Improvements in Out-of-Hospital Cardiac Arrest Survival from 1998 to 2013

Objectives: Out-of-hospital cardiac arrest (OHCA) remains a major public health burden. Aggregate OHCA survival to hospital discharge has reportedly remained unchanged at 7.6% for almost 30 years from 1970 to 2008. We examined the trends in adult OHCA survival over a 16-year period from 1998 to 2013 within a single EMS agency. Methods: Observational cohort study of adult OHCA patients treated by Tualatin Valley Fire & Rescue (TVF&R) from 1998 to 2013. This is an ALS first response fire agency that maintains an active Utstein style cardiac arrest registry and serves a population of approximately 450,000 in 9 incorporated cities in Oregon. Primary outcomes were survival to hospital discharge in all patients and in the subgroup with witnessed ventricular fibrillation/pulseless ventricular tachycardia (VF/VT). The impact of key covariates on survival was assessed using univariate logistic regression. These included patient factors (age and sex), event factors (location of arrest, witnessed status, and first recorded cardiac arrest rhythm), and EMS system factors (response time interval, bystander CPR, and non-EMS AED shock). We used multivariate logistic regression to examine the impact of year increment on survival after multiple imputation for missing data. Sensitivity analysis was performed with complete cases. Results: During the study period, 2,528 adult OHCA had attempted field resuscitation. The survival rate for treated cases increased from 6.7% to 18.2%, with witnessed VF/VT cases increasing from 14.3% to 31.4% from 1998 to 2013. Univariate analysis showed that younger age, male sex, public location of arrest, bystander or EMS witnessed event, initial rhythm of pulseless electrical activity (PEA) or VF/VT, bystander CPR, non-EMS AED shock, and a shorter EMS response time were independently associated with survival. After adjustment for covariates, the odds of survival increased by 9% (OR 1.09, 95%CI: 1.05–1.12) per year in all treated cases, and by 6% (OR 1.06, 95% 1.01–1.10) per year in witnessed VF/VT subgroups. Findings remained consistent on sensitivity analysis. Conclusions: Overall survival from treated OHCA has increased over the last 16 years in this community. These survival increases demonstrate that OHCA is a treatable condition that warrants further investigation and investment of resources.     

A prospective,randomised and blinded comparison of first shock success of monophasic and biphasic waveforms in out-of-hospital cardiac arrest

BACKGROUND: Evidence suggests that biphasic waveforms are more effective than monophasic waveforms for defibrillation in out-of-hospital cardiac arrest (OHCA), yet their performance has only been compared in un-blinded studies. METHODS AND RESULTS: We compared the success of biphasic truncated exponential (BTE) and monophasic damped sine (MDS) shocks for defibrillation in OHCA in a prospective, randomised, double blind clinical trial. First responders were equipped with MDS and BTE automated external defibrillators (AEDs) in a random fashion. Patients in ventricular fibrillation (VF) received BTE or MDS first shocks of 200 J. The ECG was recorded for subsequent analysis continuously. The success of the first shock as a primary endpoint was removal of VF and required a return of an organized rhythm for at least two QRS complexes, with an interval of <5 s, within 1 min after the first shock. The secondary endpoint was termination of VF at 5 s. VF was the initial recorded rhythm in 120 patients in OHCA, 51 patients received BTE and 69 received MDS shocks. The success rate of 200 J first shocks was significantly higher for BTE than for MDS shocks, 35/51 (69%) and 31/69 (45%), P=0.01. In a logistic regression model the odds ratio of success for a BTE shock was 4.01 (95% CI 1.01-10.0), adjusted for baseline cardiopulmonary resuscitation, VF-amplitude and time between collapse and first shock. No difference was found with respect to the secondary endpoint, termination of VF at 5 s (RR 1.07 95% CI: 0.99-1.11) and with respect to survival to hospital discharge (RR 0.73 95% CI: 0.31-1.70). CONCLUSION: BTE-waveform AEDs provide significantly higher rates of successful defibrillation with return of an organized rhythm in OHCA than MDS waveform AEDs.     

