Jocelyn Berdowski

Global incidences of out-of-hospital cardiac arrest and survival rates: Systematic review of 67 prospective studies ,

AIM The aim of this investigation was to estimate and contrast the global incidence and outcome of out-of-hospital cardiac arrest (OHCA) to provide a better understanding of the variability in risk and survival of OHCA. METHODS We conducted a review of published English-language articles about incidence of OHCA, available through MEDLINE and EmBase. For studies including adult patients and both adult and paediatric patients, we used Utstein data reporting guidelines to calculate, summarize and compare incidences per 100,000 person-years of attended OHCAs, treated OHCAs, treated OHCAs with a cardiac cause, treated OHCA with ventricular fibrillation (VF), and survival-to-hospital discharge rates following OHCA. RESULTS Sixty-seven studies from Europe, North America, Asia or Australia met inclusion criteria. The weighted incidence estimate was significantly higher in studies including adults than in those including adults and paediatrics for treated OHCAs (62.3 vs 34.7; P<0.001); and for treated OHCAs with a cardiac cause (54.6 vs 40.8; P=0.004). Neither survival to discharge rates nor VF survival to discharge rates differed statistically significant among studies. The incidence of treated OHCAs was higher in North America (54.6) than in Europe (35.0), Asia (28.3), and Australia (44.0) (P<0.001). In Asia, the percentage of VF and survival to discharge rates were lower (11% and 2%, respectively) than those in Europe (35% and 9%, respectively), North America (28% and 6%, respectively), or Australia (40% and 11%, respectively) (P<0.001, P<0.001). CONCLUSIONS OHCA incidence and outcome varies greatly around the globe. A better understanding of the variability is fundamental to improving OHCA prevention and resuscitation.

Importance of the First Link Description and Recognition of an Out-of-Hospital Cardiac Arrest in an Emergency Call

Background— The content of emergency calls for suspected cardiac arrest is rarely analyzed. This study investigated the recognition of a cardiac arrest by dispatchers and its influence on survival rates. Methods and Results— During 8 months, voice recordings of 14 800 consecutive emergency calls were collected to audit content and cardiac arrest recognition. The presence of cardiac arrest during the call was assessed from the ambulance crew report. Included calls were placed by laypersons on site and did not involve trauma. Prevalence of cardiac arrest was 3.0%. Of the 285 cardiac arrests, 82 (29%) were not recognized during the call, and 64 of 267 suspected calls (24%) were not cardiac arrest. We analyzed a random sample (n=506) of 9230 control calls. Three-month survival was 5% when a cardiac arrest was not recognized versus 14% when it was recognized (P=0.04). If the dispatcher did not recognize the cardiac arrest, the ambulance was dispatched a mean of 0.94 minute later (P<0.001) and arrived 1.40 minutes later on scene (P=0.01) compared with recognized calls. The main reason for not recognizing the cardiac arrest was not asking if the patient was breathing (42 of 82) and not asking to describe the type of breathing (16 of 82). Normal breathing was never mentioned in true cardiac arrest calls. A logistic regression model identified spontaneous trigger words like facial color that could contribute to cardiac arrest recognition (odds ratio, 7.8 to 9.7). Conclusions— Not recognizing a cardiac arrest during emergency calls decreases survival. Spontaneous words that the caller uses to describe the patient may aid in faster and better recognition of a cardiac arrest.

Impact of Onsite or Dispatched Automated External Defibrillator Use on Survival After Out-of-Hospital Cardiac Arrest

Background— There have been few studies on the effectiveness of bystander automated external defibrillator (AED) use in out-of-hospital cardiac arrest. The objective of this study was to determine whether actual use of onsite or dispatched AED reduces the time to first shock compared with no AED use and thereby improves survival. Methods and Results— We performed a population-based cohort study of 2833 consecutive patients with a nontraumatic out-of-hospital cardiac arrest before emergency medical system arrival between 2006 and 2009. The primary outcome, neurologically intact survival to discharge, was compared by use of multivariable logistic regression analysis. An onsite AED had been applied in 128 of the 2833 cases, a dispatched AED in 478, and no AED in 2227. Onsite AED use reduced the time to first shock from 11 to 4.1 minute. Neurologically intact survival was 49.6% for patients treated with an onsite AED compared with 14.3% without an AED (unadjusted odds ratio, 5.63; 95% confidence interval, 3.91–8.10). The odds ratio remained statistically significant after adjustment for confounding (odds ratio, 2.72; 95% confidence interval, 1.77–4.18). Dispatched AED use reduced the time from call to first shock to 8.5 minutes. Neurologically intact survival was 17.2% for patients treated with a dispatched AED (unadjusted odds ratio, 1.07; 95% confidence interval, 0.82–1.39). Every year, onsite AEDs saved 3.6 lives per 1 million inhabitants; dispatched AEDs saved 1.2 lives. Conclusions— The use of an onsite AED leads to a doubling of neurologically intact survival. In our system, the survival benefit of dispatched AED use was much smaller than that of onsite AED use.

