Selected Abstracts: 2008

1. Public health impact of full implementation of therapeutic hypothermia after cardiac arrest
    
2. Results from Austria's nationwide public access defibrillation (ANPAD) programme collected over two years
    
3. Public Access Defibrillation: Psychological consequences in responders

Selected Abstracts: 2007

1. Cardiac arrest patients rarely receive chest compressions before ambulance arrival despite the availability of pre-arrival CPR instructions
    
2. Cardiopulmonary resuscitation alone vs. cardiopulmonary resuscitation plus automated external defibrillator use by non-healthcare professionals: A meta-analysis on 1583 cases of out-of-hospital cardiac arrest
    
3. Sex differences in the use of implantable cardioverter-defibrillators for primary and secondary prevention of sudden cardiac death
    
4. 30:2 is tiring, but it works: The effect on quality of chest compressions and exhaustion of a compression–ventilation ratio of 30:2 versus 15:2 during cardiopulmonary resuscitation—A randomized trial
    
5. The effect of time on CPR and automated external defibrillator skills in the Public Access Defibrillation Trial

Selected Abstracts: 2006

1. Trends in sudden cardiovascular death in young competitive athletes after implementation of a preparticipation screening program
    
2. Risk of aborted cardiac arrest or sudden cardiac death during adolescence in the long-QT syndrome
    
3. Management of recalled pacemakers and implantable cardioverter-defibrillators a decision analysis model
   
4. Recalls and safety alerts affecting automated external defibrillators
   
5. Validation of a rule for termination of resuscitation in out-of-hospital cardiac arrest
    
6. Clinical and hemodynamic comparison of 15:2 and 30:2 compression-to-ventilation ratios for cardiopulmonary resuscitation.

Selected Abstracts: 2005

1. Effectiveness of a 30-min CPR self-instruction program for lay responders: a controlled randomized study.
    
2. Effect of an inspiratory impedance threshold device on hemodynamics during conventional manual cardiopulmonary resuscitation.
    
3. Out-of-hospital cardiac arrest rectilinear biphasic to monophasic damped sine defibrillation waveforms with advanced life support intervention trial (ORBIT).
    
4. Incomplete chest wall decompression: a clinical evaluation of CPR performance by EMS personnel and assessment of alternative manual chest compression-decompression techniques.
    
5. Chest compression rates during cardiopulmonary resuscitation are suboptimal: a prospective study during in-hospital cardiac arrest.
    
6. Trends in treated ventricular fibrillation in out-of-hospital cardiac arrest: ischemic compared to non-ischemic heart disease.

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Public health impact of full implementation of therapeutic hypothermia after cardiac arrest

Jennifer J. Majersik, Robert Silbergleit, William J. Meurer, Devin L. Brown, Lynda D. Lisabeth and Lewis B. Morgenstern

Resuscitation, Online February 4, 2008

Aim
Induced hypothermia improves outcomes in patients resuscitated successfully after cardiac arrest due to ventricular fibrillation. However, a minority of US physicians currently use the therapy. The aim of this study was to project the public health impact of implementing hypothermia in all eligible US out-of-hospital cardiac arrest (OHCA) survivors.

Methods
The number of OHCA patients expected to have a good outcome after hypothermia was calculated using a linear model. Literature-derived input variables included OHCA incidence rates and US 2000 census data, percent with return to spontaneous circulation (ROSC), percent eligible for hypothermia, and the expected benefit from hypothermia. Sensitivity analyses were performed to calculate a plausible range around the reference case.

RESULTS
An additional 2298 US patients per year are expected to have a good neurological outcome if US physicians implement hypothermia fully in comatose survivors of OHCA. The two-way sensitivity analyses found that this number ranged from 766 to 5171 patients. This model is similarly sensitive to varying the incidence of OHCA, percent with ROSC, percent of patients eligible for hypothermia, and the number needed to treat.

CONCLUSIONS
If US physicians adopt therapeutic hypothermia fully in eligible patients with OHCA, 2298 additional patients per year would be expected to achieve a good neurological outcome, a substantial public health impact. Barriers to adoption should be researched and addressed to increase acceptance and use by US physicians.

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Results from Austria's nationwide public access defibrillation (ANPAD) programme collected over two years

Roman Fleischhackl, Bernhard Roessler, Hans Domanovits, Florian Singer, Sabine Fleischhackl, Gerald Foitik, Gerald Czech, Martina Mittlboeck, Reinhard Malzer, Philip Eisenburger and Klaus Hoerauf

Resuscitation, Online January 31, 2008

AIM
To analyze two years of experience after introducing automated external defibrillators (AEDs) all over Austria.

Materials and methods
This observational study evaluated the number of privately purchased devices and the rate of local bystander-triggered AED deployments from November 2002 to December 2004. As outcome measurements, the hospital discharge rate and neurological condition were recorded. Arrival times of the emergency medical service (EMS) on scene and the time intervals until shock decisions were made were calculated. Shock decisions were verified according to ECG downloads. Results were compared with historical data if applicable.

Results
During the study period, 1865 devices were installed. Seventy-three AED deployments were recorded. Eleven cases were excluded from the study because bystanders were part of the local EMS. Seventeen out of the remaining 62 (27%) compared to a historical 27 out of 623 (4.3%) individuals were discharged alive from hospital. Fourteen out of 26 (54%) patients who were found with a shockable rhythm survived to hospital discharge. Fifteen of our patients survived in good neurological condition (CPC I and II), two suffered from severe neurological deficit (CPC III and IV) and 45 people died.

The median “call-to-AED advice interval” was 3.5 min (IQR 2–6 min; N = 24). In two cases, the AED made inappropriate decisions because of artefacts.

Conclusions
Compared to historical data, short ‘intervals to shock’ delivery and the frequent start of basic life support resulted in an increased hospital discharge rate in good neurological condition. Despite the relatively high number of installed devices, the number of patients reached remained small.

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Public Access Defibrillation: Psychological consequences in responders

Ellen Davies, Benjamin Maybury, Michael Colquhoun, Richard Whitfield, Tony Rossetti and Norman Vetter

Resuscitation, January 18, 2008

Background
Adverse psychological reactions are relatively frequent in professional ambulance crews who attend traumatic events, yet appear unusual in laypersons who attempt resuscitation of victims of out of hospital cardiac arrest.

