Increased survival after EMS witnessed cardiac arrest. Observations from the Resuscitation Outcomes Consortium (ROC) Epistry—Cardiac arrest

Background

Out of hospital cardiac arrest (OHCA) is common and lethal. It has been suggested that OHCA witnessed by EMS providers is a predictor of survival because advanced help is immediately available. We examined EMS witnessed OHCA from the Resuscitation Outcomes Consortium (ROC) to determine the effect of EMS witnessed vs. bystander witnessed and unwitnessed OHCA.

Methods

Data were analyzed from a prospective, population-based cohort study in 10 U.S. and Canadian ROC sites. Individuals with non-traumatic OHCA treated 04/01/06-03/31/07 by EMS providers with defibrillation or chest compressions were included. Cases were grouped into EMS-witnessed, bystander witnessed, and unwitnessed and further stratified for bystander CPR. Multiple logistic regressions evaluated the odds ratio (OR) for survival to discharge relative to the EMS-witnessed group after adjusting for age, sex, public/private location of collapse, ROC site, and initial ECG rhythm. Of 9991 OHCA, 1022 (10.2%) of EMS-witnessed, 3369 (33.7%) bystander witnessed, and 5600 (56.1%) unwitnessed.

Results

The most common initial rhythm in the EMS-witnessed group was PEA which was higher than in the bystander- and unwitnessed groups (p < 0.001). The adjusted OR (95% CI) of survival compared to the EMS-witnessed group was 0.41, (0.36, 0.46) in bystander witnessed with bystander CPR, 0.37 (0.33, 0.43) in bystander witnessed without bystander CPR, 0.17 (0.14, 0.20) in unwitnessed with bystander CPR and 0.21 (0.18, 0.24) in unwitnessed cases without bystander CPR.

Conclusions

Immediate application of prehospital care for OHCA may improve survival. Efforts should be made to educate patients to access 9-1-1 for prodromal symptoms.     

Are trained individuals more likely to perform bystander CPR? An observational study

Background

This study aimed to evaluate the association of cardiopulmonary resuscitation (CPR) training with bystander resuscitation performance and patient outcomes after out-of-hospital cardiac arrest (OHCA).

Methods

This was a prospective, population-based cohort study of all persons aged 18 years or older with OHCA of presumed intrinsic origin and their rescuers from January through December 2008 in Takatsuki, Osaka prefecture, Japan. Data on resuscitation of OHCA patients were obtained by emergency medical service (EMS) personnel in charge based on the Utstein style. Rescuers’ characteristics including experience of CPR training were obtained by EMS personnel interview on the scene. The primary outcome was the attempt of bystander CPR.

Results

Data were collected for 120 cases out of 170 OHCAs of intrinsic origin. Among the available cases, 60 (50.0%) had previous CPR training (trained rescuer group). The proportion of bystander CPR was significantly higher in the trained rescuer group than in the untrained rescuer group (75.0% and 43.3%; p = 0.001). Bystanders who had previous experience of CPR training were 3.40 times (95% confidence interval 1.31-8.85) more likely to perform CPR compared with those without previous CPR training. The number of patients with neurologically favorable one-month survival was too small to evaluate statistical difference between the groups (2 [3.3%] in the trained rescuer group versus 1 [1.7%] in the untrained rescuer group; p = 0.500).

Conclusions

People who had experienced CPR training had a greater tendency to perform bystander CPR than people without experience of CPR training. Further studies are needed to prove the effectiveness of CPR training on survival.     

Resuscitation of out-of-hospital cardiac arrests in residential aged care facilities in Melbourne, Australia

Introduction

CPR in patients in residential aged care facilities (RACF) deserves careful consideration. We examined the characteristics, management and outcomes of out-of-hospital cardiac arrest (OHCA) in RACF patients in Melbourne, Australia.

Methods

The Victorian Ambulance Cardiac Arrest Registry (VACAR) was searched for all OHCAs occurring in RACFs in Melbourne. The characteristics and outcomes were compared to non-RACF patients in the VACAR.

