What is the optimal chest compression depth during out-of-hospital cardiac arrest resuscitation of adult patients?

BACKGROUND: The 2010 American Heart Association guidelines suggested an increase in cardiopulmonary resuscitation compression depth with a target >50 mm and no upper limit. This target is based on limited evidence, and we sought to determine the optimal compression depth range. METHODS AND RESULTS: We studied emergency medical services-treated out-of-hospital cardiac arrest patients from the Resuscitation Outcomes Consortium Prehospital Resuscitation Impedance Valve and Early Versus Delayed Analysis clinical trial and the Epistry-Cardiac Arrest database. We calculated adjusted odds ratios for survival to hospital discharge, 1-day survival, and any return of circulation. We included 9136 adult patients from 9 US and Canadian cities with a mean age of 67.5 years, mean compression depth of 41.9 mm, and a return of circulation of 31.3%, 1-day survival of 22.8%, and survival to hospital discharge of 7.3%. For survival to discharge, the adjusted odds ratios were 1.04 (95% CI, 1.00-1.08) for each 5-mm increment in compression depth, 1.45 (95% CI, 1.20-1.76) for cases within 2005 depth range (>38 mm), and 1.05 (95% CI, 1.03-1.08) for percentage of minutes in depth range (10% change). Covariate-adjusted spline curves revealed that the maximum survival is at a depth of 45.6 mm (15-mm interval with highest survival between 40.3 and 55.3 mm) with no differences between men and women. CONCLUSIONS: This large study of out-of-hospital cardiac arrest patients demonstrated that increased cardiopulmonary resuscitation compression depth is strongly associated with better survival. Our adjusted analyses, however, found that maximum survival was in the depth interval of 40.3 to 55.3 mm (peak, 45.6 mm), suggesting that the 2010 American Heart Association cardiopulmonary resuscitation guideline target may be too high. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00394706.

Endotracheal intubation versus supraglottic airway insertion in out-of-hospital cardiac arrest.

OBJECTIVE: To simplify airway management and minimize cardiopulmonary resuscitation (CPR) chest compression interruptions, some emergency medical services (EMS) practitioners utilize supraglottic airway (SGA) devices instead of endotracheal intubation (ETI) as the primary airway adjunct in out-of-hospital cardiac arrest (OHCA). We compared the outcomes of patients receiving ETI with those receiving SGA following OHCA. METHODS: We performed a secondary analysis of data from the multicenter Resuscitation Outcomes Consortium (ROC) PRIMED trial. We studied adult non-traumatic OHCA receiving successful SGA insertion (King Laryngeal Tube, Combitube, and Laryngeal Mask Airway) or successful ETI. The primary outcome was survival to hospital discharge with satisfactory functional status (Modified Rankin Scale ≤3). Secondary outcomes included return of spontaneous circulation (ROSC), 24-h survival, major airway or pulmonary complications (pulmonary edema, internal thoracic or abdominal injuries, acute lung injury, sepsis, and pneumonia). Using multivariable logistic regression, we studied the association between out-of-hospital airway management method (ETI vs. SGA) and OHCA outcomes, adjusting for confounders. RESULTS: Of 10,455 adult OHCA, 8487 (81.2%) received ETI and 1968 (18.8%) received SGA. Survival to hospital discharge with satisfactory functional status was: ETI 4.7%, SGA 3.9%. Compared with successful SGA, successful ETI was associated with increased survival to hospital discharge (adjusted OR 1.40; 95% CI: 1.04, 1.89), ROSC (adjusted OR 1.78; 95% CI: 1.54, 2.04) and 24-h survival (adjusted OR 1.74; 95% CI: 1.49, 2.04). ETI was not associated with secondary airway or pulmonary complications (adjusted OR 0.84; 95% CI: 0.61, 1.16). CONCLUSIONS: In this secondary analysis of data from the multicenter ROC PRIMED trial, ETI was associated with improved outcomes over SGA insertion after OHCA.

Delayed prehospital implementation of the 2005 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiac care.