AIM
To investigate the psychological profile of first responders to gain insight into possible factors that might protect them against such reactions.

METHODS
Qualitative study of first responders in a community scheme in Barry, South Wales. In depth semi-structured interviews with six subjects were analyzed using Interpretive Phenomenological Analysis (IPA).

Results
The study identified a resilience phenomenon in first responders accounted for by certain enabling core beliefs about their role, their capacity, and about the meaning of negative and positive outcomes for themselves. A realistic appreciation of their own limitations, confidence in their ability to perform as trained and being able to handle positive and negative outcomes were prominent features. The ability to act with emotional detachment appears a further protective mechanism. This mindset, loosely described as ‘a philosophy’, protects against the development of adverse reactions to stress or from becoming unduly concerned about negative outcomes. The responders had altruistic motives for undertaking the role yet were capable of operating with a high degree of naturally occurring resilience to stress or undermining anxiety. It is the combination of being motivated by altruism coupled with an inherent resilience that appears to be the crucial protective mechanism.

Conclusions
The group demonstrated an apparently innate resilience to the adverse psychological effects of responding with an AED in a PAD scheme. This enables them to operate optimally in stressful situations without experiencing the negative psychological consequences that might otherwise arise. This information may be used to raise awareness about the psychological requirements for the role and to assist screening or selection processes.

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Cardiac arrest patients rarely receive chest compressions before ambulance arrival despite the availability of pre-arrival CPR instructions

E. Brooke Lerner, Michael R. Sayre, Jane H. Brice, Lynn J. White, Amy J. Santin, Anthony J. Billittier IV and Samuel D. Cloud

Resuscitation, Online December 26, 2007

Objectives
To determine the proportion of out-of-hospital cardiac arrest (OOHCA) patients who received chest compressions, before EMS arrival, from bystanders who called the EMS emergency telephone number (9-1-1) at dispatch centers that provided telephone CPR instructions and to describe barriers to following instructions.

Methods
A retrospective case series was conducted in 2004 at three dispatch centers all of which provided sequential airway, breathing and chest compression pre-arrival instructions. All calls for which the call-taker established that the patient was in OOHCA were identified, and the recorded interaction was reviewed using a structured data collection tool. Data included whether the caller performed compressions, the sequence of instructions, whether there were barriers to performing CPR and characteristics of the caller, call taker and patient. Descriptive statistics were used to evaluate the data.

Results
343 calls were reviewed. 3 were excluded because it was unclear whether compressions were provided. 172 calls were not eligible for pre-arrival instructions (e.g. obviously dead, already receiving CPR). Of the 168 calls eligible for CPR instructions, chest compressions were actually given to 25 patients (15%, 95% confidence interval 10–21%) before EMS arrival. Leading reasons for not following CPR instructions included: caller disconnected phone before directions were complete (19%), caller's refusal (18%), emotional state of the caller (14%), inability to listen to telephone instructions and care for patient at the same time (13%) and physical limitations of the caller (8%). Failure to complete airway and breathing steps prevented 8% of callers from providing compressions.

Conclusions
Few 9-1-1 callers provided chest compressions following telephone CPR instructions that included airway and breathing steps. The majority of callers were unwilling or emotionally or physically unable to follow the instructions.

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Cardiopulmonary resuscitation alone vs. cardiopulmonary resuscitation plus automated external defibrillator use by non-healthcare professionals: A meta-analysis on 1583 cases of out-of-hospital cardiac arrest

Tommaso Sanna, Giuseppe La Torre, Chiara de Waure, Andrea Scapigliati, Walter Ricciardi, Antonio Dello Russo, Gemma Pelargonio, Michela Casella and Fulvio Bellocci

Resuscitation, Online September 17, 2007.

Background
Out-of-hospital cardiac arrest (OHCA) accounts for 250,000–350,000 sudden cardiac deaths per year in the United States. The availability of automated external defibrillators (AEDs) promoted the implementation of public access defibrillation programs based on out-of-hospital early defibrillation by non-healthcare professionals.

AIM
To perform a systematic review and a meta-analysis of the pooled effect of studies comparing the outcome of pts receiving cardiopulmonary resuscitation plus AED therapy (CPR + AED) vs. cardiopulmonary resuscitation (CPR) alone, both delivered by non-healthcare professionals, for the treatment of OHCA.

METHODS
We performed a search of the relevant literature exploring major scientific databases, carrying out a hand search of key journals, analyzing conference proceedings and abstracts and discussing the topic with other researchers. Two analyses were planned to assess the outcomes of interest (survival to hospital admission and survival to hospital discharge).

RESULTS
Three studies were selected for the meta-analysis. The first meta-analysis evidenced a RR of 1.22 (95% C.I.: 1.04–1.43) of surviving to hospital admission for people treated with CPR + AED as compared to CPR-only. The second meta-analysis showed a RR of 1.39 (95% C.I.: 1.06–1.83) of surviving to hospital discharge for people treated with CPR + AED as compared to CPR-only.

CONCLUSIONS
The results of our meta-analysis demonstrate that programs based on CPR plus early defibrillation with AEDs by trained non-healthcare professionals offer a survival advantage over CPR-only in OHCA. The conclusions of our meta-analysis add to previous evidence in favour of developing public-health strategies based on AED use by trained layrescuers.

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Sex differences in the use of implantable cardioverter-defibrillators for primary and secondary prevention of sudden cardiac death

Lesley H. Curtis, PhD; Sana M. Al-Khatib, MD, MHS; Alisa M. Shea, MPH; Bradley G. Hammill, MS; Adrian F. Hernandez, MD, MHS; Kevin A. Schulman, MD

JAMA. 2007;298:1517-1524.

CONTEXT 
Previous studies of sex differences in the use of implantable cardioverter-defibrillators (ICDs) predate recent expansions in Medicare coverage and did not provide patient follow-up over multiple years.

OBJECTIVE
To examine sex differences in ICD use for primary and secondary prevention of sudden cardiac death.

