Blair L. Bigham

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)

Relationship Between Chest Compression Rates and Outcomes From Cardiac Arrest

Background— Guidelines for cardiopulmonary resuscitation recommend a chest compression rate of at least 100 compressions per minute. Animal and human studies have reported that blood flow is greatest with chest compression rates near 120/min, but few have reported rates used during out-of-hospital (OOH) cardiopulmonary resuscitation or the relationship between rate and outcome. The purpose of this study was to describe chest compression rates used by emergency medical services providers to resuscitate patients with OOH cardiac arrest and to determine the relationship between chest compression rate and outcome. Methods and Results— Included were patients aged ≥20 years with OOH cardiac arrest treated by emergency medical services providers participating in the Resuscitation Outcomes Consortium. Data were abstracted from monitor-defibrillator recordings during cardiopulmonary resuscitation. Multiple logistic regression analysis assessed the association between chest compression rate and outcome. From December 2005 to May 2007, 3098 patients with OOH cardiac arrest were included in this study. Mean age was 67±16 years, and 8.6% survived to hospital discharge. Mean compression rate was 112±19/min. A curvilinear association between chest compression rate and return of spontaneous circulation was found in cubic spline models after multivariable adjustment (P=0.012). Return of spontaneous circulation rates peaked at a compression rate of ≈125/min and then declined. Chest compression rate was not significantly associated with survival to hospital discharge in multivariable categorical or cubic spline models. Conclusions— Chest compression rate was associated with return of spontaneous circulation but not with survival to hospital discharge in OOH cardiac arrest.

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.

Ventricular Tachyarrhythmias after Cardiac Arrest in Public versus at Home

BACKGROUND The incidence of ventricular fibrillation or pulseless ventricular tachycardia as the first recorded rhythm after out-of-hospital cardiac arrest has unexpectedly declined. The success of bystander-deployed automated external defibrillators (AEDs) in public settings suggests that this may be the more common initial rhythm when out-of-hospital cardiac arrest occurs in public. We conducted a study to determine whether the location of the arrest, the type of arrhythmia, and the probability of survival are associated. METHODS Between 2005 and 2007, we conducted a prospective cohort study of out-of-hospital cardiac arrest in adults in 10 North American communities. We assessed the frequencies of ventricular fibrillation or pulseless ventricular tachycardia and of survival to hospital discharge for arrests at home as compared with arrests in public. RESULTS Of 12,930 evaluated out-of-hospital cardiac arrests, 2042 occurred in public and 9564 at home. For cardiac arrests at home, the incidence of ventricular fibrillation or pulseless ventricular tachycardia was 25% when the arrest was witnessed by emergency-medical-services (EMS) personnel, 35% when it was witnessed by a bystander, and 36% when a bystander applied an AED. For cardiac arrests in public, the corresponding rates were 38%, 60%, and 79%. The adjusted odds ratio for initial ventricular fibrillation or pulseless ventricular tachycardia in public versus at home was 2.28 (95% confidence interval [CI], 1.96 to 2.66; P < 0.001) for bystander-witnessed arrests and 4.48 (95% CI, 2.23 to 8.97; P<0.001) for arrests in which bystanders applied AEDs. The rate of survival to hospital discharge was 34% for arrests in public settings with AEDs applied by bystanders versus 12% for arrests at home (adjusted odds ratio, 2.49; 95% CI, 1.03 to 5.99; P = 0.04). CONCLUSIONS Regardless of whether out-of-hospital cardiac arrests are witnessed by EMS personnel or bystanders and whether AEDs are applied by bystanders, the proportion of arrests with initial ventricular fibrillation or pulseless ventricular tachycardia is much greater in public settings than at home. The incremental value of resuscitation strategies, such as the ready availability of an AED, may be related to the place where the arrest occurs.

Predicting Survival After Out-of-Hospital Cardiac Arrest: Role of the Utstein Data Elements

STUDY OBJECTIVE Survival after out-of-hospital cardiac arrest depends on the links in the chain of survival. The Utstein elements are designed to assess these links and provide the basis for comparing outcomes within and across communities. We assess whether these measures sufficiently predict survival and explain outcome differences. METHODS We used an observational, prospective data collection, case-series of adult persons with nontraumatic out-of-hospital cardiac arrest from December 1, 2005, through March 1, 2007, from the multisite, population-based Resuscitation Outcomes Consortium Epistry-Cardiac Arrest. We used logistic regression, receiver operating curves, and measures of variance to estimate the extent to which the Utstein elements predicted survival to hospital discharge and explained outcome variability overall and between 7 Resuscitation Outcomes Consortium sites. Analyses were conducted for all emergency medical services-treated cardiac arrests and for the subset of bystander-witnessed patient arrests because of presumed cardiac cause presenting with ventricular fibrillation or ventricular tachycardia. RESULTS Survival was 7.8% overall (n=833/10,681) and varied from 4.6% to 14.7% across Resuscitation Outcomes Consortium sites. Among bystander-witnessed ventricular fibrillation or ventricular tachycardia, survival was 22.1% overall (n=323/1459) and varied from 12.5% to 41.0% across sites. The Utstein elements collectively predicted 72% of survival variability among all arrests and 40% of survival variability among bystander-witnessed ventricular fibrillation. The Utstein elements accounted for 43.6% of the between-site survival difference among all arrests and 22.3% of the between-site difference among the bystander-witnessed ventricular fibrillation subset. CONCLUSION The Utstein elements predict survival but account for only a modest portion of outcome variability overall and between Resuscitation Outcomes Consortium sites. The results underscore the need for ongoing investigation to better understand characteristics that influence cardiac arrest survival.

