitated patient treatment which has been updated periodically since. [1] This statement addresses the practice of chemical restraint for prevention of injuries to patient and prehospital providers. Benzodiazepines with or without antipsychotic agents were the staple of prehospital chemical sedation until ketamine began to emerge in emergency medicine and prehospital literature. [2,3] Many papers have attempted to determine the best combination and dosing regimen, but consensus has yet to be reached. [4,5]

Methods:

The investigators performed a single center retrospective chart review of all patients transported with and received treatment for agitation from January 2014 to February 2018. During this time options for treatment were physical restraint only until November 2014 at which time intramuscular haloperidol and benzodiazepine (lorazepam or midazolam) were added and then in 2016 intramuscular ketamine was added. Patients who did not have medications administered for agitation and those who had restraints placed for noncombative patients by protocol were excluded. Also excluded were patients who were transported outside the medical system, patients whose emergency department clinical course could not be ascertained, and those who received haloperidol and benzodiazepines after ketamine had been was available. Descriptive and comparative statistics were performed. 

Results:

Patients who received ketamine versus haloperidol and benzodiazepine were more likely to be intubated (11.6% vs 1.5%). They were also more likely to require additional medication or physical restraints for agitation compared to those who received haloperidol and benzodiazepine. The ketamine cohort had longer length of stays as compared to the physical restraints only cohort but was almost the same as for the haloperidol and benzodiazepine cohort. In the intubated ketamine group, no differences were found in demographics but there was a non-statistically significant tendency for these patients to have a co-ingestion and present between midnight and 6 AM. Of the ketamine patients who were intubated, 6 of 11 of the intubations were associated with the same EM provider.  

How does this affect EMS?

This study adds to the body of literature surrounding prehospital sedation agents and dosing. The 4mg/kg of ketamine dosing in this study showed that there is still a significant percentage of patients who were intubated but much fewer than other studies so perhaps the optimal dosing is closer to 4mg/kg. 

Bottom Line:

The optimal sedation agents and dosing for treatment of prehospital agitation are still unclear. 

References:

1.     Kupas DF, Wydro GC, Tan DK, Kamin R, Harrell IV AJ, Wang A. 10/17/2020 Clinical Care and Restraint of Agitated or Combative Patients by Emergency Medical Services Practitioners. The National Organization of State EMS Officials. https://nasemso.org/wp-content/uploads/Clinical-Care-and-Restraint-of-Agitated-or-Combative-Patients-by-Emergency-Medical-Services-Practitioners.pdf. Published October 2020. Accessed March 20, 2022. 

2.     Svenson JE, Abernathy MK. Ketamine for prehospital use: new look at an old drug. Am J Emerg Med. 2007;25(8):977-980. doi:10.1016/j.ajem.2007.02.040

3.     Burnett AM, Salzman JG, Griffith KR, Kroeger B, Frascone RJ. The emergency department experience with prehospital ketamine: a case series of 13 patients. Prehosp Emerg Care. 2012;16(4):553-559. doi:10.3109/10903127.2012.695434

4.     Isenberg DL, Jacobs D. Prehospital Agitation and Sedation Trial (PhAST): A Randomized Control Trial of Intramuscular Haloperidol versus Intramuscular Midazolam for the Sedation of the Agitated or Violent Patient in the Prehospital Environment. Prehosp Disaster Med. 2015;30(5):491-495. doi:10.1017/S1049023X15004999

5.     Cole JB, Moore JC, Nystrom PC, et al. A prospective study of ketamine versus haloperidol for severe prehospital agitation. Clin Toxicol (Phila). 2016;54(7):556-562. doi:10.1080/15563650.2016.1177652

Edited and accompanying figure by James Li MD (@jamesli_17)

Article Bites #37: In the absence of STEMI, do we need to rush to the cath lab following ROSC?

 by Casey Patrick, MD @cpatrick_89

Article: Lemkes JS, Janssens GN, van der Hoeven NW, Jewbali LSD, Dubois EA, Meuwissen M, Rijpstra TA, Bosker HA, Blans MJ, Bleeker GB, Baak R, Vlachojannis GJ, Eikemans BJW, van der Harst P, van der Horst ICC, Voskuil M, van der Heijden JJ, Beishuizen A, Stoel M, Camaro C, van der Hoeven H, Henriques JP, Vlaar APJ, Vink MA, van den Bogaard B, Heestermans TACM, de Ruijter W, Delnoij TSR, Crijns HJGM, Jessurun GAJ, Oemrawsingh PV, Gosselink MTM, Plomp K, Magro M, Elbers PWG, van de Ven PM, Oudemans-van Straaten HM, van Royen N. Coronary Angiography after Cardiac Arrest without ST-Segment Elevation. N Engl J Med. 2019 Apr 11;380(15):1397-1407. [1]

Background:

Let’s start with a brief overview of the evolution of care for OHCA post-ROSC.  While it is generally accepted that post-ROSC patients with evidence of STEMI warrant emergent cardiac catheterization, the timing of coronary angiography for post-ROSC patients without acute ST elevation has been unclear.  Based on retrospective data, approximately 25%-50% of VF/VT arrests without STEMI have acute coronary occlusion and ~2/3 have significant coronary disease.  Additionally, early retrospective studies showed improved mortality and neurologic outcomes with early angiography in post-arrest patients with and without STEMI. [2]  This led many to surmise that early angiography was indicated for all post-ROSC OHCA patients without a clear non-cardiac source.  However, as with any retrospective data, there were numerous sources of bias in these early studies such as concern for the selection of only “well” patients for emergent catheterization and wide variations in angiography timing across the various retrospective studies.  This brings us to the first randomized, prospective trial of emergent versus delayed angiography for post-ROSC OHCA patients presenting with shockable rhythms – The COACT trial.

Prospective and Randomized: Finally!

COACT was a prospective, randomized, multi-center (19 hospitals), Dutch trial by Lemkes et al. published in NEJM. The study period was from January 2015 through July 2018.  90-day mortality was assessed as the primary outcome from over 500 post-arrest patients, without post-ROSC STEMI, randomized to immediate versus delayed angiography.  All initial rhythms were shockable and patients were unconscious on ED arrival. Patients with STEMI on EKG, shock or obvious non-cardiac cause of the cardiac arrest were excluded.  In the delayed coronary angiography group, coronary angiography was generally performed after neurologic recovery, with exception of patients who underwent urgent coronary angiography in advance of their planned procedure because they developed cardiogenic shock, recurrent life-threatening arrhythmias or recurrent ischemia during hospitalization (38 out 265 patients randomized to the delayed group). Coronary angiography was performed in 97.0% of the patients in the immediate group and 64.7% of patients in the delayed group.

There were no significant differences in 90-day survival between the immediate and delayed groups with a 64.5% survival in the immediate group as compared to a 67.2% survival in the delayed cath group.   Overall, an acute thrombotic occlusion was found in 3.4% in the immediate angiography group and 7.6% in the delayed angiography group. The immediate group time to intervention averaged 45 minutes from ED arrival as opposed to angiography at 5 days in the delayed group.  Without the gory details, the two groups were extremely similar from a demographic comparison standpoint.  The immediate intervention group did have a slightly longer time to targeted temperature management goals and there were some minor variations between antiplatelet and GIIb/IIIa administration between groups.  Otherwise, treatment between groups was quite uniform.

