Outcomes from out-of-hospital cardiac arrest in Detroit

OBJECTIVE: To determine the out-of-hospital cardiac arrest survival rate, and prevalence of modifiable factors associated with survival, in Detroit, Michigan, over a 6-month period of time in 2002. METHODS: A retrospective review of all out-of-hospital cardiac arrests responded to by the Detroit Fire Department, Division of Emergency Medical Services. All elements of the EMS runsheet were transcribed to a database for analysis. Patient hospital records were reviewed to determine survival to hospital admission. All survivors to hospital admission were surveyed later in the Michigan Department of Vital Records death registry search. RESULTS: During this study timeframe, there were 538 confirmed out-of-hospital cardiac arrests within the City of Detroit, of which 67 were excluded for being dead on scene [51 (12.5%)] or having no available hospital records [16 (3.0%)]. Of the remaining 471 patients, 443 (94.1%) died before hospital admission. Only 44 (9.9%) of the 471 patients had a first recorded rhythm of ventricular fibrillation (VF), and 339 (76.5%) were asystolic. Of the 28 patients who survived to hospital admission, only 2 (7.1%) were noted to have a first rhythm of VF, and 15 (53.6%) were asystolic. Only one patient survived to hospital discharge. CONCLUSIONS: In this urban setting, out-of-hospital cardiac arrest is an almost uniformly fatal event.     

Effect of protocol compliance to cardiac arrest identification by emergency medical dispatchers

OBJECTIVES: The objective of the study was to assess the effect of protocol compliance to the accuracy of cardiac arrest (CA) identification by the dispatchers. METHODS: The study was conducted prospectively over a 1-year period in 1996. The calls categorized as non-traumatic CAs by the dispatcher and calls where the patient was in non-traumatic CA when ambulance crew arrived were included in the study. The data was collected from emergency call tape recordings and ambulance run sheets. The compliance to the protocol was defined as gathering information to two questions: (1) Is the patient awake or can she/he be awakened? and (2) Is she/he breathing normally? RESULTS: The number of calls included in the study was 776 and the dispatchers identified 83% of the CAs. The protocol was adhered in 52.4% of calls, more often in witnessed than unwitnessed cases (72.3% versus 45.0%, P<0.001). In correctly identified CAs, the protocol compliance was 49.4%. The compliance was higher in cases of unidentified CAs (60.3%, P=0.0326) and in cases of wrongly identified as CAs (false positives, 61.9%, P=0.0276). CONCLUSIONS: A high identification rate of CAs seems to be achievable despite poor protocol compliance by dispatchers.     

Survival from out-of-hospital cardiac arrest in New Zealand following the 2005 resuscitation guideline changes

Aims

The effect of cardiopulmonary resuscitation guideline changes on out-of-hospital survival rates and defibrillation efficacy was investigated. The guideline changes were those recommended by the International Liaison Committee on Resuscitation in 2005.

Methods

A retrospective comparative study was undertaken of out-of-hospital cardiac arrests in the Wellington region. The effect of guideline changes between the periods of 1st July 2005-30th June 2006 and 1st June 2007-31st May 2008 was examined. Data was collected from Wellington Free Ambulance and hospital records in accordance with the Utstein template. The primary outcome measure was survival to hospital discharge. Additional end points included individual shock success, return of spontaneous circulation (ROSC) and survival to hospital admission.

Results

There was no significant increase in survival to hospital discharge with 11% (18/162) pre-change and 12% (20/170) post-change (p = 0.5). First-shock efficacy decreased from 68% (65/96) to 62% (57/92) (p = 0.75). Second shock efficacy decreased from 47% (14/30) to 27% (9/33) (p = 0.12). The proportion of patients with ROSC increased from 34% (55/162) to 42% (72/170) (p = 0.07, Chi squared). The proportion surviving to hospital increased significantly from 22% (36/162) to 36% (61/170) (p = 0.006). Withdrawal of atropine in 2005 had no adverse effect on the outcome.