Design, Setting, and Participants
Analysis of a 5% national sample of research-identifiable files obtained from the US Centers for Medicare & Medicaid Services for the period 1991 through 2005. Patients were those aged 65 years or older with Medicare fee-for-service coverage and diagnosed with acute myocardial infarction and either heart failure or cardiomyopathy but no prior cardiac arrest or ventricular tachycardia (ie, the primary prevention cohort [n = 65 917 men and 70 504 women]), or with cardiac arrest or ventricular tachycardia (ie, the secondary prevention cohort [n = 52 252 men and 47 411 women]), from 1999 through 2005.

Main Outcome Measures
Receipt of ICD therapy and all-cause mortality at 1 year.

RESULTS
In the 2005 primary prevention cohort, 32.3 per 1000 men and 8.6 per 1000 women received ICD therapy within 1 year of cohort entry. In multivariate analyses, men were more likely than women to receive ICD therapy (hazard ratio [HR], 3.15; 95% confidence interval [CI], 2.86-3.47). Among men and women alive at 180 days after cohort entry, the hazard of mortality in the subsequent year was not significantly lower among those who received ICD therapy (HR, 1.01; 95% CI, 0.82-1.23). In the 2005 secondary prevention cohort, 102.2 per 1000 men and 38.4 per 1000 women received ICD therapy. Controlling for demographic variables and comorbid conditions, men were more likely than women to receive ICD therapy (HR, 2.44; 95% CI, 2.30-2.59). Among men and women alive at 30 days after cohort entry, the hazard of mortality in the subsequent year was significantly lower among those who received ICD therapy (HR, 0.65; 95% CI, 0.60-0.71).

CONCLUSION
In the Medicare population, women are significantly less likely than men to receive ICD therapy for primary or secondary prevention of sudden cardiac death.

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30:2 is tiring, but it works: The effect on quality of chest compressions and exhaustion of a compression–ventilation ratio of 30:2 versus 15:2 during cardiopulmonary resuscitation—A randomized trial

Koen Deschilder, Rien De Vos, and Willem Stockman

Resuscitation, Volume 74, Issue 1, July 2007, Pages 113-118, Online March 23, 2007.
BACKGROUND
Recent cardio pulmonary resuscitation (CPR) guidelines changed the compression:ventilation ratio in 30:2.

OBJECTIVE
To compare the quality of chest compressions and exhaustion using the ratio 30:2 versus 15:2.

METHODS
A prospective, randomized crossover design was used. Subjects were recruited from the H.-Hart hospital personnel and the University College Katho for nurses and bio-engineering. Each participant performed 5 min of CPR using either the ratio 30:2 or 15:2, then after a 15 min rest switched to the other ratio. The data were collected using a questionnaire and an adult resuscitation manikin. The outcomes included exhaustion as measured by a visual analogue scale (VAS) score, depth of chest compressions, rates of chest compressions, total number of chest compressions, number of correct chest compressions and incomplete release. Data were compared using the Wilcoxon Signed Ranks Test. The results are presented as medians and interquartile ranges (IQR).

RESULTS
One hundred and thirty subjects completed the study. The exhaustion-score using the VAS was 5.9 (IQR 2.25) for the ratio 30:2 and 4.5 (IQR 2.88) for the ratio 15:2 (P < 0.001). The compression depth was 40.5 mm (IQR 15.75) for 30:2 and 41 mm (IQR 15.5) for 15:2 (P = 0.5). The compression rate was 118 beats/min (IQR 29) for 30:2 and 115 beats/min (IQR 32) for 15:2 (P = 0.02). The total number of compressions/5 min was 347 (IQR 79) for 30:2 and 244 compressions/5 min (IQR 72.5) for 15:2 (P < 0.001). The number of correct compression/5 min was 61.5 (IQR 211.75) for 30:2 and 55.5 (IQR 142.75) for 15:2 (P = 0.001). The relative risk (RR) of incomplete release in 30:2 versus 15:2 was 1.087 (95% CI = 0.633–1.867).

CONCLUSIONS
Although the 30:2 ratio is rated to be more exhausting, the 30:2 technique delivers more chest compressions and the quality of chest compressions remains unchanged.

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The effect of time on CPR and automated external defibrillator skills in the Public Access Defibrillation Trial

Jim Christenson , Sarah Nafziger, Scott Compton, Kris Vijayaraghavan, Brian Slater, Robert Ledingham, Judy Powell, Mary Ann McBurnie and the PAD Investigators

Resuscitation Volume 74, Issue 1, July 2007, Online February 14, 2007

Background
The time to skill deterioration between primary training/retraining and further retraining in cardiopulmonary resuscitation (CPR) and automated external defibrillation (AED) for lay-persons is unclear. The Public Access Defibrillation (PAD) trial was a multi-center randomized controlled trial evaluating survival after CPR-only versus CPR + AED delivered by onsite non-medical volunteer responders in out-of-hospital cardiac arrest.

AIMS
This sub-study evaluated the relationship of time between primary training/retraining and further retraining on volunteer performance during pretest AED and CPR skill evaluation.

METHODS
Volunteers at 1260 facilities in 24 North American regions underwent training/retraining according to facility randomization, which included an initial session and a refresher session at approximately 6 months. Before the next retraining, a CPR and AED skill test was completed for 2729 volunteers. Primary outcome for the study was assessment of global competence of CPR or AED performance (adequate versus not adequate) using χ2-test for trends by time interval (3, 6, 9, and 12 months). Confirmatory (GEE) logistic regression analysis, adjusted for site and potential confounders was done.

Results
The proportion of volunteers judged to be competent did not diminish by interval (3, 6, 9, and 12 months) for either CPR or AED skills. After adjusting for site and potential confounders, longer intervals to further retraining was associated with a slightly lower likelihood of performing adequate CPR but not with AED scores.

Conclusions
After primary training/retraining, the CPR skills of targeted lay responders deteriorate nominally but 80% remain competent up to 1 year. AED skills do not deteriorate significantly and 90% of volunteers remain competent up to 1 year.

