Sheldon Cheskes

What is the Role of Chest Compression Depth during Out-of-Hospital Cardiac Arrest Resuscitation?

Background:The 2010 international guidelines for cardiopulmonary resuscitation recently recommended an increase in the minimum compression depth from 38 to 50 mm, although there are limited human data to support this. We sought to study patterns of cardiopulmonary resuscitation compression depth and their associations with patient outcomes in out-of-hospital cardiac arrest cases treated by the 2005 guideline standards. Design:Prospective cohort. Setting:Seven U.S. and Canadian urban regions. Patients:We studied emergency medical services treated out-of-hospital cardiac arrest patients from the Resuscitation Outcomes Consortium Epistry–Cardiac Arrest for whom electronic cardiopulmonary resuscitation compression depth data were available, from May 2006 to June 2009. Measurements:We calculated anterior chest wall depression in millimeters and the period of active cardiopulmonary resuscitation (chest compression fraction) for each minute of cardiopulmonary resuscitation. We controlled for covariates including compression rate and calculated adjusted odds ratios for any return of spontaneous circulation, 1-day survival, and hospital discharge. Main Results:We included 1029 adult patients from seven U.S. and Canadian cities with the following characteristics: Mean age 68 yrs; male 62%; bystander witnessed 40%; bystander cardiopulmonary resuscitation 37%; initial rhythms: Ventricular fibrillation/ventricular tachycardia 24%, pulseless electrical activity 16%, asystole 48%, other nonshockable 12%; outcomes: Return of spontaneous circulation 26%, 1-day survival 18%, discharge 5%. For all patients, median compression rate was 106 per minute, median compression fraction 0.65, and median compression depth 37.3 mm with 52.8% of cases having depth <38 mm and 91.6% having depth <50 mm. We found an inverse association between depth and compression rate ( p < .001). Adjusted odds ratios for all depth measures (mean values, categories, and range) showed strong trends toward better outcomes with increased depth for all three survival measures. Conclusions:We found suboptimal compression depth in half of patients by 2005 guideline standards and almost all by 2010 standards as well as an inverse association between compression depth and rate. We found a strong association between survival outcomes and increased compression depth but no clear evidence to support or refute the 2010 recommendations of >50 mm. Although compression depth is an important component of cardiopulmonary resuscitation and should be measured routinely, the most effective depth is currently unknown. (Crit Care Med 2012; 40:–1198)

Perishock Pause An Independent Predictor of Survival From Out-of-Hospital Shockable Cardiac Arrest

Background— Perishock pauses are pauses in chest compressions before and after defibrillatory shock. We examined the relationship between perishock pauses and survival to hospital discharge. Methods and Results— We included out-of-hospital cardiac arrest patients in the Resuscitation Outcomes Consortium Epistry–Cardiac Arrest who suffered arrest between December 2005 and June 2007, presented with a shockable rhythm (ventricular fibrillation or pulseless ventricular tachycardia), and had cardiopulmonary resuscitation process data for at least 1 shock (n=815). We used multivariable logistic regression to determine the association between survival and perishock pauses. In an analysis adjusted for Utstein predictors of survival, the odds of survival were significantly lower for patients with preshock pause ≥20 seconds (odds ratio, 0.47; 95% confidence interval, 0.27 to 0.82) and perishock pause ≥40 seconds (odds ratio, 0.54; 95% confidence interval, 0.31 to 0.97) compared with patients with preshock pause <10 seconds and perishock pause <20 seconds. Postshock pause was not independently associated with a significant change in the odds of survival. Log-linear modeling depicted a decrease in survival to hospital discharge of 18% and 14% for every 5-second increase in both preshock and perishock pause interval (up to 40 and 50 seconds, respectively), with no significant association noted with changes in the postshock pause interval. Conclusions— In patients with cardiac arrest presenting in a shockable rhythm, longer perishock and preshock pauses were independently associated with a decrease in survival to hospital discharge. The impact of preshock pause on survival suggests that refinement of automatic defibrillator software and paramedic education to minimize preshock pause delays may have a significant impact on survival. # Clinical Perspective {#article-title-32}Background— Perishock pauses are pauses in chest compressions before and after defibrillatory shock. We examined the relationship between perishock pauses and survival to hospital discharge. Methods and Results— We included out-of-hospital cardiac arrest patients in the Resuscitation Outcomes Consortium Epistry–Cardiac Arrest who suffered arrest between December 2005 and June 2007, presented with a shockable rhythm (ventricular fibrillation or pulseless ventricular tachycardia), and had cardiopulmonary resuscitation process data for at least 1 shock (n=815). We used multivariable logistic regression to determine the association between survival and perishock pauses. In an analysis adjusted for Utstein predictors of survival, the odds of survival were significantly lower for patients with preshock pause ≥20 seconds (odds ratio, 0.47; 95% confidence interval, 0.27 to 0.82) and perishock pause ≥40 seconds (odds ratio, 0.54; 95% confidence interval, 0.31 to 0.97) compared with patients with preshock pause <10 seconds and perishock pause <20 seconds. Postshock pause was not independently associated with a significant change in the odds of survival. Log-linear modeling depicted a decrease in survival to hospital discharge of 18% and 14% for every 5-second increase in both preshock and perishock pause interval (up to 40 and 50 seconds, respectively), with no significant association noted with changes in the postshock pause interval. Conclusions— In patients with cardiac arrest presenting in a shockable rhythm, longer perishock and preshock pauses were independently associated with a decrease in survival to hospital discharge. The impact of preshock pause on survival suggests that refinement of automatic defibrillator software and paramedic education to minimize preshock pause delays may have a significant impact on survival.