What about other clinical outcomes?

Mortality is not the only relevant outcome following out-of-hospital cardiac arrest.  Indeed, it is possible to survive with compromised cardiac function which may impair quality of life or longer term survival. The trial investigators subsequently published a study of one-year outcomes of the COACT Randomized Clinical Trial.[3]  Follow-up data was obtained on 522 of the 552 patients (94.6%) in the original trial.  Outcomes were obtained by telephone interview by a study investigator who was blinded to the original treatment allocation. What they found?  No significant difference in outcomes including myocardial infarction since index hospitalization (0.8% immediate vs. 0.4% delayed), hospitalization due to heart failure since index hospitalization (0.8% immediate vs. 0.4% delayed), ICD shock (20.4% in immediate vs. 16.2% delayed) or survival at one year (61.4% immediate vs. 64.0% delayed).

The Questions?

This seems to be a large and sturdy nail in the coffin containing emergent angiography for OHCA patients without STEMI.  Why doesn’t this study show what prior meta-analyses have?  Are there reasons this study may not represent US patients?  First, meta-analyses of retrospective data have just as much bias risk as any individual retrospective study.  Secondly, while the rate of coronary disease in COACT was similar to past data in shockable arrest sans STEMI (~2/3), the rate of unstable lesions seen in COACT was much lower at ~20% with an “acute” thrombosis rate of only ~5%.  Often the definitions of “unstable” and “acute” lesions are poorly defined, and the rate of these lesions are possibly higher in the US population as compared to the Dutch so unstable coronary disease prevalence differences across populations could have resulted in less benefit for immediate angiography in the COACT study.  Finally, 38 of 172 of those in the delayed group underwent the procedure “urgently” due to deterioration (shock, elevated trop) so, not unexpectedly, crossover and decompensation did occur. 

Don’t dig too much further in looking for holes in COACT though, TOMAHAWK came along in 2021 and further confirmed COACT.  TOMAHAWK included patients > 30 years of age with OHCA from both shockable and non-shockable rhythms without evidence of STEMI or evidence of non-cardiac etiology of arrest.  Like the COACT trial, the trial also excluded patients with cardiogenic shock or life-threatening arrhythmias.   This study found an increase in death from any cause and severe neurologic deficit amongst patients who underwent immediate coronary angiography rather than a delayed approach [Death: 54.0% immediate vs. 46.0% delayed, Hazard ratio 1.28 with 95% CI of 1.00-1.63); severe neurologic deficit: 18.8% immediate vs. 12.7% delayed, RR 1.48 with 95% CI 0.82-2.67).

The conclusion?

Best current, prospective evidence provides no evidence of benefit for immediate over delayed coronary angiography for post-ROSC OHCA patients without STEMI, cardiogenic shock or hemodynamically unstable arrhythmias.  In this population, waiting until neurologic recovery reduces the number of procedures (and associated cost and resources) by 30% without negative impact on patient outcomes.

 Edited / Images by EMS MEd Editor Maia Dorsett, @maiadorsett

References

1. Lemkes JS, et al. Coronary Angiography after Cardiac Arrest without ST-Segment Elevation. N Engl J Med. 2019 Apr 11;380(15):1397-1407.

2.  Kern KB, et al; INTCAR-Cardiology Registry. Outcomes of Comatose Cardiac Arrest Survivors With and Without ST-Segment Elevation Myocardial Infarction: Importance of Coronary Angiography. JACC Cardiovasc Interv. 2015 Jul;8(8):1031-1040. 

3.   Lemkes, J. S., Janssens, G. N., van der Hoeven, N. W., Jewbali, L. S., Dubois, E. A., Meuwissen, M. M., ... & van Royen, N. (2020). Coronary angiography after cardiac arrest without ST segment elevation: one-year outcomes of the COACT randomized clinical trial. JAMA cardiology, 5(12), 1358-1365.

4. Desch S et al; TOMAHAWK Investigators. Angiography after Out-of-Hospital Cardiac Arrest without ST-Segment Elevation. N Engl J Med. 2021 Dec 30;385(27):2544-2553. 

Article Bites #36: Is Using of Warning Lights and Sirens Associated With Increased Risk of Ambulance Crashes? A Contemporary Analysis Using National EMS Information System (NEMSIS) Data

Article Summary by James Li, MD (@jamesli_17)

Article:

Watanabe, B. L., Patterson, G. S., Kempema, J. M., Magallanes, O., & Brown, L. H. (2019). Is use of warning lights and sirens associated with increased risk of ambulance crashes? A contemporary analysis using National EMS Information System (NEMSIS) data.

Background:

Emergency response vehicles frequently utilize lights and sirens to respond to the scene of a 911 call and to transport critical patients to the hospital. The thought process of lights and sirens utilization is that it results in more rapid treatment of patients with a time-critical diagnosis.  However, a review of the literature by Murray et al. in 2017 found the use of lights and sirens for response and transport only saves between 43.5 to 181 seconds in urban and up to 363 seconds in a rural settings. [1] A study based in New Jersey found average time savings of 2.62 minutes during the transport phase of care, however none of the patients received time-critical hospital interventions within time saved by utilizing lights and sirens. [2]

There are significant risks to emergent transport with lights and sirens. The risk of transportation-related injury for EMS personnel has been reported to be about five times higher than national average and result in fatalities, injuries, and lost workdays. [3] The number of emergency response accidents may be greater than reported due to the “wake effect”. A “wake effect” collision is due to emergency vehicle transit but does not involve the emergency vehicle. A survey-based study in Salt Lake City suggested that this is a real phenomenon and likely outnumbers accidents involving the emergency vehicle. [4]

Methods:

This was a retrospective cohort study that used NEMSIS data from 2016 to identify EMS scene responses and patient transports. The authors excluded interfacility transports, intercepts, medical transports, standbys, response by non-transport vehicles, mutual aid, supervisor response, and air responses. They used the “type of response delay” and “type of transport delay” fields as a proxy to identify responses and transports that were delayed due to a crash involving the ambulance. Responses and transports documented as “no lights and sirens” served as a control group for their analysis. Multivariable logistic regression with clustered standard errors were used to calculate adjusted odds ratios for rate of crash-related delays per 100,000 responses or transports.

Results:

In this analysis the authors reported lights and sirens use during response was 77% and during transport was 23%. Among the 19 million emergency scene responses included in analysis, the response phase crash rate was 4.6 of 100,000 without lights and sirens and 5.4 of 100,000 with lights and sirens. The adjusted odds ratio was 1.5 (95% CI 1.2 to 1.9). 

The transport phase crash rate was 7.0 of 100,000 without lights and sirens and 17.1 of 100,000 with lights and sirens. The adjusted odds ratio was 2.9 (CI 2.2 to 3.9).

How does this affect EMS?

