Development and validation of a prehospital termination of resuscitation (TOR) rule for out - of hospital cardiac arrest (OHCA) cases using general purpose artificial intelligence (AI)

BACKGROUND

Prehospital identification of futile resuscitation efforts (defined as a predicted probability of survival lower than 1%) for out-of-hospital cardiac arrest (OHCA) may reduce unnecessary transport. Reliable prediction variables for OHCA 'termination of resuscitation' (TOR) rules are needed to guide treatment decisions. The Universal TOR rule uses only three variables (Absence of Prehospital ROSC, Event not witnessed by EMS and no shock delivered on the scene) has been externally validated and is used by many EMS systems. Deep learning, an artificial intelligence (AI) platform is an attractive model to guide the development of TOR rule for OHCA. The purpose of this study was to assess the feasibility of developing an AI-TOR rule for neurologically favorable outcomes using general purpose AI and compare its performance to the Universal TOR rule.

METHODS

We identified OHCA cases of presumed cardiac etiology who were 18 years of age or older from 2016 to 2019 in the All-Japan Utstein Registry. We divided the dataset into 2 parts, the first half (2016-2017) was used as a training dataset for rule development and second half (2018-2019) for validation. The AI software (Prediction One®) created the model using the training dataset with internal cross-validation. It also evaluated the prediction accuracy and displayed the ranking of influencing variables. We performed validation using the second half cases and calculated the prediction model AUC. The top four of the 11 variables identified in the model were then selected as prognostic factors to be used in an AI-TOR rule, and sensitivity, specificity, positive predictive value, and negative predictive value were calculated from validation cohort. This was then compared to the performance of the Universal TOR rule using same dataset.

RESULTS

There were 504,561 OHCA cases, 18 years of age or older, 302,799 cases were presumed cardiac origin. Of these, 149,425 cases were used for the training dataset and 153,374 cases for the validation dataset. The model developed by AI using 11 variables had an AUC of 0.969, and its AUC for the validation dataset was 0.965. The top four influencing variables for neurologically favorable outcome were Prehospital ROSC, witnessed by EMS, Age (68 years old and younger) and nonasystole. The AUC calculated using the 4 variables for the AI-TOR rule was 0.953, and its AUC for the validation dataset was 0.952 (95%CI 0.949 -0.954). Of 80,198 patients in the validation cohort that satisfied all four criteria for the AI-TOR rule, 58 (0.07%) had a neurologically favorable one-month survival. The specificity of AI-TOR rule was 0.990, and the PPV was 0.999 for predicting lack of neurologically favorable survival, both the specificity and PPV were higher than that achieved with the universal TOR (0.959, 0.998).

CONCLUSIONS

The accuracy of prediction models using AI software to determine outcomes in OHCA was excellent and the AI-TOR rule's variables from prediction model performed better than the Universal TOR rule. External validation of our findings as well as further research into the utility of using AI platforms for TOR prediction in clinical practice is needed.

Utility of end-tidal carbon dioxide to guide resuscitation termination in prolonged out-of-hospital cardiac arrest

STUDY OBJECTIVE

To evaluate if the change in end-tidal carbon dioxide (ETCO2) over time has improved discriminatory value for determining resuscitation futility compared to a single ETCO2 value in prolonged, refractory non-shockable out-of-hospital cardiac arrest (OHCA).

METHODS

This is a retrospective analysis of adult refractory non-shockable, non-traumatic OHCA patients in the Portland Cardiac Arrest Epidemiologic Registry (PDX Epistry) from 2018 to 2021. We defined refractory non-shockable OHCA cases as patients with lack of a shockable rhythm at any time or return of spontaneous circulation at any time prior to 30-min of on-scene resuscitation. We abstracted ETCO2 values first recorded after advanced airway placement and nearest to the 30-min mark of on-scene resuscitation (30 min-ETCO2) from EMS charts. The primary outcome was survival to hospital discharge. We compared 30 min-ETCO2 cutoffs of 10 mmHg and 20 mmHg to the trend (increasing or not) from initial to 30 min-ETCO2 (delta-ETCO2) using sensitivity, specificity, and area under the receiver operating curves (AUROC).

RESULTS

Of 3837 adult OHCA, 2850 were initially non-shockable, and there were 617 (16.1%) cases of refractory non-shockable OHCA at 30-min. We excluded 320 cases without at least two ETCO2 recordings in the EMS chart, leaving 297 cases that met inclusion criteria. Of these, 176 (59.3%) were transported and 2 (0.7%) survived to discharge. Using absolute 30 min-ETCO2 cutoffs, both survivors were in the >10 mmHg group (sensitivity 100.0%, specificity 12.5%), whereas only one survivor was identified in the >20 mmHg group (sensitivity 50.0%, specificity 32.5%). Using delta-ETCO2, both survivors were in the increasing ETCO2 group (sensitivity 100.0%, specificity 60.7%). In comparing the two tests that did not misclassify survivors, the AUROC [95% CI] was higher when using delta-ETCO2 (0.803 [0.775-0.831]) compared to an absolute cutoff of 10 mmHg (0.563 [0.544-0.582]).

CONCLUSIONS

Nearly one-sixth of EMS-treated adult OHCA patients had refractory non-shockable arrests after at least 30 min of ongoing resuscitation. In this group, the ETCO2 trend following advanced airway placement may be more accurate in guiding termination of resuscitation than an absolute ETCO2 cutoff of 10 or 20 mmHg.

Adverse Safety Events in Emergency Medical Services Care of Children With Out-of-Hospital Cardiac Arrest

Importance

Survival for children with out-of-hospital cardiac arrest (OHCA) remains poor despite improvements in adult OHCA survival.

Objective

To characterize the frequency of and factors associated with adverse safety events (ASEs) in pediatric OHCA.

Design, Setting, and Participants

This population-based retrospective cohort study examined patient care reports from 51 emergency medical services (EMS) agencies in California, Georgia, Oregon, Pennsylvania, Texas, and Wisconsin for children younger than 18 years with an OHCA in which resuscitation was attempted by EMS personnel between 2013 and 2019. Medical record review was conducted from January 2019 to April 2022 and data analysis from October 2022 to February 2023.

Main Outcomes and Measure

Severe ASEs during the patient encounter (eg, failure to give an indicated medication, 10-fold medication overdose).

Results

A total of 1019 encounters of EMS-treated pediatric OHCA were evaluated; 465 patients (46%) were younger than 12 months. At least 1 severe ASE occurred in 610 patients (60%), and 310 patients (30%) had 2 or more. Neonates had the highest frequency of ASEs. The most common severe ASEs involved epinephrine administration (332 [30%]), vascular access (212 [19%]), and ventilation (160 [14%]). In multivariable logistic regression, the only factor associated with severe ASEs was young age. Neonates with birth-related and non-birth-related OHCA had greater odds of a severe ASE compared with adolescents (birth-related: odds ratio [OR], 7.0; 95% CI, 3.1-16.1; non-birth-related: OR, 3.4; 95% CI, 1.2-9.6).

Conclusions and Relevance

In this large geographically diverse cohort of children with EMS-treated OHCA, 60% of all patients experienced at least 1 severe ASE. The odds of a severe ASE were higher for neonates than adolescents and even higher when the cardiac arrest was birth related. Given the national increase in out-of-hospital births and ongoing poor outcomes of OHCA in young children, these findings represent an urgent call to action to improve care delivery and training for this population.

Out-of-hospital cardiac arrest outcomes when law enforcement arrives before emergency medical services

BACKGROUND

Law enforcement (LE) professionals are often dispatched to out-of-hospital cardiac arrests (OHCA) to provide early cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED) application with mixed evidence of a survival benefit. Our objective was to comprehensively evaluate LE care in OHCA.

METHODS

This is a secondary analysis of adults with non-traumatic OHCA not witnessed by EMS and without bystander AED use from 2018-2021. Our primary outcome was survival with Cerebral Perfusion Category score ≤ 2 (functional survival). Our exposures included: LE On-scene Only (without providing care); LE CPR Only (without applying an AED); LE Ideal Care (ensuring CPR and AED application). Our control group had no LE arrival before EMS. We performed multivariable logistic regression analyses adjusting for confounders and stratified our analyses by patients with and without bystander CPR.