Early versus Later Rhythm Analysis in Patients with Out-of-Hospital Cardiac Arrest

BACKGROUND In a departure from the previous strategy of immediate defibrillation, the 2005 resuscitation guidelines from the American Heart Association-International Liaison Committee on Resuscitation suggested that emergency medical service (EMS) personnel could provide 2 minutes of cardiopulmonary resuscitation (CPR) before the first analysis of cardiac rhythm. We compared the strategy of a brief period of CPR with early analysis of rhythm with the strategy of a longer period of CPR with delayed analysis of rhythm. METHODS We conducted a cluster-randomized trial involving adults with out-of-hospital cardiac arrest at 10 Resuscitation Outcomes Consortium sites in the United States and Canada. Patients in the early-analysis group were assigned to receive 30 to 60 seconds of EMS-administered CPR and those in the later-analysis group were assigned to receive 180 seconds of CPR, before the initial electrocardiographic analysis. The primary outcome was survival to hospital discharge with satisfactory functional status (a modified Rankin scale score of ≤3, on a scale of 0 to 6, with higher scores indicating greater disability). RESULTS We included 9933 patients, of whom 5290 were assigned to early analysis of cardiac rhythm and 4643 to later analysis. A total of 273 patients (5.9%) in the later-analysis group and 310 patients (5.9%) in the early-analysis group met the criteria for the primary outcome, with a cluster-adjusted difference of -0.2 percentage points (95% confidence interval, -1.1 to 0.7; P=0.59). Analyses of the data with adjustment for confounding factors, as well as subgroup analyses, also showed no survival benefit for either study group. CONCLUSIONS Among patients who had an out-of-hospital cardiac arrest, we found no difference in the outcomes with a brief period, as compared with a longer period, of EMS-administered CPR before the first analysis of cardiac rhythm. (Funded by the National Heart, Lung, and Blood Institute and others; ROC PRIMED ClinicalTrials.gov number, NCT00394706.).

The impact of increased chest compression fraction on return of spontaneous circulation for out-of-hospital cardiac arrest patients not in ventricular fibrillation

OBJECTIVE Greater chest compression fraction (CCF, or proportion of CPR time spent providing compressions) is associated with better survival for out-of-hospital cardiac arrest (OOHCA) patients in ventricular fibrillation (VF). We evaluated the effect of CCF on return of spontaneous circulation (ROSC) in OOHCA patients with non-VF ECG rhythms in the Resuscitation Outcomes Consortium Epistry. METHODS This prospective cohort study included OOHCA patients if: not witnessed by EMS, no automated external defibrillator (AED) shock prior to EMS arrival, received >1 min of CPR with CPR process measures available, and initial non-VF rhythm. We reviewed the first 5 min of electronic CPR records following defibrillator application, measuring the proportion of compressions/min during the resuscitation. RESULTS Demographics of 2103 adult patients from 10 U.S. and Canadian centers were: mean age 67.8; male 61.2%; public location 10.6%; bystander witnessed 32.9%; bystander CPR 35.4%; median interval from 911 to defibrillator turned on 8 min:27 s; initial rhythm asystole 64.0%, PEA 28.0%, other non-shockable 8.0%; median compression rate 110/min; median CCF 71%; ROSC 24.2%; survival to hospital discharge 2.0%. The estimated linear effect on adjusted odds ratio with 95% confidence interval (OR; 95%CI) of ROSC for each 10% increase in CCF was (1.05; 0.99, 1.12). Adjusted (OR; 95%CI) of ROSC for each CCF category were: 0-40% (reference group); 41-60% (1.14; 0.72, 1.81); 61-80% (1.42; 0.92, 2.20); and 81-100% (1.48; 0.94, 2.32). CONCLUSIONS This is the first study to demonstrate that increased CCF among non-VF OOHCA patients is associated with a trend toward increased likelihood of ROSC.

