Wolf Creek XVII Part 6: Physiology-Guided CPR.

Introduction: Physiology-guided cardiopulmonary resuscitation (CPR) offers the potential to optimize resuscitation and enable early prognosis. Methods: Physiology-Guided CPR was one of six focus topic for the Wolf Creek XVII Conference held on June 14-17, 2023 in Ann Arbor, Michigan, USA. International thought leaders and scientists in the field of cardiac arrest resuscitation from academia and industry were invited. Participants submitted via online survey knowledge gaps, barriers to translation and research priorities for each focus topic. Expert panels used the survey results and their own perspectives and insights to create and present a preliminary unranked list for each category, which was then debated, revised and ranked by all attendees to identify the top 5 for each category. Results: Top knowledge gaps include identifying optimal strategies for the evaluation of physiology-guided CPR and the optimal values for existing patients using patient outcomes. The main barriers to translation are the limited usability outside of critical care environments and the training and equipment required for monitoring. The top research priorities are the development of clinically feasible and reliable methods to continuously and non-invasively monitor physiology during CPR and prospective human studies proving targeting parameters during CPR improves outcomes. Conclusion: Physiology-guided CPR has the potential to provide individualized resuscitation and move away from a one-size-fits-all approach. Current understanding is limited, and clinical trials are lacking. Future developments need to consider the clinical application and applicability of measurement to all healthcare settings. Therefore, clinical trials using physiology-guided CPR for individualisation of resuscitation efforts are needed.

Bag-Valve-Mask Ventilation and Survival From Out-of-Hospital Cardiac Arrest: A Multicenter Study.

BACKGROUND: Few studies have measured ventilation during early cardiopulmonary resuscitation (CPR) before advanced airway placement. Resuscitation guidelines recommend pauses after every 30 chest compressions to deliver ventilations. The effectiveness of bag-valve-mask ventilation delivered during the pause in chest compressions is unknown. We sought to determine: (1) the incidence of lung inflation with bag-valve-mask ventilation during 30:2 CPR; and (2) the association of ventilation with outcomes after out-of-hospital cardiac arrest. METHODS: We studied patients with out-of-hospital cardiac arrest from 6 sites of the Resuscitation Outcomes Consortium CCC study (Trial of Continuous Compressions versus Standard CPR in Patients with Out-of-Hospital Cardiac Arrest). We analyzed patients assigned to the 30:2 CPR arm with ≥2 minutes of thoracic bioimpedance signal recorded with a cardiac defibrillator/monitor. Detectable ventilation waveforms were defined as having a bioimpedance amplitude ≥0.5 Ω (corresponding to ≥250 mL VT) and a duration ≥1 s. We defined a chest compression pause as a 3- to 15-s break in chest compressions. We compared the incidence of ventilation and outcomes in 2 groups: patients with ventilation waveforms in <50% of pauses (group 1) versus those with waveforms in ≥50% of pauses (group 2). RESULTS: Among 1976 patients, the mean age was 65 years; 66% were male. From the start of chest compressions until advanced airway placement, mean±SD duration of 30:2 CPR was 9.8±4.9 minutes. During this period, we identified 26 861 pauses in chest compressions; 60% of patients had ventilation waveforms in <50% of pauses (group 1, n=1177), and 40% had waveforms in ≥50% of pauses (group 2, n=799). Group 1 had a median of 12 pauses and 2 ventilations per patient versus group 2, which had 12 pauses and 12 ventilations per patient. Group 2 had higher rates of prehospital return of spontaneous circulation (40.7% versus 25.2%; P<0.0001), survival to hospital discharge (13.5% versus 4.1%; P<0.0001), and survival with favorable neurological outcome (10.6% versus 2.4%; P<0.0001). These associations persisted after adjustment for confounders. CONCLUSIONS: In this study, lung inflation occurred infrequently with bag-valve-mask ventilation during 30:2 CPR. Lung inflation in ≥50% of pauses was associated with improved return of spontaneous circulation, survival, and survival with favorable neurological outcome.

Telecommunicator Cardiopulmonary Resuscitation: A Policy Statement From the American Heart Association.