Incidence, Causes, and Outcomes of Out-of-Hospital Cardiac Arrest in Children: A Comprehensive, Prospective, Population-Based Study in the Netherlands

OBJECTIVES This study sought to determine comprehensively the incidence of pediatric out-of-hospital cardiac arrest (OHCA) and its contribution to total pediatric mortality, the causes of pediatric OHCA, and the outcome of resuscitation of pediatric OHCA patients. BACKGROUND There is a paucity of complete studies on incidence, causes, and outcomes of pediatric OHCA. METHODS In this prospective, population-based study, OHCA victims younger than age 21 years in 1 province of the Netherlands were registered through both emergency medical services and coroners over a period of 4.3 years. Death certificate data on total pediatric mortality, survival status, and neurological outcome at hospital discharge also were obtained. RESULTS With a total mortality of 923 during the study period and 233 victims of OHCA (including 221 who died and 12 who survived), OHCA caused 24% (221 of 923) of total pediatric mortality. Natural causes of OHCA amounted to 115 (49%) cases, with cardiac causes being most prevalent (n = 90, 39%). The incidence of pediatric OHCA was 9.0 per 100,000 pediatric person-years (95% confidence interval: 7.8 to 10.3), whereas the incidence of pediatric OHCA from cardiac causes was 3.2 (95% confidence interval: 2.5 to 3.9). Of 51 resuscitated patients, 12 (24%) survived; among survivors, 10 (83%) had a neurologically intact outcome. CONCLUSIONS Out-of-hospital cardiac arrest accounts for a significant proportion of pediatric mortality, and cardiac causes are the most prevalent causes of OHCA. The vast majority of OHCA survivors have a neurologically intact outcome.

Exercise-related out-of-hospital cardiac arrest in the general population: incidence and prognosis

AIMS Although regular physical activity has beneficial cardiovascular effects, exercise can trigger an acute cardiac event. We aimed to determine the incidence and prognosis of exercise-related out-of-hospital cardiac arrest (OHCA) in the general population. METHODS AND RESULTS We prospectively collected all OHCAs in persons aged 10-90 years from January 2006 to January 2009 in the Dutch province North Holland. The relation between exercise during or within 1 h before OHCA and outcome was analysed using multivariable logistic regression, adjusted for age, gender, location, bystander witness, bystander cardiopulmonary resuscitation (CPR), automated external defibrillator (AED) use, initial rhythm, and Emergency Medical System response time. Of 2524 OHCAs, 143 (5.7%) were exercise related (7 ≤35 years, 93% men). Exercise-related OHCA incidence was 2.1 per 100 000 person-years overall and 0.3 per 100 000 person-years in those ≤35 years. Survival after exercise-related OHCA was distinctly better than after non-exercise related OHCA (46.2 vs. 17.2%) [unadjusted odds ratio (OR) 4.12; 95%CI 2.92-5.82; P < 0.001], even after adjustment for abovementioned variables (OR 2.63; 95%CI, 1.23-5.54; P = 0.01). In the 69 victims aged ≤35 years, exercise was not associated with better survival: 14.3 vs. 17.7% in non-exercise-related OHCA (OR 0.77; 95%CI 0.08-7.08; P = 0.82). CONCLUSION Exercise-related OHCA has a low incidence, particularly in the young. Cardiac arrests occurring during or shortly after exercise carry a markedly better prognosis than non-exercise-related arrests in persons >35 years. This study establishes the favourable outcome of exercise-related OHCA and should have direct implications for public health programs to prevent exercise-related sudden death.