The prevalence of bacteremia in out of hospital cardiac arrest patients presenting to the emergency department of a tertiary care hospital

BackgroundOut-of-hospital cardiac arrest (OHCA) remains one of the most common causes of death. There is a scarcity of evidence concerning the prevalence of bacteraemia in cardiac arrest patients presenting to the Emergency Department (ED). We aimed to determine the prevalence of bacteraemia in OHCA patients presenting to the ED, as well as study the association between bacteraemia and in-hospital mortality in OHCA patients. In addition, the association between antibiotic use during resuscitation and in-hospital mortality was examined.Methods and resultsThis was a study of 200 adult OHCA patients who presented to the ED between 2015 and 2019. Bacteraemia was confirmed if at least one of the blood culture bottles grew a non-skin flora pathogen or if two blood culture bottles grew a skin flora pathogen from two different sites. The prevalence of bacteraemia was 46.5%. Gram positive bacteria, specifically Staphylococcus species, were the most common pathogens isolated from the bacteremic group. 42 patients survived to hospital admission. The multivariate analysis revealed that there was no association between bacteraemia and hospital mortality in OHCA patients (OR = 1.3, 95% CI= 0.2–9.2) with a p-value of .8. There was no association between antibiotic administration during resuscitation and hospital mortality (OR = 0.6, 95% CI= 0.1 − 3.8) with a p-value of .6.ConclusionIn our study, the prevalence of bacteraemia among OHCA patients presenting to the ED was found to be 46.5%. Bacteremic and non-bacteremic OHCA patients had similar initial baseline characteristics and laboratory parameters except for higher serum creatinine and BUN in the bacteremic group. In OHCA patients who survived their ED stay there was no association between hospital mortality and bacteraemia or antibiotic administration during resuscitation. There is a need for randomised controlled trials with a strong patient oriented primary outcome to better understand the association between in-hospital mortality and bacteraemia or antibiotic administration in OHCA patients.

KEY MESSAGES

• We aimed to determine the prevalence of bacteraemia in OHCA patients presenting to the Emergency Department. In our study, we found that 46.5% of patients presenting to our ED with OHCA were bacteremic.
• Bacteremic and non-bacteremic OHCA patients had similar initial baseline characteristics and laboratory parameters except for higher serum creatinine and BUN in the bacteremic group.
• We found no association between bacteraemia and hospital mortality. There was no association between antibiotic administration during resuscitation and hospital mortality.
• There is a need for randomised controlled trials with a strong patient oriented primary outcome to better understand the association between in-hospital mortality and bacteraemia or antibiotic administration in OHCA patients.

     

Outcomes and in-hospital treatment of out-of-hospital cardiac arrest patients resuscitated from ventricular fibrillation by early defibrillation

OBJECTIVE: To describe and evaluate the in-hospital treatment of ventricular arrhythmias and underlying structural heart disease in patients who survive ventricular fibrillation (VF) out-of-hospital cardiac arrest (OHCA) in a region with a high survival rate after hospital discharge. PATIENTS AND METHODS: The study included all patients presenting in Olmsted County, Minnesota, who had experienced OHCA between November 1990 and December 2000 and who underwent defibrillation of VF by an emergency medical service system. RESULTS: Of 200 patients who experienced VF arrest, 138 (69%) survived to hospital admission (7 died in the emergency department before admission), and 79 (40%) were discharged. Of patients who were discharged, 37 (47%) had a reversible cause of the arrest (perimyocardial infarction) and received treatment of the primary process. The other 42 patients who were discharged had ischemic coronary heart disease (CHD) (n=25), nonischemic CHD (n=10), or idiopathic VF (n=7). Four of the patients with CHD but no left ventricular dysfunction were treated with coronary artery bypass grafting or percutaneous coronary intervention alone. A total of 52 patients (66%) were candidates for electrophysiologic testing. Of these patients, 48 (92%) underwent electrophysiologic testing; of these patients, 10 received amiodarone alone, and 35 received an implantable cardioverter-defibrillator (ICD) (of whom 3 also received amiodarone). Patients who did not receive ICD therapy typically presented before 1998 with CHD and underwent coronary artery bypass grafting or percutaneous coronary intervention only. Of 79 patients who were discharged, 14 (18%) with an ICD have received subsequent shocks. Nineteen (24%) of 79 patients have died, 5 of a primary cardiac etiology (including 2 with repeated OHCA). CONCLUSIONS: The VF OHCA survival rate is high in the setting of rapid defibrillation, with 40% of patients being discharged from the hospital. By the end of the 10-year study, more patients were receiving antiarrhythmic therapy, in particular ICD implantation, after hospital admission. Overall, the long-term survival in patients with VF OHCA is favorable.     