Every year in the United States, >350 000 people have sudden cardiac arrest outside of a hospital environment. Sudden cardiac arrest is the unexpected loss of heart function, breathing, and consciousness and is commonly the result of an electric disturbance in the heart. Unfortunately, only ≈1 in 10 victims survives this dramatic event. Early access to 9-1-1 and early cardiopulmonary resuscitation (CPR) are the first 2 links in the chain of survival for out-of-hospital cardiac arrest. Although 9-1-1 is frequently accessed, in the majority of cases, individuals with out-of-hospital cardiac arrest do not receive lay rescuer CPR and wait for the arrival of professional emergency rescuers. Telecommunicators are the true first responders and a critical link in the cardiac arrest chain of survival. In partnership with the 9-1-1 caller, telecommunicators have the first opportunity to identify a patient in cardiac arrest and provide initial care by delivering CPR instructions while quickly dispatching emergency medical services. The telecommunicator and the caller form a unique team in which the expertise of the telecommunicator is provided just in time to a willing caller, transforming the caller into a lay rescuer delivering CPR. The telecommunicator CPR (T-CPR) process, also previously described as dispatch CPR, dispatch-assisted CPR, or telephone CPR, represents an important opportunity to improve survival from sudden cardiac arrest. Conversely, failure to provide T-CPR in this manner results in preventable harm. This statement describes the public health impact of out-of-hospital cardiac arrest, provides guidance and resources to construct and maintain a T-CPR program, outlines the minimal acceptable standards for timely and high-quality delivery of T-CPR instructions, and identifies strategies to overcome common implementation barriers to T-CPR.

Medic One Pediatric (MOPed) cards: standardising paramedic paediatric resuscitation.

OBJECTIVE: Paediatric resuscitation is highly stressful, technically challenging and infrequently performed by paramedics. Length-based equipment selection, weight-based medication dosing and less familiar paediatric clinical scenarios create high cognitive load. Our project aimed to decrease cognitive load and increase paramedic comfort by providing standardised paediatric resuscitation cards across an entire Emergency Medical Services (EMS) system. METHODS: After 2 years of collaboration between EMS and regional paediatric subspecialists, we created and implemented a novel set of length-based, colour-coded cards: Medic One Pediatric (MOPed) cards. MOPed cards standardise the approach to paediatric scenarios, such as rapid sequence intubation (RSI), seizure management and cardiac arrest. We standardised drug concentrations across all five EMS agencies to allow for volume-based dosing, removing medication calculations, simplifying the process of medication administration and potentially decreasing both calculation error and time to intervention. We consolidated medications on MOPed cards to the 12 most commonly used in Paediatric Advanced Life Support scenarios. We surveyed 240 EMS personnel before and after implementation to determine use and effect on paramedic comfort. RESULTS: After 12 months of implementation, 97% of respondents reported using the new cards as their primary reference, and 94% reported improved speed and accuracy of medication administration. Specifically, RSI medication administration received the greatest improvement in comfort (p=0.001). Additionally, paramedics increased the use of MOPed cards when selecting endotracheal tubes: 45% of the respondents had done so by 6 months, and 60% had done so after 12 months of implementation (p=0.01). CONCLUSIONS: MOPed cards were well adopted across a large EMS system, with improvement in paramedic comfort in managing some paediatric resuscitation scenarios.

Bystander automated external defibrillator application in non-shockable out-of-hospital cardiac arrest.

BACKGROUND: An increasing proportion of patients with OHCA present with non-shockable rhythms, among whom the benefit from AED application is not known. METHODS: We performed a retrospective analysis of adults with non-traumatic, public, bystander-witnessed, non-shockable OHCA occurring between 2005-2015 at 9 locations participating in the Resuscitation Outcomes Consortium. Non-shockable arrest was defined as when no shock was administered by a bystander applied AED and confirmed by the initial rhythm on EMS arrival. Outcomes were compared between patients with non-shockable OHCA in whom a bystander AED was or was not applied. RESULTS: Among 2809 patients with non-shockable public, witnessed OHCA, 8.4% had an AED applied. CPR was more often performed in the AED-applied group (99% vs. 51% of patients, p < 0.001). Among patients in whom an AED was not applied, 39.8% had any pre-hospital ROSC, 29.6% had a pulse at ED arrival and 11.1% survived to hospital discharge compared to 44.1%, 29.6% and 9.7%, respectively with AED application. After adjustment for the Utstein variables excluding bystander CPR, the OR for survival to hospital discharge for AED application was 0.90 (95% CI:0.57-1.42); when adjusted for the higher frequency of CPR in the AED group the OR was 0.92 (95% CI:0.57-1.47). CONCLUSIONS: The application of an AED in non-shockable public witnessed OHCA was associated with a higher frequency of bystander CPR. The probabilities of pre-hospital ROSC, pulse at ED arrival, and survival to hospital discharge were not altered by the application of an AED.

