Gena K. Sears

Epidemiology and Outcomes From Out-of-Hospital Cardiac Arrest in Children The Resuscitation Outcomes Consortium Epistry–Cardiac Arrest

Background— Population-based data for pediatric cardiac arrest are scant and largely from urban areas. The Resuscitation Outcomes Consortium (ROC) Epistry–Cardiac Arrest is a population-based emergency medical services registry of out-of-hospital nontraumatic cardiac arrest (OHCA). This study examined age-stratified incidence and outcomes of pediatric OHCA. We hypothesized that survival to hospital discharge is less frequent from pediatric OHCA than adult OHCA. Methods and Results— This prospective population-based cohort study in 11 US and Canadian ROC sites included persons <20 years of age who received cardiopulmonary resuscitation or defibrillation by emergency medical service providers and/or received bystander automatic external defibrillator shock or who were pulseless but received no resuscitation by emergency medical services between December 2005 and March 2007. Patients were stratified a priori into 3 age groups: <1 year (infants; n=277), 1 to 11 years (children; n=154), and 12 to 19 years (adolescents; n=193). The incidence of pediatric OHCA was 8.04 per 100 000 person-years (72.71 in infants, 3.73 in children, and 6.37 in adolescents) versus 126.52 per 100 000 person-years for adults. Survival for all pediatric OHCA was 6.4% (3.3% for infants, 9.1% for children, and 8.9% for adolescents) versus 4.5% for adults (P=0.03). Unadjusted odds ratio for pediatric survival to discharge compared with adults was 0.71 (95% confidence interval, 0.37 to 1.39) for infants, 2.11 (95% confidence interval, 1.21 to 3.66) for children, and 2.04 (95% confidence interval, 1.24 to 3.38) for adolescents. Conclusions— This study demonstrates that the incidence of OHCA in infants approaches that observed in adults but is lower among children and adolescents. Survival to discharge was more common among children and adolescents than infants or adults.

Toxic and therapeutic effects of amiodarone in the treatment of cardiac arrhythmias

Amiodarone was used to treat cardiac arrhythmias that had been refractory to conventional medical therapy. The first 70 consecutive patients treated with amiodarone in this study had at least 6 months of follow-up (range 6 to 24, mean 11) and form the basis for this report. Sixty-six patients were treated for ventricular arrhythmias and four for supraventricular tachycardias. Amiodarone therapy consisted of a loading dose of 600 mg orally twice a day for 7 days, and 600 mg daily thereafter. Doses were reduced only if side effects occurred. Because of frequent side effects, the dose was reduced from 572 +/- 283 mg per day (mean +/- standard deviation) at 45 days to 372 +/- 174 mg per day at 6 months. With a mean follow-up of 11 months in the 54 patients who continued to take amiodarone, only 4 patients had ventricular fibrillation. Three additional patients experienced recurrent sustained ventricular tachycardia in long-term follow-up. All 70 patients had extensive clinical and laboratory evaluation in follow-up. Side effects were common, occurring in 93% of patients. Thirteen patients (19%) had to discontinue the medication because of severe side effects. Fifty-six patients had gastrointestinal side effects, most commonly constipation. All patients but 1 eventually developed corneal microdeposits, and 43 patients were symptomatic. Cardiovascular side effects were uncommon. Symptomatic pulmonary side effects occurred in seven patients, with unequivocal pulmonary toxicity occurring in five. Neurologic side effects, most commonly tremor and ataxia, occurred in 52 patients. Thyroid dysfunction occurred in 3 patients, and 32 patients had cutaneous abnormalities. Miscellaneous other side effects occurred in 32 patients. Amiodarone appears to be useful in the management of refractory arrhythmias. Because virtually all patients develop side effects when given a maintenance daily dose of 600 mg, lower maintenance doses should be used. It is unknown if the more severe side effects are dose-related. Amiodarone is difficult to administer because of its narrow toxic-therapeutic range and prolonged loading phase. More importantly, the first sign of antiarrhythmic failure may be manifest as sudden cardiac death.