RESULTS

There were 2569 adult, non-traumatic OHCAs from 2018-2021 meeting inclusion criteria. There were no differences in the odds of functional survival for LE On-scene Only (adjusted odds ratio [95% CI]: 1.28 [0.47-3.45]), LE CPR Only (1.26 [0.80-1.99]), or LE Ideal Care (1.36 [0.79-2.33]). In patients without bystander CPR, LE Ideal Care had significantly higher odds of functional survival (2.01 [1.06-3.81]) compared to no LE on-scene, with no significant associations for LE On-scene Only or LE CPR Only. There were no significant differences by LE care in patients already receiving bystander CPR.

CONCLUSIONS

LE arrival before EMS and ensuring both CPR and AED application is associated with significantly improved functional survival in OHCA patients not already receiving bystander CPR.

Outcomes with Tibial and Humeral Intraosseous Access Compared to Peripheral Intravenous Access in Out-of-Hospital Cardiac Arrest

BACKGROUND

The optimal initial vascular access strategy for out-of-hospital cardiac arrest (OHCA) remains unknown. Our objective was to evaluate the association between peripheral intravenous (PIV), tibial intraosseous (TIO), or humeral intraosseous (HIO) as first vascular attempt strategies and outcomes for patients suffering OHCA.

METHOD

This was a secondary analysis of the Portland Cardiac Arrest Epidemiologic Registry, which included adult patients (≥18 years-old) with EMS-treated, non-traumatic OHCA from 2018-2021. The primary independent variable in our analysis was the initial vascular access strategy, defined as PIV, TIO, or HIO based on the first access attempt. The primary outcome for this study was the return of spontaneous circulation (ROSC) at emergency department (ED) arrival (a palpable pulse on arrival to the hospital). Secondary outcomes included survival to: admission, discharge, and discharge with a favorable outcome (Cerebral Perfusion Category score of ≤2). We conducted multivariable logistic regressions, adjusting for confounding variables and for clustering using a mixed-effects approach, with prespecified subgroup analyses by initial rhythm.

RESULTS

We included 2,993 patients with initial vascular access strategies of PIV (822 [27.5%]), TIO (1,171 [39.1%]), and HIO (1,000 [33.4%]). Multivariable analysis showed lower odds of ROSC at ED arrival (adjusted odds ratio [95% CI]) with TIO (0.79 [0.64-0.98]) or HIO (0.75 [0.60-0.93]) compared to a PIV-first strategy. These associations remained in stratified analyses for those with shockable initial rhythms (0.60 [0.41-0.88] and 0.53 [0.36-0.79]) but not in patients with asystole or pulseless electrical activity for TIO and HIO compared to PIV, respectively. There were no statistically significant differences in adjusted odds for survival to admission, discharge, or discharge with a favorable outcome for TIO or HIO compared to the PIV-first group in the overall analysis. Patients with shockable initial rhythms had lower adjusted odds of survival to discharge (0.63 [0.41-0.96] and 0.64 [0.41-0.99]) and to discharge with a favorable outcome (0.60 [0.39-0.93] and 0.64 [0.40-1.00]) for TIO and HIO compared to PIV, respectively.

CONCLUSIONS

TIO or HIO as first access strategies in OHCA were associated with lower odds of ROSC at ED arrival compared to PIV.

Survival by time-to-administration of amiodarone, lidocaine, or placebo in shock-refractory out-of-hospital cardiac arrest

BACKGROUND

Amiodarone and lidocaine have not been shown to have a clear survival benefit compared to placebo for out-of-hospital cardiac arrest (OHCA). However, randomized trials may have been impacted by delayed administration of the study drugs. We sought to evaluate how timing from emergency medical services (EMS) arrival on scene to drug administration affects the efficacy of amiodarone and lidocaine compared to placebo.

METHOD

This is a secondary analysis of the 10-site, 55-EMS-agency double-blind randomized controlled amiodarone, lidocaine, or placebo in OHCA study. We included patients with initial shockable rhythms who received the study drugs of amiodarone, lidocaine, or placebo before achieving return of spontaneous circulation. We performed logistic regression analyses evaluating survival to hospital discharge and secondary outcomes of survival to admission and functional survival (modified Rankin scale score ≤ 3). We evaluated the samples stratified by early (<8 min) and late administration groups (≥8 min). We compared outcomes for amiodarone and lidocaine compared to placebo and adjust for potential confounders.

RESULTS

There were 2802 patients meeting inclusion criteria, with 879 (31.4%) in the early (<8 min) and 1923 (68.6%) in the late (≥8 min) groups. In the early group, patients receiving amiodarone, compared to placebo, had significantly higher survival to admission (62.0% vs. 48.5%, p = 0.001; adjusted OR [95% CI] 1.76 [1.24-2.50]), survival to discharge (37.1% vs. 28.0%, p = 0.021; 1.56 [1.07-2.29]), and functional survival (31.6% vs. 23.3%, p = 0.029; 1.55 [1.04-2.32]). There were no significant differences with early lidocaine compared to early placebo (p > 0.05). Patients in the late group who received amiodarone or lidocaine had no significant differences in outcomes at discharge compared to placebo (p > 0.05).

CONCLUSIONS

The early administration of amiodarone, particularly within 8 min, is associated with greater survival to admission, survival to discharge, and functional survival compared to placebo in patients with an initial shockable rhythm.

Characterization of non-cardiac arrest PulsePoint activations in public and private settings

BACKGROUND

Geospatial smartphone application alert systems are used in some communities to crowdsource community response for out-of-hospital cardiac arrest (OHCA). Although the clinical focus of this strategy is OHCA, dispatch identification of OHCA is imperfect so that activation may occur for the non-arrest patient. The frequency and clinical profile of such non-arrest patients has not been well-investigated.

METHODS

We undertook a prospective 3-year cohort investigation of patients for whom a smartphone geospatial application was activated for suspected OHCA in four United States communities (total population ~1 million). The current investigation evaluates those patients with an activation for suspected OHCA who did not experience cardiac arrest. The volunteer response cohort included off-duty, volunteer public safety personnel (verified responders) notified regardless of location (public or private) and laypersons notified to public locations. The study linked the smartphone application information with the EMS records to report the frequency, condition type, and EMS treatment for these non-arrest patients.

RESULTS

Of 1779 calls where volunteers were activated, 756 had suffered OHCA, resulting in 1023 non-arrest patients for study evaluation. The most common EMS assessments were syncope (15.9%, n=163), altered mental status (15.5%, n=159), seizure (14.3%, n=146), overdose (13.0%, n=133), and choking (10.5%, n=107). The assessment distribution was similar for private and public locations. Overall, the most common EMS interventions included placement of an intravenous line (43.1%, n=441), 12-Lead ECG(27.9%, n=285), naloxone treatment (9.8%, n=100), airway or ventilation assistance (8.7%, n=89), and oxygen administration (6.6%, n=68).

CONCLUSIONS

More than half of patients activated for suspected OHCA had conditions other than cardiac arrest. A subset of these conditions may benefit from earlier care that could be provided by both layperson and public safety volunteers if they were appropriately trained and equipped.

Urine culture practices for complicated urinary tract infections in an academic emergency department

OBJECTIVE

Complicated UTIs (cUTIs) are defined by a heterogenous group of risk factors that place the patient at increased risk of treatment failure in whom urine cultures are recommended. We evaluated the ordering practices for urine cultures for cUTI patients and patient outcomes in an academic hospital setting.

METHODS

Retrospective chart review of adults of 18 years and older with cUTIs diagnosed in a single academic emergency department (ED). We reviewed 398 patient encounters based on a range of ICD-10 diagnosis codes consistent with cUTI between 1/1/2019 and 6/30/2019. The definition of cUTI consisted of thirteen subgroups composited from existing literature and guidelines. The primary outcome was ordering a urine culture for cUTI. We also assessed impact of the urine culture results and compared clinical course severity and readmission rates between cultured and not cultured patients.

