The Association of Combined Prehospital Hypotension and Hypoxia with Outcomes following Out-of-Hospital Cardiac Arrest Resuscitation.

BACKGROUND: Prehospital post-resuscitation hypotension and hypoxia have been associated with adverse outcomes in the context of out-of-hospital cardiac arrest (OHCA). We aimed to investigate the association between clinical outcomes and post-resuscitation hypoxia alone, hypotension alone, and combined hypoxia and hypotension. METHODS: We used the 2018-2021 ESO annual datasets to conduct this study. All EMS-treated non-traumatic OHCA patients who had a documented prehospital return of spontaneous circulation (ROSC) and two or more SpO2 readings and systolic blood pressures recorded were evaluated for inclusion. Patients who were less than 18 years of age, pregnant, had a do-not-resuscitate order or similar, achieved ROSC after bystander CPR only, or had an EMS-witnessed cardiac arrest were excluded. Multivariable logistic regression adjusted for standard Utstein factors and highest prehospital Glasgow Coma Scale (GCS) score was used to investigate the association between hypoxia, hypotension, and outcomes. RESULTS: We analyzed data for 17,943 patients, of whom 3,979 had hospital disposition data. Hypotension and hypoxia were not documented in 1,343 (33.8%) patients, 1,144 (28.8%) had only hypoxia documented, 507 (12.7%) had only hypotension documented, and 985 (24.8%) had both hypoxia and hypotension documented. In comparison to patients who did not have documented hypotension or hypoxia, patients who had documented hypoxia (aOR: 1.76 [1.38, 2.24]), documented hypotension (aOR: 3.00 [2.15, 4.18]), and documented hypoxia and hypotension combined (aOR: 4.87 [3.63, 6.53]) had significantly increased mortality. The relationship between mortality and vital sign abnormalities (hypoxia and hypotension > hypotension > hypoxia) was observed in every evaluated subgroup. CONCLUSIONS: In this large dataset, hypotension and hypoxia were independently associated with mortality both alone and in combination. Compared to patients without documented hypotension and hypoxia, patients with documented hypotension and hypoxia had nearly five-fold greater odds of mortality.

The Association of Prehospital End-Tidal Carbon Dioxide with Survival Following Out-of-Hospital Cardiac Arrest.

OBJECTIVE: End tidal carbon dioxide (ETCO2) is often used to assess ventilation and perfusion during cardiac arrest resuscitation. However, few data exist evaluating the relationship between ETCO2 values and mortality in the context of contemporary resuscitation practices. We aimed to explore the association between ETCO2 and mortality following out-of-hospital cardiac arrest (OHCA). METHODS: We used the 2018-2021 ESO annual datasets to query all non-traumatic OHCA patients with attempted resuscitation. Patients with documented DNR/POLST, EMS-witnessed arrest, ROSC after bystander CPR only, or < 2 documented ETCO2 values were excluded. The lowest and highest ETCO2 values recorded during the total prehospital interval, in addition to the pre- and post-ROSC intervals for resuscitated patients, were calculated. Multivariable logistic regression models adjusted for age, sex, initial rhythm, witnessed status, bystander CPR, etiology, OHCA location, sodium bicarbonate administration, number of milligrams of epinephrine administered, and response interval were used to evaluate the association between measures of ETCO2 and mortality. RESULTS: Hospital outcome data were available for 14,122 patients, and 2,209 (15.6%) were classified as surviving to discharge. Compared to patients with maximum prehospital ETCO2 values of 30-40 mmHg, odds of mortality were increased for patients with maximum prehospital ETCO2 values of <20 mmHg (aOR: 3.5 [2.1, 5,9]), 20-29 mmHg (aOR: 1.5 [1.1, 2.1]), and >50 mmHg (aOR: 1.5 [1.2, 1.8]). After 20 minutes of ETCO2 monitoring, <12% of patients had ETCO2 values <10 mmHg. This cutpoint was 96.7% specific and 6.9% sensitive for mortality. CONCLUSION: In this dataset, both high and low ETCO2 values were associated with increased mortality. Contemporary resuscitation practices may make low ETCO2 values uncommon, and field termination decision algorithms should not use ETCO2 values in isolation.