Conclusion

This study suggests that in the Wellington Region of New Zealand, the new guidelines have improved survival to hospital but not to discharge. Whilst the guideline changes have resulted in a trend towards decreased shock success rates, ROSC and survival to hospital admission have both increased.     

Out-of-hospital cardiac arrest in patients aged 35 years and under: A 4-year study of frequency and survival in London

Background

The aim of this study was to describe the frequency and characteristics of cardiac arrest patients of 35 years and under attended by the London Ambulance Service NHS Trust between April 2003 and March 2007. Few large studies have described the occurrence, mechanism, resuscitation viability and outcome of this substantial subset of the cardiac arrest population. By documenting over 3000 cardiac arrests in young people we sought to improve understanding, awareness and ultimately survival of a condition notorious for high mortality rates.

Methods and results

Data were analysed for 3084 young cardiac arrest patients and reported retrospectively. Patients were categorised by age, gender, aetiology and whether or not resuscitation attempts were made.Over 75% of patients were aged 18-35 years. There were significantly more males in this age group (p < 0.001) compared to those aged 17 years or less. The most common cause of cardiac arrest was an underlying cardiac cause (44.9%). Overdoses, hanging and other suicides were found to be major causes of cardiac arrests of non-cardiac origin in young adult males. Sudden Infant Death Syndrome (SIDS) was the most common known cause of death in infants aged less than 1 year. This age group received bystander CPR most often. 5.6% of young cardiac arrest patients who were taken to hospital survived to hospital discharge.

Conclusions

Mortality in young cardiac arrest patients remains high. Focus should be placed on tackling social and psychological causes of cardiac arrest as well as cardiac aetiologies.     

Presumed futility in paramedic-treated out-of-hospital cardiac arrest: an Utstein style analysis in Tampere, Finland

AIM: To report prospectively the outcome from prehospital cardiac arrest according to the Utstein template in the city of Tampere, Finland, with special reference to those patients in whom resuscitation was not attempted. MATERIALS AND METHODS: In Tampere (population 203,000), a two-tiered emergency medical service (EMS) system provides first response and basic life support (BLS), supported by advanced life support (ALS) units staffed with nurse-paramedics. We analysed all out-of-hospital cardiac arrests considered for resuscitation during a 12-month period. RESULTS: Of 191 patients with prehospital cardiac arrest, resuscitation was not attempted in 98 patients (51%). Reasons to withhold from resuscitation were estimated futility (97 cases) and a do-not-attempt-resuscitation order (1). Sixty percent of the patients with no resuscitation had secondary signs of death, 97% had asystole as the initial cardiac rhythm and 98% had suffered an unwitnessed cardiac arrest. Resuscitation was successful in 45 of the remaining 93 patients with attempted resuscitation. Twelve patients were discharged (overall survival rate 13%), nine of them with a CPC score of 1 or 2. Fifteen patients were treated with therapeutic hypothermia. Of the bystander-witnessed cardiac arrests with VF as initial rhythm, 29% survived. CONCLUSIONS: The Tampere EMS system initiated resuscitation less frequently than reported from other EMS systems, but the reasons to withhold resuscitation seemed justified. The overall and Utstein's 'golden standard' survival rates were comparable with previous reports.     

Out-of-hospital cardiac arrest due to drowning: An Utstein Style report of 10 years of experience from St. Mary's Hospital

Background

Drowning is a unique form of cardiac arrest and is often preventable. “Utstein Style for Drowning” was published in 2003 by the International Liaison Committee on Resuscitation (ILCOR) to improve the knowledge-base, to provide epidemiological stratification, to recommend appropriate treatments and to ultimately save lives. We report on the largest single-center study of the Utstein Style resuscitation for drowning.

Methods

All patients with out-of-hospital cardiac arrest (OHCA) due to drowning admitted to St. Mary's Hospital between 1998 and 2007 were included. Utstein Style variables and other time intervals not included in the Utstein Style guidelines were evaluated for their ability to predict survival. The primary end point of this study was survival to discharge.