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Trends in sudden cardiovascular death in young competitive athletes after implementation of a preparticipation screening program

Domenico Corrado, MD, PhD; Cristina Basso, MD, PhD; Andrea Pavei, MD; Pierantonio Michieli, MD, PhD; Maurizio Schiavon, MD; Gaetano Thiene, MD

JAMA. 2006;296:1593-1601.

CONTEXT: A nationwide systematic preparticipation athletic screening was introduced in Italy in 1982. The impact of such a program on prevention of sudden cardiovascular death in the athlete remains to be determined.

OBJECTIVE: To analyze trends in incidence rates and cardiovascular causes of sudden death in young competitive athletes in relation to preparticipation screening.

DESIGN, SETTING, PARTICIPANTS: A population-based study of trends in sudden cardiovascular death in athletic and nonathletic populations aged 12 to 35 years in the Veneto region of Italy between 1979 and 2004. A parallel study examined trends in cardiovascular causes of disqualification from competitive sports in 42 386 athletes undergoing preparticipation screening at the Center for Sports Medicine in Padua (22 312 in the early screening period [1982-1992] and 20 074 in the late screening period [1993-2004]).

MAIN OUTCOME MEASURES: Incidence trends of total cardiovascular and cause-specific sudden death in screened athletes and unscreened nonathletes of the same age range over a 26-year period.

RESULTS:  During the study period, 55 sudden cardiovascular deaths occurred in screened athletes (1.9 deaths/100 000 person-years) and 265 sudden deaths in unscreened nonathletes (0.79 deaths/100 000 person-years). The annual incidence of sudden cardiovascular death in athletes decreased by 89% (from 3.6/100 000 person-years in 1979-1980 to 0.4/100 000 person-years in 2003-2004; P for trend < .001), whereas the incidence of sudden death among the unscreened nonathletic population did not change significantly. The mortality decline started after mandatory screening was implemented and persisted to the late screening period. Compared with the prescreening period (1979-1981), the relative risk of sudden cardiovascular death in athletes was 0.56 in the early screening period (95% CI, 0.29-1.15; P = .04) and 0.21 in the late screening period (95% CI, 0.09-0.48; P = .001). Most of the reduced mortality was due to fewer cases of sudden death from cardiomyopathies (from 1.50/100 000 person-years in the prescreening period to 0.15/100 000 person-years in the late screening period; P for trend = .002). During the study period, 879 athletes (2.0%) were disqualified from competition due to cardiovascular causes at the Center for Sports Medicine: 455 (2.0%) in the early screening period and 424 (2.1%) in the late screening period. The proportion of athletes who were disqualified for cardiomyopathies increased from 20 (4.4%) of 455 in the early screening period to 40 (9.4%) of 424 in the late screening period (P = .005).

CONCLUSIONS:  The incidence of sudden cardiovascular death in young competitive athletes has substantially declined in the Veneto region of Italy since the introduction of a nationwide systematic screening. Mortality reduction was predominantly due to a lower incidence of sudden death from cardiomyopathies that paralleled the increasing identification of athletes with cardiomyopathies at preparticipation screening.

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Risk of aborted cardiac arrest or sudden cardiac death during adolescence in the long-QT syndrome

Jenny B. Hobbs, MD; Derick R. Peterson, PhD; Arthur J. Moss, MD; Scott McNitt, MS; Wojciech Zareba, MD, PhD; Ilan Goldenberg, MD; Ming Qi, PhD; Jennifer L. Robinson, MS; Andrew J. Sauer, BS; Michael J. Ackerman, MD, PhD; Jesaia Benhorin, MD; Elizabeth S. Kaufman, MD; Emanuela H. Locati, MD, PhD; Carlo Napolitano, MD; Silvia G. Priori, MD, PhD; Jeffrey A. Towbin, MD; G. Michael Vincent, MD; Li Zhang, MD. JAMA.2006;296:1249-1254.

CONTEXT: Analysis of predictors of cardiac events in hereditary long-QT syndrome (LQTS) has primarily considered syncope as the predominant end point. Risk factors specific for aborted cardiac arrest and sudden cardiac death have not been investigated.

OBJECTIVE: To identify risk factors associated with aborted cardiac arrest and sudden cardiac death during adolescence in patients with clinically suspected LQTS.

Design, Setting, and Participants: The study involved 2772 participants from the International Long QT Syndrome Registry who were alive at age 10 years and were followed up during adolescence until age 20 years. The registry enrollment began in 1979 at 5 cardiology centers in the United States and Europe.

Main Outcome Measures: Aborted cardiac arrest or LQTS-related sudden cardiac death; follow-up ended on February 15, 2005.

RESULTS: There were 81 patients who experienced aborted cardiac arrest and 45 who had sudden cardiac death; 9 of the 81 patients who had an aborted cardiac arrest event experienced subsequent sudden cardiac death. Significant independent predictors of aborted cardiac arrest or sudden cardiac death during adolescence included recent syncope, QTc interval, and sex. Compared with those with no syncopal events in the last 10 years, patients with 1 or 2 or more episodes of syncope 2 to 10 years ago (but none in the last 2 years) had an adjusted hazard ratio (HR) of 2.7; (95% confidence interval [CI], 1.3-5.7; P<.01) and an adjusted HR of 5.8 (95% CI, 3.6-9.4; P<.001), respectively, for life-threatening events; those with 1 syncopal episodes in the last 2 years had an adjusted HR of 11.7 (95% CI, 7.0-19.5; P<.001) and those with 2 or more syncopal episodes in the last 2 years had an adjusted HR of 18.1 (95% CI, 10.4-31.2; P<.001). Irrespective of events occurring more than 2 years ago, QTc of 530 ms or longer was associated with increased risk (adjusted HR, 2.3; 95% CI, 1.6-3.3; P<.001) compared with those having a shorter QTc. Males between the ages of 10 and 12 years had higher risk than females (HR, 4.0; 95% CI, 1.8-9.2; P=.001), but there was no significant risk difference between males and females between the ages of 13 and 20 years. Among individuals with syncope in the past 2 years, -blocker therapy was associated with a 64% reduced risk (HR, 0.36; 95% CI, 0.18-0.72; P<.01).