Disparities in Out-of-Hospital Cardiac Arrest Treatment and Outcomes of Males and Females.

Background: Previous studies comparing the treatment of males and females during out-of-hospital cardiac arrests (OHCA) have been contradictory. Understanding differences in treatment and outcomes is important to assuring appropriate care to both sexes.Hypothesis: Females with OHCA receive fewer interventions and have lower rates of survival to hospital discharge when compared to males with OHCA.Methods: We conducted a secondary analysis of the Resuscitation Outcomes Consortium (ROC) Cardiac Arrest Epistry 3 data collected from April 2011 to June 2015. We included all OHCA cases treated by emergency medical services (EMS) who had sex recorded. We analyzed 36 treatment and outcome variables. We calculated descriptive statistics and compared treatment and outcomes between males and females using chi-square and t-tests. We performed multivariate regressions adjusting for baseline characteristics.Results: Of 120,306 total subjects, 65,241 were included (23,924 female, 41,317 male). Females were 9.9% less likely to have OHCA in public, 10.9% less likely to have a shockable rhythm, and were a median of 5 years older. In the unadjusted analysis, females were defibrillated by EMS less often (OR 1.81, 95% CI [1.74, 1.88]), received epinephrine less often (OR 1.15, 95% CI [1.10, 1.19]), took an average of 67 seconds longer to achieve first return of spontaneous circulation (ROSC) (coefficient -66.75, 95% CI [-83.98, -49.52]), and had 2.2% lower survival to emergency department (ED) arrival (OR 1.09, 95% CI [1.06, 1.13]). After adjusting for age, bystander CPR, witness status, episode location, and initial rhythm, the odds of surviving to hospital discharge were higher in males (OR 1.12, 95% CI [1.05, 1.21]), and the odds of surviving to ED arrival favored females (OR 0.87, 95% CI [0.84-0.90]). Additionally, odds of receiving epinephrine (OR 1.22, 95% CI [1.16, 1.27]) and odds of receiving defibrillation (OR 1.36, 95% CI [1.29, 1.44]) were both higher in males, and time to achieve first ROSC was no longer associated with sex (p = 0.114, 95% CI [-3.32, 31.11]).Conclusions: After adjusting for case characteristics, females were less likely to receive some key treatments, including epinephrine and defibrillation. Females also had poorer survival to hospital discharge but had higher odds of surviving to ED arrival.

Sudden Electrocardiogram Rhythm Changes after Return of Spontaneous Circulation in Porcine Models of Out-of-Hospital Cardiac Arrest: A Phenomenological Report.

BACKGROUND: Observation of the electrocardiogram (ECG) immediately following return of spontaneous circulation (ROSC) in resuscitated swine has revealed the interesting phenomenon of sudden ECG rhythm changes (SERC) that occur in the absence of pharmacological, surgical, or other medical interventions. OBJECTIVE: We sought to identify, quantify, and characterize post-ROSC SERC in successfully resuscitated swine. METHODS: We reviewed all LabChart data from resuscitated approximately 4- to 6-month-old swine used for various experimental protocols from 2006 to 2019. We identified those that achieved sustained ROSC and analyzed their entire post-ROSC periods for evidence of SERC in the ECG, and arterial and venous pressure tracings. Presence or absence of SERC was confirmed independently by two reviewers (ACK, DDS). We measured the interval from ROSC to first SERC, analyzed the following metrics, and calculated the change from 60 sec pre-SERC (or from ROSC if less than 60 sec) to 60 sec post-SERC: heart rate, central arterial pressure (CAP), and central venous pressure (CVP). RESULTS: A total of 52 pigs achieved and sustained ROSC. Of these, we confirmed at least one SERC in 25 (48.1%). Two pigs (8%) each had two unique SERC events. Median interval from ROSC to first SERC was 3.8 min (inter-quartile range 1.0-6.9 min; range 16 sec to 67.5 min). We observed two distinct types of SERC: type 1) the post-SERC heart rate and arterial pressure increased (72% of cases); and type 2) the post-SERC heart rate and arterial pressure decreased (28% of cases). For type 1 cases, the mean (standard deviation [SD]) heart rate increased by 33.6 (45.7) beats per minute (bpm). The mean (SD) CAP increased by 20.6 (19.2) mmHg. For type 2 cases, the mean (SD) heart rate decreased by 39.7 (62.3) bpm. The mean (SD) CAP decreased by 21.9 (15.6) mmHg. CONCLUSIONS: SERC occurred in nearly half of all cases with sustained ROSC and can occur multiple times per case. First SERC most often occurred within the first 4 minutes following ROSC. Heart rate, CAP, and CVP changed at the moment of SERC. We are proceeding to examine whether this phenomenon occurs in humans post-cardiac arrest and ROSC.