RESULTS

During this period, the ED had 398 potential cUTI visits based on ICD-10 code, of which 330 (82.9%) met the study inclusion criteria for cUTI. Of these cUTI encounters, clinicians failed to obtain urine cultures in 92 (29.8%). Of the 217 cUTI with cultures, 121 (55.8%) demonstrated sensitivity to original treatment, 10 (4.6%) demonstrated the need to change antimicrobial coverage, 49 (22.6%) demonstrated the presence of contamination, and 29 (13.4%) demonstrated insignificant growth. Patients with cUTI who received cultures experienced higher rates of admission to both ED observation (33.2% vs 16.3%, p = 0.003) and the hospital (41.9% vs 23.8%, p = 0.003) compared to those with missed cultures. Admitted cUTI patients experienced greater length of hospital stay when cultures were obtained (3.23 vs 1.53 days, p < 0.001). Readmission rates for patients with cUTI discharged from the ED within 30 days were 4.0% for patients with urine cultures and 7.3% for patients without urine cultures (p = 0.155).

CONCLUSION

Over a quarter of cUTI patients in this study did not receive a urine culture. Further studies are needed to assess if improving adherence to urine culturing practices for cUTIs will impact clinical outcomes.

Development of a clinical decision rule for the early prediction of Shock-Refractory Out-of-Hospital cardiac arrest

BACKGROUND

Nearly half of ventricular fibrillation or ventricular tachycardia (VF/VT) out-of-hospital cardiac arrest (OHCA) patients receive three or more shocks, often referred to as refractory VF/VT. Our objective was to derive a clinical decision rule (CDR) for the early stratification of patients into risk categories for refractory VF/VT.

METHODS

We included adults with non-traumatic OHCA in the Resuscitation Outcomes Consortium Epistry (2011-2015) with ≥ 1 EMS shock. We used Classification and Regression Tree analysis for CDR building using variables known at initial EMS rhythm analysis including age, sex, witness, location, bystander interventions, initial EMS rhythm, obvious non-cardiac etiology, and dispatch to arrival times. The outcome was refractory VF/VT (≥3 shocks). We calculated sensitivity, specificity, area under the receiver operating curve (AUROC), and odds ratios (OR). The rule was validated using the Portland Cardiac Arrest Epidemiologic Registry (2018-2020).

RESULTS

There were 17,140 eligible patients and 8,146 (47.5%) had refractory VF/VT. The optimal CDR (AUROC = 0.671) defined three groups: high-risk were any patients requiring an EMS shock after a bystander AED shock; moderate-risk were any non-EMS witnessed arrests with shockable initial EMS rhythms; and the remainder were low-risk. Refractory VF/VT increased across the low (30.7%), moderate (58.5%) and high-risk (84.8%) groups. Compared to low-risk, being moderate-risk or higher (OR [95% CI]:3.37 [3.16-3.59]; sensitivity 72.7%; specificity 55.9%) or high-risk (OR:12.63 [9.89-16.13]; sensitivity 5.4%; specificity 99.1%) had higher odds of refractory VF/VT. Results was similar in the validation cohort (n = 765, AUROC = 0.672).

CONCLUSIONS

Patients at higher risk for refractory VF/VT can be identified early in EMS care.

Improved neurologically favorable survival after OHCA is associated with increased pre-hospital advanced airway management at the prefecture level in Japan

Out-of-hospital cardiac arrest (OHCA) has high incidence and mortality. The survival benefit of pre-hospital advanced airway management (AAM) for OHCA remains controversial. In Japan, pre-hospital AAM are performed for OHCA by emergency medical services (EMS), however the relationship between resuscitation outcomes and AAM at the prefecture level has not been evaluated. The purpose of this study was to describe the association between AAM and neurologically favorable survival (cerebral performance category (CPC) ≦2) at prefecture level. This was a retrospective, population-based study of adult OHCA patients (≧ 18) from January 1, 2014 to December 31, 2017 in Japan. We excluded patients with EMS witnessed arrests. We also only included patients that had care provided by an ELST with the ability to provided AAM and excluded cases that involved prehospital care delivered by a physician. We categorized OHCA into four quartiles (four group: G1-G4) based on frequency of pre-hospital AAM approach rate by prefecture, which is the smallest geographical classification unit, and evaluated the relationship between frequency of pre-hospital AAM approach rates and CPC ≦ 2 for each quartile. Multivariable logistic regression was used to assess effectiveness of AAM on neurologically favorable survival. Among 493,577 OHCA cases, 403,707 matched our inclusion criteria. The number of CPC ≦ 2 survivors increased from G1 to G4 (p for trend < 0.001). In the adjusted multivariable regression, higher frequency of pre-hospital AAM approach was associated with CPC ≦ 2 (p < 0.001). High prefecture frequency of pre-hospital AAM approach was associated with neurologically favorable survival (CPC ≦ 2) in OHCA.

Utilization and Effect of Direct Medical Oversight during Out-of-Hospital Cardiac Arrest

STUDY OBJECTIVE

Direct medical oversight (DMO), where emergency medical services (EMS) clinicians contact a physician for real-time medical direction, is used by many EMS systems across the United States. Our objective was to characterize the recommendations made by DMO during out-of-hospital cardiac arrests (OHCA) and to determine their effect on EMS transport decisions and patient outcomes.

METHODS

This is a secondary analysis of DMO call recordings from OHCA cases in the Portland, Oregon metropolitan area from January 1, 2018 to February 28, 2021. Data extracted from the audio recordings were linked to OHCA cases in the Portland Cardiac Arrest Epidemiologic Registry (PDX Epistry). The primary outcomes are recommendations made by DMO: transport, continued field resuscitation, or termination of resuscitation (TOR). Secondary outcomes include EMS transport decisions, survival to hospital admission, and survival to hospital discharge. We used descriptive statistics, unpaired t-tests, and chi-square tests as appropriate for data analysis.

RESULTS

There were 239 OHCA cases for which DMO was contacted by EMS. The median time from EMS arrival to DMO contact was 25.6 min, and EMS requested TOR for 72.0% of patients. Compared to patients where EMS requested further treatment advice, patients for whom EMS requested TOR had poor prognostic signs including older age, asystole as an initial rhythm, and lower rates of transient return of spontaneous circulation prior to DMO call compared with cases where EMS did not request TOR. DMO recommended transport, continued field resuscitation, or TOR in 21.8%, 18.0%, and 60.2% of patients, respectively. Of the 239 patients, 59 (24.7%) were ultimately transported by EMS to the hospital, 14 (5.9%) survived to admission, and only 1 patient (0.4%) survived to hospital discharge and had an acceptable neurologic outcome (Cerebral Performance Category score of 2).

CONCLUSIONS

Patients for whom EMS contacts DMO for further treatment advice or requesting field TOR after prolonged OHCA resuscitation have poor outcomes, even when DMO recommends transport or further resuscitation, and may represent opportunities to reduce unnecessary DMO contact or patient transports. More research is needed to determine which OHCA patients benefit from DMO contact.

There is little association between prehospital delay, persistent symptoms, and post-discharge healthcare utilization in patients evaluated for acute coronary syndrome

AIMS

Test for an association between prehospital delay for symptoms suggestive of acute coronary syndrome (ACS), persistent symptoms, and healthcare utilization (HCU) 30-days and 6-months post hospital discharge.

BACKGROUND

Delayed treatment for ACS increases patient morbidity and mortality. Prehospital delay is the largest factor in delayed treatment for ACS.

METHODS

Secondary analysis of data collected from a multi-center prospective study. Included were 722 patients presenting to the Emergency Department (ED) with symptoms that triggered a cardiac evaluation. Symptoms and HCU were measured using the 13-item ACS Symptom Checklist and the Froelicher's Health Services Utilization Questionnaire-Revised instrument. Logistic regression models were used to examine hypothesized associations.

RESULTS

For patients with ACS (n = 325), longer prehospital delay was associated with fewer MD/NP visits (OR, 0.986) at 30 days. Longer prehospital delay was associated with higher odds of calling 911 for any reason (OR, 1.015), and calling 911 for chest related symptoms (OR, 1.016) 6 months following discharge. For non-ACS patients (n = 397), longer prehospital delay was associated with higher odds of experiencing chest pressure (OR, 1.009) and chest discomfort (OR, 1.008) at 30 days. At 6 months, longer prehospital delay was associated with higher odds of upper back pain (OR, 1.013), palpitations (OR 1.014), indigestion (OR, 1.010), and calls to the MD/NP for chest symptoms (OR, 1.014).

CONCLUSIONS

There were few associations between prehospital delay and HCU for patients evaluated for ACS in the ED. Associations between prolonged delay and persistent symptoms may lead to increased HCU for those without ACS.