Results

Between 2000 and 2009 there were 30,006 OHCAs, 2350 (7.8%) occurring in a RACF.A shockable rhythm was present in 179 (7.6%) patients on arrival of paramedics of whom bystander CPR had been performed in 118 (66%); 173 (97%) received an EMS attempted resuscitation. ROSC was achieved in 71 (41%) patients and 15 (8.7%) patients survived to leave hospital. Non shockable rhythm was present in 2171 patients (92%) of whom 804 (37%) had an attempted resuscitation by paramedics. ROSC was achieved in 176 patients (22%) and 10 patients (1.2%) were discharged alive. Survival from OHCA occurring in a RACF was less than survival in those aged >70 years of age who suffered OHCA in their own homes (1.8% vs. 4.7%, p = 0.001). On multivariable analysis, witnessed OHCA (OR 3.0, 95% CI 2.4-3.7) and the presence of bystander CPR (OR 4.6, 95% CI 3.7-5.8) was associated with the paramedic decision to resuscitate.

Conclusion

Resuscitation of patients in RACF is not futile. However, informed decisions concerning resuscitation status should be made by patients and their families on entry to a RACF. Where it is appropriate to perform resuscitation, outcomes may be improved by the provision of BLS training and possibly AED equipment to RACF staff.     

Bystander CPR in south east Scotland increases over 16 years

Background

Out-of-hospital cardiac arrest (OHCA) remains a leading cause of mortality and serious neurological disability across Europe. Without immediate bystander cardiopulmonary resuscitation (CPR), chances of survival are minimal. Despite community initiatives to increase the number of trained CPR providers, the effectiveness of these measures remains unknown and the proportion of OHCA patients receiving bystander CPR in the United Kingdom yet to be established. We sought to identify the change in the rate of bystander CPR in south east Scotland over a 16-year period.

Methods

Retrospective cohort study of all adult non-traumatic OHCA in south east Scotland from 1 January 1992 to 31 December 2007 using the Heartstart Scotland database.

Results

7928 OHCA were included. The proportion of patients receiving bystander CPR increased from 34% in 1992 to 52% in 2007 (p for trend <0.0001). The rate of CPR from bystanders, spouses and from relatives increased significantly over the study period. Patients arresting at home received significantly less bystander CPR than those arresting away from home (39% vs 52%, p < 0.0001) regardless of age or sex.

Conclusion

There has been a significant increase in bystander CPR in south east Scotland during the 16-year period. Bystander CPR is associated with an increased rate of survival and targeted CPR training for relatives of patients at risk of sudden cardiac death may be beneficial.     

Changing EMS dispatcher CPR instructions to 400 compressions before mouth-to-mouth improved bystander CPR rates

Background

To examine the impact of changing dispatcher CPR instructions (400 compressions: 2 breaths, followed by 100:2 ratio) on rates of bystander CPR and survival in adults with presumed cardiac out-of-hospital arrest (OHCA) in Melbourne, Australia.

Methods

The Victorian Ambulance Cardiac Arrest Registry (VACAR) was searched for OHCA where Emergency Medical Services (EMS) attempted CPR between August 2006 and August 2009. OHCA included were: (1) patients aged ≥18 years old; (2) presumed cardiac etiology; and (3) not witnessed by EMS.

Results

For the pre- and post-study periods, 1021 and 2101 OHCAs met inclusion criteria, respectively. Rates of bystander CPR increased overall (45-55%, p < 0.001) and by initial rhythm (shockable 55-70%, p < 0.001 and non-shockable 40-46%, p = 0.01). In VF/VT OHCA, there were improvements in the number of patients arriving at hospital with a return of spontaneous circulation (ROSC) (48-56%, p = 0.02) and in survival to hospital discharge (21-29%, p = 0.002), with improved outcomes restricted to patients receiving bystander CPR. After adjusting for factors associated with survival, the period of time following the change in CPR instructions was a significant predictor of survival to hospital discharge in VF/VT patients (OR 1.57, 95% CI: 1.15-2.20, p = 0.005).

Conclusion

Following changes to dispatcher CPR instructions, significant increases were seen in rates of bystander CPR and improvements were seen in survival in VF/VT patients who received bystander CPR, after adjusting for factors associated with survival.     

Association between deprivation status at community level and outcomes from out-of-hospital cardiac arrest: a nationwide observational study

Study objectives

We sought to examine the association between area deprivation and outcomes of out-of-hospital cardiac arrest in Korea.

Methods

Data were obtained from the emergency medical service (EMS) system. A nationwide OHCA cohort database from January2006 to December 2007 was constructed via hospital chart review and ambulance run sheet data. We enrolled all EMS-assessed OHCA victims and excluded cases without available hospital outcome data or residential address. The Carstairs index was used to categorize districts according to level of deprivation into five quintiles, from (Q1, the least deprived) to (Q5, the most deprived). Main outcomes were survival to hospital discharge, survival to admission, and return of spontaneous circulation (ROSC).