This analysis adds to the existing data that lights and sirens have significant risks to safety, patients, and EMS personnel. The greatest risks occur during the transport phase of care.  There is likely significant underreporting of accidents do not directly involve the emergency response vehicle due to the wake effect. 

Given existing data that does not suggest a significant time savings to lights and sirens transport, in many situations, the harms may not outweigh the potential benefits.  Indeed, EMS may opt for judicious use of lights and sirens during response based on analysis of dispatch codes . After arriving on scene to assess the patient, there can be careful consideration of the risks and benefits of lights and sirens transport. It may be important for QA/QI of dispatch data to monitor for overtriage and undertriage of medical emergencies to ensure appropriate use of lights and sirens to scenes.

Indeed, reducing unnecessary lights and sirens use to the scene and during the transport phase of care are two of the national quality measures released by the National EMS Quality Alliance. Together with key stakeholder organizations, the National Association of EMS Physicians recently released a Joint Statement on Lights and Siren Vehicle Operation on Emergency Medical Services Responses in February 2022. [5]

Bottom Line:

Lights and sirens response/transport is associated with increase ambulance accidents which impact the safety of patients, EMS clinicians, and public. EMS leaders should advocate for using quality, evidence-based emergency medical dispatch protocols to identify calls that require lights and sirens.

References:

1.     Murray, B., & Kue, R. (2017). The use of emergency lights and sirens by ambulances and their effect on patient outcomes and public safety: a comprehensive review of the literature. Prehospital and disaster medicine, 32(2), 209-216.

2.     Marques-Baptista, A., Ohman-Strickland, P., Baldino, K. T., Prasto, M., & Merlin, M. A. (2010). Utilization of warning lights and siren based on hospital time-critical interventions. Prehospital and disaster medicine, 25(4), 335-339.

3.     Maguire, Brian J. "Transportation-related injuries and fatalities among Emergency Medical Technicans and Paramedics." Prehospital and disaster medicine 26.5 (2011): 346-352.

4.     Clawson, J. J., Martin, R. L., Cady, G. A., & Maio, R. F. (1997). The wake-effect—emergency vehicle-related collisions. Prehospital and disaster medicine, 12(4), 41-44.

5.     Kupas, D. F., Zavadsky, M., Burton, B., Baird, S., Clawson, J. J., Decker, C., ... & Wilson, B. R. (2022). Joint Statement on Lights & Siren Vehicle Operations on Emergency Medical Services (EMS) Responses.

Checkout the PEC podcast Deep Dive episode on lights & sirens use:
https://podcasts.apple.com/us/podcast/pec-podcast-episode-102-deep-dive-series/id925204308?i=1000540159266

Article Bites #35: The Negative association between Number of airway attempts and neuro-intact survival following OHCA

Article Summary by Casey Patrick, @cpatrick_89

Article: Murphy, D. L., Bulger, N. E., Harrington, B. M., Skerchak, J. A., Counts, C. R., Latimer, A. J., ... & Sayre, M. R. (2021). Fewer tracheal intubation attempts are associated with improved neurologically intact survival following out-of-hospital cardiac arrest. Resuscitation, 167, 289-296.

Who, What, When, Where and How?

• Who? – 1205 non-trauma OHCA patients with a endotracheal intubation attempt, defined as “the introduction of a laryngoscope past the teeth and concluded when the laryngoscope was removed from the mouth, regardless of whether or not an endotracheal tube was inserted.”

• What? – Retrospective, observational, cohort (cohort = OHCA/intubation)

• When? – Jan 2015 – June 2019

• Where? – Seattle Fire

• How? – Primary outcome = neuro intact survival (CPC1/2)

• Excluded No attempt, BLS only, intubated after ROSC, DNR, other services

The Results

• Age = 60’s/68% male/33% witnessed/61% received bystander CPR/ 21%  shockable rhythm

• ROSC 44%/Hospital admission 38%/Survival to d/c 11%

• First attempt success 65%/2nd 86%

• Overall rate of supraglottic use – 2.8%/0.7% after 2 attempts/11.2% after 3 attempts/28.4% after 4+ attempts

• Primary outcome = CPC 1/2

  • There was a negative correlation between # of ET attempts and neurologically intact outcome: 11% CPC 1/2 with ONE intubation attempt/4% with TWO/3% with THREE and 2% with FOUR+ (see Figure)

  • These differences held for shockable vs. non-shockable rhythms

  • Multivariable stats modeling adjusted for: age/sex/witness/bystander/times/initial rhythm



The Questions

• What about SGA’s? - This isn’t a rehash of PART/AIRWAYS-2.  Overall rate of SGA use was very low.

• Mean time to airway = 5min in this study

• Yes, this is retrospective but… Very granular (especially in OHCA world)

• Incorporated monitor data PLUS audio (1200 patients!!)

What Should We Do Now?

• No, this doesn’t translate directly to agencies using “primary SGA” in OHCA

• BUT…More evidence airway delays = worsened patient-oriented outcome

  • Should there be a more rapid transition to SGA use after failed primary intubation attempt?

• BOTTOM LINE - Concentrate on the interventions that we KNOW matter: Early recognition and bystander CPR, access to early defibrillation, minimize pauses, proper compression rate and depth.

Edited & Accompanying Figure by EMS MEd Editor Maia Dorsett, MD PhD FAEMS (@maiadorsett)

Article Bites #34: Bringing the Stroke Center to the Stroke: How Effective are Mobile Stroke Units?

Article Summary by Ian Brodka and Andrew Lee

Article: Grotta, J. C., Yamal, J. M., Parker, S. A., Rajan, S. S., Gonzales, N. R., Jones, W. J., ... & Bowry, R. (2021). Prospective, Multicenter, Controlled Trial of Mobile Stroke Units. New England Journal of Medicine, 385(11), 971-981.

Background:

 The traditional pre-hospital model for stroke care has been to have EMS clinicians rapidly identify and transport any potential stroke patients from the scene of their stroke to the closest, most appropriate stroke center in order to decrease their time to treatment. At the center of all of this is the tenet: Time is Tissue. So, how do we reduce the time between stroke onset and treatment delivery? One idea is to bring the treatment to the patient through the use of a Mobile Stroke Units (MSUs), which have become available in many urban areas (approximately 20 US and 10 European cities). Given the resource-intensive nature of an MSU, the question remains: do they impact meaningful patient outcomes?

Previous research from Germany in the area of mobile stroke units has demonstrated decreased time from dispatch to thrombolysis [1,2].  One prospective trial from Berlin compared patients treated by the MSU versus those for whom the MSU was not available and found an improvement in functional outcomes at 3 months.[3]  With that in mind, the primary objective of this study was to evaluate the impact of mobile stroke unit in multiple US cities on patient disability at three months.

Methods:

This was a prospective, non-blinded, multi-center trial that included all subjects evaluated by EMS/MSU during designated times (e.g. 0800 to 1800, Monday to Saturday) who presented with symptoms consistent with acute stroke, onset within 4.5 hours, and no contraindications to t-PA usage (e.g. evidence of hemorrhage, known intracranial AVM, malignancy, or aneurysm). The enrollment in the trial groups was predetermined by designating each week as an MSU week or an EMS week in an alternating fashion. The subjects were enrolled in the study between August 2014 and August 2020, with varying beginning dates depending on the site.