Results

We enrolled 131 patients with OHCA due to drowning; 21 patients (16.03%) had survival to discharge and 9 patients (6.87%) were discharged with a good neurologic outcome, i.e., cerebral performance categories (CPC) of 1 or 2. For the Utstein Style variables witnessed, the duration of submersion and the time of first emergency medical systems (EMS) resuscitation attempt influenced survival. For other time intervals, the transportation time (i.e., time interval from witnessing of the drowning to EMS arrival at the hospital, or if events were not witnessed, the time interval from calling the EMS to EMS arrival at the hospital), the duration of advanced cardiovascular life support (ACLS) and the duration of total arrest time were associated with survival.

Conclusions

Our report is the largest single-center study of OHCA due to drowning reported according to the guidelines of the Utstein Style. Being witnessed, having a short duration of submersion, having early resuscitation by EMS, and rapid transportation are important for survival after drowning.     

The relationship between age and outcome in out-of-hospital cardiac arrest patients

AimTo determine the association between age and outcome in a large multicenter cohort of out-of-hospital cardiac arrest patients.MethodsRetrospective, observational, cohort study of out-of-hospital cardiac arrest from the CARES registry between 2006 and 2013. Age was categorized into 5-year intervals and the association between age group and outcomes (return of spontaneous circulation (ROSC), survival and good neurological outcome) was assessed in univariable and multivariable analysis. We performed a subgroup analysis in patients who had return of spontaneous circulation.ResultsA total of 101,968 people were included. The median age was 66 years (quartiles: 54, 78) and 39% were female. 31,236 (30.6%) of the included patients had sustained ROSC, 9761 (9.6%) survived to hospital discharge and 8058 (7.9%) survived with a good neurological outcome. The proportion of patients with ROSC was highest in those with age <20 years (34.1%) and lowest in those with age 95–99 years (23.5%). Patients with age <20 years had the highest proportion of survival (16.7%) and good neurological outcome (14.8%) whereas those with age 95–99 years had the lowest proportion of survival (1.7%) and good neurological outcome (1.2%). In the full cohort and in the patients with ROSC there appeared to be a progressive decline in survival and good neurological outcome after the age of approximately 45–64 years. Age alone was not a good predictor of outcome.ConclusionsAdvanced age is associated with outcomes in out-of-hospital cardiac arrest. We did not identify a specific age threshold beyond which the chance of a meaningful recovery was excluded.     

A trend in epidemiology and outcomes of out-of-hospital cardiac arrest by urbanization level: A nationwide observational study from 2006 to 2010 in South Korea

Background

The goal of this study is to better understand the trend in epidemiological features and the outcomes of emergency medical service (EMS)-assessed out-of-hospital cardiac arrest (OHCA) according to the community urbanization level: metropolitan, urban, and rural.

Methods

This study was performed within a nationwide EMS system with a single-tiered basic-to-intermediate service level and approximately 900 destination hospitals for eligible OHCA cases in South Korea (with 48 million people). A nationwide OHCA database, which included information regarding demographics, Utstein criteria, EMS, and hospital factors and outcomes, was constructed using the EMS run sheets of eligible cases who were transported by 119 EMS ambulances and followed by a medical record review from 2006 to 2010. Cases with an unknown outcome were excluded. The community urbanization level was categorized according to population size, with metropolitan areas (more than 500,000 residents), urban areas (100,000–500,000 residents), and rural areas (<100,000 residents). The primary end point was the survival to discharge rate. Age- and sex-adjusted survival rates (ASRs) and standardized survival ratios (SSRs) with 95% confidence intervals (CIs) were calculated compared to a standard population. The adjusted odds ratios (AORs) and 95% CIs for survival were calculated and adjusted for potential risk factors using stratified multivariable logistic regression analysis.