Airway Strategy and Ventilation Rates in the Pragmatic Airway Resuscitation Trial

BACKGROUND

We sought to describe ventilation rates during out-of-hospital cardiac arrest (OHCA) resuscitation and their associations with airway management strategy and outcomes.

METHODS

We analyzed continuous end-tidal carbon dioxide capnography data from adult OHCA enrolled in the Pragmatic Airway Resuscitation Trial (PART). Using automated signal processing techniques, we determined continuous ventilation rate for consecutive 10-second epochs after airway insertion. We defined hypoventilation as a ventilation rate <6 breaths/min. We defined hyperventilation as a ventilation rate >12 breaths/min. We compared differences in total and percentage post-airway hyper- and hypoventilation between airway interventions (laryngeal tube (LT) vs. endotracheal intubation (ETI). We also determined associations between hypo-/hyperventilation and OHCA outcomes (ROSC, 72-hour survival, hospital survival, hospital survival with favorable neurologic status).

RESULTS

Adequate post-airway capnography were available for 1,010 (LT n=714, ETI n=296) of 3,004 patients. Median ventilation rates were: LT 8.0 (IQR 6.5-9.6) breaths/min, ETI 7.9 (6.5-9.7) breaths/min. Total duration and percentage of post-airway time with hypoventilation were similar between LT and ETI: median 1.8 vs. 1.7 minutes, p=0.94; median 10.5% vs. 11.5%, p=0.60. Total duration and percentage of post-airway time with hyperventilation were similar between LT and ETI: median 0.4 vs. 0.4 minutes, p=0.91; median 2.1% vs. 1.9%, p=0.99. Hypo- and hyperventilation exhibited limited associations with OHCA outcomes.

CONCLUSION

In the PART Trial, EMS personnel delivered post-airway ventilations at rates satisfying international guidelines, with only limited hypo- or hyperventilation. Hypo- and hyperventilation durations did not differ between airway management strategy and exhibited uncertain associations with OCHA outcomes.

Bayesian analysis of amiodarone or lidocaine versus placebo for out-of-hospital cardiac arrest

OBJECTIVE

Clinical trials for patients with shock-refractory out-of-hospital cardiac arrest (OHCA), including the Amiodarone, Lidocaine or Placebo (ALPS) trial, have been unable to demonstrate definitive benefit after treatment with antiarrhythmic drugs. A Bayesian approach, combining the available evidence, may yield additional insights.

METHODS

We conducted a reanalysis of the ALPS trial comparing treatment with amiodarone or lidocaine with placebo in patients with OHCA following shock-refractory ventricular fibrillation or ventricular tachycardia (VF/VT). We used Bayesian regression to assess the probability of improved survival or improved neurological outcome on the 7-point modified Rankin Scale. We derived weak, moderate and strong priors from a previous clinical trial.

RESULTS

The original ALPS trial randomised 3026 adult patients with OHCA to amiodarone (n=974, survival to hospital discharge 24.4%), lidocaine, (n=993, survival 23.7%) or placebo (n=1059, survival 21.0%). In our reanalysis the probability of improved survival from amiodarone ranged from 83% (strong prior) to 95% (weak prior) compared with placebo and from 78% (strong) to 90% (weak) for lidocaine-an estimated improvement in survival of 2.9% (IQR 1.4%-3.8%) for amiodarone and 1.7% (IQR 0.84%-3.2%) for lidocaine over placebo (moderate prior). The probability of improved neurological outcome from amiodarone ranged from 96% (weak) to 99% (strong) compared with placebo and from 88% (weak) to 96% (strong) for lidocaine.

CONCLUSIONS

In a Bayesian reanalysis of patients with shock-resistant VF/VT OHCA, treatment with amiodarone had high probabilities of improved survival and neurological outcome, while treatment with lidocaine had a more modest benefit.

Developing a National Trauma Research Action Plan: Results from the prehospital and mass casualty research Delphi survey

BACKGROUND

The National Academies of Sciences, Engineering, and Medicine 2016 trauma system report recommended a National Trauma Research Action Plan to strengthen and guide future trauma research. To address this recommendation, 11 expert panels completed a Delphi survey process to create a comprehensive research agenda, spanning the continuum of trauma care. We describe the gap analysis and high-priority research questions generated from the National Trauma Research Action Plan panel on prehospital and mass casualty trauma care.

METHODS

We recruited interdisciplinary national experts to identify gaps in the prehospital and mass casualty trauma evidence base and generate prioritized research questions using a consensus-driven Delphi survey approach. We included military and civilian representatives. Panelists were encouraged to use the Patient/Population, Intervention, Compare/Control, and Outcome format to generate research questions. We conducted four Delphi rounds in which participants generated key research questions and then prioritized the questions on a 9-point Likert scale to low-, medium-, and high-priority items. We defined consensus as ≥60% agreement on the priority category and coded research questions using a taxonomy of 118 research concepts in 9 categories.

RESULTS

Thirty-one interdisciplinary subject matter experts generated 490 research questions, of which 433 (88%) reached consensus on priority. The rankings of the 433 questions were as follows: 81 (19%) high priority, 339 (78%) medium priority, and 13 (3%) low priority. Among the 81 high-priority questions, there were 46 taxonomy concepts, including health systems of care (36 questions), interventional clinical trials and comparative effectiveness (32 questions), mortality as an outcome (30 questions), prehospital time/transport mode/level of responder (24 questions), system benchmarks (17 questions), and fluid/blood product resuscitation (17 questions).

CONCLUSION

This Delphi gap analysis of prehospital and mass casualty care identified 81 high-priority research questions to guide investigators and funding agencies for future trauma research.

Prehospital Cardiac Arrest Airway Management: An NAEMSP Position Statement and Resource Document

Airway management is a critical component of out-of-hospital cardiac arrest (OHCA) resuscitation. Multiple cardiac arrest airway management techniques are available to EMS clinicians including bag-valve-mask (BVM) ventilation, supraglottic airways (SGAs), and endotracheal intubation (ETI). Important goals include achieving optimal oxygenation and ventilation while minimizing negative effects on physiology and interference with other resuscitation interventions. NAEMSP recommends:Based on the skill of the clinician and available resources, BVM, SGA, or ETI may be considered as airway management strategies in OHCA.Airway management should not interfere with other key resuscitation interventions such as high-quality chest compressions, rapid defibrillation, and treatment of reversible causes of the cardiac arrest.EMS clinicians should take measures to avoid hyperventilation during cardiac arrest resuscitation.Where available for clinician use, capnography should be used to guide ventilation and chest compressions, confirm and monitor advanced airway placement, identify return of spontaneous circulation (ROSC), and assist in the decision to terminate resuscitation.

The Association Between the Number of Prehospital Providers On-Scene and Out-of-Hospital Cardiac Arrest Outcomes

Objective: The ideal number of emergency medical services (EMS) providers needed on-scene during an out-of-hospital cardiac arrest (OHCA) resuscitation is unknown. Our objective was to evaluate the association between the number of providers on-scene and OHCA outcomes. Methods: This was a secondary analysis of adults (≥18 years old) with non-traumatic OHCA from a 10-site North American prospective cardiac arrest registry (Resuscitation Outcomes Consortium) including a 2005-2011 cohort and a 2011-2015 cohort. The primary outcome was survival to hospital discharge. We calculated the median number of EMS providers on-scene during the first 10 minutes of the resuscitation and used multivariable logistic regression adjusting for age, sex, witness status, bystander CPR, arrest location, initial rhythm, and dispatch to EMS arrival time. Results: There were 30,613 and 41,946 patients with necessary variables in the 2005-2011 and 2011-2015 cohorts, respectively. Survival to hospital discharge (95% CI) was higher with 9 or more providers on-scene (17.2% [15.8-18.5] and 14.0% [12.6-15.4]) compared to 7-8 (14.1% [13.4-14.8] and 10.5% [9.9-11.1]), 5-6 (10.0% [9.5-10.5] and 8.5% [8.1-8.9]), 3-4 (10.5% [9.3-11.6] and 9.3% [8.5-10.1]), and 1-2 (8.6% [7.2-10.0] and 8.0% [7.1-9.0]) providers for the 2005-2011 and 2011-2015 cohorts, respectively. In multivariable logistic regressions, compared to 5-6 providers, there were no significant differences in survival to hospital discharge for 1-2 or 3-4 providers, while having 7-8 (adjusted odds ratios (aORs) 1.53 [1.39-1.67] and 1.31 [1.20-1.44]) and 9 or more (aORs 1.76 [1.56-1.98] and 1.63 [1.41-1.89]) providers were associated with improved survival in both the 2005-2011 and 2011-2015 cohorts, respectively. Conclusions: The presence of seven or more prehospital providers on-scene was associated with significantly greater adjusted odds of survival to hospital discharge after OHCA compared to fewer on-scene providers.