Magnesium in cardiac arrest (the magic trial)

The prognosis of out of hospital cardiac arrest (OHCA) is dismal. Recent reports indicate that high dose magnesium may improve survival. A prospective randomized double blind placebo controlled trial was conducted at the emergency department (ED) of Royal Perth Hospital, a University teaching hospital. Patients with OHCA of cardiac origin received either 5 g MgSO4 or placebo as first line drug therapy. The remainder of their management was standard advanced cardiac life support (ACLS). Study endpoints were: (1) ECG rhythm 2 min after the trial drug; (2) return of spontaneous circulation; (3) survival to leave the ED; (4) survival to leave intensive care; and (5) survival to hospital discharge. Of 67 patients enrolled, 31 received magnesium and 36 placebo. There were no significant differences between groups for all criteria, except that there were significantly more arrests witnessed after arrival of EMS personnel in the magnesium group (11 or 35% vs 4 or 11%). Return of spontaneous circulation occurred in seven (23%) patients receiving magnesium and eight (22%) placebo. Four patients in each group survived to leave the ED and one from the magnesium group survived to hospital discharge. There were no survivors in the placebo group. In this study, the use of high dose magnesium as first line drug therapy for OHCA was not associated with a significantly improved survival. Early defibrillation remains the single most important treatment for ventricular fibrillation (VF). Further studies are required to evaluate the role of magnesium in cardiac and cerebral resuscitation.     

Increasing hospital volume is not associated with improved survival in out of hospital cardiac arrest of cardiac etiology

Background

Resuscitation centers may improve patient outcomes by achieving sufficient experience in post-resuscitation care. We analyzed the relationship between survival and hospital volume among patients suffering out-of-hospital cardiac arrest (OHCA).

Methods

This prospective cohort investigation collected data from the Cardiac Arrest Registry to Enhance Survival database from 10/1/05 to 12/31/09. Primary outcome was survival to discharge. Hospital characteristics were obtained via 2005 American Hospital Association Survey. A hospital's use of hypothermia was obtained via direct survey. To adjust for hospital- and patient-level variation, multilevel, hierarchical logistic regression was performed. Hospital volume was modeled as a categorical (OHCA/year ≤ 10, 11–39, ≥40) variable. A stratified analysis evaluating those with ventricular fibrillation or pulseless ventricular tachycardia (VF/VT) was also performed.

Results

The cohort included 4125 patients transported by EMS to 155 hospitals in 16 states. Overall survival to hospital discharge was 35% among those admitted to the hospital. Individual hospital rates of survival varied widely (0–100%). Unadjusted survival did not differ between the 3 hospital groups (36% for ≤10 OHCA/year, 35% for 11–39, and 36% for ≥40; p = 0.75). After multilevel adjustment, differences in survival across the groups were not statistically significant. Compared to patients at hospitals with ≤10 OHCA/year, adjusted OR for survival was 1.04 (CI₉₅ 0.83–1.28) among 11–39 annual volume and 0.97 (CI₉₅ 0.73–1.30) among the ≥40 volume hospitals. Among patients presenting with VF/VT, no difference in survival was identified between the hospital groups.

Conclusion

Survival varied substantially across hospitals. However, hospital OHCA volume was not associated with likelihood of survival. Additional efforts are required to determine what hospital characteristics might account for the variability observed in OHCA hospital outcomes.     

Cardiac arrest in Saudi Arabia: a 7-year experience in Riyadh.