Results

34,227 patients were included. Initial rhythm, witnessed status, attempted bystander cardiopulmonary resuscitation (CPR), CPR by EMS, CPR in the emergency department (ED), and elapsed time interval significantly varied according to area deprivation level (p < 0.001). OHCA outcomes were consistently worse in the most deprived areas. The adjusted OR (95% CI) for survival to hospital discharge was 0.58 (0.45-0.77) in the most deprived areas compared to the least deprived areas.

Conclusion

Community deprivation was strongly associated with survival among out-of-hospital cardiac arrest patients in Korea.     

Assessment of outcomes and differences between in- and out-of-hospital cardiac arrest patients treated with cardiopulmonary resuscitation using extracorporeal life support

Aim

Cardiopulmonary resuscitation (CPR) using extracorporeal life support (ECLS) for in-hospital cardiac arrest (IHCA) patients has been assigned a low-grade recommendation in current resuscitation guidelines. This study compared the outcomes of IHCA and out-of-hospital cardiac arrest (OHCA) patients treated with ECLS.

Methods

A total of 77 patients were treated with ECLS. Baselines characteristics and outcomes were compared for 38 IHCA and 39 OCHA patients.

Results

The time interval between collapse and starting ECLS was significantly shorter after IHCA than after OHCA (25 (21-43) min versus 59 (45-65) min, p < 0.001). The weaning rate from ECLS (61% versus 36%, p = 0.03) and 30-day survival (34% versus 13%, p = 0.03) were higher for IHCA compared with OHCA patients. IHCA patients had a higher rate of favourable neurological outcome compared to OHCA patients, but the difference was not statistically significant (26% versus 10%, p = 0.07). Kaplan-Meier analysis showed improved 30-day and 1-year survival for IHCA patients treated with ECLS compared to OHCA patients who had ECLS. However, multivariate stepwise Cox regression model analysis indicated no difference in 30-day (odds ratio 0.94 (95% confidence interval 0.68-1.27), p = 0.67) and 1-year survival (0.99 (0.73-1.33), p = 0.95).

Conclusion

CPR with ECLS led to more favourable patient outcomes after IHCA compared with OHCA in our patient group. The difference in outcomes for ECLS after IHCA and OHCA disappeared after adjusting for patient factors and the time delay in starting ECLS.     

Multiple cluster analysis for the identification of high-risk census tracts for out-of-hospital cardiac arrest (OHCA) in Denver,Colorado

Background

Prior research has shown that high-risk census tracts for out-of-hospital cardiac arrest (OHCA) can be identified. High-risk neighborhoods are defined as having a high incidence of OHCA and a low prevalence of bystander cardiopulmonary resuscitation (CPR). However, there is no consensus regarding the process for identifying high-risk neighborhoods.

Objective

We propose a novel summary approach to identify high-risk neighborhoods through three separate spatial analysis methods: Empirical Bayes (EB), Local Moran's I (LISA), and Getis Ord Gi* (Gi*) in Denver, Colorado.

Methods

We conducted a secondary analysis of prospectively collected Emergency Medical Services data of OHCA from January 1, 2009 to December 31, 2011 from the City and County of Denver, Colorado. OHCA incidents were restricted to those of cardiac etiology in adults ≥18 years. The OHCA incident locations were geocoded using Centrus. EB smoothed incidence rates were calculated for OHCA using Geoda and LISA and Gi* calculated using ArcGIS 10.

Results

A total of 1102 arrests in 142 census tracts occurred during the study period, with 887 arrests included in the final sample. Maps of clusters of high OHCA incidence were overlaid with maps identifying census tracts in the below the Denver County mean for bystander CPR prevalence. Five census tracts identified were designated as Tier 1 high-risk tracts, while an additional 7 census tracts where designated as Tier 2 high-risk tracts.

Conclusion

This is the first study to use these three spatial cluster analysis methods for the detection of high-risk census tracts. These census tracts are possible sites for targeted community-based interventions to improve both cardiovascular health education and CPR training.     