Out-of-Hospital Research in the Era of Electronic Health Records.

Conducting out-of-hospital research is unique and challenging and requires tracking patients across multiple phases of care, using multiple sources of patient records and multiple hospitals. The logistics and strategies used for out-of-hospital research are distinct from other forms of clinical research. The increasing use of electronic health records (EHRs) by hospitals and emergency medical services (EMS) agencies presents a large opportunity for accelerating out-of-hospital research, as well as particular challenges. In this study, we describe seven key aspects of designing and implementing out-of-hospital research in the era of EHRs: (1) selection of research sites, (2) defining the patient population, (3) patient sampling and sample size calculations, (4) EMS data, (5) hospital selection, (6) handling missing data, and (7) statistical analysis. We use examples from a recent prospective out-of-hospital cohort study to illustrate these topics, including lessons learned.

Simulation training to improve 9-1-1 dispatcher identification of cardiac arrest: A randomized controlled trial.

BACKGROUND: The objective of this study was to test the effectiveness of simulation training, using actors to make mock calls, on improving Emergency Medical Dispatchers' (EMDs) ability to recognize the need for, and reduce the time to, telephone-assisted CPR (T-CPR) in simulated and real cardiac arrest 9-1-1 calls. METHODS: We conducted a parallel prospective randomized controlled trial with n=157 EMDs from thirteen 9-1-1 call centers. Study participants were randomized within each center to intervention (i.e., completing 4 simulation training sessions over 12-months) or control (status quo). After the intervention period, performance on 9 call processing skills and 2 time-intervals were measured in 2 simulation assessment calls for both arms. Six of the 13 call centers provided recordings of real cardiac arrest calls taken by study participants during the study period. RESULTS: Of the N=128 EMDs who completed the simulation assessment, intervention participants (n=66) performed significantly better on 6 of 9 call processing skills and started T-CPR 23s faster (73 vs 91s respectively, p<0.001) compared to participants in the control arm (n=62). In real cardiac arrest calls, EMDs who completed 3 or 4 training sessions were more likely to recognize the need for T-CPR for more challenging cardiac arrest calls than EMDs who completed fewer than 3, including controls who completed no training (68% vs 53%, p=0.018). CONCLUSIONS: Simulation training improves call processing skills and reduces time to T-CPR in simulated call scenarios, and may improve the recognition of the need for T-CPR in more challenging real-life cardiac arrest calls. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov Trial # NCT01972087.

Intraosseous compared to intravenous drug resuscitation in out-of-hospital cardiac arrest.

AIMS: Although the intraosseous (IO) route is increasingly used for vascular access in out-of-hospital cardiac arrest (OHCA), little is known about its comparative effectiveness relative to intravenous (IV) access. We evaluated clinical outcomes following OHCA comparing drug administration via IO versus IV routes. METHODS: This retrospective cohort study evaluated Emergency Medical Services (EMS)-treated adults with atraumatic OHCA in a large metropolitan EMS system between 9/1/2012-12/31/2014. Access was classified as IO or IV based on the route of first EMS drug administration. Study endpoints were survival to hospital discharge, return of spontaneous circulation (ROSC) and survival to hospital admission. RESULTS: Among 2164 adults with OHCA, 1800 met eligibility criteria, 1525 of whom were treated via IV and 275 principally via tibial-IO routes. Compared to IV, IO-treated patients were younger, more often women, had unwitnessed OHCA, a non-cardiac aetiology, and presented with non-shockable rhythms. IO versus IV-treated patients were less likely to survive to hospital discharge (14.9% vs 22.8%, p=0.003), achieve ROSC (43.6% vs 55.5%, p<0.001) or be hospitalized (38.5% vs 50.0% p<0.001). In multivariable adjusted analyses, IO treatment was not associated with survival to discharge (odds ratio (OR) (95% confidence interval) 0.81 (0.55, 1.21), p=0.31), but was associated with a lower likelihood of ROSC (OR=0.67 (0.50, 0.88), p=0.004) and survival to hospitalization (OR=0.68 (0.51, 0.91), p=0.009). CONCLUSION: Though not independently associated with survival to discharge, principally tibial IO versus IV treatment was associated with a lower likelihood of ROSC and hospitalization. How routes of vascular access influence clinical outcomes after OHCA merits additional study.

The association between AHA CPR quality guideline compliance and clinical outcomes from out-of-hospital cardiac arrest.