All out-of-hospital and Emergency Department (ED) cardiac arrests treated at a tertiary care hospital in Riyadh, Saudi Arabia, from 1989 through 1995 were studied. Of patients arresting out-of-hospital, 3.0% received bystander cardiopulmonary resuscitation (CPR), 9.1% had some prehospital CPR, 12.1% were transported via ambulance, and 13.6% had ventricular fibrillation (VF) on ED arrival. In the witnessed arrests (80%), the estimated interval from arrest to initiation of CPR was 21.1 +/- 14.7 min. None of these variables was shown to influence outcome. Survival to hospital discharge from out-of-hospital arrest was 5.1% for adults and 7.4% for children; all had poor neurologic outcome. For patients arresting in the ED, an initial rhythm of ventricular tachycardia (VT) or VF was strongly correlated with survival. Survival from ED arrest was 30.4% in adults, 42.9% in children; all but one had normal neurologic outcome. These results are similar to those reported from large cities and EDs elsewhere. The unique set of variables influencing out-of-hospital care and transportation in Riyadh are discussed, and potential areas for improvement are noted.     

Outcome of out-of-hospital cardiac arrest--why do physicians withhold resuscitation attempts?

OBJECTIVE: To describe the outcome of out-of-hospital cardiac arrest (OHCA) with a focus on why physicians withhold resuscitation attempts. METHODS: Prospective collection of data during 12 months by the anaesthesiologists from the Advanced Life Support unit (ALS) of the Emergency Medical Service (EMS) according to the Utstein template. RESULTS: In total, 499 OHCA were analysed and 266 patients received cardiopulmonary resuscitation (CPR) by the ALS unit. Initial rhythm was ventricular fibrillation (VF)/pulseless ventricular tachycardia (VT) in 35%, asystole in 38%, and other rhythm in 27%. Of the 266 treated patients, 83 (31%) patients had a spontaneous circulation on admission to hospital. Survival to discharge from hospital was 6.2% for all cases of OHCA, 11.7% for all 266 treated patients, and 20.5% for patients with witnessed cardiac arrest and presumed cardiac aetiology in VF. On arrival, the physician decided in 233 cases to withhold or discontinue CPR. The explanation for this was prolonged anoxia (74%), terminal cancer (8%), and severe trauma (7%). The most common incident locations were the patient's home and nursing homes. These locations were more common in the group where resuscitation was not attempted and these patients were older and the proportions of females and asystole were significantly higher. Bystander CPR was provided in 82 (16%) overall, but only in 8 (3%) in the group where resuscitation was not attempted. CONCLUSION: Survival to discharge from hospital in all cases of OHCA was 6.2% but 20.5% in witnessed, presumed cardiac aetiology in VF. The decision to withhold resuscitation was based upon presumed prolonged anoxia in the majority of cases.     

Epidemiology, trends, and outcome of out-of-hospital cardiac arrest of non-cardiac origin

INTRODUCTION: The majority of victims who experience out-of-hospital cardiac arrest (OHCA) have ventricular fibrillation (VF) as the presenting rhythm and are thought to have a cardiac etiology for their arrest. Over the past decade, the incidence of VF OHCA has declined. The aims of this study were to describe the epidemiology of OHCA of non-cardiac origin in Olmsted County MN and to determine the trends that have occurred over time. METHODS: All residents with a traumatic OHCA from 1995 to 2005 were included for analysis. OHCA data were collected prospectively according to the Utstein method. Cardiac arrests were classified as cardiac or non-cardiac in origin and the etiology determined based on autopsy reports, electronic medical records, and/or emergency medical services reports. RESULTS: During the study period, 414 OHCAs were identified, 90 (21.7%) of which were classified as non-cardiac. Mean age was 61.5+/-19.7 years. Response time was 7.73+/-2.9 min, and 40 (44.4%) were bystander-witnessed. Sixty-eight (75.6%) arrests occurred at home, 13 (14.4%) in a public place, and 9 (10%) in other locations. Bystander CPR was performed in 17 (18.9%) cases. The presenting rhythm was VF in 2 (2.2%) cases, PEA in 54 (60%), and asystole in 34 (37.8%). Eight (8.9%) patients survived to hospital discharge. Respiratory failure (35.6%), unknown (15.6%), and pulmonary embolism (13.3%) were the most common etiologies. The mean percentage of arrests due to a non-cardiac cause in three sequential time-periods (1995-1999, 2000-2002, 2003-2005) was 9.4%, 20.1% and 37.7%, respectively. CONCLUSIONS: Over the study period, 21.7% of OHCAs were non-cardiac in origin. PEA was the most common presenting rhythm and respiratory failure the most common etiology. 8.9% of patients survived. The decreasing number of VF arrests may be a contributing factor to the increasing proportion of OHCAs of non-cardiac etiology observed in the out-of-hospital setting.     