Association of neighborhood characteristics with incidence of out-of-hospital cardiac arrest and rates of bystander-initiated CPR: Implications for community-based education intervention

Objective

A 10-fold regional variation in survival after out-of-hospital cardiac arrest (OHCA) has been reported in the United States, which partly relates to variability in bystander cardiopulmonary resuscitation (CPR) rates. In order for resources to be focused on areas of greatest need, we conducted a geospatial analysis of variation of CPR rates.

Methods

Using 2010–2011 data from Durham, Mecklenburg, and Wake counties in North Carolina participating in the Cardiac Arrest Registry to Enhance Survival (CARES) program, we included all patients with OHCA for whom resuscitation was attempted. Geocoded data and logistic regression modeling were used to assess incidence of OHCA and patterns of bystander CPR according to census tracts and factors associated herewith.

Results

In total, 1466 patients were included (median age, 65 years [interquartile range 25]; 63.4% men). Bystander CPR by a layperson was initiated in 37.9% of these patients. High-incidence OHCA areas were characterized partly by higher population densities and higher percentages of black race as well as lower levels of education and income. Low rates of bystander CPR were associated with population composition (percent black: OR, 3.73; 95% CI, 2.00–6.97 per 1% increment in black patients; percent elderly: 3.25; 1.41–7.48 per 1% increment in elderly patients; percent living in poverty: 1.77, 1.16–2.71 per 1% increase in patients living in poverty).

Conclusions

In 3 counties in North Carolina, areas with low rates of bystander CPR can be identified using geospatial data, and education efforts can be targeted to improve recognition of cardiac arrest and to augment bystander CPR rates.     

Predicting non-cardiac aetiology: a strategy to allocate rescue breathing during bystander CPR

Aims

Optimal care for out-of hospital cardiac arrest (OHCA) patients may depend on the underlying aetiology of OHCA. Specifically chest compression only bystander CPR may provide greater benefit among those with cardiac aetiology and chest compressions plus rescue breathing may provide greater benefit among those with non-cardiac aetiology. The aim of this study was to generate a simple predictor model to identify OHCA patients with non-cardiac aetiology in order to accurately allocate rescue breathing.

Methods

We used two independent cohorts of OHCA patients from a randomized pre-hospital trial and a prospective hospital registry (total n = 3086) to assess whether the characteristics of age, gender and arrest location (private versus public) could sufficiently discriminate non-cardiac aetiology. We used logistic regression models to generate a receiver operator curve and likelihood ratios.

Results

Overall, 965/3086 (31%) had a final diagnosis of a non-cardiac cause. Using 8 exclusive groups according to age, gender, and location, the frequency of non-cardiac aetiology varied from a low of 16% (55/351) among men >age 50 in a public location up to 58% (199/346) among women <60 in a private location. Although each characteristic was predictive in the logistic regression model, the area under the curve in the receiver operating curve was only 0.66. The associated positive likelihood ratios ranged from 1 to 3 and the negative likelihood ratios ranged from 1 to 0.4.

Conclusion

The results highlight the challenge of accurately identifying non-cardiac aetiology by characteristics that could be consistently used to allocate bystander rescue breathing.     

Evaluation of telephone-cardiopulmonary resuscitation advice for paediatric cardiac arrest

Introduction

Telephone-cardiopulmonary resuscitation (CPR) advice aims to increase the quality and quantity of bystander CPR, one of the few interventions shown to improve outcome in cardiac arrest. We evaluated a current paediatric telephone protocol (AMPDS v11.1) to assess the effectiveness of verbal CPR instructions in paediatric cardiac arrest.

Methods

Consecutive emergency calls classified by the AMPDS as cardiac arrests in children <8 years old, over an 11 month period, were compared with their corresponding patient report forms (PRFs) to confirm the diagnosis. Audio recordings and PRFs were then evaluated to assess whether bystander CPR was given, and when it was, the time taken to perform CPR interventions, before paramedic arrival.

Results

Of the 42 calls reviewed, 19 (45.2%) were confirmed as cardiac arrest. CPR was already underway in two cases (10.5%). Of the remaining callers, 11 (64.7%) agreed to attempt T-CPR, resulting in an overall bystander-CPR rate of 68.4%. The median time to open the airway was 126 s (62-236 s, n = 11), deliver the first ventilation was 180 s (135-360 s, n  = 11), and perform the first chest compression was 280 s (164-420 s, n  = 9).

Conclusion

Although current telephone-CPR instructions improve the numbers of children in whom bystander CPR is attempted, effectiveness is likely to be limited by the significant delays in actually delivering basic life support.     