BACKGROUND: Measures of chest compression fraction (CCF), compression rate, compression depth and pre-shock pause have all been independently associated with improved outcomes from out-of-hospital (OHCA) cardiac arrest. However, it is unknown whether compliance with American Heart Association (AHA) guidelines incorporating all the aforementioned metrics, is associated with improved survival from OHCA. METHODS: We performed a secondary analysis of prospectively collected data from the Resuscitation Outcomes Consortium Epistry-Cardiac Arrest database. As per the 2015 American Heart Association (AHA) guidelines, guideline compliant cardiopulmonary resuscitation (CPR) was defined as CCF >0.8, chest compression rate 100-120/minute, chest compression depth 50-60mm, and pre-shock pause <10s. Multivariable logistic regression models controlling for Utstein variables were used to assess the relationship between global guideline compliance and survival to hospital discharge and neurologically intact survival with MRS ≤3. Due to potential confounding between CPR quality metrics and cases that achieved early ROSC, we performed an a priori subgroup analysis restricted to patients who obtained ROSC after ≥10min of EMS resuscitation. RESULTS: After allowing for study exclusions, 19,568 defibrillator records were collected over a 4-year period ending in June 2015. For all reported models, the reference standard included all cases who did not meet all CPR quality benchmarks. For the primary model (CCF, rate, depth), there was no significant difference in survival for resuscitations that met all CPR quality benchmarks (guideline compliant) compared to the reference standard (OR 1.26; 95% CI: 0.80, 1.97). When the dataset was restricted to patients obtaining ROSC after ≥10min of EMS resuscitation (n=4,158), survival was significantly higher for those resuscitations that were guideline compliant (OR 2.17; 95% CI: 1.11, 4.27) compared to the reference standard. Similar findings were obtained for neurologically intact survival with MRS ≤3 (OR 3.03; 95% CI: 1.12, 8.20). CONCLUSIONS: In this observational study, compliance with AHA guidelines for CPR quality was not associated with improved outcomes from OHCA. Conversely, when restricting the cohort to those with late ROSC, compliance with guidelines was associated with improved clinical outcomes. Strategies to improve overall guideline compliance may have a significant impact on outcomes from OHCA.

Intensive care medicine research agenda on cardiac arrest.

Over the last 15 years, treatment of comatose post-cardiac arrest patients has evolved to include therapeutic strategies such as urgent coronary angiography with percutaneous coronary intervention (PCI), targeted temperature management (TTM)-requiring mechanical ventilation and sedation-and more sophisticated and cautious prognostication. In 2015, collaboration between the European Resuscitation Council (ERC) and the European Society for Intensive Care Medicine (ESICM) resulted in the first European guidelines on post-resuscitation care. This review addresses the major recent advances in the treatment of cardiac arrest, recent trials that have challenged current practice and the remaining areas of uncertainty.

Cost-Effectiveness of Field Trauma Triage among Injured Adults Served by Emergency Medical Services.

BACKGROUND: The American College of Surgeons Committee on Trauma sets national targets for the accuracy of field trauma triage at ≥95% sensitivity and ≥65% specificity, yet the cost-effectiveness of realizing these goals is unknown. We evaluated the cost-effectiveness of current field trauma triage practices compared with triage strategies consistent with the national targets. STUDY DESIGN: This was a cost-effectiveness analysis using data from 79,937 injured adults transported by 48 emergency medical services agencies to 105 trauma and nontrauma hospitals in 6 regions of the western United States from 2006 through 2008. Incremental differences in survival, quality-adjusted life years (QALYs), costs, and the incremental cost-effectiveness ratio (costs per QALY gained) were estimated for each triage strategy during a 1-year and lifetime horizon using a decision analytic Markov model. We considered an incremental cost-effectiveness ratio threshold of <$100,000 to be cost-effective. RESULTS: For these 6 regions, a high-sensitivity triage strategy consistent with national trauma policy (sensitivity 98.6%, specificity 17.1%) would cost $1,317,333 per QALY gained, and current triage practices (sensitivity 87.2%, specificity 64.0%) cost $88,000 per QALY gained, compared with a moderate sensitivity strategy (sensitivity 71.2%, specificity 66.5%). Refining emergency medical services transport patterns by triage status improved cost-effectiveness. At the trauma-system level, a high-sensitivity triage strategy would save 3.7 additional lives per year at a 1-year cost of $8.78 million, and a moderate sensitivity approach would cost 5.2 additional lives and save $781,616 each year. CONCLUSIONS: A high-sensitivity approach to field triage consistent with national trauma policy is not cost-effective. The most cost-effective approach to field triage appears closely tied to triage specificity and adherence to triage-based emergency medical services transport practices.