CONCLUSIONS: In LQTS, the timing and frequency of syncope, QTc prolongation, and sex were predictive of risk for aborted cardiac arrest and sudden cardiac death during adolescence. Among patients with recent syncope, blocker treatment was associated with reduced risk.

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Management of recalled pacemakers and implantable cardioverter-defibrillators a decision analysis model

Mitesh S. Amin, MD; David B. Matchar, MD; Mark A. Wood, MD; Kenneth A. Ellenbogen, MD, JAMA. 2006;296:412-420

CONTEXT: Limited information exists to direct clinical management after an implantable device has been put under advisory. A better understanding of the risks and benefits of device replacement compared with continued clinical follow-up would be helpful to clinicians.

OBJECTIVE: Using the tools of decision analysis, to determine the best management approach (immediate device replacement vs continued monitoring) in the setting of a device advisory.

DESIGN: A decision model was constructed to evaluate the risks and benefits associated with immediate device replacement compared with continued monitoring.

MAIN OUTCOME MEASURES: Variables considered included indications for device implantation, anticipated course following device failure, device failure rates from the advisory ranging from 0.0001% to 1.0% per year, and device replacement mortality rates ranging from 0.10% to 1.00% per procedure. Device replacement was preferred to continued follow-up when replacement led to greater patient survival.

RESULTS: The decision to replace a recalled device depends primarily on the advisory's estimated device failure rate and the likely effects of device failure on mortality. Procedural mortality is an important secondary factor, while patient age and remaining generator life have the least influence on the decision. For pacemaker-dependent patients, advisory device failure rates exceeding 0.3% warrant device replacement in most situations. In patients with implantable cardioverter-defibrillators for primary or secondary prevention, a failure rate associated with an advisory of 3.0% is needed to favor replacement in most cases, decreasing to close to 1.0% as procedural mortality rates decrease to 0.1% or risk of fatal arrhythmias increase to near 20% per year. In cases of pacemaker implantation for non–life-threatening situations (eg, carotid sinus hypersensitivity), most device advisories do not warrant device replacement.

CONCLUSIONS: The decision to replace a device under advisory is determined primarily by the incidence of device malfunction and the likely effects of device failure. This analysis provides a framework for managing recalled devices in the context of device, patient, and institutional characteristics.

http://jama.ama-assn.org/cgi/content/abstract/296/4/412

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Recalls and safety alerts affecting automated external defibrillators

Jignesh S. Shah, MD; William H. Maisel, MD, MPH, JAMA. 2006;296:655-660.

CONTEXT: Automated external defibrillators (AEDs) play a key role in the community resuscitation of persons with cardiac arrest and are of proven clinical benefit. Although AEDs are complex medical devices designed to function during life-threatening emergencies, little is known about their reliability. 

OBJECTIVES: To determine the number and rate of AED recalls and safety alerts, to identify trends in these rates, and to identify the types of malfunctions prompting AED and AED accessory advisories. 

DESIGN AND SETTING:  Analysis of weekly US Food and Drug Administration (FDA) Enforcement Reports between January 1996 and December 2005 was performed to identify all recalls and safety alerts (collectively referred to as "advisories") involving AEDs and AED accessories. Confirmed AED device malfunctions were identified by reviewing AED-related adverse events reported to the FDA. 

MAIN OUTCOME MEASURES: Number of AEDs and AED accessories subject to FDA recall or safety alert between January 1996 and December 2005; annual AED advisory rates; and number of confirmed  fatal AED-related device malfunctions reported to the FDA. 

RESULTS: During 2.78 million AED device-years of observation, 52 advisories (median [25th and 75th percentiles], 4.5 [3.0 and 5.0] per year) affecting 385 922 AEDs and AED accessories were issued. The mean (SE) annual number of AEDs affected by advisories was 5.1 (1.5) devices per 100 AED device-years. Overall, 21.2% of AEDs distributed during the study period were recalled, most often because of electrical or software problems. The AED advisory rate did not significantly increase during the study period, although the annual number of AED advisories (P for trend =.02) and AED advisory devices (P for trend = .01) did increase. Confirmed fatal AED-related device malfunctions occurred in 370 patients. 

CONCLUSIONS: Automated external defibrillators and AED accessory advisories occur frequently and affect many devices. Actual AED malfunctions do occur occasionally, although the number of observed malfunctions is small compared with the number of lives saved by these important devices. As the prevalence of AEDs continues to increase, the number of devices affected by advisories can also be expected to increase. Efforts should be directed at developing a reliable system to locate and repair  potentially defective devices in a timely fashion.

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Validation of a rule for termination of resuscitation in out-of-hospital cardiac arrest

Laurie J. Morrison, M.D., Laura M. Visentin, B.Sc., Alex Kiss, Ph.D., Rob Theriault, Don Eby, M.D., Marian Vermeulen, B.Sc.N., M.H.Sc., Jonathan Sherbino, M.D., P. Richard Verbeek, M.D., for the TOR Investigators

BACKGROUND: We prospectively evaluated a clinical prediction rule to be used by emergency medical technicians (EMTs) trained in the use of an automated external defibrillator for the termination of basic life support resuscitative efforts during out-of-hospital cardiac arrest. The rule recommends termination when there is no return of spontaneous circulation, no shocks are administered, and the arrest is not witnessed by emergency medical-services personnel. Otherwise, the rule recommends transportation to the hospital, in accordance with routine practice.

METHODS: The study included 24 emergency medical systems in Ontario, Canada. All patients 18 years of age or older who had an arrest of presumed cardiac cause and who were treated by EMTs trained in the use of an automated external defibrillator were included. The patients were treated according to standard guidelines. Characteristics of diagnostic tests for the prediction rule were calculated. These characteristics include sensitivity, specificity, and positive and negative predictive values.

RESULTS: Follow-up data were obtained for all 1240 patients. Of 776 patients with cardiac arrest for whom the rule recommended termination, 4 survived (0.5 percent). The rule had a specificity of 90.2 percent for recommending transport of survivors to the emergency department and had a positive predictive value for death of 99.5 percent when termination was recommended. Implementation of this rule would result in a decrease in the rate of transportation from 100 percent of patients to 37.4 percent. The addition of other criteria (a response interval greater than eight minutes or a cardiac arrest not witnessed by a bystander) would further improve both the specificity and positive predictive value of the rule but would result in the transportation of a larger proportion of patients.