Shock on T versus direct current voltage for induction of ventricular fibrillation: a randomized prospective comparison

VF is induced during ICD implantation to determine efficacy of therapy. Establishing the best clinical method of induction of VF would potentially be beneficial in reducing the number of induction attempts and reducing the frequency of inadvertent induction of VT. Commonly used methods to induce VF include shock in the T wave vulnerable period (T shock) and high frequency stimulation. This study compared the efficacy of T shock with a new induction method using a 9-V DC pulse. The study was a randomized, prospective, case crossover trial in patients receiving ICDs. VF was induced by T shock and DC in a randomized sequence during an ICD implant. VF was induced at least four times in each patient (two T shocks and two DC inductions) and with each induction; attempts were continued with modifications until successful. A paired evaluation between the T shock/DC induction was performed in 37 patients (28 men, age 64 +/- 12 years) with a left ventricular ejection fraction of 0.40 +/- 0.20. Arrhythmia indications were VT (n = 23), VF (n = 10), and VT/VF (n = 4). Drug therapy included amiodarone (n = 10), metoprolol (n = 6), digoxin (n = 1), and lidocaine (n = 1). The average T shock voltage was 207.0 +/- 16.1 V. The S1 cycle drive length was consistently 400 ms, and the mean S2 coupling interval was 317.8 +/- 19.6 ms. The length of time DC applied averaged 3.8 +/- 1.4 seconds. A total of 148 episodes of VF were included in the analysis. T shock induced VF with a cycle length of 213.5 +/- 35.1 ms, and DC induced VF with a cycle length of 214.6 +/- 34.5 ms (P = 0.86). Although VF was eventually induced for each randomization, the number of attempts required were dependent on the method of induction. The successful DC first attempt VF induction rate was 96%, with three patients requiring two attempts during one of the DC inductions. T shock had a 68% first attempt success rate with 21 patients requiring multiple T shocks to induce VF. All nine female patients had at least one unsuccessful first attempt T shock, which contributed to an overall unsuccessful first attempt induction rate significantly higher in women then men (36.1% vs 12.5%, P = 0.001). A constant DC voltage induction of VF may be more effective than T shock for induction of VF in a clinical setting because it reduces the number of attempts required to induce VF. By either method, VF appears to be more difficult to induce in women. DC induction has the advantage of simple programming of only duration of stimulation. These findings have implications particularly for ICD implantation with conscious sedation.     

Systemic thrombolysis for refractory cardiac arrest due to presumed myocardial infarction

The empiric usage of systemic thrombolysis for refractory out of hospital cardiac arrest (OHCA) is considered for pulmonary embolism (PE), but not for undifferentiated cardiac etiology [1, 2]. We report a case of successful resuscitation after protracted OHCA with suspected non-PE cardiac etiology, with favorable neurological outcome after empiric administration of systemic thrombolysis.A 47-year-old male presented to the emergency department (ED) after a witnessed OHCA with no bystander cardiopulmonary resuscitation (CPR). His initial rhythm was ventricular fibrillation (VF) which had degenerated into pulseless electrical activity (PEA) by ED arrival. Fifty-seven minutes into his arrest, we gave systemic thrombolysis which obtained return of spontaneous circulation (ROSC). He was transferred to the coronary care unit (CCU) and underwent therapeutic hypothermia. On hospital day (HD) 4 he began following commands and was extubated on HD 5. Subsequent percutaneous coronary intervention (PCI) revealed non-obstructive stenosis in distal LAD. He was discharged home directly from the hospital, with one-month cerebral performance category (CPC) score of one. He was back to work three months post-arrest.Emergency physicians (EP) should be aware of this topic since we are front-line health care professionals for OHCA. Thrombolytics have the advantage of being widely available in ED and therefore offer an option on a case-by-case basis when intra-arrest PCI and ECPR are not available. This case report adds to the existing literature on systemic thrombolysis as salvage therapy for cardiac arrest from an undifferentiated cardiac etiology. The time is now for this treatment to be reevaluated.     