The primary analysis included only subjects who were deemed eligible for t-PA in a retrospective review by a trained investigator who was blinded to the assigned trial group, whether or not they received t-PA . The primary outcome was the score on the utility-weighted modified Rankin scale at 90 days, which is a patient-centered outcome measure that takes into account patients’ value of functional status. They also assessed various secondary outcomes, which includes changes in the modified Rankin scale of all subjects eligible for t-PA, the percentage of eligible subjects treated with t-PA, and treatment times from stroke onset.

Results:

Of the 1515 subjects enrolled in the study, 1047 of them were included in the final analysis after accounting for t-PA eligibility, subjects lost to follow up, and subjects that withdrew (617 in the MSU group, 430 in the EMS group). A single trial site (Houston) enrolled 77.6% of all the patients; therefore, while it is technically a “multi-center” trial, the overwhelming majority of patients originate from a single center.

Within the treatment groups, 97.1% of the MSU group and 79.5% of the EMS group were ultimately given t-PA as a treatment for their strokes. Across the two groups, controlling factors were nearly identical across age, sex, ethnicity, NIHSS score, and previous strokes.

The key results of the study were the following:

 ·       Median time from last known well to t-PA administration was 72 minutes (IQR 55-105) in the MSU group and 108 minutes (IQR 84-147) in the standard EMS group.  Time from 911 alert to t-PA treatment was 46 minutes (IQR 39-55 minutes) for the MSU and 78 minutes (IQR 66-93 minutes) for standard EMS dispatch. Median time from EMS arrival to ED arrival was 55 min (IQR 47-62) for MSU and 27 min (IQR 21-33 min).

·       For patients who underwent endovascular therapy, time from EMS alert to EVT start was 141 minutes (IQR 116-171) in the MSU group and 132 minutes (IQR 114-160) in the EMS group.  An interesting note as well is that the EMS group has a roughly 10 minute advantage in 911 alert to thrombectomy, but has a 20 minute disadvantage in ED arrival to thrombectomy. The 20 minute delay from arrival to thrombectomy also makes sense in this study, since the EMS group would require the imaging workup to diagnose the stroke in the first place, as opposed to the MSU group diagnosing in the field in the case of availability of CT angiography.

·       For the primary outcome of UW-mRS score at 90 days after stroke onset, the MSU group had improvement in functional outcome over the EMS group [MSU 0.72 +/- 0.35 vs. EMS group 0.66 +/- 0.36]. The mean score at discharge was 0.57 +/- 0.37 for the MSU group and 0.51 +/- 0.36 for EMS.

·       55.5% of patients in the MSU group has a mRS of 0 or 1 (good neurologic outcome) compared with 44.4% in the EMS group. Mortality at 90 days was 8.9% in the MSU group and 11.9% in the EMS group.

What this means for EMS:

This study found that Mobile Stroke Units decrease time from 911 notification to t-PA administration and likely improve functional neurologic outcomes for patient suffering from acute ischemic stroke. Implementation of MSUs have been increasing in cities around the country, but their effectiveness must be considered in the context of their environment rather than in isolation.  From a system perspective, they are resource intensive and whether they are a cost-effective means to improve community health outcomes remains to be determined.

About the Authors: Ian Brodka and Andrew Lee are third year medical students at the University of Rochester Medical Center. They actively work as EMTs and also run the quarterly EMS Journal club in the Monroe-Livingston Region, during which this article was discussed.

Edited by Maia Dorsett, MD PhD FAEMS, @maiadorsett

References:

1. Walter, S., Kostopoulos, P., Haass, A., Keller, I., Lesmeister, M., Schlechtriemen, T., ... & Fassbender, K. (2012). Diagnosis and treatment of patients with stroke in a mobile stroke unit versus in hospital: a randomised controlled trial. The Lancet Neurology, 11(5), 397-404.

2. Ebinger, M., Winter, B., Wendt, M., Weber, J. E., Waldschmidt, C., Rozanski, M., ... & STEMO Consortium. (2014). Effect of the use of ambulance-based thrombolysis on time to thrombolysis in acute ischemic stroke: a randomized clinical trial. Jama, 311(16), 1622-1631.

3. Ebinger, M., Siegerink, B., Kunz, A., Wendt, M., Weber, J. E., Schwabauer, E., ... & Audebert, H. J. (2021). Association between dispatch of mobile stroke units and functional outcomes among patients with acute ischemic stroke in Berlin. JAMA, 325(5), 454-466.

Article Bites #33: Is Death Notification Training associated with decreased burnout among EMS professionals.

Campos, A., Ernest, E. V., Cash, R. E., Rivard, M. K., Panchal, A. R., Clemency, B. M., ... & Crowe, R. P. (2021). The association of death notification and related training with burnout among emergency medical services professionals. Prehospital Emergency Care, 25(4), 539-548.

Background:

Death notification is the process by which we inform family members or friends that someone they are close to has died.  EMS professionals do this as part of their clinical roles – both in cases of obvious death and in cases of termination of resuscitation in the field.  In the clinical sphere of prehospital care, the deaths that we deal with are often sudden and unexpected, which makes these conversations even more difficult.

It is known that the communication of bad news has been linked to psychological consequences such as depression, anxiety or PTSD amongst healthcare professionals. In medical school or other training paradigms, there is standardized training in delivering bad news.  Such education has been shown to improve the ability of healthcare professionals to deliver such news with clarity and improve recipients’ understanding of the information. 

Despite the role of EMS professionals in delivering bad news, little is known regarding:

1)     The frequency with which EMS professional deliver death notifications;

2)     The prevalence of training related to performing this task;

3)     Whether an association exists between delivering death notification and burnout in EMS professionals.

Therefore this study had two objectives:

1)     Described EMS professionals’ experience with death notification and related training.

2)     Assess the associations between death notification delivery, training, and burnout.

Methods:

This was a cross-sectional study of data obtained via electronic survey administered to a randomly selected cohort of national-certified EMS professionals at the BLS and ALS level.  An e-mail invitation that included the unique survey link was sent out in April 2017.  EMS professionals who took the survey were not made aware of the study objectives.

Respondents were asked to self-report the number of death notifications they had made for patients age > 18 in the preceding 12 months.   They were also asked whether they had received any form of death notification training during their initial and continued EMS education and their level of comfort in performing death notification.  Burnout was assessed using the Copenhagen Burnout Inventory, which has previously been validated for use with EMS professionals.

Results:

The survey was sent to 19,330 EMS professionals and they had 2,333 responses. After accounting for exclusion criteria (e.g. not a care provider, military EMS, practicing at EMR level etc.), 1,514 responses were included in the analysis.  55% of the survey respondents operated at the BLS level and 45% operated at the ALS level.

They found that experience in delivering death notification varied by certification level. 77% of ALS respondents reported delivering at least one adult death notification in the previous 12 months, compared to 33% of BLS respondents.  Only half of all EMS clinicians reported receiving death notification training as part of their initial education, which did not vary between BLS and ALS clinicians.  Most commonly, this training took the form of classroom lecture and classroom discussion.