CONCLUSION: The use of a clinical prediction rule for the termination of resuscitation may help clinicians decide whether to terminate basic life support resuscitative efforts in patients having an out-of-hospital cardiac arrest.

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Clinical and hemodynamic comparison of 15:2 and 30:2 compression-to-ventilation ratios for cardiopulmonary resuscitation.

Yannopoulos D, Aufderheide TP, Gabrielli A, Beiser DG, McKnite SH, Pirrallo RG, Wigginton J, Becker L, Vanden Hoek T, Tang W, Nadkarni VM, Klein JP, Idris AH, Lurie KG. Crit Care Med. 2006 May;34(5):1444-9. University of Minnesota, Minneapolis, MN, USA.

OBJECTIVE: To compare cardiopulmonary resuscitation (CPR) with a compression to ventilation (C:V) ratio of 15:2 vs. 30:2, with and without use of an impedance threshold device (ITD).

DESIGN: Prospective randomized animal and manikin study.

SETTING: Animal laboratory and emergency medical technician training facilities. SUBJECTS: Twenty female pigs and 20 Basic Life Support (BLS)-certified rescuers.

INTERVENTIONS, MEASUREMENTS, AND MAIN RESULTS:

ANIMALS: Acid-base status, cerebral, and cardiovascular hemodynamics were evaluated in 18 pigs in cardiac arrest randomized to a C:V ratio of 1 5:2 or 30:2. After 6 mins of cardiac arrest and 6 mins of CPR, an ITD was added. Compared to 15:2, 30:2 significantly increased diastolic blood pressure (20 +/- 1 to 26 +/- 1; p < .01); coronary perfusion pressure (18 +/- 1 to 25 +/- 2; p = .04); cerebral perfusion pressure (16 +/- 3 to 18 +/- 3; p = .07); common carotid blood flow (48 +/- 5 to 82 +/- 5 mL/min; p < .001); end-tidal CO2 (7.7 +/- 0.9 to 15.7 +/- 2.4; p < .0001); and mixed venous oxygen saturation (26 +/- 5 to 36 +/- 5, p < .05). Hemodynamics improved further with the ITD. Oxygenation and arterial pH were similar. Only one of nine pigs had return of spontaneous circulation with 15:2, vs. six of nine
with 30:2 (p < 0.03).

HUMANS: Fatigue and quality of CPR performance were evaluated in 20 BLS-certified rescuers randomized to perform CPR for 5 mins at 15:2 or 30:2 on a recording CPR manikin. There were no significant differences in the quality of CPR performance or measurement of fatigue. Significantly more compressions per minute were delivered with 30:2 in both the animal and human studies.

CONCLUSIONS: These data strongly support the contention that a ratio of 30:2 is superior to 15:2 during manual CPR and that the ITD further enhances circulation with both C:V ratios.

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Effectiveness of a 30-min CPR self-instruction program for lay responders: a controlled randomized study. Lynch B, Einspruch EL, Nichol G, Becker LB, Aufderheide TP, Idris A.Resuscitation. 2005 Oct;67(1):31-43.

RMC Research Corporation, 522 SW Fifth Avenue, Suite 1407, Portland, OR 97204, USA. blynch@rmccorp.com

BACKGROUND: The length of current 4-h classes in cardiopulmonary resuscitation (CPR) is a barrier to widespread dissemination of CPR training. The effectiveness of video-based self-instruction (VSI) has been demonstrated in several studies; however, the effectiveness of this method with older adults is not
certain. Although older adults are most likely to witness out-of-hospital cardiac arrests, these potential rescuers are underrepresented in traditional classes. We evaluated a VSI program that comprised a 22-min video, an inflatable training manikin, and an audio prompting device with individuals 40-70 years old. The
hypotheses were that VSI results in performance of basic CPR skills superior to that of untrained learners and similar to that of learners in Heartsaver classes.

METHODS: Two hundred and eighty-five adults between 40 and 70 years old who had had no CPR training within the past 5 years were assigned to an untrained control group, Heartsaver training, or one of three versions of VSI. Basic CPR skills were measured by instructor assessment and by a sensored manikin. RESULTS: The percentage of subjects who assessed unresponsiveness, called the emergency telephone number 911, provided adequate ventilation, proper hand placement, and adequate compression depth was significantly better (P<0.05) for the VSI groups than for untrained controls. VSI subjects tended to have better overall performance and better ventilation performance than did Heartsaver subjects.

CONCLUSIONS: Older adults learned the fundamental skills of CPR with this training program in about half an hour. If properly distributed, this type of training could produce a significant increase in the number of lay responders who can perform CPR.

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Effect of an inspiratory impedance threshold device on hemodynamics during conventional manual cardiopulmonary resuscitation.

Pirrallo RG, Aufderheide TP, Provo TA, Lurie KG. Resuscitation. 2005 Jul;66(1):13-20. Medical College of Wisconsin, Department of Emergency Medicine, 9200 W. Wisconsin Ave., FEH Room 1870, Milwaukee, WI 53226, USA. pirrallo@mcw.edu

BACKGROUND: In animals in cardiac arrest, an inspiratory impedance threshold device (ITD) has been shown to improve hemodynamics and neurologically intact survival. The objective of this study was to determine whether an ITD would improve blood pressure (BP) in patients receiving CPR for out-of-hospital cardiac arrest.

METHODS: This prospective, randomized, double-blind, intention-to-treat study was conducted in the Milwaukee, WI, emergency medical services (EMS) system. EMS personnel used an active (functional) or sham (non-functional) ITD on a tracheal tube on adults in cardiac arrest of presumed cardiac etiology. Care between groups was similar except for ITD type. Low dose epinephrine (1mg) was
used per American Heart Association Guidelines. Femoral arterial BP (mmHg) was measured invasively during CPR.