Injury characteristics and hemodynamics associated with guideline-compliant CPR in a pediatric porcine cardiac arrest model.

BACKGROUND: Guidelines for depth of chest compressions in pediatric cardiopulmonary resuscitation (CPR) are based on sparse evidence. OBJECTIVE: We sought to evaluate the performance of the two most widely recommended chest compression depth levels for pediatric CPR (1.5 in. and 1/3 the anterior-posterior diameter- APd) in a controlled swine model of asphyxial cardiac arrest. METHODS: We executed a 2-group, randomized laboratory study with an adaptive design allowing early termination for overwhelming injury or benefit. Forty mixed-breed domestic swine (mean weight = 26 kg) were sedated, anesthetized and paralyzed along with endotracheal intubation and mechanical ventilation. Asphyxial cardiac arrest was induced with fentanyl overdose. Animals were untreated for 9 min followed by mechanical CPR with a target depth of 1.5 in. or 1/3 the APd. Advanced life support drugs were administered IV after 4 min of basic resuscitation followed by defibrillation at 14 min. The primary outcomes were return of spontaneous circulation (ROSC), hemodynamics and CPR-related injury severity. RESULTS: Enrollment in the 1/3 APd group was stopped early due to overwhelming differences in injury. Twenty-three animals were assigned to the 1.5 in. group and 15 assigned to the 1/3 APd group, per an adaptive group design. The 1/3 APd group had increased frequency of rib fracture (6.7 vs 1.7, p < 0.001) and higher proportions of several anatomic injury markers than the 1.5 in. group, including sternal fracture, hemothorax and blood in the endotracheal tube (p < 0.001). ROSC and hemodynamic measures were similar between groups. CONCLUSION: In this pediatric model of cardiac arrest, chest compressions to 1/3APd were more harmful without a concurrent benefit for resuscitation outcomes compared to the 1.5 in. compression group.

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.

Simulating Public Buses as a Mobile Platform for Deployment of Publicly Accessible Automated External Defibrillators.

Introduction: Public access defibrillation (PAD) programs seek to optimize locations of automated external defibrillators (AEDs) to minimize the time from out-of-hospital cardiac arrest (OHCA) recognition to defibrillation. Most PAD programs have focused on static AED (S-AED) locations in high traffic areas; pervasive electronic data infrastructure incorporating real-time geospatial data opens the possibility for AED deployment on mobile infrastructure for retrieval by nearby non-passengers. Performance characteristics of such systems are not known. Hypothesis: We hypothesized that publicly accessible AEDs located on buses would increase publicly accessible AED coverage and reduce AED retrieval time relative to statically located AEDs. Methods: S-AED sites in Pittsburgh, PA were identified and consolidated to 1 AED per building for analysis (n = 582). Public bus routes and schedules were obtained from the Port Authority of Allegheny County. OHCA locations and times were obtained from the Pittsburgh site of the Resuscitation Outcomes Consortium. Two simulations were conducted to assess the characteristics and impact of AEDs located on buses. In Simulation #1, geographic coverage area of AEDs located on buses (B-AEDs) was estimated using a 1/8th mile (201 m) retrieval radius during weekday, Saturday and Sunday periods. Cumulative geographic coverage across each period of the week was compared to S-AED coverage and the added coverage provided by B-AEDs was calculated. In Simulation #2, spatiotemporal event coverage was estimated for historical OHCA events, assuming constraints designed to reflect real world AED retrieval scenarios. Event coverage and AED retrieval time were compared between B-AEDs and S-AEDs across periods of the week and residential/nonresidential spatial areas. Results: Cumulative geographic coverage by S-AEDs was 23% across all periods, assuming uniform access hours. B-AEDs alone versus B-AEDs + S-AEDs covered 20% vs. 34% (weekday), 14% + 30% (Saturday), and 10% + 28% (Sunday). There was no statistically significant difference in 3-minute historical AED accessibility between only B-AEDs and only S-AEDs in standalone deployments (12% vs. 14%). However, when allowing for retrieval of either type of AED in the same scenario, event coverage was improved to 22% (p < 0.001). Conclusion: Deployment of B-AEDs may improve AED coverage but not as a standalone deployment strategy.