INTRODUCTION: In 2005, the American Heart Association (AHA) released guidelines to improve survival rates from out-of-hospital cardiac arrest (OHCA). OBJECTIVE: To determine if, and when, emergency medical services (EMS) agencies participating in the Resuscitation Outcomes Consortium (ROC) implemented these guidelines. METHODS: We contacted 178 EMS agencies and completed structured telephone interviews with 176 agencies. The survey collected data on specific treatment protocols before and after implementation of the 2005 guidelines as well as the date of implementation crossover (the "crossover date"). The crossover date was then linked to a database describing the size, type, and structure of each agency. Descriptive statistics and regression were used to examine patterns in time to crossover. RESULTS: The 2005 guidelines were implemented by 174 agencies (99%). The number of days from guideline release to implementation was as follows: mean 416 (standard deviation 172), median 415 (range 49-750). There was no difference in time to implementation in fire-based agencies (mean 432), nonfire municipal agencies (mean 365), and private agencies (mean 389, p = 0.31). Agencies not providing transport took longer to implement than agencies that transported patients (463 vs. 384 days, p = 0.004). Agencies providing only basic life support (BLS) care took longer to implement than agencies who provided advanced life support (ALS) care (mean 462 vs. 397 days, p = 0.03). Larger agencies (>10 vehicles) were able to implement the guidelines more quickly than smaller agencies (mean 386 vs. 442 days, p = 0.03). On average, it took 8.9 fewer days to implement the guidelines for every 50% increase in EMS-treated runs/year to which an agency responded. CONCLUSION: ROC EMS agencies required an average of 416 days to implement the 2005 AHA guidelines for OHCA. Small EMS agencies, BLS-only agencies, and nontransport agencies took longer than large agencies, agencies providing ALS care, and transport agencies, respectively, to implement the guidelines. Causes of delays to guideline implementation and effective methods for rapid EMS knowledge translation deserve investigation.

Knowledge translation in emergency medical services: a qualitative survey of barriers to guideline implementation.

BACKGROUND: The American Heart Association (AHA) released guidelines to improve survival rates from out-of-hospital cardiac arrest in 2005. We sought to identify what barriers delayed the implementation of these guidelines in EMS agencies. METHODS: We surveyed 178 EMS agencies as part of a larger quantitative survey regarding guideline implementation and conducted a single-question semi-structured interview using the Grounded Theory method. We asked "What barriers if any, delayed implementation of the (2005 AHA) guidelines in your EMS agency?" Data were coded and member validation was employed to verify our findings. RESULTS: 176/178 agencies completed the quantitative survey. Qualitative data collection ceased after reaching theoretical saturation with 34 interviews. Ten unique barriers were identified. We categorized these 10 barriers into three themes. The theme instruction delays (reported by 41% of respondents) included three barriers: booking/training instructors (9%), receiving training materials (15%), and scheduling staff for training (18%). The second theme, defibrillator delays (38%), included two barriers; reprogramming defibrillators (24%) and receiving new defibrillators to replace non-upgradeable units (15%). The third theme was decision-making (38%) and included five barriers; coordinating with allied agencies (9%), government regulators such as state and provincial health authorities (9%), medical direction and base hospitals (9%), ROC participation (9%), and internal crises (3%). CONCLUSION: Many barriers contributed to delays in the implementation of the 2005 AHA guidelines in EMS agencies. These identified barriers should be proactively addressed prior to the 2010 Guidelines to facilitate rapid translation of science into clinical practice.

Chest compression fraction determines survival in patients with out-of-hospital ventricular fibrillation.

BACKGROUND: Quality cardiopulmonary resuscitation contributes to cardiac arrest survival. The proportion of time in which chest compressions are performed in each minute of cardiopulmonary resuscitation is an important modifiable aspect of quality cardiopulmonary resuscitation. We sought to estimate the effect of an increasing proportion of time spent performing chest compressions during cardiac arrest on survival to hospital discharge in patients with out-of-hospital ventricular fibrillation or pulseless ventricular tachycardia. METHODS AND RESULTS: This is a prospective observational cohort study of adult patients from the Resuscitation Outcomes Consortium Cardiac Arrest Epistry with confirmed ventricular fibrillation or ventricular tachycardia, no defibrillation before emergency medical services arrival, electronically recorded cardiopulmonary resuscitation before the first shock, and a confirmed outcome. Patients were followed up to discharge from the hospital or death. Of the 506 cases, the mean age was 64 years, 80% were male, 71% were witnessed by a bystander, 51% received bystander cardiopulmonary resuscitation, 34% occurred in a public location, and 23% survived. After adjustment for age, gender, location, bystander cardiopulmonary resuscitation, bystander witness status, and response time, the odds ratios of surviving to hospital discharge in the 2 highest categories of chest compression fraction compared with the reference category were 3.01 (95% confidence interval 1.37 to 6.58) and 2.33 (95% confidence interval 0.96 to 5.63). The estimated adjusted linear effect on odds ratio of survival for a 10% change in chest compression fraction was 1.11 (95% confidence interval 1.01 to 1.21). CONCLUSIONS: An increased chest compression fraction is independently predictive of better survival in patients who experience a prehospital ventricular fibrillation/tachycardia cardiac arrest.