RESULTS: Mean+/-S.D. time from ITD placement to first invasive BP recording was approximately 14 min. Twelve patients were treated with a sham ITD versus 10 patients with an active ITD. Systolic BPs (mean+/-S.D.) [number of patients treated at given time point] at T = 0 (time of first arterial BP measurement), and T=2, 5 and 7 min were 85+/-29 [10], 85+/-23 [10], 85+/-16 [9] and 69+/-22 [8] in the group receiving an active ITD compared with 43+/-15 [12], 47+/-16 [12], 47+/-20 [9], and 52+/-23 [9] in subjects treated with a sham ITD, respectively (p < 0.01 for all times). Diastolic BPs at T = 0, 2, 5 and 7 min were 20+/-12, 21+/-13, 23+/-15 and 25+/-14 in the group receiving an active ITD compared with 15+/-9, 17+/-8, 17+/-9 and 19+/-8 in subjects treated with a sham ITD, respectively (p = NS for all times). No significant adverse device events were reported.

CONCLUSIONS: Use of the active ITD was found to increase systolic pressures safely and significantly in patients in cardiac arrest compared with sham controls.

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Out-of-hospital cardiac arrest rectilinear biphasic to monophasic damped sine defibrillation waveforms with advanced life support intervention trial (ORBIT). 

Morrison LJ, Dorian P, Long J, Vermeulen M, Schwartz B, Sawadsky B, Frank J, Cameron B, Burgess R, Shield J, Bagley P, Mausz V, Brewer JE, Lerman BB; Steering Committee, Central Validation Committee, Safety and Efficacy Committee. Resuscitation. 2005 Aug;66(2):149-57. Prehospital and Transport Medicine Research Program, Sunnybrook and Women's College Health Sciences Centre, Institute for Clinical and Evaluative Sciences, Department of Medicine, University of Toronto, Toronto, Ont., Canada. laurie.morrison@sw.ca

BACKGROUND: Although biphasic defibrillation waveforms appear to be superior to monophasic waveforms in terminating VF, their relative benefits in out-of-hospital resuscitation are incompletely understood. Prior comparisons of defibrillation waveform efficacy in out-of-hospital cardiac arrest (OHCA) are confined to patients presenting in a shockable rhythm and resuscitated by first responder (basic life support). This effectiveness study compared monophasic and biphasic defibrillation waveform for conversion of ventricular arrhythmias in all OHCA treated with advance life support (ALS).

METHODS AND RESULTS: This prospective randomized controlled trial compared the rectilinear biphasic (RLB) waveform with the monophasic damped sine (MDS) waveform, using step-up energy levels. The study enrolled OHCA patients requiring at least one shock delivered by ALS providers, regardless of initial presenting rhythm. Shock success was defined as conversion at 5s to organized rhythm after one to three escalating shocks. We report efficacy results for the cohort of patients treated by ALS paramedics who presented with an initially shockable rhythm who had not received a shock from a first responder (MDS: n=83; RLB: n=86). Shock success within the first three ascending energy shocks for RLB
(120, 150, 200J) was superior to MDS (200, 300, 360J) for patients initially presenting in a shockable rhythm (52% versus 34%, p=0.01). First shock conversion was 23% and12%, for RLB and MDS, respectively (p=0.07). There were no significant differences in return of spontaneous circulation (47% versus 47%), survival to 24h (31% versus 27%), and survival to discharge (9% versus 7%).
Mean 24h survival rates of bystander witnessed events showed differences between waveforms in the early circulatory phase at 4-10 min post event (mean (S.D.) RLB 0.45 (0.07) versus MDS 0.31 (0.06), p=0.0002) and demonstrated decline as time to first shock increased to 20 min.

CONCLUSION: Shock success to an organized rhythm comparing step-up protocol for energy settings demonstrated the RLB waveform was superior to MDS in ALS treatment of OHCA. Survival rates for both waveforms are consistent with current theories on the circulatory and metabolic phases of out-of-hospital cardiac arrest.

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Incomplete chest wall decompression: a clinical evaluation of CPR performance by EMS personnel and assessment of alternative manual chest compression-decompression techniques. 

Aufderheide TP, Pirrallo RG, Yannopoulos D, Klein JP, von Briesen C, Sparks CW, Deja KA, Conrad CJ, Kitscha DJ, Provo TA, Lurie KG. Resuscitation. 2005 Mar;64(3):353-62. Department of Emergency Medicine, Medical College of Wisconsin, 9200W. Wisconsin Avenue, FEH Room 1870, Milwaukee, WI 53226, USA.

BACKGROUND: Complete chest wall recoil improves hemodynamics during cardiopulmonary resuscitation (CPR) by generating relatively negative intrathoracic pressure and thus draws venous blood back to the heart, providing cardiac preload prior to the next chest compression phase.

OBJECTIVE: Phase I was an observational case series to evaluate the quality of chest wall recoil during CPR performed by emergency medical services (EMS) personnel on patients with an out-of-hospital cardiac arrest. Phase II was designed to assess the quality of CPR delivered by EMS personnel using an electronic
test manikin. The goal was to determine if a change in CPR technique or hand position would improve complete chest wall recoil, while maintaining adequate duty cycle, compression depth, and correct hand position placement. Standard manual CPR and three alternative manual CPR approaches were assessed.