Synchronized Chest Compressions for Pseudo-PEA: Proof of Concept and a Synching Algorithm.

Objective: The two objectives of this report are: first, to describe a comparison of chest compressions unsynchronized or synchronized to native cardiac activity in a porcine model of hypotension, and second, to develop an algorithm to provide synchronized chest compressions throughout a range of native heart rates likely to be encountered when treating PEA cardiac arrest. Methods: We adapted our previously developed signal-guided CPR system to provide compressions synchronized to native electrical activity in a porcine model of hypotension as a surrogate of PEA arrest. We describe the first comparison of unsynchronized to synchronized compressions in a single animal as a proof-of-concept. We developed an algorithm to provide optimal synchronized chest compressions regardless of intrinsic PEA heart rate while simultaneously maintaining the chest compression rate within a desired range. We tested the algorithm with computer simulations measuring the proportion of intrinsic and compression beats that were synchronized, and the compression rate and its standard deviation, as a function of intrinsic heart rate and heart rate jitter. Results: We demonstrate and compare unsynchronized versus synchronized chest compressions in a single porcine model with an intrinsic rhythm and hypotension. Synchronized, but not unsynchronized, chest compressions were associated with increased blood pressure and coronary perfusion pressure. Our synchronized chest compression algorithm is able to provide synchronized chest compressions to over 90% of intrinsic beats for most heart rates while maintaining an average compression rate between 90 and 140 compressions per minute with relatively low variability. Conclusions: Synchronized chest compression therapy for pulseless electrical rhythms is feasible. A high degree of synchronization can be maintained over a broad range of intrinsic heart rates while maintaining the compression rate within a satisfactory range. Further investigation to assess benefit for treatment of PEA is warranted.

Association of Intra-arrest Transport vs Continued On-Scene Resuscitation With Survival to Hospital Discharge Among Patients With Out-of-Hospital Cardiac Arrest.