Effect of real-time feedback during cardiopulmonary resuscitation outside hospital: prospective, cluster-randomised trial

Objective To investigate whether real-time audio and visual feedback during cardiopulmonary resuscitation outside hospital increases the proportion of subjects who achieved prehospital return of spontaneous circulation. Design A cluster-randomised trial. Subjects 1586 people having cardiac arrest outside hospital in whom resuscitation was attempted by emergency medical services (771 procedures without feedback, 815 with feedback). Setting Emergency medical services from three sites within the Resuscitation Outcomes Consortium in the United States and Canada. Intervention Real-time audio and visual feedback on cardiopulmonary resuscitation (CPR) provided by the monitor-defibrillator. Main outcome measure Prehospital return of spontaneous circulation after CPR. Results Baseline patient and emergency medical service characteristics did not differ between groups. Emergency medical services muted the audible feedback in 14% of cases during the period with feedback. Compared with CPR clusters lacking feedback, clusters assigned to feedback were associated with increased proportion of time in which chest compressions were provided (64% v 66%, cluster-adjusted difference 1.9 (95% CI 0.4 to 3.4)), increased compression depth (38 v 40 mm, adjusted difference 1.6 (0.5 to 2.7)), and decreased proportion of compressions with incomplete release (15% v 10%, adjusted difference −3.4 (−5.2 to −1.5)). However, frequency of prehospital return of spontaneous circulation did not differ according to feedback status (45% v 44%, adjusted difference 0.1% (−4.4% to 4.6%)), nor did the presence of a pulse at hospital arrival (32% v 32%, adjusted difference −0.8 (−4.9 to 3.4)), survival to discharge (12% v 11%, adjusted difference −1.5 (−3.9 to 0.9)), or awake at hospital discharge (10% v 10%, adjusted difference −0.2 (−2.5 to 2.1)). Conclusions Real-time visual and audible feedback during CPR altered performance to more closely conform with guidelines. However, these changes in CPR performance were not associated with improvements in return of spontaneous circulation or other clinical outcomes. Trial Registration Clinical Trials NCT00539539

Early coronary angiography and induced hypothermia are associated with survival and functional recovery after out-of-hospital cardiac arrest

BACKGROUND The rate and effect of coronary interventions and induced hypothermia after out-of-hospital cardiac arrest (OHCA) are unknown. We measured the association of early (≤24h after arrival) coronary angiography, reperfusion, and induced hypothermia with favorable outcome after OHCA. METHODS We performed a secondary analysis of a multicenter clinical trial (NCT00394706) conducted between 2007 and 2009 in 10 North American regions. Subjects were adults (≥18 years) hospitalized after OHCA with pulses sustained ≥60min. We measured the association of early coronary catheterization, percutaneous coronary intervention, fibrinolysis, and induced hypothermia with survival to hospital discharge with favorable functional status (modified Rankin Score≤3). RESULTS From 16,875 OHCA subjects, 3981 (23.6%) arrived at 151 hospitals with sustained pulses. 1317 (33.1%) survived to hospital discharge, with 1006 (25.3%) favorable outcomes. Rates of early coronary catheterization (19.2%), coronary reperfusion (17.7%) or induced hypothermia (39.3%) varied among hospitals, and were higher in hospitals treating more subjects per year. Odds of survival and favorable outcome increased with hospital volume (per 5 subjects/year OR 1.06; 95%CI: 1.04-1.08 and OR 1.06; 95%CI: 1.04, 1.08, respectively). Survival and favorable outcome were independently associated with early coronary angiography (OR 1.69; 95%CI 1.06-2.70 and OR 1.87; 95%CI 1.15-3.04), coronary reperfusion (OR 1.94; 95%CI 1.34-2.82 and OR 2.14; 95%CI 1.46-3.14), and induced hypothermia (OR 1.36; 95%CI 1.01-1.83 and OR 1.42; 95%CI 1.04-1.94). INTERPRETATION Early coronary intervention and induced hypothermia are associated with favorable outcome and are more frequent in hospitals that treat higher numbers of OHCA subjects per year.