As one might expect, respondents attitudes toward delivering death notification correlated with their past training experience, with them feeling significantly more prepared if they had received prior training. Interestingly, after using a multivariable regression model to control for known confounders, delivering death notification was associated with work-related burnout amongst EMS professionals. Compared with EMS professionals who had not delivered any death notifications, EMS professionals who had delivered 1-5 in the previous 12 months had a 36% greater odds of burnout and those who had delivered > 5 demonstrated 73% greater odds of burnout.   Importantly, ongoing education appeared to make a difference: death notification training as part of ongoing education was associated with a 29% reduction in the odds of burnout.  Interestingly, the same was not true regarding death notification training as part of an initial EMS education program.

There are some potential confounders here that are worth considering.  Systems with more death notification may be busier systems with other factors that correlate with burnout other than call volume alone which was accounted for by the regression model.  EMS agencies that do continuing education on this subject may have a different cultures.  Exposure to death and tragedy may drive burnout.  However, the correlation between continuing death notification training and a reduction in burnout is not explained well by these confounders and suggests that it is not just exposure to death that drives burnout, but that preparation to communicate with families plays a role as well.

Discussion: What does this mean for EMS leaders and educators?

This study demonstrates three important things:

-        Death notification takes an emotional toll on EMS clinicians.

-        Death notification is not the purview of ALS clinicians alone.

-        Continuing education in death notification may be an important factor not only in preparing EMS clinicians to communicate more clearly during these difficult conversations, but potentially mitigating the risk of burnout as a result.

 As EMS leaders and educators, we should ask ourselves whether we offering this training to our clinicians and what should this training look like?  There is no clear right answer here, but ignoring the need is definitely the wrong one.  

Some ideas:

Teach and implement the GRIEV_ING algorithm and use simulation to practice and provide feedback - not every cardiac arrest ends in save in real life, do your simulations reflect this?

Additional Resources:

1)     GRIEV_ING algorithm paper

2)     This video was made by the Monroe-Livingston EMS Region at the beginning of the COVID-19 pandemic in anticipation of the rise of out-of-hospital death.

Article Summary by Maia Dorsett, MD PhD FAEMS, @maiadorsett

Article Bites #32. 12-Leads After ROSC: It's All in the Timing

By Casey Patrick MD and Brad Ward EMT-P

Article: E Baldi, S Schnaubelt, et al. Post-ROSC electrocardiogram timing in the management of out-of-hospital cardiac arrest: results of an international multicentric study (PEACE study). European Heart Journal, Volume 41, November 2020

Background

The initial hospital destination for OHCA patients, post-ROSC, has been a moving target over the past few years.  Initial retrospective data suggested that “likely cardiac source” post-arrest patients, STEMI or not, had improved outcomes with emergent cardiac catheterization (1).  However, the prospective and randomized COACT study showed no benefit for emergent revascularization in non-STEMI/post-ROSC patients (2).  What about those post-ROSC with STEMI?  How sure are we that this group has an acute occlusion warranting emergent cath lab transport, and is there a way for better prehospital prognostication?  The PEACE study set out to assist in this complex decision. 

Patients who achieve ROSC after cardiac arrest are a wildly heterogeneous group with correspondingly variable courses of treatment. The 12-Lead ECG is a vital tool in our EMS diagnostic armamentarium, and we’ve taught that the sooner, the better. How soon is too soon?  Does the timing of ECG capture post return of circulation affect its accuracy in diagnosing actual acute occlusive coronary disease?

Methods

This was a retrospective, cohort, multi-center study that included all OHCA patients with ECGs and eventual angiography in three European (Italy/Switzerland/Austria) hospitals from January 2015 – December 2018. 

The primary outcome was false positive ECG (STEMI with no coronary obstruction).  ECG’s were evaluated by two cardiologists who were blinded to all times and angiography results, and if any disagreement, a third broke the tie.  Isolated posterior MI’s and Sgarbossa positive ECGs were included.  Significant stenosis was defined as >50% LMCA lesion or >75% elsewhere.

All patients greater than 18yo were included with the exception of non-medical cardiac arrest causes.  Five hundred eighty-six consecutive post-ROSC patients were admitted, but 152 had no ECG, and 64 did not undergo angiography.  This yielded 370 patients in the final analysis.

The Results

Of the 370 patients, 198 had STEMI, and 172 did not.  ~85% of patients had witnessed OHCA, with 73% receiving bystander CPR.  85% presented with an initial shockable rhythm, and 57% had good neurologic survival (defined as CPC1/2).  The patients were primarily male (~75%) and in their 60’s.

How did the STEMI and non-STEMI patient groups compare?  The STEMI patients were more likely initially shockable and, therefore, received more defibrillations and higher doses of epinephrine.  Also, 80% of STEMI patients got PTCA vs. 57% of non-STEMI, making sense from a therapeutic momentum standpoint. 

What about ECG timing? Let’s get to the good stuff and answer their question, did the timing of ECG post-ROSC change the predictive value for finding acute coronary occlusion?  A logical hypothesis is yes, as earlier ECGs might be more likely false positive due to an overlap of ST-elevation from cardiac arrest ischemia/low flow (similar to type 2 MI) as opposed to signifying a true culprit lesion.  The groups were stratified into ROSC-to-ECG time cohorts and then analyzed for the rate of false positives:

·       128 ECGs <8 minutes                False Positive Rate = 18.5%

·       126 ECGs 8-33 minutes             False Positive Rate = 7%

·       121 ECGs >33 minutes              False Positive Rate = 5.8%

These differences in accuracy remained when adjusted for age, sex, epinephrine dose, defibrillation number, and pulse.

~60% improvement in ECG accuracy for actual coronary occlusion if ECG is delayed at least 8 minutes.

What Should We Do Now?

The PEACE study addressed a novel question that warrants additional investigation.  On the strength side, this was a multi-center data set, but the retrospective nature is a potential source of bias.  Additionally, post-ROSC ECGs were missing in 25% of patients, and angiography was not performed in a significant portion due to death before intervention.

We know that COACT and other more recent retrospective data (3) suggest immediate cath is not warranted in post-ROSC patients without STEMI.  The PEACE study suggests that delaying our EMS ECG at least 8 minutes may lead to better accuracy in identifying those with acute occlusion.  Should we overhaul our protocols?  My opinion (take it with a grain of salt) is probably not.  However, PEACE is an excellent reminder to focus on proven “lifesavers” after ROSC, and to remember that an immediate 12-lead is likely NOT one of those.  Our focus should be on oxygenation, circulatory support, lung-protective ventilation, and adequate sedation.  THEN…capture the ECG.  Realistically, those critical steps, which we know impact mortality, should probably take 8-10 minutes anyway, so we won’t actually change as much as we’ll rearrange.

The BOTTOM LINE…

In patients with OHCA, ROSC, and subsequent angiography, the ECG was 60% more accurate for acute occlusion when delayed >8min post-ROSC.  Presumably, this resulted from weeding out some ST elevation due to low flow ischemia as opposed to true obstruction.  Lung protection, sedation, circulatory support, and oxygenation FIRST/ECG last - REARRANGE/DON’T CHANGE.