METHODS AND RESULTS: Phase I--The clinical observational study was performed by an independent observer noting incomplete chest wall decompression and correlating that observation with electronically measured airway pressures during CPR in adult patients with out-of-hospital cardiac arrest. Rescuers were observed to maintain some residual and continuous pressure on the chest wall during the decompression phase of CPR, preventing full chest wall recoil, at some time during resuscitative efforts in 6 (46%) of 13 consecutive adults (average +/- S.D. age 63 +/-5.8 years). Airway pressures were consistently positive during the decompression phase (>0 mmHg) during those observations. Phase II: This randomized prospective trial was performed on an electronic test manikin. Thirty EMS providers (14 EMT-Basics, 5 EMT-Intermediates, and 11 EMT-Paramedics), with an average age +/- S.D. of 32 +/- 8 years and 6.5 +/- 4.2 years of EMS experience, performed 3 min of CPR on a Laerdal Skill Reporter CPR manikin using the Standard Hand Position followed by 3 min of CPR (in random order) using three alternative CPR techniques: (1) Two-Finger Fulcrum Technique--lifting the heel of the hand slightly but completely off the chest during the decompression phase of CPR using the thumb and little finger as a fulcrum; (2) Five-Finger Fulcrum Technique--lifting the heel of the hand slightly but completely
off the chest during the decompression phase of CPR using all five fingers as a fulcrum; and (3) Hands-Off Technique--lifting the heel and all fingersof the hand slightly but completely off the chest during the decompression phase of CPR. These EMS personnel did not know the purpose of the studies prior to or during this investigation. Adequate compression depth was poor for all hand positions tested and ranged only from 29.9 to 48.5% of all compressions. When compared with the Standard Hand Position, the Hands-Off Technique decreased mean compression duty cycle from 46.9 +/- 6.4% to 33.3 +/- 4.6%, (P < 0.0001) but achieved the highest rate of complete chest wall recoil (95.0% versus 16.3%, P < 0.0001) and was 129 times more likely to provide complete chest wall recoil (OR: 129.0; CI: 43.4-382.0). There were no significant differences in accuracy of hand placement, depth of compression, or reported increase in fatigue or discomfort with its use compared with the Standard Hand Position.

CONCLUSIONS: Incomplete chest wall decompression was observed at some time during resuscitative efforts in 6 (46%) of 13 consecutive adult out-of-hospital cardiac arrests. The Hands-Off Technique decreased compression duty cycle but was 129 times more likely to provide complete chest wall recoil (OR: 129.0; CI: 43.4-382.0) compared to the Standard Hand Position without differences in accuracy of hand placement, depth of compression, or reported increase in fatigue or discomfort with its use. All forms of manual CPR tested (including the Standard Hand Position) in professional EMS rescuers using a recording manikin produced an inadequate depth of compression more than half the time. These data support development and testing of more effective means to deliver manual as well as mechanical CPR.

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Chest compression rates during cardiopulmonary resuscitation are suboptimal: a prospective study during in-hospital cardiac arrest. 

Abella BS, Sandbo N, Vassilatos P, Alvarado JP, O'Hearn N, Wigder HN, Hoffman P, Tynus K, Vanden Hoek TL, Becker LB. 2005 Feb 1;111(4):428-34. Emergency Resuscitation Center and Section of Emergency Medicine, University of Chicago Hospitals, Chicago, Ill 60637, USA.

BACKGROUND: Recent data highlight a vital link between well-performed cardiopulmonary resuscitation (CPR) and survival after cardiac arrest; however, the quality of CPR as actually performed by trained healthcare providers is largely unknown. We sought to measure in-hospital chest compression rates and
to determine compliance with published international guidelines.

METHODS AND RESULTS: We developed and validated a handheld recording device to measure chest compression rate as a surrogate for CPR quality. A prospective observational study of adult cardiac arrests was performed at 3 hospitals from April 2002 to October 2003. Resuscitations were witnessed by trained observers using a customized personal digital assistant programmed to store the exact time of each chest compression, allowing offline calculation of compression rates at serial time points. In 97 arrests, data from 813 minutes during which chest compressions were delivered were analyzed in 30-second time segments. In 36.9% of the total number of segments, compression rates were <80 compressions per minute (cpm), and 21.7% had rates <70 cpm. Higher chest compression rates were significantly correlated with initial return of spontaneous circulation (mean chest compression rates for initial survivors and nonsurvivors,
90+/-17 and 79+/-18 cpm, respectively; P=0.0033).

CONCLUSIONS: In-hospital chest compression rates were below published resuscitation recommendations, and suboptimal compression rates in our study correlated with poor return of spontaneous circulation. CPR quality is likely a critical determinant of survival after cardiac arrest, suggesting the need for routine measurement, monitoring, and feedback systems during actual resuscitation.

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Trends in treated ventricular fibrillation in out-of-hospital cardiac arrest: ischemic compared to non-ischemic heart disease.

Bunch TJ, White RD. 2005 Oct;67(1):51-4. Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, College of Medicine, 200 First Street SW, Rochester, MN 55905, USA.

BACKGROUND: The incidence of ventricular fibrillation (VF) out-of-hospital cardiac arrest (OHCA) treated by first responders has declined over the past decade. Since VF OHCA occurs primarily in the setting of severe coronary artery disease, primary and secondary prevention strategies may in part account for the decline. However, such strategies may not have a similar impact on non-ischemic arrest.

METHODS: All Rochester Minnesota residents who presented with a VF OHCA from 1991 to 2004, treated by emergency medical services (EMS), were included in the study. Incidence rates were calculated based on the population for Rochester during the time period. Changes over time were tested using Poisson
regression models. The significance of the trends was estimated according to the Mantel-Haenszel test for association, and two-tailed p-values reported. RESULTS: The overall incidence of EMS-treated VF OHCA in Rochester during the study period was 10.6 per 100,000 (95% CI 9.1-11.8). The incidence decreased significantly (p<0.001) over the study period [1991-1994: 18.2/100,000 (95% CI 13.4-21.9); 1995-1999: 11.8/100,000 (95% CI 10.4-17.9); 2000-2004: 8.7/100,000 (95% CI 6.0-13.0)]. The incidence of VF OHCA with ischemic heart disease also declined [1991-1994: 13.4/100,000 (95% CI 8.9-16.9); 1995-1999: 11.1/100,000 (95% CI 8.2-15.9); 2000-2004: 5.5/100,000 (95% CI 3.8-8.2), p<0.001]. In contrast, the incidence VF OHCA with non-ischemic heart disease increased [1991-1994: 2.1/100,000 (95% CI 1.13-3.1); 1995-1999: 2.3/100,000 (95% CI 1.9-3.7); 2000-2004: 2.9/100,000 (95% CI 2.0-3.4), p<0.001].

CONCLUSION: The incidence of VF OHCA is declining. The decline is attributable to the reduction of VF cardiac arrest with ischemic heart disease; suggesting an impact of treatment strategies targeted at coronary artery disease. The relative increasing incidence of non-ischemic VF OHCA suggests that more efforts are required to minimize mortality in this cohort population.

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