Aspects on the increase in bystander CPR in Sweden and its association with outcome

Aim

To describe changes in the proportion of bystanders performing cardiopulmonary resuscitation (CPR) in out of hospital cardiac arrest (OHCA) in Sweden and to study the impact of bystander CPR on ventricular fibrillation and on survival during various times.

Patients and methods

All patients who suffered from OHCA in Sweden in whom CPR was attempted and who were included in the Swedish cardiac arrest register (SCAR) between 1992 and 2005. Crew witnessed cases were excluded.

Results

In all 34,125 patients were included in the survey. Among witnessed OHCA the proportion of patients receiving bystander CPR increased from 40% in 1992 to 55% in 2005 (p < 0.0001). In non-witnessed OHCA the corresponding proportion increased from 22% to 44% (p < 0.0001). There was a significant increase in bystander CPR regardless of age, sex and place. The increase was only found when CPR was performed by lay persons (21% in 1992 to 40% in 2005; p < 0.0001). Bystander CPR was associated with an increased proportion of patients found in a shockable rhythm and a lower number of shocks to receive return of spontaneous circulation. Bystander CPR was associated with a similar increase in survival early and late in the evaluation.

Conclusion

There was a marked increase in bystander CPR in OHCA, when performed by lay persons, during the last 14 years in Sweden. Bystander CPR was associated with positive effects both on ventricular fibrillation and survival.     

Education in cardiopulmonary resuscitation in Sweden and its clinical consequences

Aim

To describe the use of cardiopulmonary resuscitation (CPR) training programmes in Sweden for 25 years and relate those to changes in the percentage of patients with out of hospital cardiac arrest (OHCA) who receive bystander CPR.

Methods

Information was gathered from (a) the Swedish CPR training registry established in 1983 and includes most Swedish education programmes in CPR and (b) the Swedish Cardiac Arrest Register (SCAR) established in 1990 and currently covers about 70% of ambulance districts in Sweden.

Results

CPR education in Sweden functions according to a cascade principle (instructor-trainers who train instructors who then train rescuers in CPR). Since 1989, 5000 instructor-trainers have taught more than 50,000 instructors who have taught nearly 2 million of Sweden's 9 million inhabitants adult CPR. This is equivalent to one new rescuer per 100 inhabitants every year in Sweden. In addition, since 1989, there are 51,000 new rescuers in Advanced Life Support (ALS), since 1996, 41,000 new Basic Life Support (BLS) rescuers with Automated External Defibrillation (AED) training, and since 1998, there are 93,000 new rescuers in child CPR. As a result of this CPR training the number of bystander CPR attempts for OHCA in Sweden increased from 31% in 1992 to 55% in 2007.

Conclusion

By using a cascade principle for CPR education nearly 2 million rescuers were educated in Sweden (9 million inhabitants) between 1989 and 2007. This resulted in a marked increase in bystander CPR attempts.     

CPR knowledge and attitude to performing bystander CPR among secondary school students in Norway

Background

Early bystander cardiopulmonary resuscitation (CPR) is essential for survival from out-of-hospital cardiac arrest (OHCA). Young people are potentially important bystander CPR providers, as basic life support (BLS) training can be distributed widely as part of the school curriculum.

Methods

Questionnaires were distributed to nine secondary schools in North Norway, and 376 respondents (age 16-19 years) were included. The completed questionnaires were statistically analysed to assess CPR knowledge and attitude to performing bystander CPR.

Results

Theoretical knowledge of handling an apparently unresponsive adult person was high, and 90% knew the national medical emergency telephone number (113). The majority (83%) was willing to perform bystander CPR in a given situation with cardiac arrest. However, when presented with realistic hypothetical cardiac arrest scenarios, the option to provide full BLS was less frequently chosen, to e.g. a family member (74%), a child (67%) or an intravenous drug user (18%). Students with BLS training in school and self-reported confidence in their own BLS skills reported stronger willingness to perform BLS. 8% had personally witnessed a cardiac arrest, and among these 16% had performed full BLS. Most students (86%) supported mandatory BLS training in school, and three out of four wanted to receive additional training.

Conclusion

Young Norwegians are motivated to perform bystander CPR, but barriers are still seen when more detailed cardiac arrest scenarios are presented. By providing students with good quality BLS training in school, the upcoming generation in Norway may strengthen the first part of the chain of survival in OHCA.     