Results

There were 97,291 EMS-assessed OHCAs with 73,826 (75.9%) EMS-treated cases analyzed, after excluding the patients with unknown outcome (N = 4172). The standardized incidence rate increased from 37.5 in 2006 to 46.8 in 2010 per 100,000 person-years for EMS-assessed OHCAs, and the survival rate was 3.0% for EMS-assessed OHCAs (3.3% for cardiac etiology and 2.3% for non-cardiac etiology) and 3.6% for EMS-treated OHCAs. Significantly different trends were found by urbanization level for bystander CPR, EMS performance, and the level of the destination hospital. The ASRs for survival were significantly improved by year in the metropolitan areas (3.6% in 2006 to 5.3% in 2010) but remained low in the urban areas (1.4% in 2006 to 2.3% in 2010) and very low in the rural areas (0.5 in 2006 and 0.8 in 2010). The SSRs (95% CIs) in the metropolitan areas were 1.19 (1.06–1.34) in 2006 and 1.77 (1.64–1.92) in 2010, whereas the SSRs were observed to be less than 1.00 during the five-year period in both urban and rural areas. The AORs (95% CIs) for survival significantly increased to 1.42 (1.22–1.66) in the metropolitan areas and to 1.58 (1.18–2.11) in the urban areas while not increasing in the rural areas, compared to the level of each group of areas in 2006.

Conclusions

In this nationwide cohort study from 2006 to 2010, the standardized incidence rate and survival to discharge rate of EMS-assessed OHCAs increased annually in metropolitan and urban communities but did not increase in rural communities. Further investigations should be undertaken to improve the performance and outcomes in rural communities.     

New treatment bundles improve survival in out-of-hospital cardiac arrest patients: A historical comparison

Introduction

Before the introduction of the new international cardiac arrest treatment guidelines in 2005, patients with out-of-hospital cardiac arrest (OHCA) of cardiac origin in Northern Italy had very poor prognosis. Since 2006, a new bundle of care comprising use of automated external defibrillators (AEDs) and therapeutic hypothermia (TH) was started, while extracorporeal CPR program (ECPR) for selected refractory CA and dispatcher-assisted cardio-pulmonary resuscitation (CPR) was started in January 2010.

Objectives

We hypothesized that a program of bundled care might improve outcome of OHCA patients.

Methods

We analyzed data collected in the OHCA registry of the MB area between September 2007 and August 2011 and compared this with data from 2000 to 2003.

Results

Between 2007 and 2011, 1128 OHCAs occurred in the MB area, 745 received CPR and 461 of these had a CA of presumed cardiac origin. Of these, 125 (27%) achieved sustained ROSC, 60 (13%) survived to 1 month, of whom 51 (11%) were discharged from hospital with a good neurological outcome (CPC ≤ 2), and 9 with a poor neurological outcome (CPC > 2).Compared with data from the 2000 to 2003 periods, survival increased from 5.6% to 13.01% (p < 0.0001). In the 2007–2011 group, low-flow time and bystander CPR were independent markers of survival.

Conclusions

OHCA survival has improved in our region. An increased bystander CPR rate associated with dispatcher-assisted CPR was the most significant cause of increased survival, but duration of CA remains critical for patient outcome.     

Survival rates in out-of-hospital cardiac arrest patients transported without prehospital return of spontaneous circulation: An observational cohort study

Background

Some Emergency Medical Services currently use just one component of the Universal Termination of Resuscitation (TOR) Guideline, the absence of prehospital return of spontaneous circulation (ROSC), as the single criteria to terminate resuscitation, which may deny transport to potential survivors.

Objective

This study aimed to report the survival to hospital discharge rate in non-traumatic, adult out-of-hospital cardiac arrest (OHCA) patients transported to hospital without a prehospital ROSC.

Methods

An observational study of OHCA patients without a prehospital ROSC who met the Universal TOR Guideline for transport to hospital with ongoing resuscitation. Multivariable logistic regression was used to determine the association of each variable with survival to hospital discharge.