Variation in Out-of-Hospital Cardiac Arrest Resuscitation and Transport Practices in the Resuscitation Outcomes Consortium: ROC Epistry–Cardiac Arrest

OBJECTIVES To identify variation in patient, event, and scene characteristics of out-of-hospital cardiac arrest (OOHCA) patients assessed by emergency medical services (EMS), and to investigate variation in transport practices in relation to documented prehospital return of spontaneous circulation (ROSC) within eight regional clinical centers participating in the Resuscitation Outcomes Consortium (ROC) Epistry-Cardiac Arrest. METHODS OOHCA patient, event, and scene characteristics were compared to identify variation in treatment and transport practices across sites. Findings were adjusted for site and standard Utstein covariates. Using logistic regression, these covariates were modeled to identify factors related to the initiation of transport without documented prehospital ROSC as well as survival in these patients. SETTING Eight US and Canadian sites participating in the ROC Epistry-Cardiac Arrest. POPULATION Persons ≥ 20 years with OOHCA who (a) received compressions or shock by EMS providers and/or received bystander AED shock or (b) were pulseless but received no EMS compressions or shock between December 2005 and May 2007. RESULTS 23,233 OOHCA cases were assessed by EMS in the defined period. Resuscitation (treatment) was initiated by EMS in 13,518 cases (58%, site range: 36-69%, p < 0.0001). Of treated cases, 59% were transported (site range: 49-88%, p < 0.0001). Transport was initiated in the absence of documented ROSC for 58% of transported cases (site range: 14-95%, p < 0.0001). Of these transported cases, 8% achieved ROSC before hospital arrival (site range: 5-21%, p < 0.0001) and 4% survived to hospital discharge (site range: 1-21%, p < 0.0001). In cases with transport from the scene initiated after documented ROSC, 28% survived to hospital discharge (site range: 18-44%, p < 0.0001). CONCLUSION Initiation of resuscitation and transport of OOHCA and the reporting of ROSC prior to transport markedly varies among ROC sites. This variation may help clarify reported differences in survival rates among sites and provide a target for identifying EMS practices most likely to enhance survival from OOHCA.

Out-of-Hospital Cardiac Arrest Frequency and Survival: Evidence for Temporal Variability

AIM Some cardiac phenomena demonstrate temporal variability. We evaluated temporal variability in out-of-hospital cardiac arrest (OHCA) frequency and outcome. METHODS Prospective cohort study (the Resuscitation Outcomes Consortium) of all OHCA of presumed cardiac cause who were treated by emergency medical services within 9 US and Canadian sites between 12/1/2005 and 02/28/2007. In each site, Emergency Medical System records were collected and analyzed. Outcomes were individually verified by trained data abstractors. RESULTS There were 9667 included patients. Median age was 68 (IQR 24) years, 66.7% were male and 8.3% survived to hospital discharge. The frequency of cardiac arrest varied significantly across time blocks (p<0.001). Compared to the 0001-0600 hourly time block, the odds ratios and 95% CIs for the occurrence of OHCA were 2.02 (1.90, 2.15) in the 0601-1200 block, 2.01 (1.89, 2.15) in the 1201-1800 block, and 1.73 (1.62, 1.85) in the 1801-2400 block. The frequency of all OHCA varied significantly by day of week (p=0.03) and month of year (p<0.001) with the highest frequencies on Saturday and during December. Survival to hospital discharge was lowest when the OHCA occurred during the 0001-0600 time block (7.3%) and highest during the 1201-1800 time block (9.6%). Survival was highest for OHCAs occurring on Mondays (10.0%) and lowest for those on Wednesdays (6.8%) (p=0.02). CONCLUSION There is temporal variability in OHCA frequency and outcome. Underlying patient, EMS system and environmental factors need to be explored to offer further insight into these observed patterns.

Effect of amiodarone on serum quinidine and procainamide levels

Serum levels of quinidine or procainamide were measured in patients who had amiodarone added to their antiarrhythmic regimen. Dosages of quinidine or procainamide were held constant. Eleven of 11 patients had an increase in the serum quinidine level, and 11 of 12 other patients had an increase in the serum procainamide level. The dose requirement to maintain a stable plasma level of quinidine or procainamide decreased by 37% and 20%, respectively. Clinical toxicity occasionally occurred with the increase in serum levels of quinidine and procainamide, and the dose of these drugs should be decreased when amiodarone is administered concurrently.