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.

Trial of Continuous or Interrupted Chest Compressions during CPR

BACKGROUND During cardiopulmonary resuscitation (CPR) in patients with out-of-hospital cardiac arrest, the interruption of manual chest compressions for rescue breathing reduces blood flow and possibly survival. We assessed whether outcomes after continuous compressions with positive-pressure ventilation differed from those after compressions that were interrupted for ventilations at a ratio of 30 compressions to two ventilations. METHODS This cluster-randomized trial with crossover included 114 emergency medical service (EMS) agencies. Adults with non-trauma-related cardiac arrest who were treated by EMS providers received continuous chest compressions (intervention group) or interrupted chest compressions (control group). The primary outcome was the rate of survival to hospital discharge. Secondary outcomes included the modified Rankin scale score (on a scale from 0 to 6, with a score of ≤3 indicating favorable neurologic function). CPR process was measured to assess compliance. RESULTS Of 23,711 patients included in the primary analysis, 12,653 were assigned to the intervention group and 11,058 to the control group. A total of 1129 of 12,613 patients with available data (9.0%) in the intervention group and 1072 of 11,035 with available data (9.7%) in the control group survived until discharge (difference, -0.7 percentage points; 95% confidence interval [CI], -1.5 to 0.1; P=0.07); 7.0% of the patients in the intervention group and 7.7% of those in the control group survived with favorable neurologic function at discharge (difference, -0.6 percentage points; 95% CI, -1.4 to 0.1, P=0.09). Hospital-free survival was significantly shorter in the intervention group than in the control group (mean difference, -0.2 days; 95% CI, -0.3 to -0.1; P=0.004). CONCLUSIONS In patients with out-of-hospital cardiac arrest, continuous chest compressions during CPR performed by EMS providers did not result in significantly higher rates of survival or favorable neurologic function than did interrupted chest compressions. (Funded by the National Heart, Lung, and Blood Institute and others; ROC CCC ClinicalTrials.gov number, NCT01372748.).

The impact of peri-shock pause on survival from out-of-hospital shockable cardiac arrest during the Resuscitation Outcomes Consortium PRIMED trial.

BACKGROUND Previous research has demonstrated significant relationships between peri-shock pause and survival to discharge from out-of-hospital shockable cardiac arrest (OHCA). OBJECTIVE To determine the impact of peri-shock pause on survival from OHCA during the ROC PRIMED randomized controlled trial. METHODS We included patients in the ROC PRIMED trial who suffered OHCA between June 2007 and November 2009, presented with a shockable rhythm and had CPR process data for at least one shock. We used multivariable logistic regression to determine the association between peri-shock pause duration and survival to hospital discharge. RESULTS Among 2006 patients studied, the median (IQR) shock pause duration was: pre-shock pause 15s (8, 22); post-shock pause 6s (4, 9); and peri-shock pause 22.0 s (14, 31). After adjusting for Utstein predictors of survival as well as CPR quality measures, the odds of survival to hospital discharge were significantly higher for patients with pre-shock pause <10s (OR: 1.52, 95% CI: 1.09, 2.11) and peri-shock pause <20s (OR: 1.82, 95% CI: 1.17, 2.85) when compared to patients with pre-shock pause ≥ 20s and peri-shock pause ≥ 40s. Post-shock pause was not significantly associated with survival to hospital discharge. Results for neurologically intact survival (Modified Rankin Score ≤ 3) were similar to our primary outcome. CONCLUSIONS In patients with cardiac arrest presenting in a shockable rhythm during the ROC PRIMED trial, shorter pre- and peri-shock pauses were significantly associated with higher odds of survival. Future cardiopulmonary education and technology should focus on minimizing all peri-shock pauses.

Trends in Short- and Long-Term Survival Among Out-of-Hospital Cardiac Arrest Patients Alive at Hospital Arrival

Background— Out-of-hospital cardiac arrest (OHCA) is associated with a poor prognosis and poses a significant burden to the healthcare system, but few studies have evaluated whether OHCA incidence and survival have changed over time. Methods and Results— A population-based cohort study was conducted, including 34 291 OHCA patients >20 years of age who were transported alive to the emergency department of an acute-care hospital from April 1, 2002, to March 31, 2012, in Ontario, Canada. Patients with life-threatening trauma and those who died before hospital arrival were excluded. The overall age- and sex-standardized incidence of OHCA patients who were transported alive was 36 cases per 100 000 persons and did not significantly change over the study period. Cardiac risk factor prevalence increased significantly, whereas the rate of most cardiovascular conditions decreased significantly. The 30-day survival improved from 9.4% in 2002 to 13.6% in 2011; 1-year survival improved from 7.7% to 11.8% (P<0.001). Patients hospitalized in 2011 were significantly more likely to survive 30 days (adjusted odds ratio, 1.47 [95% CI, 1.22–1.77]) and 1 year (adjusted odds ratio, 1.55 [95% CI, 1.27–1.91]) compared with 2002. A significant interaction between temporal trends in survival improvement and age group was observed in which the improvement in survival was largest in the youngest age groups. Conclusions— OHCA patients who were transported alive are increasingly likely to have cardiovascular risk factors but less likely to have previous cardiovascular conditions. The overall incidence of OHCA patients transported to hospital alive did not change over the past decade. Short- and longer-term survival after OHCA has substantially improved, with younger patients experiencing the greatest improvement.