Results

Of 20,207 OHCA treated by EMS, 3374 (16.4%) did not have a prehospital ROSC but met the Universal TOR guideline for transport to hospital with ongoing resuscitation. Of these patients, 122 (3.6%) survived to hospital discharge. Survival to discharge was associated with initial shockable VF/VT rhythms (OR 5.07; 95% CI 2.77–9.30), EMS-witnessed arrests (OR 3.51; 95% CI 1.73–7.15), bystander-witnessed arrests (OR 2.11; 95% CI 1.18–3.77), and public locations (OR 1.57; 95% CI 1.02–2.40).

Conclusion

In OHCA patients without a prehospital ROSC who met the Universal TOR Guideline for transport with ongoing resuscitation survival rates were above the 1% futility rate. Employing only the lack of ROSC as criteria for termination of resuscitation may miss survivors after OHCA.     

A model of survival from out-of-hospital cardiac arrest using the Boston EMS arrest registry

Objectives

To characterize the survival rate for out-of-hospital arrests of cardiac aetiology and predictor variables associated with survival in Boston, MA, and to develop a composite multivariate logistic regression model for projecting survival rates.

Methods

This is a retrospective analysis of all arrests of presumed cardiac aetiology (from January 1, 2004 to December 31, 2007) where resuscitation was attempted (n = 1156) by 911 emergency responders.

Results

The survival-at-hospital discharge rate was 11% (vs. 1-10% often reported). The coefficients and odds ratios in the first equation of the model show that joint presence of presenting rhythm of ventricular fibrillation/tachycardia (VF/VT) and return of spontaneous circulation in the pre-hospital setting (ROSC) is a substantial direct predictor of survival (e.g., 54% of such cases survive). Response time, public location, witnessed, and age are significant but less sizable direct predictors of survival. A second equation shows that these four variables make an additional indirect contribution to survival by affecting the probability of joint presence of VF/VT and ROSC; bystander CPR also makes such an indirect contribution but no significant direct one as shown in the first equation. The projected survival rate if cases had always experienced bystander CPR and rapid response time of less than four minutes is 21%.

Conclusions

The unique model describes the major contribution of VF/VT and ROSC, and key relationships among predictors of survival. These connections may have otherwise gone underreported using standard approaches and should be considered when allocating scarce resources to impact cardiac arrest survival.     

Beyond the pre-shock pause: the effect of prehospital defibrillation mode on CPR interruptions and return of spontaneous circulation

Aims

The pattern of interruptions to chest compressions in pre-hospital cardiac arrests in Wellington, New Zealand, was examined prospectively to determine whether the mode of defibrillation chosen by paramedics influenced interruptions, shock success and the return of spontaneous circulation (ROSC).

Methods

A prospective observational cohort study of 44 adult cardiac arrests in which 203 shocks were administered by Wellington Free Ambulance (WFA) paramedics was undertaken to compare Code-stat^® electronic records from Medtronic^® Lifepak 12 and Lifepak 15 defibrillators used in semi-automated (AED) or manual mode. Interruptions during the 30 s prior to shock delivery as well as pre-shock and post-shock pauses were calculated. Shock success and ROSC were the outcome measures.

Results

Pre-shock pauses were shorter in manual mode (median 3 s, IQR 2–5) versus AED mode (median 4 s, IQR 3–6; p = 0.003). Interruptions of CPR in the 30 s prior to shock delivery were also shorter in manual mode (median 7 s, IQR 4–11) versus AED mode (median 14 s, IQR 12–16; p = <0.001). Shock success rates and post-shock pauses were not statistically different between modes. ROSC was significantly higher in manual mode (18.49%) versus AED mode (8.33%, p = 0.042).

Conclusion

When paramedics used the defibrillator in manual mode as compared to AED mode, interruptions to CPR during the 30 s prior to shock delivery were significantly reduced and pre-shock pauses were also shorter. This was associated with increased ROSC. Manual defibrillation should be the preferred option for appropriately trained paramedics. Training in this locality has been changed accordingly.     