Prospective Validation of the National Field Triage Guidelines for Identifying Seriously Injured Persons.

BACKGROUND: The national field trauma triage guidelines have been widely implemented in US trauma systems, but never prospectively validated. We sought to prospectively validate the guidelines, as applied by out-of-hospital providers, for identifying high-risk trauma patients. STUDY DESIGN: This was an out-of-hospital prospective cohort study from January 1, 2011 through December 31, 2011 with 44 Emergency Medical Services agencies in 7 counties in 2 states. We enrolled injured patients transported to 28 acute care hospitals, including 7 major trauma centers (Level I and II trauma hospitals) and 21 nontrauma hospitals. The primary exposure term was Emergency Medical Services' use of one or more field triage criteria in the national field triage guidelines. Outcomes included Injured Severity Score ≥16 (primary) and critical resource use within 24 hours of emergency department arrival (secondary). RESULTS: We enrolled 53,487 injured children and adults transported by Emergency Medical Services to an acute care hospital, 17,633 of which were sampled for the primary analysis; 13.9% met field triage guidelines, 3.1% had Injury Severity Score ≥16, and 1.7% required early critical resources. The sensitivity and specificity of the field triage guidelines were 66.2% (95% CI, 60.2-71.7%) and 87.8% (95% CI, 87.7-88.0%) for Injury Severity Score ≥16 and 80.1% (95% CI, 65.8-89.4%) and 87.3% (95% CI 87.1-87.4%) for early critical resource use. Triage guideline sensitivity decreased with age, from 87.4% in children to 51.8% in older adults. CONCLUSIONS: The national field triage guidelines are relatively insensitive for identifying seriously injured patients and patients requiring early critical interventions, particularly among older adults.

Chest compression fraction: A time dependent variable of survival in shockable out-of-hospital cardiac arrest.

INTRODUCTION: The role of chest compression fraction (CCF) in resuscitation of shockable out-of-hospital cardiac arrest (OHCA) is uncertain. We evaluated the relationship between CCF and clinical outcomes in a secondary analysis of the Resuscitation Outcomes Consortium PRIMED trial. METHODS: We included patients presenting in a shockable rhythm who suffered OHCA prior to EMS arrival. Multivariable logistic regression was used to determine the relationship between CCF and survival to hospital discharge, return of spontaneous circulation (ROSC), and neurologically intact survival. We also performed a secondary analysis restricted to patients without ROSC in the first 10 min of EMS resuscitation. RESULTS: Among the 2011 patients, median (IQR) age was 65 (54, 75) years, 78.2% were male, and mean (SD) CCF was 0.71 (0.14). Compared to the reference group (CCF<0.60), the odds ratio (OR) for survival was 0.49 (95% CI: 0.36, 0.68) for CCF 0.60-0.79 and 0.30 (95% CI: 0.20, 0.44) for CCF≥0.80. Results were similar for outcomes of ROSC and neurologically intact survival. Conversely, when restricted to the cohort who did not achieve ROSC during the first 10 min (n=1633), compared to the reference group (CCF<0.60), the OR for survival was 0.79 (95% CI: 0.53, 1.18) for CCF 0.60-0.79 and OR 0.88 (95% CI: 0.56, 1.36) for CCF≥0.80. CONCLUSIONS: In this study of OHCA patients presenting in a shockable rhythm, CCF was paradoxically associated with lower odds of survival. CCF is a complex measure and taken by itself may not be a consistent predictor of good clinical outcomes.

Volume versus outcome: More emergency medical services personnel on-scene and increased survival after out-of-hospital cardiac arrest.