Importance: There is wide variability among emergency medical systems (EMS) with respect to transport to hospital during out-of-hospital cardiac arrest (OHCA) resuscitative efforts. The benefit of intra-arrest transport during resuscitation compared with continued on-scene resuscitation is unclear. Objective: To determine whether intra-arrest transport compared with continued on-scene resuscitation is associated with survival to hospital discharge among patients experiencing OHCA. Design, Setting, and Participants: Cohort study of prospectively collected consecutive nontraumatic adult EMS-treated OHCA data from the Resuscitation Outcomes Consortium (ROC) Cardiac Epidemiologic Registry (enrollment, April 2011-June 2015 from 10 North American sites; follow-up until the date of hospital discharge or death [regardless of when either event occurred]). Patients treated with intra-arrest transport (exposed) were matched with patients in refractory arrest (at risk of intra-arrest transport) at that same time (unexposed), using a time-dependent propensity score. Subgroups categorized by initial cardiac rhythm and EMS-witnessed cardiac arrests were analyzed. Exposures: Intra-arrest transport (transport initiated prior to return of spontaneous circulation), compared with continued on-scene resuscitation. Main Outcomes and Measures: The primary outcome was survival to hospital discharge, and the secondary outcome was survival with favorable neurological outcome (modified Rankin scale <3) at hospital discharge. Results: The full cohort included 43 969 patients with a median age of 67 years (interquartile range, 55-80), 37% were women, 86% of cardiac arrests occurred in a private location, 49% were bystander- or EMS-witnessed, 22% had initial shockable rhythms, 97% were treated by out-of-hospital advanced life support, and 26% underwent intra-arrest transport. Survival to hospital discharge was 3.8% for patients who underwent intra-arrest transport and 12.6% for those who received on-scene resuscitation. In the propensity-matched cohort, which included 27 705 patients, survival to hospital discharge occurred in 4.0% of patients who underwent intra-arrest transport vs 8.5% who received on-scene resuscitation (risk difference, 4.6% [95% CI, 4.0%- 5.1%]). Favorable neurological outcome occurred in 2.9% of patients who underwent intra-arrest transport vs 7.1% who received on-scene resuscitation (risk difference, 4.2% [95% CI, 3.5%-4.9%]). Subgroups of initial shockable and nonshockable rhythms as well as EMS-witnessed and unwitnessed cardiac arrests all had a significant association between intra-arrest transport and lower probability of survival to hospital discharge. Conclusions and Relevance: Among patients experiencing out-of-hospital cardiac arrest, intra-arrest transport to hospital compared with continued on-scene resuscitation was associated with lower probability of survival to hospital discharge. Study findings are limited by potential confounding due to observational design.

Automated External Defibrillator Shock Advisement Discordance Among Multiple Electrocardiographic Rhythms and Devices: A Preliminary Report.

Background: The early use of automated external defibrillators (AEDs) can save lives by correcting lethal ventricular arrhythmias with minimal operator intervention. AED shock advisements also play a role in termination of resuscitation strategies. AED function is dependent on the accuracy of their shock advisement algorithms, which may differ between manufacturers. We sought to compare the shock advisement performance characteristics of several AEDs. Methods: We conducted a prospective, laboratory-based simulation study evaluating five commercially available AEDs from Cardiac Science, Defibtech, Medtronic, Philips, and Zoll. Shock advisement performance was evaluated for eight ECG rhythms {ventricular fibrillation (VF), ventricular tachycardia (VT), toursades de pointes (TdP), sinus rhythm (SR), atrial fibrillation (AF), atrial flutter (AFL), idioventricular rhythm (IDV), and asystole} that were generated using the SimMan Classic Manikin and the LLEAP Simulator software (Laerdal Medical Inc., Norway). We recorded shock advisement decisions for each of the ECG rhythms three times per device. Shock advisements were coded as discordant if a shock was advised for a non-shockable rhythm or not advised for a shockable rhythm. Results: We analyzed 330 rhythm trials in total (66 per device), finding 28 (8.5%) discordant shock advisements overall. Discordance ranged from 6% to 11% among the five AED models. VF rhythm variants were the most frequent (43%) source of discordant advisements. No shocks were advised for any of the sinus rhythms, AFL, AF with QRS > 40, IDV, or asystole. Conclusions: Discordant shock advisements were observed for each AED and varied between manufacturers, most often involving VF. There may be implications for termination of resuscitation decision making.

Perishock Pause Intervals and Rearrest after Out-of-Hospital Cardiac Arrest.