Association of Advanced Airway Insertion Timing and Outcomes After Out-of-Hospital Cardiac Arrest

STUDY OBJECTIVE

While often prioritized in the resuscitation of patients with out-of-hospital cardiac arrest, the optimal timing of advanced airway insertion is unknown. We evaluated the association between the timing of advanced airway (laryngeal tube and endotracheal intubation) insertion attempt and survival to hospital discharge in adult out-of-hospital cardiac arrest.

METHODS

We performed a secondary analysis of the Pragmatic Airway Resuscitation Trial (PART), a clinical trial comparing the effects of laryngeal tube and endotracheal intubation on outcomes after adult out-of-hospital cardiac arrest. We stratified the cohort by randomized airway strategy (laryngeal tube or endotracheal intubation). Within each subset, we defined a time-dependent propensity score using patients, arrest, and emergency medical services systems characteristics. Using the propensity score, we matched each patient receiving an initial attempt of laryngeal tube or endotracheal intubation with a patient at risk of receiving laryngeal tube or endotracheal intubation attempt within the same minute.

RESULTS

Of 2,146 eligible patients, 1,091 (50.8%) and 1,055 (49.2%) were assigned to initial laryngeal tube and endotracheal intubation strategies, respectively. In the propensity score-matched cohort, timing of laryngeal tube insertion attempt was not associated with survival to hospital discharge: 0 to lesser than 5 minutes (risk ratio [RR]=1.35, 95% confidence interval [CI] 0.53 to 3.44); 5 to lesser than10 minutes (RR=1.07, 95% CI 0.66 to 1.73); 10 to lesser than 15 minutes (RR=1.17, 95% CI 0.60 to 2.31); or 15 to lesser than 20 minutes (RR=2.09, 95% CI 0.35 to 12.47) after advanced life support arrival. Timing of endotracheal intubation attempt was also not associated with survival: 0 to lesser than 5 minutes (RR=0.50, 95% CI 0.05 to 4.87); 5 to lesser than10 minutes (RR=1.20, 95% CI 0.51 to 2.81); 10 to lesser than15 minutes (RR=1.03, 95% CI 0.49 to 2.14); 15 to lesser than 20 minutes (RR=0.85, 95% CI 0.30 to 2.42); or more than/equal to 20 minutes (RR=0.71, 95% CI 0.07 to 7.14).

CONCLUSION

In the PART, timing of advanced airway insertion attempt was not associated with survival to hospital discharge.

Variation in time to notification of enrollment and rates of withdrawal in resuscitation trials conducted under exception from informed consent

IMPORTANCE

Emergency research is challenging to do well as it involves time sensitive interventions in unstable patients. There is limited time to obtain informed consent from the patient or their legally authorized representative (LAR). Such research is permitted under exception from informed consent (EFIC) if specific criteria are met, including notification after enrollment. Some question whether the risks of EFIC outweighs its benefits. To date, there is limited empiric information about time to notification (TTN) and rates of withdrawal in such trials.

OBJECTIVE

To describe variation in TTN and rates of withdrawal among that patients enrolled in EFIC trials over a twelve-year period.

DESIGN

We performed post hoc descriptive analyses of data from five trials conducted under EFIC.

SETTING

Emergency medical services and receiving hospitals participating in the Resuscitation Outcomes Consortium in the United States and Canada.

PARTICIPANTS

Patients with out-of-hospital cardiac arrest or life-threatening traumatic injury.

EXPOSURES

Notification strategies were specified at each site before initiation of enrollment by a local institutional review board. We monitored TTN within each site centrally throughout each study's enrollment period.

OUTCOMES

TTN was defined as time from randomization to first-reported notification of patient or LAR of enrollment. Withdrawal was defined as patient or LAR opt out of ongoing participation at the time of notification.

RESULTS

Of 35,442 patients enrolled in five trials, 33,805 had cardiac arrest; and 1636 had traumatic injury. TTN varied overall and by patient outcome. Among those with cardiac arrest, TTN ranged from median (5%ile, 95%ile) of 6 (1,27) days to 28 (2, 53) days across sites. 0.3% of notified patients with cardiac arrest withdrew. Among those with traumatic injury, TTN ranged from 0 (0, 5) days to 36 (5, 68) days across sites. 7.7% of notified patients with traumatic injury withdrew.

CONCLUSIONS AND RELEVANCE

There is large variation in TTN in trials conducted under EFIC for emergency research. This may be due to several factors. It may or may not be modifiable. Overall rates of withdrawal are low, which suggests current practices related to EFIC are acceptable to those who have participated in emergency research.

Compression depth measured by accelerometer vs. outcome in patients with out-of-hospital cardiac arrest

BACKGROUND

Analyses of data recorded by monitor-defibrillators that measure CPR depth with different methods show significant relationships between the process and outcome of CPR. Our objective was to evaluate whether chest compression depth was significantly associated with outcome based on accelerometer-recordings obtained with monitor-defibrillators from a single manufacturer, and to assess whether an accelerometer-based analysis corroborated evidence-based practice guidelines on performance of CPR.

METHODS AND RESULTS

We included 5434 adult patients treated from seven US and Canadian cities between January 2007 and May 2015. These had mean (SD) age of 64.2 (17.2) years, mean compression depth of 45.9 (12.7) mm, ROSC sustained to ED arrival of 26%, and survival to hospital discharge of 8%. For survival to discharge, the adjusted odds ratios were 1.15 (95% CI, 0.86, 1.55) for cases within 2005 depth range (38-51 mm), and 1.17 (95% CI, 0.91, 1.50) for cases within 2010 depth range (>50 mm) compared to those with an average depth of <38 mm. The adjusted odds ratio of survival was 1.33 (95% CI, 1.01, 1.75) for cases within 2015 depth range (50 to 60 mm) for at least 60% of minutes.

CONCLUSIONS

This analysis of patients with OHCA demonstrated that increased chest compression depth measured by accelerometer is associated with better survival. It confirms that current evidence-based recommendations to compress within 50-60 mm are likely associated with greater survival than compressing to another depth.

CPR compression strategy 30:2 is difficult to adhere to, but has better survival than continuous chest compressions when done correctly

BACKGROUND

A large, randomized trial showed no significant difference in survival to discharge between cardiopulmonary resuscitation (CPR) strategies of 30 compressions with pause for 2 ventilations per cycle (30:2) and continuous chest compression with asynchronous ventilations (CCC). Data from the same trial suggested that adherence to the intended CPR strategy was associated with significantly greater survival. We sought to determine the adherence rate with intended strategy and then explore the association of adherence with survival to discharge in the Resuscitation Outcomes Consortium (ROC).

METHODS

This secondary analysis of data from the ROC included three interventional trials and a prospective registry. We modified an automated software algorithm that classified care as 30:2 or CCC before intubation based on compression segment length (defined as the elapsed time from start of compressions to subsequent pause of ≥2 s), number of pauses per minute ≥2 s in length and chest compression fraction. Intended CPR strategy for individual agencies was based on study randomization (during trial phase) or local standard of care (during registry phase). We defined CPR delivered as adherent when its classification matched the intended strategy. We characterized adherence with intended strategy across trial and registry periods. We examined its association with survival to hospital discharge using multivariate logistic regression after adjustment for Utstein and other potential confounders. Effect modification with intended strategy was assessed through a multiplicative interaction term.

RESULTS

Included were 26,810 adults with out of hospital cardiac arrest, of which 10,942 had an intended strategy of 30:2 and 15,868 an intended strategy of CCC. The automated algorithm classified 12,276 cases as CCC, 7037 as 30:2 and left 7497 as unclassified. Adherence to intended strategy was 54.4%; this differed by intended strategy (58.6% for CCC vs 48.3% for 30:2). Overall adherence was less during the registry phase as compared to during the trial phase(s). The association between adherence and survival was modified by treatment arm (CCC OR: 0.72, 95% CI: 0.64-0.81 vs 30:2 OR: 1.05, 95% CI: 0.90-1.22; interaction p-value<0.01) after adjustment for known confounders.