Improving outcome after out-of-hospital cardiac arrest by strengthening weak links of the local Chain of Survival; quality of advanced life support and post-resuscitation care

Background

Survival after out-of-hospital cardiac arrest (OHCA) depends on a well functioning Chain of Survival. We wanted to assess if targeted attempts to strengthen the weak links of our local chain; quality of advanced life support (ALS) and post-resuscitation care, would improve outcome.

Materials and methods

Utstein data from all OHCAs in Oslo during three distinct 2-year time periods 1996-1998, 2001-2003 and 2004-2005 were collected. Before the second period the local ALS guidelines changed with increased focus on good quality chest compressions with minimal pauses, while standardized post-resuscitation care including goal directed therapy with therapeutic hypothermia and percutaneous coronary intervention was added in the third period. Additional a priori sub-group analyses of arrests with cardiac aetiology as well as bystander witnessed ventricular fibrillation/tachycardia (VF/VT) arrests with cardiac aetiology were performed.

Results

ALS was attempted in 454, 449, and 417 patients with OHCA in the first, second and last time period, respectively. From the first to the third period VF/VT arrests declined (40% vs. 33%, p = 0.039) and fewer arrests were witnessed (80% vs. 72%, p = 0.022) and response intervals increased (7 ± 4 to 9 ± 4 min, p < 0.001). Overall survival increased from 7% (first period) to 13% (last period), p = 0.002, and survival in the sub-group of bystander witnessed VF/VT arrests with cardiac aetiology increased from 15% (first period) to 35% (last period), p = 0.001.

Conclusions

Survival after OHCA was increased after improving weak links of our local Chain of Survival, quality of ALS and post-resuscitation care.     

Association of out-of-hospital cardiac arrest with prior activity and ambient temperature

Objective

Little is known about triggers of sudden cardiac arrest. This study aimed to analyze the association of the occurrence of out-of-hospital cardiac arrest (OHCA) with patient activities just before the arrest and ambient temperature as one of the major environmental factors.

Methods

This prospective, population-based cohort study enrolled all person aged 18 years or older with OHCA of presumed cardiac origin in Osaka Prefecture, Japan, from 2005 through 2007. Patient activities before arrest were divided into six categories: sleeping, bathing, working, exercising, non-specific activities, and unknown. Age-adjusted annual incidence rate of OHCA according to their prior activity and an hourly event rate in each activity by temperature were calculated.

Results

Among 19,303 OHCAs, 10,723 were presumed to be of cardiac etiology. The event rate of OHCA was 6.22, 54.49, 1.15, and 10.11 per 10,000,000 population per hour for sleeping, bathing, working, and exercising, respectively. Among patients who suffered OHCA during bathing, the event rate of OHCA per 10,000,000 per hour increased with decreasing temperature from 18.27 (≥25.1 °C) to 111.42 (≤5.0 °C) (odds ratio [OR] for 1 °C increase in temperature, 0.915; 95% confidence interval [CI], 0.907-0.923), while it was almost constant among those who were working (OR for 1 °C increase, 0.994; 95% CI, 0.981-1.007) or exercising (OR for 1 °C increase, 1.004; 95% CI, 0.971-1.038) before arrest.

Conclusion

Both activities before cardiac arrest and ambient temperature were associated with the occurrence of OHCA. Preventive measures against OHCA should be enveloped considering these behavioral and environmental factors.     

Estimating cost-effectiveness of mass cardiopulmonary resuscitation training strategies to improve survival from cardiac arrest in private locations

Introduction

Most cardiopulmonary resuscitation (CPR) trainees are young, and most cardiac arrests occur in private residences witnessed by older individuals.

Objective

To estimate the cost-effectiveness of a CPR training program targeted at citizens over the age of 50 years compared with that of current nontargeted public CPR training.

Methods

A model was developed using cardiac arrest and known demographic data from a single suburban zip code (population 36,325) including: local data (1997-1999) regarding cardiac arrest locations (public vs. private); incremental survival with CPR (historical survival rate 7.8%, adjusted odds ratio for CPR 2.0); arrest bystander demographics obtained from bystander telephone interviews; zip code demographics regarding population age and distribution; and $12.50 per student for the cost of CPR training. Published rates of CPR training programs by age were used to estimate the numbers typically trained. Several assumptions were made: 1) there would be one bystander per arrest; 2) the bystander would always perform CPR if trained; 3) cardiac arrest would be evenly distributed in the population; and 4) CPR training for a proportion of the population would proportionally increase CPR provision. Rates of arrest, bystanders by age, number of CPR trainees needed to result in increased arrest survival, and training cost per life saved for a one-year study period were calculated.