BACKGROUND: The loss of pulses after successful return of spontaneous circulation (ROSC) in out-of-hospital cardiac arrest (OHCA) is known as rearrest (RA). The causes of RA are not well understood. OBJECTIVES: To investigate the association between shock pause intervals and RA. METHODS: Data from treated OHCA with ROSC and one or more defibrillation attempts were obtained from one site of the Resuscitation Outcomes Consortium. All analyses were conducted internally. Data available for analysis included cases spanning 2006-2008 and 2010-2011. Defibrillator tracings were used to calculate both components of the perishock pause (PSP) interval: the pre- (preSP) and the postshock pauses (postSP). RA and no-RA shock pauses were compared and independent associations between shock pause intervals, patient characteristics, and RA were assessed with the appropriate statistical tests. RESULTS: Analysis included 241 shocks from 101 cases. Forty-one cases (41%) had RA. RA vs. no-RA median (interquartile range) shock pauses in seconds were: preSP 13.5 (6.0-18.0) vs. 15.0 (10.9-21.5) (p = 0.121); postSP 6.0 (3.5-8.2) vs. 8.7 (4.5-13.9) (p = 0.053); and PSP 18.0 (12.3-24.0) vs. 24.0 (16.7-30.2) (p = 0.022). Considering all possible shock pause durations, shock pause lengths and various patient characteristics were not associated with RA. If 30 s or shorter, the preSP (odds ratio [OR] 0.90, 955 confidence interval [CI] 0.82-0.98) and postSP (OR 0.89, 95% CI 0.79-0.99) were related to RA. CONCLUSION: Shock pause length was inversely associated with RA when shock pause intervals were limited to 30 s or less. Shock pauses and RA were not associated when all durations of shock pauses were considered.

Chest compression rates and survival following out-of-hospital cardiac arrest.

OBJECTIVE: Guidelines for cardiopulmonary resuscitation recommend a chest compression rate of at least 100 compressions/min. A recent clinical study reported optimal return of spontaneous circulation with rates between 100 and 120/min during cardiopulmonary resuscitation for out-of-hospital cardiac arrest. However, the relationship between compression rate and survival is still undetermined. DESIGN: Prospective, observational study. SETTING: Data is from the Resuscitation Outcomes Consortium Prehospital Resuscitation IMpedance threshold device and Early versus Delayed analysis clinical trial. PARTICIPANTS: Adults with out-of-hospital cardiac arrest treated by emergency medical service providers. INTERVENTIONS: None. MEASUREMENTS MAIN RESULTS: Data were abstracted from monitor-defibrillator recordings for the first five minutes of emergency medical service cardiopulmonary resuscitation. Multiple logistic regression assessed odds ratio for survival by compression rate categories (<80, 80-99, 100-119, 120-139, ≥140), both unadjusted and adjusted for sex, age, witnessed status, attempted bystander cardiopulmonary resuscitation, location of arrest, chest compression fraction and depth, first rhythm, and study site. Compression rate data were available for 10,371 patients; 6,399 also had chest compression fraction and depth data. Age (mean±SD) was 67±16 years. Chest compression rate was 111±19 per minute, compression fraction was 0.70±0.17, and compression depth was 42±12 mm. Circulation was restored in 34%; 9% survived to hospital discharge. After adjustment for covariates without chest compression depth and fraction (n=10,371), a global test found no significant relationship between compression rate and survival (p=0.19). However, after adjustment for covariates including chest compression depth and fraction (n=6,399), the global test found a significant relationship between compression rate and survival (p=0.02), with the reference group (100-119 compressions/min) having the greatest likelihood for survival. CONCLUSIONS: After adjustment for chest compression fraction and depth, compression rates between 100 and 120 per minute were associated with greatest survival to hospital discharge.

Inaccuracy of patient care reports for identification of critical resuscitation events during out-of-hospital cardiac arrest.

OBJECTIVE: Out-of-hospital cardiac arrest (OHCA) is a leading cause of mortality in the United States. We sought to evaluate the accuracy of the patient care report (PCR) for detection of 2 clinically important events: return of spontaneous circulation (ROSC) and rearrest (RA). METHODS: We used defibrillator recordings and PCRs for Emergency Medical Services-treated OHCA collected by the Resuscitation Outcomes Consortium's Pittsburgh site from 2006 to 2008 and 2011 to 2012. Defibrillator data included electrocardiogram rhythm tracing, chest compression measurement, and audio voice recording. Sensitivity analysis was performed by comparing the accuracy of the PCR to detect the presence and number of ROSC and RA events to integrated defibrillator data. RESULTS: In the 158 OHCA cases, there were 163 ROSC events and 53 RA events. The sensitivity of PCRs to identify all ROSC events was 85% (confidence interval [CI], .795-.905); to identify primary ROSC events, it was 85% (CI, .793-.907); and to identify secondary ROSC events, it was 78% (CI, .565-.995). The sensitivity of PCRs to identify the presence of all RA events was .60 (CI, .469-.731); to identify primary RA events, it was 71% (CI, .578-.842); and to identify secondary RA events, it was 0. Of the 32 RA incidents captured by the PCR, only 15 (47%) correctly identified the correct lethal arrhythmia. CONCLUSIONS: We found that PCRs are not a reliable source of information for assessing the presence of ROSC and post-RA electrocardiogram rhythm. For quality control and research purposes, medical providers should consider augmenting data collection with continuous defibrillator recordings before making any conclusions about the occurrence of critical resuscitation events.