References:

1.     Hollenbeck RD, McPherson JA, Mooney MR, Unger BT, Patel NC, McMullan PW Jr, Hsu CH, Seder DB, Kern KB. Early cardiac catheterization is associated with improved survival in comatose survivors of cardiac arrest without STEMI. Resuscitation. 2014 Jan;85(1):88-95. 

2.     Lemkes JS, Janssens GN, van der Hoeven NW, et al. Coronary Angiography After Cardiac Arrest Without ST-Segment Elevation. N Engl J Med 2019;380:1397-407.

3.     Voicu S, Bajoras V, Gall E, Deye N, Malissin I, Dillinger JG, Benajiba C, Logeart D, Henry P, Megarbane B, Sideris G. Immediate coronary angiogram in out-of-hospital cardiac arrest patients with non-shockable initial rhythm and without ST-segment elevation - Is there a clinical benefit? Resuscitation. 2020 Oct;155:226-233.

Article Bites #31: Recommendations to Mitigate Risk of Pediatric Medication Dosing Errors

Article: Medication Dosing Safety for Pediatric Patients: Recognizing Gaps, Safety Threats, and Best Practices in the Emergency Medical Services Setting.  A Position Statement and Resource Document from NAEMSP.

Background: Medication dosing errors in pediatrics are a common occurrence. Dosing errors are the result of multiple causes:  infrequent exposure to pediatric patients coupled with complex calculations for weight-based dosing performed in a stressful environment.  The NAEMSP Pediatrics Committee undertook a scoping review of EMS, interfacility and emergency literature to develop a series of evidence-based recommendations to reduce the incidence of pediatric medication errors in the prehospital environment.

Methods:  The authors identified four key concepts areas to review:

1.     What is known about enhanced dosing safety for patients in the EMS setting?

2.     What are the greatest latent and active safety threats to medication dosing?

3.     Can dosing safety education and strategies from other settings be adapted to the EMS setting?

4.     What is known about the role of standardized formularies in dosing safety?  Is a standardized formulary protocol a means for precalculation of doses and decreasing errors? Are drug shortages and concerns for medical director autonomy barriers to standardization of formularies?

From these 4 concept areas, 17 PICO (Population-Intervention-Control-Outcome) Questions were iteratively developed and used as a basis for a subsequent literature search.  70 research articles were ultimately included in the qualitative synthesis which extracted relevant findings of the study and also graded the strength of evidence using a standardized rubric. The summary of this data was then used to draft evidence-based recommendations for pediatric EMS medication dosing safety.

Results: Overall, 70 articles on pediatric dosing safety were included. There was a paucity of EMS-specific research pertinent to medication safety.  Data from hospital-based studies required extrapolation to EMS. Using the information contained in these articles, the authors make the following recommendations:

 Take home for EMS: Pediatric medication dosing errors are common in EMS. Incorporating the above recommendations may help decrease this risk.

 Article Bites summary by Maia Dorsett, MD PhD FAEMS FACEP, @maiadorsett

Article Bites #30: What is the incidence of awareness during paralysis following emergent intubation? The ED-AWARENESS study.

Article Summary by Casey Patrick, MD, FAEMS @cpatrick_89

Article: Pappal RD, Roberts BW, Mohr NM, Ablordeppey E, Wessman BT, Drewry AM, Winkler W, Yan Y, Kollef MH, Avidan MS, Fuller BM. The ED-AWARENESS Study: A Prospective, Observational Cohort Study of Awareness With Paralysis in Mechanically Ventilated Patients Admitted From the Emergency Department. Ann Emerg Med. 2021 Jan 20:S0196-0644(20)31314-7. 

Background

On the list of “worst nightmares” is being paralyzed and awake, which is truly the stuff of horror movies.  Anytime neuromuscular blockade medications are used in airway management, this phenomenon must be anticipated and prevented at all costs.  There is a large volume of literature addressing and investigating the risks and incidence of paralysis while awake in the operating room setting.  Surprisingly, however, there is a sparsity of emergency department (ED) research in this area. Many EMS systems allow the use of neuromuscular blockade in addition to sedation medications, making it incumbent for prehospital providers to have a solid pharmacologic and physiologic knowledge of the agents used to facilitate intubation. 

This study’s goal was to quantify the rate of being awake and paralyzed following intubation in the ED and additionally attempted to investigate possible risk factors influencing its occurrence.

Methods

This was a single-center, prospective cohort study that included all patients >18yo who were intubated and mechanically ventilated in a large volume (90k yearly visits) academic center in St. Louis.  Data from June 2019 through May 2020 were included in the study. 

The primary outcome was the incidence of being awake while paralyzed.  The Brice Questionnaire, which has been used extensively in the prior anesthesia work in this area, was used to assess consciousness following paralysis.  Three reviewers independently reviewed the questionnaires to determine yes/possible/no to whether the patient was awake while paralyzed.

Those who died, had severe neurologic injury, were lost to attrition, or transferred were excluded.

But wait, “Awake and Paralyzed” is subjective; how do you “measure” it?

The Brice Questionnaire has been validated extensively in the anesthesia literature.  Specifically, question #3 is critical.  “Can you remember anything between LOC and waking?” The patients had to report a sensation of wakeful paralysis AND have had administration of neuromuscular blockade to qualify.  The questioning occurred after extubation and before hospital discharge.  After reviewing the patient’s answers, the independent investigators graded the possibility of awake paralysis as “No, Possible, or Definite.”  Complete patient survey answers were included in the manuscript, and the authors were cautious to handle the results as conservatively and transparently as possible.  There was ultimately good agreement between the three investigators as the intraclass correlation coefficient was 0.72.

What Else Do We Know About being awake while sedated?

As mentioned earlier, the majority of the literature in the area comes from the OR setting.  Does it even matter if someone experiences this?  That is a dumb question, but yes, up to 70% of cases develop long-term severe psychiatric problems (PTSD).  Remember these numbers for later – 0.1-0.2% incidence of being awake and paralyzed occurs in the OR setting.  What increases the risk in the OR?  IV anesthesia, underdosing sedatives, long-acting neuromuscular agents (rocuronium) all increase the risk of awake paralysis.  SOUND FAMILIAR??  THESE ARE ED/EMS INTUBATING CONDITIONS.

Has anybody looked at this in the ED?  There are four studies with a combined n=123 using non-validated and non-standardized questions, emphasizing the need for additional work.

 The Results

There were 833 patients intubated in the ED during the study period. Four hundred fifty were excluded, leaving 383 for final analysis.  10/383 (2.6%) of study patients were determined to be possibly or likely awake while sedated. 70% of the ten awake paralyzed patients got rocuronium vs. only 31% of the other 373 patients in the study.  This yields an odds ratio of 5.1 (95% CI 1.3 – 20) for rocuronium exposure.  

To summarize, the investigators found 3x the rate of awake paralysis in the ED following intubation as compared to the highest risk OR patients (the actual value may be higher than 2.6%, as they handed their data as conservatively as possible).