CONCLUSION

For intended strategy CCC, survival was significantly lower, OR (95%CI) = 0.72 (0.64, 0.81), when adhered to while for intended strategy 30:2, survival was higher, OR (95%CI) = 1.05 (0.90, 1.22), when adhered to. Intended strategy of 30:2 had lower adherence rates than CCC possibly a result of being a more difficult strategy to administer.

Outcomes of patients with OHCA of presumed cardiac etiology that did not achieve prehospital restoration of spontaneous circulation: The All-Japan Utstein Registry experience

BACKGROUND

Correct identification of futile prehospital resuscitation for out-of-hospital cardiac arrest (OHCA) may reduce unnecessary transports. Prehospital return of spontaneous circulation (ROSC) is considered by many to be an important predictor of outcome. The purpose of this study was to evaluate OHCA victims without prehospital ROSC characteristics and their outcomes in relation to the universal Termination of Resuscitation (TOR) rule.

METHODS

A retrospective, population-based review of OHCA victims without prehospital ROSC from January 1, 2010 to December 31, 2017 in the All-Japan Utstein Registry. We compared those that met the universal TOR rule and those that did not for the primary outcome: one-month survival with neurologically favorable Cerebral Performance Category (CPC) 1 or 2.

RESULTS

989,929 OHCA cases, 18 years of age or older, were registered in the All-Japan Utstein Registry and 525,801 cases were of presumed cardiac origin and had no prehospital ROSC. Of these, the one-month CPC was 1 or 2 for 3957 cases (0.8%). In the 'no ROSC' group who also met the TOR rule, the number of cases was 433,571 with a one-month survival of 0.9% (3799 cases), and the proportion with a CPC 1or 2 was 0.2% (699 cases).

CONCLUSIONS

Continued resuscitation and transport of cases with no field ROSC who fulfill the TOR rule is futile and could be considered for adoption in Japan.

Airway insertion first pass success and patient outcomes in adult out-of-hospital cardiac arrest: The Pragmatic Airway Resuscitation Trial

OBJECTIVE

While emphasized in clinical practice, the association between advanced airway insertion first-pass success (FPS) and patient outcomes is incompletely understood. We sought to determine the association of airway insertion FPS with adult out-of-hospital cardiac arrest (OHCA) outcomes in the Pragmatic Airway Resuscitation Trial (PART).

METHODS

We performed a secondary analysis of PART, a multicenter clinical trial comparing LT and ETI upon adult OHCA outcomes. We defined FPS as successful LT insertion or ETI on the first attempt as reported by EMS personnel. We examined the outcomes return of spontaneous circulation (ROSC), 72-h survival, hospital survival, and hospital survival with favorable neurologic status (Modified Rankin Scale ≤3). Using multivariable GEE (generalized estimating equations), we determined the association between FPS and OHCA outcomes, adjusting for age, sex, witnessed arrest, bystander CPR, initial rhythm, and initial airway type.

RESULTS

Of 3004 patients enrolled in the trial, 1423 received LT, 1227 received ETI, 354 received bag-valve-mask ventilation only. FPS was: LT 86.2% and ETI 46.7%. FPS was associated with increased ROSC (aOR 1.23; 95%CI: 1.07-1.41)), but not 72-h survival (1.22; 0.94-1.58), hospital survival (0.90; 0.68-1.19) or hospital survival with favorable neurologic status (0.66; 0.37-1.19).

CONCLUSION

In adult OHCA, airway insertion FPS was associated with increased ROSC but not other OHCA outcomes. The influence of airway insertion FPS upon OHCA outcomes is unclear.

Out-of-hospital Circulatory Measures to Identify Patients With Serious Injury: A Systematic Review

OBJECTIVE

The objective was to systematically identify and summarize out-of-hospital measures of circulatory compromise as diagnostic predictors of serious injury, focusing on measures usable by emergency medical services to inform field triage decisions.

METHODS

We searched Ovid MEDLINE, CINAHL, and the Cochrane databases from 1996 through August 2017 for published literature on individual circulatory measures in trauma. We reviewed reference lists of included articles for additional relevant citations. Measures of diagnostic accuracy included sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC). Indicators of serious injury included resource need, serious anatomic injury, and mortality. We pooled estimates when data permitted.

RESULTS

We identified 114 articles, reporting results of 111 studies. Measures included systolic blood pressure (sBP), heart rate (HR), shock index (SI), lactate, base deficit, and HR variability. Pooled out-of-hospital sensitivity estimates were sBP < 90 mm Hg = 19% (95% confidence interval [CI] = 12% to 29%), HR ≥ 110 beats/min = 28% (95% CI = 20% to 37%), SI > 0.9 = 37% (95% CI = 22% to 56%), and lactate > 2.0 mmol/L = 74% (95% CI = 48% to 90%). Pooled specificity estimates were sBP < 90 mm Hg = 95% (95% CI = 91% to 97%), HR ≥ 110 beats/min = 85% (95% CI = 74% to 91%), SI > 0.9 = 85% (95% CI = 72% to 92%), and lactate > 2.0 mmol/L = 62% (95% CI = 51% to 72%). Pooled AUROCs included sBP = 0.67 (95% CI = 0.58 to 0.75), HR = 0.67 (95% CI = 0.56 to 0.79), SI = 0.72 (95% CI = 0.66 to 0.77), and lactate = 0.77 (95% CI = 0.67 to 0.82). Strength of evidence was low to moderate.

CONCLUSIONS

Out-of-hospital circulatory measures are associated with poor to fair discrimination for identifying trauma patients with serious injuries. Many seriously injured patients have normal circulatory measures (low sensitivity), but when present, the measures are highly specific for identifying patients with serious injuries.

Out-of-hospital Respiratory Measures to Identify Patients With Serious Injury: A Systematic Review

OBJECTIVES

The objective was to systematically review the published literature on the diagnostic accuracy of out-of-hospital respiratory measures for identifying patients with serious injury, focusing on measures feasible for field triage by emergency medical services personnel.

METHODS

We searched Ovid MEDLINE, CINAHL, and the Cochrane databases from January 1, 1996, through August 31, 2017. We included studies on the diagnostic accuracy (sensitivity, specificity, and area under the receiver operating characteristic curve [AUROC]) for all respiratory measures used to identify patients with serious injury (resource use, serious anatomic injury, and mortality). We assessed studies for risk of bias and strength of evidence (SOE). We performed meta-analysis for measures with sufficient data.

RESULTS

We identified 46 articles reporting results of 44 studies. Out-of-hospital respiratory measures included respiratory rate, pulse oximetry, and airway support. Meta-analysis was only possible for respiratory rate, which demonstrated a pooled sensitivity for serious injury of 13% (95% confidence interval [CI] = 5 to 29, I²  = 97.8%), specificity of 96% (95% CI = 83 to 99, I²  = 99.6%), and AUROC of 0.70 (95% CI = 0.66 to 0.79, I²  = 16.6%). For oxygen saturation, sensitivity ranged from 13% to 63%; specificity, 85% to 99%; and AUROC, 0.53 to 0.76. Need for airway support had a sensitivity of 8% to 53% and specificity of 61% to 100%; studies did not report AUROC. Across respiratory measures, the SOE was low. Other respiratory measures (pH, end-tidal carbon dioxide [CO₂ ], and sublingual partial pressure of CO₂ ) were reported only in emergency department studies.

CONCLUSIONS

Data on the accuracy of out-of-hospital respiratory measures for field triage are limited and of low quality. Based on available research, respiratory rate, oxygen saturation, and need for airway intervention all have low sensitivity, high specificity, and poor to fair discrimination for identifying seriously injured patients.

Unusual Fatigue and Failure to Utilize EMS Are Associated With Prolonged Prehospital Delay for Suspected Acute Coronary Syndrome

BACKGROUND

Rapid reperfusion reduces infarct size and mortality for acute coronary syndrome (ACS), but efficacy is time dependent. The aim of this study was to determine if transportation factors and clinical presentation predicted prehospital delay for suspected ACS, stratified by final diagnosis (ACS vs. no ACS).