Physician and nonphysician health-care provider perspectives on resuscitation of suspected drug-related out-of-hospital cardiac arrest.

INTRODUCTION: In the United States, out-of-hospital cardiac arrest from drug overdose (OD-OHCA) caused over 38,000 deaths in 2010. A study in Pittsburgh found that OD-OHCA patients differed demographically and in the resuscitation treatments they received, despite identical AHA resuscitation guidelines. We hypothesized that health-care provider perceptions affect decision-making in the treatment of OD-OHCA versus non-OD OHCA. METHODS: We conducted this survey at the National Association of EMS Physicians 2013 Scientific Assembly. Physicians and non-physician health-care providers were given one of two surveys containing 19 questions pertaining to the respondents' affiliated EMS agencies, the estimated proportion of OD-OHCA as well as the drugs involved, and the respondents' belief about the treatments for OD versus non-OD OHCA. RESULTS: One hundred ninety-three respondents participated in this survey. Of the 193, 144 (75%) were physicians and 49 (25%) were nonphysicians. Seventy-nine percent of physicians identified current status as a medical director and 76% of nonphysicians identified as a paramedic. Participants estimated the average monthly proportion of all OHCA due to OD to be 9.4%. Participants ranked opioids, alcohol, antidepressants, and benzodiazepines as the most commonly utilized agents in OD-OHCA. The majority of physicians (42%) felt that the incidence of OD-OHCA was not changing while the majority of nonphysicians (53%) felt the incidence was increasing. Eighty-four percent of all respondents reported the use of naloxone during OD-OHCA resuscitation, while 13% reported administering naloxone during non-OD OHCA resuscitation. Eighty-nine percent of physicians and 67% of nonphysicians indicated that OD-OHCA patients had different demographics than non-OD OHCA, with primary reported differences being age, comorbidities, and socioeconomic status. Sixty-three percent of physicians and 71% of nonphysicians felt that OD-OHCA patients should be treated differently, with primary differences being the incorporation of etiology-specific treatments, performing different CPR with a focus on airway support, and transporting earlier. CONCLUSIONS: When surveyed, physicians and nonphysician providers report perceiving OD-OHCA treatment, outcomes, and patient demographics differently than non-OD OHCA and making different treatment decisions based on these perceptions. This may result in etiology-oriented resuscitation in the out-of-hospital setting, despite the lack of OD-specific resuscitation guidelines.

Trends in presumed drug overdose out-of-hospital cardiac arrests in San Francisco, 2015-2023.

INTRODUCTION: Estimates of the prevalence of drug-related out of hospital cardiac arrest (OHCA) vary, ranging from 1.8% to 10.0% of medical OHCA. However, studies conducted prior to the recent wave of fentanyl deaths likely underestimate the current prevalence of drug-related OHCA. We evaluated recent trends in drug-related OHCA, hypothesizing that the proportion of presumed drug-related OHCA treated by emergency medical services (EMS) has increased since 2015. METHODS: We conducted a retrospective analysis of OHCA patients treated by EMS providers in San Francisco, California between 2015 and 2023. Participants included OHCA cases in which resuscitation was attempted by EMS. The study exposure was the year of arrest. Our primary outcome was the occurrence of drug-related OHCA, defined as the EMS impression of OHCA caused by a presumed or known overdose of medication(s) or drug(s). RESULTS: From 2015 to 2023, 5044 OHCA resuscitations attended by EMS (average 561 per year) met inclusion criteria. The median age was 65 (IQR 50-79); 3508 (69.6%) were male. The EMS impression of arrest etiology was drug-related in 446/5044 (8.8%) of OHCA. The prevalence of presumed drug-related OHCA increased significantly each year from 1% in 2015 to 17.6% in 2023 (p-value for trend = 0.0001). After adjustment, presumed drug-related OHCA increased by 30% each year from 2015-2023. CONCLUSION: Drug-related OHCA is an increasingly common etiology of OHCA. In 2023, one in six OHCA was presumed to be drug related. Among participants less than 60 years old, one in three OHCA was presumed to be drug related.