Results

There were 24.3 cardiac arrests per year, with 21.9 (90%) occurring in homes. In 66.5% of the home arrests, the bystander was more than 50 years old. To yield one additional survivor using the current CPR training strategy, 12,306 people needed to be trained (3,510 bystanders aged ≤50 years and 8,796 bystanders aged >50 years), which resulted in CPR provision to 7.14 additional patients. The training cost per life saved for a bystander aged ≤50 years was $313,214, and that for a bystander aged >50 years was $785,040. Using a strategy of training only those ≤50 years, 583 elders per cardiac arrest would need to be trained, with a cost of $53,383 per life saved.

Conclusion

Using these assumptions, current CPR training strategy is not a cost-effective intervention for home cardiac arrests. The high rate of elders witnessing CPR mandates focused CPR interventions for this population.     

Impact of transport to critical care medical centers on outcomes after out-of-hospital cardiac arrest

Background

Post-resuscitation care has emerged as an important predictor of survival from out-of-hospital cardiac arrest (OHCA). In Japan, selected hospitals are certified as Critical Care Medical Centers (CCMCs) based on their ability and expertise.

Hypothesis

Outcome after OHCA is better in patients transported to a CCMC compared a non-critical care hospital (NCCH).

Materials and methods

Adults with OHCA of presumed cardiac etiology, treated by emergency medical services systems, and transported in Osaka from January 1, 2005 to December 31, 2007 were registered using a prospective Utstein style population cohort database. Primary outcome measure was 1 month neurologically favorable survival (CPC ≤ 2). Outcomes of patients transported to CCMC were compared with patients transported to NCCH using multiple logistic regressions and stratified on the basis of stratified field ROSC.

Results

10,383 cases were transported. Of these, 2881 were transported to CCMC and 7502 to NCCH. Neurologically favorable 1-month survival was greater in the CCMC group [6.7% versus 2.8%, P < 0.001]. Among patients who were transported to hospital without field ROSC, neurologically favorable outcome was greater in the CCMC group than the NCCH group [1.7% versus 0.5%; adjusted odds ratio (OR), 3.39; 95% confidence interval (CI), 2.17-5.29; P < 0.001]. In the presence of field ROSC, survival was similar between the groups [43% versus 41%; adjusted OR, 1.09; 95% CI, 0.82-1.45; P = 0.554].

Conclusions

Survival after OHCA of presumed cardiac etiology transported to CCMCs was better than those transported to NCCHs. For OHCA patients without field ROSC, transport to a CCMC was an independent predictor for a good neurological outcome.     

Coagulopathy during cardiac arrest and resuscitation in a swine model of electrically induced ventricular fibrillation

Aims

Coagulopathy is often present after resuscitation from cardiac arrest but plays an undefined role in the post cardiac arrest syndrome. The aim of this study was to characterize coagulation changes during cardiac arrest and post-resuscitation care in order to direct further focused study.

Methods

Ventricular fibrillation (VF) was induced electrically in immature male swine, followed by normothermic American Heart Association Advanced Cardiac Life Support and a uniform post-resuscitation goal-directed resuscitation protocol. PT, aPTT, fibrinogen, Thrombelastography (TEG), platelet contractile force (PCF), clot elastic modulus (CEM), and collagen-induced platelet aggregation were compared at baseline, at 8 min of VF, during the 3rd round of chest compressions (CPR), and at 15, 90, 180, and 360 min after return of circulation using repeated measures ANOVA.

Results

8/18 (44%) animals were resuscitated after 10.9 ± 0.9 min of VF and 7.6 ± 3.4 min of CPR. TEG revealed a significant impairment in clot strength (MA) and clot formation kinetics (K, alpha angle) arising during CPR, followed by a brief prolongation of clot onset times (R) after return of circulation. Both PCF and CEM fell significantly during CPR (PCF by 50%, CEM by 47% of baseline) and platelet aggregation was significantly decreased during CPR. Coagulation changes were partially recovered by 3 h of post-resuscitation care.

Conclusion

Whole blood coagulation was rapidly impaired during CPR after electrically induced VF in this swine model by impaired platelet aggregation/contractile function and clotting kinetics. Further platelet-specific study is indicated.