METHODS

A heterogeneous sample of emergency department (ED) patients with symptoms suggestive of ACS was enrolled at 5 US sites. Accelerated failure time models were used to specify a direct relationship between delay time and variables to predict prehospital delay by final diagnosis.

RESULTS

Enrolled were 609 (62.5%) men and 366 (37.5%) women, predominantly white (69.1%), with a mean age of 60.32 (±14.07) years. Median delay time was 6.68 (confidence interval 1.91, 24.94) hours; only 26.2% had a prehospital delay of 2 hours or less. Patients presenting with unusual fatigue [time ratio (TR) = 1.71, P = 0.002; TR = 1.54, P = 0.003, respectively) or self-transporting to the ED experienced significantly longer prehospital delay (TR = 1.93, P < 0.001; TR = 1.71, P < 0.001, respectively). Predictors of shorter delay in patients with ACS were shoulder pain and lightheadedness (TR = 0.65, P = 0.013 and TR = 0.67, P = 0.022, respectively). Predictors of shorter delay for patients ruled out for ACS were chest pain and sweating (TR = 0.071, P = 0.025 and TR = 0.073, P = 0.032, respectively).

CONCLUSION

Patients self-transporting to the ED had prolonged prehospital delays. Encouraging the use of EMS is important for patients with possible ACS symptoms. Calling 911 can be positively framed to at-risk patients and the community as having advanced care come to them because EMS capabilities include 12-lead ECG acquisition and possibly high-sensitivity troponin assays.

Community lessons to understand resuscitation excellence (culture): Association between emergency medical services (EMS) culture and outcome after out-of-hospital cardiac arrest

BACKGROUND

The large geographic variation in outcome after out-of-hospital cardiac arrest (OHCA) is not well explained by traditional patient and emergency medical services (EMS) characteristics. A 'culture of excellence' in resuscitation within an EMS is believed to be an important factor that influences quality of care and outcome in patients with OHCA. However, whether a culture of excellence is associated with improved survival after OHCA is not known.

METHODOLOGY

We linked survey responses from EMS agency medical directors related to resuscitation culture to a retrospective analysis of prospectively collected data from the Resuscitation Outcomes Consortium (ROC) Epistry - Cardiac Arrest. We used a multivariable random effects model to assess whether EMS culture strategies were associated with OHCA survival to hospital discharge.

RESULTS

Of the 46 EMS medical directors surveyed, 35 (76%) provided a complete response. Included were n = 66,597 cases of OHCA who received attempted resuscitation by one of n = 123 EMS agencies from July 1, 2010, through June 30, 2015. Overall survival to discharge was 11%. Organizational values and goals were independently associated with survival to hospital discharge in all OHCAs (adjusted odds ratio [AOR] 1.27, 95% confidence interval [CI] 1.09-1.48) and the subgroup restricted to bystander witnessed OHCAs with initial shockable rhythm (AOR 1.55, 95% CI 1.21-1.99).

CONCLUSIONS

An organizational goal to improve OHCA survival was independently associated with improved survival to discharge. EMS agencies looking to improve OHCA survival should consider implementing an organizational goal to improve OHCA survival and empower quality improvement personnel to drive that goal.

Neurologic prognostication after resuscitation from cardiac arrest

Out-of-hospital cardiac arrest remains a leading cause of mortality in the United States, and the majority of patients who die after achieving return of spontaneous circulation die from withdrawal of care due to a perceived poor neurologic prognosis. Unfortunately, withdrawal of care often occurs during the first day of admission and research suggests this early withdrawal of care may be premature and result in unnecessary deaths for patients who would have made a full neurologic recovery. In this review, we explore the evidence for neurologic prognostication in the emergency department for patients who achieve return of spontaneous circulation after an out-of-hospital cardiac arrest.

Exception From Informed Consent: How IRB Reviewers Assess Community Consultation and Public Disclosure

Exception from Informed Consent (EFIC) regulations detail specific circumstances in which Institutional Review Boards (IRB) can approve studies where obtaining informed consent is not possible prior to subject enrollment. To better understand how IRB members evaluate community consultation (CC) and public disclosure (PD) processes and results, semi-structured interviews of EFIC-experienced IRB members were conducted and analyzed using thematic analysis. Interviews with 11 IRB members revealed similar approaches to reviewing EFIC studies. Most use summaries of CC activities to determine community members' attitudes; none reported using specific criteria nor recalled any CC reviews that resulted in modifications to or denials of EFIC studies. Most interviewees thought metrics based on Community VOICES's domains (feasibility, participant selection, quality of communication, community perceptions, investigator/IRB perceptions) would be helpful. IRB members had similar experiences and concerns about reviewing EFIC studies. Development of metrics to assess CC processes may be useful to IRBs reviewing EFIC studies.

Racial disparities in out-of-hospital cardiac arrest interventions and survival in the Pragmatic Airway Resuscitation Trial

BACKGROUND

Prior studies have reported racial disparities in survival from out-of-hospital cardiac arrest (OHCA). However, these studies did not evaluate the association of race with OHCA course of care and outcomes. The purpose of this study was to evaluate racial disparities in OHCA airway placement success and patient outcomes in the multicenter Pragmatic Airway Resuscitation Trial (PART).

METHOD

We conducted a secondary analysis of adult OHCA patients enrolled in PART. The parent trial randomized subjects to initial advanced airway management with laryngeal tube or endotracheal intubation. For this analysis, the primary independent variable was patient race categorized by emergency medical services (EMS) as white, black, Hispanic, other, and unknown. We used general estimating equations to examine the association of race with airway attempt success, 72-h survival, and survival to hospital discharge, adjusting for sex, age, witness status, bystander cardiopulmonary resuscitation (CPR), initial rhythm, arrest location, and PART randomization cluster.

RESULTS

Of 3002 patients, EMS-assessed race as 1537 white, 860 black, 163 Hispanic, 90 other, and 352 unknown. Initial shockable rhythms (13.8% vs. 21.5%, p < 0.001), bystander CPR (35.6% vs. 51.4%, p < 0.001), and survival to hospital discharge (7.6% vs. 10.8%, p = 0.011) were lower for black compared to white patients. After adjustment for confounders, no difference was seen in airway success, 72-h survival, and survival to hospital discharge by race.

CONCLUSIONS

In one of the largest studies evaluating differences in prehospital airway interventions and outcomes by EMS-assessed race for OHCA patients, we found no significant adjusted differences between airway success or survival outcomes.

A review of ventilation in adult out-of-hospital cardiac arrest

Out-of-hospital cardiac arrest continues to be a devastating condition despite advances in resuscitation care. Ensuring effective gas exchange must be weighed against the negative impact hyperventilation can have on cardiac physiology and survival. The goals of this narrative review are to evaluate the available evidence regarding the role of ventilation in out-of-hospital cardiac arrest resuscitation and to provide recommendations for future directions. Ensuring successful airway patency is fundamental for effective ventilation. The airway management approach should be based on professional skill level and the situation faced by rescuers. Evidence has explored the influence of different ventilation rates, tidal volumes, and strategies during out-of-hospital cardiac arrest; however, other modifiable factors affecting out-of-hospital cardiac arrest ventilation have limited supporting data. Researchers have begun to explore the impact of ventilation in adult out-of-hospital cardiac arrest outcomes, further stressing its importance in cardiac arrest resuscitation management. Capnography and thoracic impedance signals are used to measure ventilation rate, although these strategies have limitations. Existing technology fails to reliably measure real-time clinical ventilation data, thereby limiting the ability to investigate optimal ventilation management. An essential step in advancing cardiac arrest care will be to develop techniques to accurately and reliably measure ventilation parameters. These devices should allow for immediate feedback for out-of-hospital practitioners, in a similar way to chest compression feedback. Once developed, new strategies can be established to guide out-of-hospital personnel on optimal ventilation practices.

Outcomes With the Use of Bag-Valve-Mask Ventilation During Out-of-hospital Cardiac Arrest in the Pragmatic Airway Resuscitation Trial

BACKGROUND

While emergency medical services (EMS) often use endotracheal intubation (ETI) or supraglottic airways (SGA), some patients receive only bag-valve-mask (BVM) ventilation during out-of-hospital cardiac arrests (OHCA). Our objective was to compare patient characteristics and outcomes for BVM ventilation to advanced airway management (AAM) in adults with OHCA.