The association of clinical, treatment, and demographic characteristics with rearrest in a national dataset.

INTRODUCTION: Following initial resuscitation from out-of-hospital cardiac arrest, rearrest frequently occurs and has been associated with adverse outcomes. We aimed to identify clinical, treatment, and demographic characteristics associated with prehospital rearrest at the encounter and agency levels. METHODS: Adult non-traumatic cardiac arrest patients who achieved ROSC following EMS resuscitation in the 2018-2021 ESO annual datasets were included in this study. Patients were excluded if they had a documented DNR/POLST or achieved ROSC after bystander CPR only. Rearrest was defined as post-ROSC CPR initiation, administration of ≥ 1 milligram of adrenaline, defibrillation, or a documented non-perfusing rhythm on arrival at the receiving hospital. Multivariable logistic regression modeling was used to evaluate the association between rearrest and case characteristics. Linear regression modeling was used to evaluate the association between agency-level factors (ROSC rate, scene time, and scene termination rate), and rearrest rate. RESULTS: Among the 53,027 cases included, 16,116 (30.4%) experienced rearrest. Factors including longer response intervals, longer 'low-flow' intervals, unwitnessed OHCA, and a lack of bystander CPR were associated with rearrest. Among agencies that treated ≥ 30 patients with outcome data, the agency-level rate of rearrest was inversely associated with agency-level rate of survival to discharge to home (R2 = -0.393, p < 0.001). CONCLUSIONS: This multiagency retrospective study found that factors associated with increased ischaemic burden following OHCA were associated with rearrest. Agency-level rearrest frequency was inversely associated with agency-level survival to home. Interventions that decrease the burden of ischemia sustained by OHCA patients may decrease the rate of rearrest and increase survival.

Magnitude of national ED visits and resource utilization by the uninsured.

BACKGROUND: For nearly 51 million persons in the United States who lack health care insurance, the emergency department (ED) functions as a safety net where no patient is denied care based on ability to pay, and much public rhetoric has characterized ED utilization by uninsured patients. We estimated national ED utilization by uninsured patients and compared uninsured and insured ED patients in terms of demographics, diagnostic testing, disposition and final diagnoses. METHODS: We analyzed data from the National Hospital Ambulatory Medical Care Survey (2006-2009) stratified by insurance status. Demographic data, diagnoses, testing, and procedures performed in the ED were tabulated for each visit. Weighted percentages provided by National Hospital Ambulatory Medical Care Survey were used to estimate national rates for each variable, and multivariate models were constructed for predicting testing, procedures, and admission. RESULTS: The 135085 ED visits represent 475 million patients visits, of which 78.9 million (16.6%) were uninsured. Compared with insured patients, uninsured patients were more often male (51.1% vs 44.3%) and younger (age 18-44 years, 66.2% vs 35.4%). Uninsured patients had lower rates of circulatory/cardiovascular (7.5% vs 4.1%) and respiratory diagnoses (14.6% vs 11.8%). Uninsured patients had fewer diagnostic tests and procedures and fewer hospital admissions than those with insurance. In our multivariate models, insurance status was predictive of testing and procedures but not hospital admission. CONCLUSIONS: Uninsured patients account for approximately 20 million or 1 in 6 ED visits annually in the United States and have differences in demographics, diagnoses, and ED utilization patterns from those with insurance.