Out-of-hospital cardiac arrest

Myocardial disease and death from cardiac arrest remain significant public health problems. Sudden death events and out-of-hospital cardiac arrests (OHCA) are encountered frequently by emergency medical services. Despite more than 30 years of research, survival rates remain extremely low. This article reviews access and presentations, demographics, OHCA outcomes, and response systems and processes in treatment of patients with arrest in this setting.     

Evaluation of emergency medical dispatch in out-of-hospital cardiac arrest in Taipei

INTRODUCTION: Emergency medical dispatchers are the entry points to the emergency medical services (EMS). The overall performances of the dispatchers are imperative determinants of the emergency medical services dispatching system. There is little data on the cultural and language impacts on emergency medical dispatch. OBJECTIVE: This study examined the emotional content and cooperation score (ECCS) among Mandarin Chinese speaking callers for cardiac arrests, and evaluated the performances of emergency medical services dispatching system in Taipei. METHODS: This retrospective, observational study examined dispatching audio recordings obtained from the Taipei City Fire Department Dispatching Center between January 2004 to April 2004. The tapes of call relating to adult (age >or=18 years), non-traumatic cases with a presumed or field diagnosis of out-of-hospital cardiac arrest (OHCA) underwent systemic review. The caller's ECCS and the dispatcher's performances, including interview skills, provision of telephone-assisted cardiopulmonary resuscitation (T-CPR), and dispatcher's ability to identify OHCA were examined. Interrater reliability for determining ECCS and interview skills were assessed using kappa statistic. RESULTS: A total of 199 audio recordings were reviewed. A mean ECCS of 1.42+/-0.64 (95% CI: 1.33-1.51) demonstrated that most callers were emotionally stable and cooperative when calling for help, even when facing cardiac arrest patients. There was a good association between ECCS and the sex of the callers (male 1.32 versus female 1.49; p<0.05). In 82% of interviews, the interview skills of the dispatchers was high (4 or 5 points); while in one fifth the interview skills were suboptimal. About one third of the cases were provided with T-CPR by the dispatchers. The sensitivity and positive predictive value (PPV) for predicting OHCA by dispatchers were 96.9% and 97.9%, respectively. A kappa value of 0.65 and 0.68 were obtained for the interrater reliability of ECCS and interview skills. CONCLUSION: Most callers were found to be emotional stable and cooperative with dispatcher's interrogations when calling for cardiac arrest victims in this Mandarin speaking population. The dispatchers have shown satisfactory interview skills in approaching emergency calls and a good ability to identify OHCA. There is a low rate of T-CPR offered to the callers in the investigation. Efforts should be made to address the deficiencies in order to maximise the function of the EMS.     

The impact of partial resuscitation attempts on the reported outcomes of out-of-hospital cardiac arrest in Victoria,Australia: Implications for Utstein-style outcome reports

Background

Success rates from cardiopulmonary resuscitation (CPR) are often quantified by Utstein-style outcome reports in populations who receive an attempted resuscitation. In some cases, evidence of futility is ascertained after a partial resuscitation attempt has been administered, and these cases reduce the overall effectiveness of CPR. We examine the impact of partial resuscitation attempts on the reported outcomes of out-of-hospital cardiac arrest (OHCA) in Victoria, Australia.

Methods

Between 2002 and 2012, 34,849 adult OHCA cases of presumed cardiac aetiology were included from the Victorian Ambulance Cardiac Arrest Registry. Resuscitation attempts lasting ≤10 min in cases which died on scene were defined as a partial resuscitation. We used logistic regression to identify factors associated with a partial resuscitation attempt in the emergency medical service (EMS) treated population. Survival outcomes with and without partial resuscitations were compared across included years.

Results

The proportion of partial resuscitations in the overall EMS treated population increased significantly from 8.6% in 2002 to 18.8% in 2012 (p for trend < 0.001), and were largely supported by documented evidence of irreversible death. Partial resuscitations were independently associated with older age, female gender, initial non-shockable rhythm, prolonged downtime, and lower skill level of EMS personnel. Selectively excluding partial resuscitations increased event survival by 7.6% (95% CI 4.1–11.2%), and survival to hospital discharge increased by 3.1% (95% CI 0.5–5.7%) in 2012 (p < 0.001 for both).