Time needed for a regional emergency medical system to implement resuscitation Guidelines 2005-The Netherlands experience

INTRODUCTION In December 2005, updated resuscitation Guidelines (G) were introduced worldwide and will be revised again in 2010. This study sought to elucidate how long it takes to implement new guidelines. METHODS This was a prospective observational study. From July 2005 to January 2008, we included all patients with an out-of-hospital cardiac arrest of suspected cardiac cause. We analyzed Emergency Medical System (EMS) Guideline usage via defibrillator recordings of the continuous ECG and impedance signals. We excluded patients with missing or otherwise unusable ECGs. All shocks and CPR cycles were individually classified. The same Guideline needed to be applied for at least 75% of all shocks and CPR cycles. If no shocks had been given, continuous ECGs were classified by its CPR status only. Continuous ECGs were classified as G1992, G2000 or G2005. If at least 75% of the shocks were given according to G2000 and at least 75% of the CPR was according to G2005, the Guideline protocol was classified as intermediate. All analyses that did not fulfil any Guideline criteria were classified as indeterminate. RESULTS Of 1672 analyzable resuscitations, 31 (2%) used G1992, 826 (49%) G2000, 608 (36%) G2005, and 125 (7%) intermediate Guidelines. The Guideline protocol could not be identified for the remaining 81 (5%) patients. It took 17 months (from publication) until EMS personnel applied GL2005 in over 80% of cases. CONCLUSION Our experience shows it took one-and-a-half years to effectively implement new resuscitation Guidelines. We believe improvements in implementation can shorten this to six months.

Implantable Cardioverter-Defibrillators Have Reduced the Incidence of Resuscitation for Out-of-Hospital Cardiac Arrest Caused by Lethal Arrhythmias

Background— Over the last decades, a gradual decrease in ventricular fibrillation (VF) as initial recorded rhythm during resuscitation for out-of-hospital cardiac arrest (OHCA) has been noted. We sought to establish the contribution of implantable cardioverter-defibrillator (ICD) therapy to this decline. Methods and Results— Using a prospective database of all OHCA resuscitation in the province North Holland in the Netherlands (Amsterdam Resuscitation Studies [ARREST]), we collected data on all patients in whom resuscitation for OHCA was attempted in 2005–2008. VF OHCA incidence (per 100 000 inhabitants per year) was compared with VF OHCA incidence data during 1995–1997, collected in a similar way. We also collected ICD interrogations of all ICD patients from North Holland and identified all appropriate ICD shocks in 2005–2008; we calculated the number of prevented VF OHCA episodes, considering that only part of the appropriate shocks would result in avoided resuscitation. VF OHCA incidence decreased from 21.1/100 000 in 1995–1997 to 17.4/100 000 in 2005–2008 (P<0.001). Non-VF OHCA increased from 12.2/100 000 to 19.4/100 000 (P<0.001). VF as presenting rhythm declined from 63% to 47%. In 2005–2008, 1972 ICD patients received 977 shocks. Of these shocks, 339 were caused by a life-threatening arrhythmia. We estimate that these 339 shocks have prevented 81 (minimum, 39; maximum, 152) cases of VF OHCA, corresponding with 33% (minimum, 16%; maximum, 63%) of the observed decline in VF OHCA incidence. Conclusions— The incidence of VF OHCA decreased over the last 10 years in North Holland. ICD therapy explained a decrease of 1.2/100 000 inhabitants per year, corresponding with 33% of the observed decline in VF OHCA.

Chest Compressions Cause Recurrence of Ventricular Fibrillation After the First Successful Conversion by Defibrillation in Out-of-Hospital Cardiac Arrest