BACKGROUND AND AIM: The large regional variation in survival after treatment of out-of-hospital cardiac arrest (OHCA) is incompletely explained. Communities respond to OHCA with differing number of emergency medical services (EMS) personnel who respond to the scene. The effect of different numbers of EMS personnel on-scene upon outcomes is unclear. We sought to evaluate the association between number of EMS personnel on-scene and survival after OHCA. METHODS: We performed a retrospective review of prospectively collected data on 16,122 EMS-treated OHCA events from December 1, 2005 to May 31, 2007 from a combined population over 21 million people residing in an area of over 33,000 square miles in Canada and the United States. Number of EMS personnel on-scene was defined as the number of EMS personnel who responded to the scene of OHCA within 15 min after 9-1-1 call receipt and prior to patient death or transport away from the scene. Associations with survival to hospital discharge were assessed by using generalized estimating equations to construct multivariable logistic regression models. RESULTS: Compared to a reference number of EMS personnel on-scene of 5 or 6, 7 or 8 EMS personnel on-scene was associated with a higher rate of survival to hospital discharge, adjusted odds ratio [OR], 1.35 (95% CI: 1.05, 1.73). There was no significant difference in survival between 5 or 6 personnel on-scene versus fewer. CONCLUSION: More EMS personnel on-scene within 15 min of 9-1-1 call was associated with improved survival of out-of-hospital cardiac arrest. It is unlikely that this finding was mediated solely by earlier CPR or earlier defibrillation.

Resuscitation Outcomes Consortium-Amiodarone, Lidocaine or Placebo Study (ROC-ALPS): Rationale and methodology behind an out-of-hospital cardiac arrest antiarrhythmic drug trial.

BACKGROUND: Despite their wide use, whether antiarrhythmic drugs improve survival after out-of-hospital cardiac arrest (OHCA) is not known. The ROC-ALPS is evaluating the effectiveness of these drugs for OHCA due to shock-refractory ventricular fibrillation or pulseless ventricular tachycardia (VF/VT). METHODS: ALPS will randomize 3,000 adults across North America with nontraumatic OHCA, persistent or recurring VF/VT after ≥1 shock, and established vascular access to receive up to 450 mg amiodarone, 180 mg lidocaine, or placebo in the field using a double-blind protocol, along with standard resuscitation measures. The designated target population is all eligible randomized recipients of any dose of ALPS drug whose initial OHCA rhythm was VF/VT. A safety analysis includes all randomized patients regardless of their eligibility, initial arrhythmia, or actual receipt of ALPS drug. The primary outcome of ALPS is survival to hospital discharge; a secondary outcome is functional survival at discharge assessed as a modified Rankin Scale score ≤3. RESULTS: The principal aim of ALPS is to determine if survival is improved by amiodarone compared with placebo; secondary aim is to determine if survival is improved by lidocaine vs placebo and/or by amiodarone vs lidocaine. Prioritizing comparisons in this manner acknowledges where differences in outcome are most expected based on existing knowledge. Each aim also represents a clinically relevant comparison between treatments that is worth investigating. CONCLUSIONS: Results from ALPS will provide important information about the choice and value of antiarrhythmic therapies for VF/VT arrest with direct implications for resuscitation guidelines and clinical practice.

Treatment of cardiac arrest with rapid defibrillation by police in King County, Washington.

BACKGROUND: Improving survival from out-of-hospital cardiac arrest is an ongoing challenge for emergency medical services (EMS). Various strategies for shortening the time from collapse to defibrillation have been used, and one is to equip police officers with defibrillators. Objective. We evaluated the programmatic implementation of police defibrillation to determine if such a program could improve the process of care in a high-functioning and mature EMS system. METHODS: We conducted a prospective observational study of implementation of a police defibrillation in two police departments in King County, Washington, from March 1, 2010 to March 31, 2012. The program was designed to dispatch police specifically to cases with a high suspicion of cardiac arrest, defined as a patient who was unconscious and not breathing normally. We included all nontraumatic out-of-hospital cardiac arrest events that occurred prior to EMS arrival and within the city limits of the two cities. We collected both EMS and police dispatch reports to document times of call receipt, dispatch, and arrival of both agencies. We obtained rhythm recordings when the automated external defibrillators (AEDs) were used by the police. Descriptive statistics were used to measure frequency of police dispatch and to compare times to treatment between patients with a police response and those without. RESULTS: During the study period there were 231 cases of cardiac arrest that occurred prior to EMS arrival eligible for police response in the study communities. Police were dispatched to 124 (54%) of these cases. Of the 124, the police arrived before EMS 37 times, or 16% of the 231 cases. Police performed CPR in 29 of these cases and applied the AED in 21 of them. Of the 21 cases in which the AED was applied for cardiac arrest, a shock was delivered on first analysis for 6 patients. Although the response interval between dispatch to scene arrival was similar for EMS and police (4.5 minutes versus 4.6 minutes respectively, p = 0.08), police were dispatched considerably slower than EMS (1.8 minutes versus 0.6 minutes, p < 0.001). CONCLUSIONS: In the current programmatic implementation, police had a measurable but limited involvement in resuscitation. Efforts to address dispatch challenges may improve police involvement.