The Resuscitation Outcomes Consortium Epistry-Trauma: design, development, and implementation of a North American epidemiologic prehospital trauma registry.

Injury is a major public health problem generating substantial morbidity, mortality, and economic burden on society. The majority of seriously injured persons are initially evaluated and cared for by prehospital providers, however the effect of emergency medical services (EMS) systems, EMS clinical care, and EMS interventions on trauma patient outcomes is largely unknown. Outcome-based information to guide future EMS care has been hampered by the lack of comprehensive, standardized, multi-center prehospital data resources that include meaningful patient outcomes. In this paper, we describe the background, design, development, implementation, content, and potential uses of the first North American comprehensive epidemiologic prehospital data registry for injured persons. This data registry samples patients from 264 EMS agencies transporting to 287 acute care hospitals in both the United States and Canada.

Regional variations in early and late survival after out-of-hospital cardiac arrest

BACKGROUND While prior studies highlight regional variations in out-of-hospital cardiac arrest (OHCA) survival, the underlying reasons remain unknown. We sought to characterize regional variations early and later survival to hospital discharge after OHCA. METHODS We studied adult, non-traumatic OHCA treated by 10 regional sites of the Resuscitation Outcomes Consortium (ROC) during 12/01/2005-6/30/2007. We compared (1) early survival (up to one calendar day after arrest) and (2) later conditional survival to hospital discharge (early survivors progressing to eventual hospital discharge) between ROC regional sites. RESULTS Among 3763 VF/VT with complete covariates, site unadjusted early survival varied from 11.3 to 54.3%, and site unadjusted later survival varied from 33.3 to 70.5%. Compared with the largest site, adjusted VF/VT survival varied across sites: early survival OR 0.33 (95% CI: 0.17, 0.65) to 2.87 (2.20, 3.73), overall site variation p<0.001; later survival OR 0.29 (0.14, 0.59) to 1.21 (0.73, 2.00), p<0.001. Among 10,879 non-VF/VT with complete covariates, site unadjusted early survival varied from 6.6 to 14.3%, and site unadjusted later survival varied from 4.5 to 39.6%. Compared with the largest site, adjusted non-VF/VT survival varied across sites: early survival OR 1.02 (0.63, 1.64) to 2.43 (1.91, 3.12), p<0.001; later survival OR 0.11 (0.01, 0.82) to 1.56 (0.90, 2.70), p=0.02. CONCLUSIONS In this prospective multicenter North American series, there were regional disparities in early and later survival after OHCA, suggesting that there are underlying regional differences in out-of-hospital and post-arrest care beyond traditional Utstein predictors. Community efforts to improve OHCA survival must address both out-of-hospital and in-hospital care.

Prolongation of cardiac refractory times in man by clofilium phosphate, a new antiarrhythmic agent☆

The electrophysiologic effects of clofilium phosphate, a new quaternary ammonium antiarrhythmic agent, were evaluated in 15 patients with a variety of cardiac dysrhythmias. Ten patients had ventricular dysrhythmias and five patients had supraventricular dysrhythmias. Clofilium was administered as a single bolus intravenously in doses ranging from 60 to 300 micrograms/kg during electrophysiologic testing. Blood pressure and heart rate were unchanged, and there were no significant side effects. Conduction time was unchanged in atrial tissue, ventricular tissue, atrioventricular node, and in the His-Purkinje system. QT intervals lengthened, atrial effective refractory period increased, and ventricular effective refractory period increased. The effective refractory period of the AV node was unchanged. Refractoriness of the bundle branches or His-Purkinje system was increased in eight patients. Inducible supraventricular arrhythmias were improved in four of four patients, and inducible ventricular arrhythmias were improved in at least five of nine patients. Clofilium is a model for an antiarrhythmic drug which should be useful in interrupting or suppressing reentrant arrhythmias because it increases refractoriness without major changes in conduction time.