Background—Unlike Resuscitation Guidelines (GL) 2000, GL2005 advise resuming cardiopulmonary resuscitation (CPR) immediately after defibrillation. We hypothesized that immediate CPR resumption promotes earlier recurrence of ventricular fibrillation (VF). Methods and Results—This study used data of a prospective per-patient randomized controlled trial. Automated external defibrillators used by first responders were randomized to either (1) perform postshock analysis and prompt rescuers to a pulse check (GL2000), or (2) resume CPR immediately after defibrillation (GL2005). Continuous recordings of ECG and impedance signals were collected from all patients with an out-of-hospital cardiac arrest to whom a randomized automated external defibrillator was applied. We included patients with VF as their initial rhythm in whom CPR onset could be determined from the ECG and impedance signals. Time intervals are presented as median (Q1-to-Q3). Of 361 patients, 136 met the inclusion criteria: 68 were randomly assigned to GL2000 and 68 to GL2005. Rescuers resumed CPR 30 (21-to-39) and 8 (7-to-9) seconds, respectively, after the first shock that successfully terminated VF (P<0.001); VF recurred after 40 (21-to-76) and 21 (10-to-80) seconds, respectively (P=0.001). The time interval between start of CPR and VF recurrence was 6 (0-to-67) and 8 (3-to-61) seconds, respectively (P=0.88). The hazard ratio for VF recurrence in the first 2 seconds of CPR was 15.5 (95% confidence interval, 5.63 to 57.7) compared with before CPR resumption. After more than 8 seconds of CPR, the hazard of VF recurrence was similar to before CPR resumption. Conclusions—Early CPR resumption after defibrillation causes early VF recurrence. Clinical Trial Registration—clinicaltrials.gov Identifier: ISRCTN72257677.

Epilepsy is a risk factor for sudden cardiac arrest in the general population.

Background People with epilepsy are at increased risk for sudden death. The most prevalent cause of sudden death in the general population is sudden cardiac arrest (SCA) due to ventricular fibrillation (VF). SCA may contribute to the increased incidence of sudden death in people with epilepsy. We assessed whether the risk for SCA is increased in epilepsy by determining the risk for SCA among people with active epilepsy in a community-based study. Methods and Results This investigation was part of the Amsterdam Resuscitation Studies (ARREST) in the Netherlands. It was designed to assess SCA risk in the general population. All SCA cases in the study area were identified and matched to controls (by age, sex, and SCA date). A diagnosis of active epilepsy was ascertained in all cases and controls. Relative risk for SCA was estimated by calculating the adjusted odds ratios using conditional logistic regression (adjustment was made for known risk factors for SCA). We identified 1019 cases of SCA with ECG-documented VF, and matched them to 2834 controls. There were 12 people with active epilepsy among cases and 12 among controls. Epilepsy was associated with a three-fold increased risk for SCA (adjusted OR 2.9 [95%CI 1.1–8.0.], p = 0.034). The risk for SCA in epilepsy was particularly increased in young and females. Conclusion Epilepsy in the general population seems to be associated with an increased risk for SCA.

Time in Recurrent Ventricular Fibrillation and Survival After Out-of-Hospital Cardiac Arrest

Background— Current resuscitation guidelines (2005 guidelines [G2005]) accelerate ventricular fibrillation (VF) recurrence. We investigated whether patients resuscitated under G2005 spend more time in VF and have better survival rates than patients treated under the 2000 guidelines (G2000). Methods and Results— We analyzed continuous ECG recordings of out-of-hospital cardiac arrests prospectively collected from January 2006 to January 2008. Patients treated according to G2000 (n=282) or G2005 (n=240) with VF as initial rhythm were included. We measured the total time a patient was in recurrent VF (the sum of all intervals from each onset of recurrent VF to each next successful shock) and the time a patient was in initial VF (time interval from rescuer arrival to first effective shock). The primary outcome measure was neurologically intact survival to discharge. The median time in recurrent VF was 2.7 minutes (quartile 1 to 3, 0.4 to 9.0 minutes) under G2000 versus 4.0 minutes (quartile 1 to 3, 0.2 to 11.6 minutes) under G2005 (P=0.03). Median time in initial VF was 2.7 minutes (quartile 1 to 3, 1.7 to 4.3 minutes) versus 3.9 minutes (quartile 1 to 3, 2.3 to 6.5 minutes), respectively (P<0.001). Increased time in recurrent VF was significantly associated with decreased neurologically intact survival in both G2000 use (odds ratio, 0.92; 95% confidence interval, 0.87 to 0.97; P=0.001) and G2005 use (odds ratio, 0.94; 95% confidence interval, 0.90 to 0.99; P=0.02). Neurologically intact survival decreased significantly with increasing time in initial VF under G2000 (odds ratio, 0.86; 95% confidence interval, 0.74 to 0.99; P=0.04). This observation was nonexistent in patients treated under G2005. Neurologically intact survival was 29% (82 of 282) under G2000 versus 27% (65 of 240) under G2005 (P=0.61). Conclusions— With G2005, the time in recurrent VF remains associated with worse outcome. Studies of immediate defibrillation for recurrent VF are warranted.