Prehospital Predictors of Initial Shockable Rhythm in Out-of-Hospital Cardiac Arrest: Findings From the Taichung Sudden Unexpected Death Registry (THUNDER)

Objective

To identify the incidence and prehospital predictors of ventricular tachycardia/ventricular fibrillation (VT/VF) as the initial arrhythmia in patients with out-of-hospital cardiac arrest (OHCA) in central Taiwan.

Incidence and outcomes of out-of-hospital cardiac arrest with shock-resistant ventricular fibrillation: Data from a large population-based cohort

Background

The increasing survival rates after out-of-hospital cardiac arrests (OHCA) are due mainly to improvements in the first 3 steps of the chain of survival. The aim of this study was to describe the temporal trends of OHCA incidence and outcomes with shock-resistant ventricular fibrillation (VF) requiring advanced life support procedures.

Methods

All our subjects were persons aged 18 years or more who had suffered OHCA of presumed cardiac etiology, were witnessed by bystanders, treated by emergency medical service (EMS), and had VF as initial rhythm. Our study was conducted in Osaka Prefecture, Japan from May 1, 1998 through December 31, 2006. Data were collected by EMS personnel using an Utstein-style database. We evaluated the temporal trends of incidence and outcomes of shock-resistant VF.

Results

During the study period, there were 8782 witnessed OHCA cases of presumed cardiac etiology. Among them, 1733 had VF as an initial rhythm, 392 of whom were shock-resistant. While the age-adjusted annual incidence of witnessed VF increased from 2.0 to 3.3 per 100,000 inhabitants, that of shock-resistant VF underwent little change during the study period. The proportion of shock-resistant VF among witnessed VF decreased from 37.0% to 19.0%. Neurologically intact 1-month survival rates after shock-resistant VF remained low at 5.6% even in 2006.

Conclusion

The actual incidence of shock-resistant VF has remained unchanged, and their outcomes continue to be dismal. Further efforts are required to reduce the mortality rates of such shock-resistant VF to achieve improved survival after OHCA.     

Significant factors in predicting sustained ROSC in paediatric patients with traumatic out-of-hospital cardiac arrest admitted to the emergency department

BACKGROUND: Paediatric patients with out-of-hospital cardiac arrest (OHCA) due to trauma pose difficult challenges in resuscitation. Trauma is a major cause of OHCA in children. The aim of this study was to determine which factors were related to predicting a sustained return of spontaneous circulation (ROSC) in paediatric OHCA patients with trauma. METHOD: This retrospective study comprised 115 paediatric patients (56 traumatic and 59 non-traumatic OHCA patients) aged younger than 18 years who had been admitted to the emergency department (ED) from January 2000 to December 2004. We analysed the demographic data and the factors that may have influenced sustained ROSC in the group of OHCA paediatric patients with trauma. The non-trauma group was established as a control group. Survival analysis was used to compare differences in survival rate between trauma and non-trauma OHCA patients. Receiver operating characteristic (ROC) analysis was used to determine the significant in-hospital CPR duration related to sustained ROSC. RESULTS: Initial cardiac rhythm on arrival (P=0.005) and the duration of in-hospital CPR (P<0.001) were significant factors. Patients with PEA or VF had higher rate of sustained ROSC than those with asystole (PEA: P=0.003, VF: P=0.03). In the survival analysis, OHCA children with trauma had a lower chance of survival than non-trauma children as the interval from the scene to the ER increased (P=0.008). Based on the ROC analysis, the cut-off values of in-hospital CPR duration were 25min in OHCA paediatric patients with trauma. CONCLUSION: Several significant factors relating to sustained ROSC were determined in the OHCA paediatric patients with trauma; most importantly, we found that in-hospital CPR may have to be performed for at least 25min to enable a spontaneous circulation to return.     

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

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.     