Conclusion

In our EMS system, evidence of futility was often identified after the commencement of a partial resuscitation attempt. Excluding these events from OHCA outcome reports may better reflect the overall effectiveness of CPR.     

Two simple questions to assess neurologic outcomes at 3 months after out-of-hospital cardiac arrest: Experience from the Public Access Defibrillation Trial

Background

Two simple questions have been used to classify neurologic outcome in patients with stroke. Could they be similarly applied to patients with cardiac arrest?

Methods

As part of a randomized trial, study personnel interviewed by telephone survivors of out-of-hospital cardiac arrest to assess their outcomes 3 months after discharge. They asked two simple questions: (1) In the last 2 weeks, did you require help from another person for your everyday activities? and (2) Do you feel that you have made a complete mental recovery form your heart arrest? Next they administered the Mini-Mental State Examination (MMSE) from the Adult Lifestyles and Function Interview (ALFI) to assess cognition on a scale from 0 to 22 and the Health Utilities Index Mark 3 (HUI3) to assess quality of life on a scale from 0 (death) to 1 (perfect health).

Results

Based on responses to the two simple questions, 32 survivors were classified as dependent (n = 5, 16%), independent (n = 3, 9%) and full recovery (n = 24, 75%). The mean ALFI-MMSE score was 19.1 (standard deviation 5.1), and the mean HUI3 score was 0.76 (standard deviation 0.28). The classification based on the two simple questions was significantly correlated with ALFI-MMSE (p = 0.002) and HUI3 (p = 0.001). Scores for the HUI3 were missing in eight survivors.

Conclusions

Neurologic outcomes based on the two simple questions after cardiac arrest can be easily determined, sensibly applied, and readily interpreted. These preliminary findings justify further evaluation of this simple and practical approach to classify neurologic outcome in survivors of cardiac arrest.     

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.     

Use of automated external defibrillators in patients with traumatic out-of-hospital cardiac arrest

Background

Because out-of-hospital cardiac arrests (OHCAs) due to a major trauma rarely present with shockable rhythms, the potential benefits of using automated external defibrillators (AEDs) at the scene of traumatic OHCAs have not been examined.

Methods

We conducted an observational, retrospective cohort study using an Utstein-style analysis in Tainan city, Taiwan. The enrollees were adult patients with traumatic OHCAs accessed by emergency medical technicians (EMTs) from January 1, 2004 to December 31, 2010. The exposure was the use or non-use of AEDs at the scene, as determined by the clinical judgment of the EMTs. The primary outcome evaluated was a sustained (≥2 h) return of spontaneous circulation (ROSC), and the secondary outcomes were prehospital ROSC, overall ROSC, survival to hospital admission, survival at one month and favorable neurologic status at one month.

Results

A total of 424 patients (313 males) were enrolled, of whom 280 had AEDs applied, and 144 did not. Only 25 (5.9%) patients had received bystander cardiopulmonary resuscitation (CPR), and merely 21 (7.5%) patients in the AED group presented with shockable rhythms. Compared to the non-AED group, the primary and secondary outcomes of the AED group were not significantly different, except for a significantly lower prehospital ROSC rate (1.1% vs 4.9%, p < 0.05). Multivariate analysis showed no significant interactions between the use of AEDs and other key variables. Use of the AED was not associated with sustained ROSC (OR 1.33; 95% CI 0.75–2.38, p = 0.33).

Conclusions

In a community with a low prevalence of shockable rhythms and administration of bystander CPR in patients with traumatic OHCA, we found no significant differences in the sustained ROSC between the AED and the non-AED groups. Considering scene safety and the possible interruption of CPR, we do not encourage the routine use of AEDs at the scene of traumatic OHCAs.