Expanding Paramedic Scope of Practice in the Community: A Systematic Review of the Literature

Abstract Background. Paramedics are an important health human resource and are uniquely mobile in most communities across Canada. In the last dozen years, challenges in the delivery of health care have prompted governments from around the globe to consider expanding the role paramedics play in health systems. Utilizing paramedics for the management of urgent, low-acuity illnesses and injuries has been coined “community paramedicine,” but the role, safety, and effectiveness of this concept are poorly understood. Objective. We undertook a systematic review of the international literature to describe existing community paramedic programs. Method. We used the Cochrane methodology for systematic reviews. An international group of experts developed a search strategy and a health information specialist executed this search in Medline, Embase, and CINAHL starting January 1, 2000. We included all research articles in the English language that reported a research methodology. We excluded commentaries and letters to the editor. Two investigators independently screened citations in a hierarchical manner and abstracted data. Results. Of 3,089 titles, 10 articles were included in the systematic review and one additional paper was author-nominated. The nature of the 11 articles was heterogeneous, and only one randomized controlled trial (RCT) was found. This trial showed community paramedicine to be beneficial to patients and health systems. The other articles drew conclusions favoring community paramedicine. Conclusion. Community paramedicine research to date is lacking, but programs in the United Kingdom, Australia, and Canada are perceived to be promising, and one RCT shows that paramedics can safely practice with an expanded scope and improve system performance and patient outcomes. Further research is required to fully understand how expanding paramedic roles affect patients, communities, and health systems. Key words: emergency medical services; prehospital; community paramedic; extended scope; paramedic practitioner

Patient safety in emergency medical services: a systematic review of the literature.

Abstract Background. Preventable harm from medical care has been extensively documented in the inpatient setting. Emergency medical services (EMS) providers care for patients in dynamic and challenging environments; prehospital emergency care is a field that represents an area of high risk for errors and harm, but has received relatively little attention in the patient safety literature. Objective. To identify the threats to patient safety unique to the EMS environment and interventions that mitigate those threats, we completed a systematic review of the literature. Methods. We searched MEDLINE, EMBASE, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) for combinations of key EMS and patient safety terms composed by a pan-canadian expert panel using a year limit of 1999 to 2011. We excluded commentaries, opinions, letters, abstracts, and non-english publications. Two investigators performed an independent hierarchical screening of titles, abstracts, and full-text articles blinded to source. We used the kappa statistic to examine interrater agreement. Any differences were resolved by consensus. Results. We retrieved 5,959 titles, and 88 publications met the inclusion criteria and were categorized into seven themes: adverse events and medication errors (22 articles), clinical judgment (13), communication (6), ground vehicle safety (9), aircraft safety (6), interfacility transport (16), and intubation (16). Two articles were randomized controlled trials; the remainder were systematic reviews, prospective observational studies, retrospective database/chart reviews, qualitative interviews, or surveys. The kappa statistics for titles, abstracts, and full-text articles were 0.65, 0.79, and 0.87, respectively, for the first search and 0.60, 0.74, and 0.85 for the second. Conclusions. We found a paucity of scientific literature exploring patient safety in EMS. Research is needed to improve our understanding of problem magnitude and threats to patient safety and to guide interventions. Key words: emergency medical services; ambulance; prehospital; patient safety; medication error; adverse event; systematic review

Delayed Prehospital Implementation of the 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiac Care

Abstract 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.

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.

Part 8: Education, implementation, and teams: 2015 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations.

Current evidence demonstrates considerable variability in cardiac arrest survival in and out of hospital and, therefore, substantial opportunity to save many more lives.1–3 The Formula for Survival4 postulates that optimal survival from cardiac arrest requires high-quality science, education of lay providers and healthcare professionals, and a well-functioning Chain of Survival5 (implementation). The Education, Implementation, and Teams (EIT) Task Force of the International Liaison Committee on Resuscitation (ILCOR) set out to define the key PICO (population, intervention, comparator, outcome) questions related to resuscitation education (including teamwork skills) and systems-level implementation that would be reviewed by 2015. The selection of questions was supported through the use of an online anonymous task force member–only voting process where the results were considered in the ultimate consensus decisions of the task force. Topics from the 2010 evidence review process were scrutinized for relevance, the potential to improve outcomes, and the likelihood of new evidence being published since 2010. Finally, PICO questions for which the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) process was not as well developed at the time of PICO selection were deferred until at least after the 2015 cycle. We planned to reduce the total number of PICO questions reviewed to provide more in-depth and evidence-based reviews of the included questions. New topics were determined on the basis of the evolving literature and changes in resuscitation practice. Input on the selection of PICO questions was sought from the general public through the ILCOR website and from ILCOR member resuscitation councils through their council chairs and individual task force members. The EIT Task Force performed detailed systematic reviews based on the recommendations of the Institute of Medicine of the National Academies6 and using the methodological approach proposed by the …