Effectiveness of Prehospital Dual Sequential Defibrillation for Refractory Ventricular Fibrillation and Ventricular Tachycardia Cardiac Arrest

Objective: Dual sequential defibrillation (DSD) — successive defibrillations with two defibrillators — offers a novel approach to refractory ventricular fibrillation (RVF) and tachycardia (VF/VT). While associated with rescue shock success, the effect of DSD upon out-of-hospital cardiac arrest (OHCA) is unknown. We evaluated the association of DSD with survival after refractory VF/VT OHCA. Methods: We used data from a large metropolitan fire-based EMS service. We included all adult OHCA during 2013–2016 with ≥3 standard defibrillations. Physicians authorized subsequent DSD use by two separate defibrillators (PhysioControl LIFEPAK® 12/15) with pads placed anterior-lateral and anterior-posterior. Evaluated outcomes included return of spontaneous circulation (ROSC), survival to hospital admission, survival to 72?hours, and survival to hospital discharge. Using multivariable logistic regression, we evaluated the association between defibrillation type and OHCA outcomes, adjusting for patient demographics and event characteristics. Results: We included 310 patients in the analysis, 71 patients receiving DSD and 239 receiving conventional defibrillation. Patient demographics and event characteristics were similar between both groups. ROSC was lower for DSD than standard defibrillation: 39.4% vs. 60.3%, adjusted OR 0.46 (95% CI: 0.25–0.87). There were no differences in survival to hospital admission (35.2% vs. 49.2%, adjusted OR 0.57 [95% CI: 0.30–1.08]), survival to 72?hours (21.4% vs. 32.3%, adjusted OR 0.52 [95% CI: 0.26–1.10]), or survival to hospital discharge (14.3% vs. 20.9%, adjusted OR 0.63 [95% CI: 0.27–1.45]). Conclusions: Compared with conventional defibrillation, DSD was associated with lower odds of prehospital ROSC. Defibrillation type was not associated with other OHCA endpoints. DSD may not be beneficial in refractory VF/VT OHCA.     

The incidence and significance of bacteremia in out of hospital cardiac arrest

Background

The most common etiology of cardiac arrest is presumed of myocardial origin. Recent retrospective studies indicate that preexisting pneumonia, a form of sepsis, is frequent in patients who decompensate with abrupt cardiac arrest without preceding signs of septic shock, respiratory failure or severe metabolic disorders shortly after hospitalization. The contribution of pre-existing infection on pre and post cardiac arrest events remains unknown and has not been studied in a prospective fashion. We sought to examine the incidence of pre-existing infection in out-of hospital cardiac arrest (OHCA) and assess characteristics associated with bacteremia, the goal standard for presence of infection.

Methods and results

We prospectively observed 250 OHCA adult patients who presented to the Emergency Department (ED) between 2007 and 2009 to an urban academic teaching institution. Bacteremia was defined as one positive blood culture with non-skin flora bacteria or two positive blood cultures with skin flora bacteria. 77 met pre-defined exclusion criteria. Of the 173 OHCA adults, 65 (38%) were found to be bacteremic with asystole and PEA as the most common presenting rhythms. Mortality in the ED was significantly higher in bacteremic OHCA (75.4%) compared to non-bacteremic OHCA (60.2%, p < 0.05). After adjustment for potential confounders, predictive factors associated with bacteremic OHCA were lower initial arterial pH, higher lactate, WBC, BUN and creatinine.

Conclusions

Over one-third of OHCA adults were bacteremic upon presentation. These patients have greater hemodynamic instability and significantly increased short-term mortality. Further studies are warranted to address the epidemiology of infection as possible cause of cardiac arrest.     

Pre-hospital body surface potential mapping improves early diagnosis of acute coronary artery occlusion in patients with ventricular fibrillation and cardiac arrest

Aims

To determine whether 80-lead body surface potential mapping (BSPM) improves detection of acute coronary artery occlusion in patients presenting with out-of-hospital cardiac arrest (OHCA) due to ventricular fibrillation (VF) and who survived to reach hospital.