Increased survival after EMS witnessed cardiac arrest. Observations from the Resuscitation Outcomes Consortium (ROC) Epistry-Cardiac arrest.

BACKGROUND Out of hospital cardiac arrest (OHCA) is common and lethal. It has been suggested that OHCA witnessed by EMS providers is a predictor of survival because advanced help is immediately available. We examined EMS witnessed OHCA from the Resuscitation Outcomes Consortium (ROC) to determine the effect of EMS witnessed vs. bystander witnessed and unwitnessed OHCA. METHODS Data were analyzed from a prospective, population-based cohort study in 10 U.S. and Canadian ROC sites. Individuals with non-traumatic OHCA treated 04/01/06-03/31/07 by EMS providers with defibrillation or chest compressions were included. Cases were grouped into EMS-witnessed, bystander witnessed, and unwitnessed and further stratified for bystander CPR. Multiple logistic regressions evaluated the odds ratio (OR) for survival to discharge relative to the EMS-witnessed group after adjusting for age, sex, public/private location of collapse, ROC site, and initial ECG rhythm. Of 9991 OHCA, 1022 (10.2%) of EMS-witnessed, 3369 (33.7%) bystander witnessed, and 5600 (56.1%) unwitnessed. RESULTS The most common initial rhythm in the EMS-witnessed group was PEA which was higher than in the bystander- and unwitnessed groups (p<0.001). The adjusted OR (95% CI) of survival compared to the EMS-witnessed group was 0.41, (0.36, 0.46) in bystander witnessed with bystander CPR, 0.37 (0.33, 0.43) in bystander witnessed without bystander CPR, 0.17 (0.14, 0.20) in unwitnessed with bystander CPR and 0.21 (0.18, 0.24) in unwitnessed cases without bystander CPR. CONCLUSIONS Immediate application of prehospital care for OHCA may improve survival. Efforts should be made to educate patients to access 9-1-1 for prodromal symptoms.

Paramedic Contact to Balloon in Less than 90 Minutes: A Successful Strategy for St-Segment Elevation Myocardial Infarction Bypass to Primary Percutaneous Coronary Intervention in a Canadian Emergency Medical System

Abstract Introduction. Few systems worldwide have achieved the benchmark time of less than 90 minutes from emergency medical services (EMS) contact to balloon inflation (E2B) for patients sustaining ST-segment elevation myocardial infarction (STEMI). We describe a successful EMS systems approach using a combination of paramedic and 12-lead electrocardiogram (ECG) software interpretation to activate a STEMI bypass protocol. Objectives. To determine the proportion of patients who met the benchmark of E2B in less than 90 minutes after institution of a regional paramedic activated STEMI bypass to primary PCI protocol. Methods. We conducted a before-and-after observational cohort study over a 24-month period ending December 31, 2009. Included were all patients diagnosed with STEMI by paramedics trained in ECG acquisition and interpretation and transported by EMS. In the “before” phase of the study, paramedics gave emergency departments (EDs) advance notification of the arrival of STEMI patients and took the patients to the ED of the PCI center. In the “after” phase of the study, paramedics activated a STEMI bypass protocol in which STEMI patients were transported directly to the PCI suite, bypassing the local hospital EDs. Transmission of ECGs did not occur in either phase of the study. Results. We compared the times for 95 STEMI patients in the before phase with the times for 80 STEMI patients in the after phase. The proportion for whom E2B was less than 90 minutes increased from 28.4% before to 91.3% after (p < 0.001). Median E2B time decreased from 107 minutes (interquartile range [IQR] = 30) before to 70 minutes (IQR = 24) after. Median D2B time decreased from 83 minutes (IQR = 34) before to 35 minutes (IQR = 19) after. Median E2D time increased from 21 minutes (IQR = 8) before to 32 minutes (IQR = 17) after. Median differences between phases were significant at p < 0.001. The rate of false-positive PCI laboratory activation during the after phase of the study was 12.4%. Conclusions. The proportion of patients with E2B times less than 90 minutes significantly improved through the implementation of a paramedic-activated STEMI bypass protocol. Further study is required to determine whether these benefits are reproducible in other EMS systems.