Let’s put the “data” aside and talk about some of the patient stories…

•   “I remember the breathing tube going in.”

•   “I remember them putting the breathing tube down, but I could not move.”

•   “It was terrible and traumatic – I was panicking inside.”

•   “I remember waking up with someone pulling my injured leg, I tried to move, but I could not” – ED records noted a “spike in BP.”

•   “For a minute, the patient experienced paralysis in which she couldn’t move anything, including her eyes.”

•   “When I woke up, I could not move but could hear people talking about putting a camera down to look in my lungs.”

•   “I had a breathing tube in my throat and tried to move and talk but could not.”

 What Should We Do Now?

We teach post-intubation sedation in the EMS world, and most services do an excellent job.  EMS paralysis and sedation occur entirely via the IV/IM route. The continued trend from succinylcholine to rocuronium use is likely not slowing for other exceedingly valid reasons.  So, prehospital intubations, just like those in the ED, are awake paralysis risk factors from the start.  That said, a second post-intubation dose of sedative MUST be protocolized when using paralytic medication in both the field and the ED. 

The Bottom Line …

The rate of being awake and paralyzed in the emergency department following intubation is likely 3x that which occurs in the operating room setting.  Patients who experience this have substantially increased risks of subsequent mental health problems like PTSD.  This study is a vital reminder of why adequate sedation is essential and why thorough and continuous QI/QA of EMS paralyzed patients is imperative.  Let’s not get lax; one awake patient following paralysis and intubation is too many.

EMS MEd Editor & Image Credit: Maia Dorsett, MD PhD FAEMS, @maiadorsett

Article Bites #29: Is CPSS greater than or equal to 2 a reasonable tool for Large Vessel Occlusion Stroke Prediction?

Article: Crowe, R. P., Myers, J. B., Fernandez, A. R., Bourn, S., & McMullan, J. T. (2020). The cincinnati prehospital stroke scale compared to stroke severity tools for large vessel occlusion stroke prediction. Prehospital Emergency Care, 1-9.

Background: Since the first trials demonstrating significant benefit from endovascular therapy for patients with stroke secondary to large vessel occlusion (LVO) were published, the EMS community has been actively refining screening and destination protocols to optimize patient outcomes through destination choice.   Indeed, given a ~ 10% decrease in good functional outcome for every 30 minutes in delay in endovascular treatment, appropriate field triage is a critical component of stroke systems of care for patients with an LVO. [1,2]

LVO Screening tools of variable complexity have been developed. Depending on the complexity, implementation of such screening tools requires significant investment in training, documentation and tracking on the part of the EMS system.  In general, the sensitivity, specificity and positive predictive value of all the LVO scales has been suboptimal. [3] In contrast, the Cincinnati Prehospital Stroke Scale (CPSS) is widely implemented and regularly performed by EMS clinicians at all scopes of practice.  The objective of this paper was to address whether newly developed LVO scales offer a clinically-meaningful advantage over the CPSS.  

Methods:  This study was a retrospective analysis of prehospital electronic care records with linked hospital outcome data for the 2018 calendar year from the ESO research database.    Inclusion criteria included 911 responses with one or more of the stroke scales of interest (CPSS, RACE, LAMS, or VAN) documented AND linked hospital diagnosis data available.  Patients were classified as having intracerebral hemorrhage, transient ischemic attack or acute ischemic stroke based the hospital ICD-10 code.  If the ICD-10 code indicated thrombosis or embolism of the middle cerebral arteries, internal carotid artery or basilar artery, the patient was categorized as having an LVO. Sensitivity and specificity for detection of LVO for each documented stroke scale was calculated.  Receiver Operating curves were used to assess the overall discrimination of each scale for LVO.

Key Results:

-        Among 13,596 responses from 151 EMS agencies that had one or more stroke scales documented, CPSS was the most commonly documented instrumented (83% of patients), followed by RACE (14% of patients), the LAMS (7% of patients), and VAN (4% of patients). 31% of patients with documented prehospital stroke scales had a hospital ICD-10 diagnosis indicative of stroke.

-        Breakdown of types of stroke: 57% ischemic stroke, 23% TIA, 13% with TIA, 7% with multiple types.  Of patients experiencing ischemic stroke, 26% had an ICD-10 diagnosis indicative of LVO.

-        A CPSS score > 2 (positive on 2 or more physical exam elements of facial droop or palsy; arm weakness, drift or drop; and abnormal speech) had a sensitivity of 69% and specificity of 73% for LVO.  There was no statistically significant differences between this and the performance of the RACE, LAMS or VAN scales.

-        Among patients with a CPSS score > 2, 14% were diagnosed with LVO and 9% were diagnosed with ICH.  39% did not have a stroke diagnosis.

What this means for EMS:  Destination decision is a critical component of the prehospital management of stroke and this decision has increased in complexity with the availability of endovascular therapy for patients with large vessel occlusion.  On a system scale, optimizing patient and system outcomes requires a balance between over- and under-triage of these patients to specialty centers capable of providing endovascular therapy.  In this retrospective analysis of prehospital patients, a CPSS > 2 performed similarly to more complex LVO scales for large vessel occlusion prediction. While we await assessment of additional prehospital stroke scales, it may be more worthwhile to focus on incorporating CPSS > 2 into destination decisions and quality improvement efforts than training EMS clinicians on new stroke scales.

References:

1.     Saver, J. L., Goyal, M., Van der Lugt, A. A. D., Menon, B. K., Majoie, C. B., Dippel, D. W., ... & Cardona, P. (2016). Time to treatment with endovascular thrombectomy and outcomes from ischemic stroke: a meta-analysis. Jama, 316(12), 1279-1289.

2.     Jayaraman, M. V., Hemendinger, M. L., Baird, G. L., Yaghi, S., Cutting, S., Saad, A., ... & McTaggart, R. A. (2020). Field triage for endovascular stroke therapy: a population-based comparison. Journal of neurointerventional surgery, 12(3), 233-239.

3.     Smith, Eric E., et al. "Accuracy of prediction instruments for diagnosing large vessel occlusion in individuals with suspected stroke: a systematic review for the 2018 guidelines for the early management of patients with acute ischemic stroke." Stroke 49.3 (2018): e111-e122.

Article Summary by Maia Dorsett, MD PhD FAEMS, @maiadorsett

Article Bites #28: In most cases of OHCA, Resuscitate on Scene > Intra-arrest Transport

Article: Grunau B, Kime N, Leroux B, et al. Association of Intra-arrest Transport vs Continued On-Scene Resuscitation With Survival to Hospital Discharge Among Patients With Out-of-Hospital Cardiac Arrest. JAMA. 2020;324(11):1058–1067. doi:10.1001/jama.2020.14185

Background

Treatment for a non-traumatic Out-Of-Hospital Cardiac Arrest (OHCA) can occur on scene or during transport. It continues to be the standard in some systems that OHCA patients are transported early, while in other systems patients are treated on scene until return of spontaneous circulation (ROSC) is attained. There is a perception among many in the lay public, hospitals, and even EMS that optimal care is given in the Emergency Department, and all OHCA victims should be transported for best outcomes. However, treatment on scene utilizing similar protocols to the ED until ROSC is felt amongst many to provide a higher quality care than can be attained during transport.