Methods and results

Of 645 consecutive patients with OHCA who were attended by the mobile coronary care unit, VF was the initial rhythm in 168 patients. Eighty patients survived initial resuscitation, 59 of these having had BSPM and 12-lead ECG post-return of spontaneous circulation (ROSC) and in 35 patients (age 69 ± 13 yrs; 60% male) coronary angiography performed within 24 h post-ROSC. Of these, 26 (74%) patients had an acutely occluded coronary artery (TIMI flow grade [TFG] 0/1) at angiography. Twelve-lead ECG criteria showed ST-segment elevation (STE) myocardial infarction (STEMI) using Minnesota 9-2 criteria – sensitivity 19%, specificity 100%; ST-segment depression (STD) ≥0.05 mV in ≥2 contiguous leads – sensitivity 23%, specificity 89%; and, combination of STEMI or STD criteria – sensitivity 46%, specificity 100%. BSPM STE occurred in 23 (66%) patients. For the diagnosis of TFG 0/1 in a main coronary artery, BSPM STE had sensitivity 88% and specificity 100% (c-statistic 0.94), with STE occurring most commonly in either the posterior, right ventricular or high right anterior territories.

Conclusion

Among OHCA patients presenting with VF and who survived resuscitation to reach hospital, post-resuscitation BSPM STE identifies acute coronary occlusion with sensitivity 88% and specificity 100% (c-statistic 0.94).     

Cardiac arrest in private locations: different strategies are needed to improve outcome

BACKGROUND: A tremendous amount of public resources are focused on improving cardiac arrest (OHCA) survival in public places, yet most OHCAs occur in private residences. METHODS AND RESULTS: A prospective, observational study of patients transported to seven urban and suburban hospitals and the individuals who called 911 at the time of a cardiac arrest (bystander) was performed. Bystanders (N=543) were interviewed via telephone beginning 2 weeks after the incident to obtain data regarding patient and bystander demographics, including cardiopulmonary resuscitation (CPR) training. Of all arrests 80.2% were in homes. Patients who arrested in public places were significantly younger (63.2 vs. 67.2, P<0.02), more often had an initial rhythm of VF (63.0 vs. 37.7%, P<0.001), were seen or heard to have collapsed by a bystander (74.8 vs. 48.1%, P<0.001), received bystander CPR (60.2 vs. 28.6%, P<0.001), and survived to DC (17.5 vs. 5.5%, P<0.001). Patients who arrested at home were older and had an older bystander (55.4 vs. 41.3, P<0.001). The bystander was less likely to be CPR trained (65.0 vs. 47.4%, P<0.001), less likely to be trained within the last 5 years (49.2 vs. 17.9, P<0.001), and less likely to perform CPR if trained (64.2 vs. 30.0%, P<0.001). Collapse to shock intervals for public versus home VF patients were not different. CONCLUSIONS: Many important characteristics of cardiac arrest patients and the bystander differ in public versus private locations. Fundamentally different strategies are needed to improve survival from these events.     

A pilot randomised trial of thrombolysis in cardiac arrest (The TICA trial)

INTRODUCTION: The outcome after out of hospital cardiac arrest is dismal. Thrombolysis during CPR has been advocated. Our hypothesis was that early administration of bolus thrombolysis could lead to improved survival from out of hospital cardiac arrest. METHODS: A prospective, randomised, double blind placebo controlled trial. All victims of out of hospital cardiac arrest brought to the Emergency Department (ED) by the emergency medical system were eligible for inclusion. All patients received standard advanced cardiac life support, except that the first drug the patient received was either tenecteplase 50 mg or placebo. The primary end point was return of spontaneous circulation (ROSC). RESULTS: Of 35 patients enrolled, 19 received tenecteplase and 16 placebo. The tenecteplase group was younger (63 vs 72 years P = 0.04) and had significantly more ventricular fibrillation as the initial rhythm (63% versus 19%, 44% difference, 95% CI 15-73%). There was no difference in rhythm on arrival at the ED. ROSC occurred in 8 (42%) patients receiving tenecteplase and one (6%) placebo (36% difference, 95% CI 11-61%). Two tenecteplase and one placebo patient survived to leave ED, and one in each group survived to hospital discharge. Autopsy results were available on eight patients, five of whom had a thrombotic cause of death. CONCLUSION: In this pilot study, we found the use of early bolus tenecteplase for OHCA to be feasible, and that it appears to increase the rate of ROSC. Larger studies are required to determine if this translates into a survival benefit. Appropriate patient selection for OHCA studies remains problematic.