METHODS

Using data from the Pragmatic Airway Resuscitation Trial, we identified patients receiving AAM (ETI or a SGA), BVM ventilation only (BVM-only), and BVM ventilation as a rescue after at least one failed attempt at advanced airway placement (BVM-rescue). The outcomes were return of spontaneous circulation (ROSC), 72-hour survival, survival to hospital discharge, neurologically intact survival (Modified Rankin Scale ≤ 3), and the presence of aspiration on a chest radiograph. Comparisons were made using generalized mixed-effects models while adjusting for age, sex, initial rhythm, EMS-witnessed status, bystander cardiopulmonary resuscitation, response time, study cluster, and advanced life support first on scene.

RESULTS

Of 3,004 patients enrolled, there were 282 BVM-only, 2,129 AAM, and 156 BVM-rescue patients with complete covariates. Shockable initial rhythms (34% vs. 18.6%) and EMS-witnessed arrests (21.6% vs. 11.3%) were more likely in BVM-only than AAM but similar between BVM-rescue and AAM. Compared to AAM, BVM-only patients had similar ROSC (odds ratio [OR] = 1.29, 95% confidence interval [CI] = 0.96 to 1.73), but higher 72-hour survival (OR = 1.96, 95% CI = 1.42 to 2.69), survival to discharge (OR = 4.47, 95% CI = 3.03 to 6.59), and neurologically intact survival (OR = 7.05, 95% CI = 4.40 to 11.3). Compared to AAM, BVM-rescue patients had similar ROSC (OR = 0.73, 95% CI = 0.47 to 1.12) and 72-hour survival (OR = 1.08, 95% CI = 0.66 to 1.77) but higher survival to discharge (OR = 2.15, 95% CI = 1.17 to 3.95) and neurologically intact survival (OR = 2.64, 95% CI = 1.20 to 5.81). Aspiration incidence was similar.

CONCLUSIONS

Bag-valve-mask-only ventilation is associated with improved OHCA outcomes. Despite similar rates of ROSC and 72-hour survival, BVM-rescue ventilation was associated with improved survival to discharge and neurologically intact survival compared to successful AAM.

Survival After Intravenous Versus Intraosseous Amiodarone, Lidocaine, or Placebo in Out-of-Hospital Shock-Refractory Cardiac Arrest

BACKGROUND

Antiarrhythmic drugs have not proven to significantly improve overall survival after out-of-hospital cardiac arrest from shock-refractory ventricular fibrillation/pulseless ventricular tachycardia. How this might be influenced by the route of drug administration is not known.

METHODS

In this prespecified analysis of a randomized, placebo-controlled clinical trial, we compared the differences in survival to hospital discharge in adults with shock-refractory ventricular fibrillation/pulseless ventricular tachycardia out-of-hospital cardiac arrest who were randomly assigned by emergency medical services personnel to an antiarrhythmic drug versus placebo in the ALPS trial (Resuscitation Outcomes Consortium Amiodarone, Lidocaine or Placebo Study), when stratified by the intravenous versus intraosseous route of administration.

RESULTS

Of 3019 randomly assigned patients with a known vascular access site, 2358 received ALPS drugs intravenously and 661 patients by the intraosseous route. Intraosseous and intravenous groups differed in sex, time-to-emergency medical services arrival, and some cardiopulmonary resuscitation characteristics, but were similar in others, including time-to-intravenous/intrasosseous drug receipt. Overall hospital discharge survival was 23%. In comparison with placebo, discharge survival was significantly higher in recipients of intravenous amiodarone (adjusted risk ratio, 1.26 [95% CI, 1.06-1.50]; adjusted absolute survival difference, 5.5% [95% CI, 1.5-9.5]) and intravenous lidocaine (adjusted risk ratio, 1.21 [95% CI, 1.02-1.45]; adjusted absolute survival difference, 4.7% [95% CI, 0.7-8.8]); but not in recipients of intraosseous amiodarone (adjusted risk ratio, 0.94 [95% CI, 0.66-1.32]) or intraosseous lidocaine (adjusted risk ratio, 1.03 [95% CI, 0.74-1.44]). Survival to hospital admission also increased significantly when drugs were given intravenously but not intraosseously, and favored improved neurological outcome at discharge. There were no outcome differences between intravenous and intraosseous placebo, indicating that the access route itself did not demarcate patients with poor prognosis. The study was underpowered to assess intravenous/intraosseous drug interactions, which were not statistically significant.

CONCLUSIONS

We found no significant effect modification by drug administration route for amiodarone or lidocaine in comparison with placebo during out-of-hospital cardiac arrest. However, point estimates for the effects of both drugs in comparison with placebo were significantly greater for the intravenous than for the intraosseous route across virtually all outcomes and beneficial only for the intravenous route. Given that the study was underpowered to statistically assess interactions, these findings signal the potential importance of the drug administration route during resuscitation that merits further investigation.

Impact of age on survival of patients with out-of-hospital cardiac arrest transported to tertiary emergency medical institutions in Osaka, Japan

AIM

The purpose of this study was to evaluate the out-of-hospital cardiac arrest (OHCA) characteristics of patients stratified by age who had resuscitation attempted and were transported to tertiary emergency medical institutions in Osaka Prefecture, Japan; especially those of advanced age.

METHODS

A prospective, population-based, observational review was carried out of consecutive OHCA patients with emergency responder resuscitation attempts from July 2012 to December 2016 in Osaka, Japan. Patients were classified into four groups: (i) 18-64 years; (ii) 65-74 years; (iii) 75-84 years; and (iv) ≥85 years. Patient, event and treatment characteristics were examined for patients with presumed cardiac etiology of OHCA. The primary outcome was the 1-month survival with a neurologically favorable outcome.

RESULTS

A total of 4636 patients with OHCA of presumed cardiac origin were transported to tertiary emergency medical institutions. The number of patients in the four groups was as follows: (i) 1290 (27.8%); (ii) 1102 (23.8%); (iii) 1420 (30.6%); and (iv) 824 (17.8%). The 1-month survival with a neurologically favorable outcome was: (i) 207 (16.0%); (ii) 96 (8.7%); (iii) 60 (4.2%); and (iv) seven (0.85%). In a multivariate analysis for 1-month survival with a neurologically favorable outcome, increased age was a significant prognostic factor (≥85 years; adjusted odds ratio 0.08, 95% confidence interval 0.03-0.23) for poor outcomes.

CONCLUSIONS

In this population, advanced age (≥85 years) was strongly associated with poor outcomes. Further discussion of policies directed at resuscitation of very elderly OHCA patients is required, considering limited medical resources and the rapidly aging population in Japan. Geriatr Gerontol Int 2019; 19: 1088-1095.

Effect of initial airway strategy on time to epinephrine administration in patients with out-of-hospital cardiac arrest

INTRODUCTION

Epinephrine and advanced airway management are commonly used during treatment of out-of-hospital cardiac arrest (OHCA). Recent studies suggest that early but not late administration of epinephrine is associated with improved survival. The purpose of this study was to evaluate the effect of initial airway strategy on timing to the first epinephrine dose in OHCA.

METHODS

This is a secondary analysis of patients enrolled in the Pragmatic Airway Resuscitation Trial who had an advanced airway attempted. We examined differences in time to epinephrine administration by randomly assigned airway strategy, laryngeal tube (LT) or endotracheal tube (ETI); by the duration of airway attempt; and by number of attempts. We used survival methods to account for interval censoring due to unknown administration time. We also examined the association of epinephrine administration timing with survival to hospital discharge.

RESULTS

Among 2652 subjects (1299 ETI and 1353 LT), 2579 received epinephrine.There were no significant differences between ETI and LT in median time to initial epinephrine administration (min) (ETI - 9.0 vs. LT - 8.6, p = 0.55). There was no significant association between the duration of airway attempt or number of attempts and time to initial epinephrine administration (p = 0.12 and 0.66, respectively). Early administration of epinephrine (<10 min from EMS arrival) was significantly associated with survival compared to administration ≥10 min (OR 1.36, 95% CI: 1.05, 1.77).

CONCLUSIONS

There was no significant association between airway strategy and time to initial epinephrine administration. Earlier administration of epinephrine (< 10 min from EMS arrival) was associated with improved survival.