Methods

Data was obtained from the Resuscitation Outcomes Consortium (ROC) registry and collection prospectively from consecutive nontraumatic adult EMS-Treated OHCA. There were 10 sites in North America, data was obtained between 2011 and 2015, and was at the ALS and BLS level. Exclusion criteria included age < 18, a DNR order, cardiac arrest after initiation of transport, or those with missing data. Primary outcome was survival to hospital discharge. Secondary outcome was neurologically-intact survival.

Results

A total of 43,969 consecutive OHCAs were included with 11,625 underwent intra-arrest transport and 32,344 were treated on-scene until ROSC or termination of resuscitation. Survival to hospital discharge was 3.8% for patients who received intra-arrest transport and 12.6% for those who received on-scene resuscitation. Of those transported prior to ROSC, 16% achieved ROSC prior to hospital arrival.

To account for differences between the on-scene resuscitation vs. intra-arrest transport groups, the authors performed a propensity-matched analysis.  Survival of intra-arrest transport patients was 4.0%, while survival of transport after ROSC was 8.5%. This result was statistically significant, with an adjusted risk ratio of 0.48 (95% CI, 0.43-0.54).   Neurologically-intact survival, defined as a mRS < 3, was also higher in the group with continued on-scene resuscitation: 7.1% for on-scene vs. 2.9% for intra-arrest transport with a statistically-significant adjusted risk ratio of 0.60 (95% CI, 0.47-0.76). This trend held for both shockable and non-shockable rhythms.

What does this mean for EMS?

While not a randomized-controlled trial, this study uses a large prospectively gathered dataset with cohort matching. Therefore the data gathered is likely to represent real-world conditions. In addition this data continues to add to a growing trend of evidence and standard of practice that most patients suffering from cardiac arrest have a higher chance of survival if treated on-scene until ROSC. There are likely subgroups of patients, such as in pregnancy or those who may benefit from eCPR after arrival at a hospital, where transport early or after the 15 minute time mark may lead to some benefit.

Article Summary by Joshua Stilley, MD FAEMS, @JoshuaStilley

Article Bites #27: Is eCPR the future of refractory Vfib Management?

Yannopoulos D, Bartos J, Raveendran G, et al. Advanced reperfusion strategies for patients with out-of-hospital cardiac arrest and refractory ventricular fibrillation (ARREST): a phase 2, single centre, open-label, randomized controlled trial. Lancet 2020; Nov 13

Background – ECMO and CPR (eCPR)

Refractory ventricular fibrillation (rVF), often called electrical storm, has dismal outcomes which is exceedingly frustrating because we know the cause is likely acute coronary occlusion (~75%).  Recent therapies for rVF include double-sequential defibrillation, esmolol, and even ultrasound-guided stellate ganglion nerve blocks.  Others have suggested early ECMO in this patient population.  The logic behind this approach makes intuitive sense; CPR/ACLS are unlikely to work if you have a 100% left main lesion causing OHCA.  One potential solution for this dilemma is to use ECMO as a bridge to cardiac catheterization and revascularization (eCPR). Dr. Demetris Yannopoulos at The University of Minnesota has been an early champion of eCPR with multiple retrospective studies suggesting improved survival when using ECMO for rVF and OHCA.  However, the ARREST study is the first randomized trial of standard ACLS vs. eCPR.

Methods

This study occurred from August 2019 through June 2020 at The University of Minnesota and included three transporting EMS systems. Patients  were included in the study if they were 18-75yo, presented with shockable rhythm with no ROSC after three shocks, had a body habitus compatible with use of the LUCAS mechanical CPR device, and had a transfer time of < 30 minutes.  There were multiple exclusionary criteria, as well, that were all applied in an attempt to select for patients who would have the best opportunity for good functional outcomes AND be most likely to have acute coronary occlusion as the cause of their cardiac arrest: 

Exclusion Criteria

·       Trauma

·       Overdose

·       Pregnancy

·       Prisoners

·       DNR/Nursing home patients

·       Terminal cancer

·       Opt-out bracelet

·       Contrast allergy

·       Active bleeding

Patients were randomized on arrival to the emergency department into one of two arms: immediate ECMO with subsequent catheterization/revascularization or standard ACLS in the ED.   This is important, as the current standard in many systems is continue to manage the arrest in place.  

The eCPR group went directly to the cath lab for immediate cannulation and catheterization.  The standard ACLS group got at least 15min of resuscitation or until 60min from arrest.  If ROSC was obtained, the standard ACLS group received immediate angiography.  If the patient survived to admission, those in both groups got standard cardiac ICU care with targeted temperature management and no neuro prognostication for at least 72hr.

What outcomes were measured?

The primary outcome was survival to hospital discharge with secondary outcomes of safety and functionality (measured by mRS and CPC score) at hospital discharge, three months, and six months.

Results:

Were the two groups similar?

Although many historical specifics were unknown (not surprising for a study of OHCA), the two groups were similar at baseline although there were more women and ESRD patients in the standard ACLS arm.  All patients presented with an initial rhythm of rVF.  Rates of witnessed arrest and bystander CPR, time to EMS arrival, and prehospital ACLS treatments were similar.  No patients had ROSC on arrival to the ED.  These patients were SICK with hospital arrival lactates of 10-11, pH values of 6.9-7, and measured ETCO2 levels of 28-33.  Six patients were excluded:  two with initial PEA, one with a transport time >30min, and three with ROSC after the 2nd shock. 

What were the key results?

Survival to discharge in the eCPR group was 43% (6/14) vs. 7% (1/15) in those treated with standard ACLS.

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But what was the functional status of the survivors?  At the 6-month mark, all 6 ECMO survivors had an mRS of 3 or lower.  Only 2 of the 15 standard ACLS patients even made it to the cardiac catheterization lab.  One died in hospital from cerebral edema and the other after hospital discharge from anoxic injury.  Two patients in the eCPR/ECMO group were declared dead prior to cannulation (2 or more of ETCO2<10/PaO2<50/lactate>18 = dead).  Six ECMO patients died before hospital discharge due to anoxia/cerebral edema.  ECMO complications included one tubing break, two access site bleeds, and one retroperitoneal bleed.

One criticism of this study will obviously be the small patient numbers, but the data safety monitoring board actually stopped the study early due to lack of equipoise.

What would a program like this require?

From a prehospital standpoint, our portion of care will be the beginning in a long process that will require coordination of care across EMS/ED/cath lab/ICU and even rehabilitation.  That said, the authors specifically stated that the time from 911 call to ECMO cannulation is the prime predictor of survival.  Implementation of an eCPR program will not be something that EMS can tackle alone.  A streamlined system of care with a dedicated resuscitation center will be critical and must include ECMO availability with ED, cardiology, an intensive care buy-in.  Yes, an eCPR approach is expensive and labor-intensive, but improving survival to almost 50% with good functional outcomes in a condition with an otherwise bleak prognosis seems promising at the very least.

Article Summary by Casey Patrick, MD

Figure by Maia Dorsett, MD PhD