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.     

Esophageal temperature after out-of-hospital cardiac arrest: An observational study

Introduction

Out-of-hospital cardiac arrest (OHCA) is a significant cause of death and severe neurological disability. The only post-return of spontaneous circulation (ROSC) therapy shown to increase survival is mild therapeutic hypothermia (MTH). The relationship between esophageal temperature post OHCA and outcome is still poorly defined.

Methods

Prospective observational study of all OHCA patients admitted to a single centre for a 14-month period (1/08/2008 to 31/09/2009). Esophageal temperature was measured in the Emergency Department and Intensive Care Unit (ICU). Selected patients had pre-hospital temperature monitoring. Time taken to reach target temperature after ROSC was recorded, together with time to admission to the Emergency Department and ICU.

Results

164 OHCA patients were included in the study. 105 (64.0%) were pronounced dead in the Emergency Department. 59 (36.0%) were admitted to ICU for cooling; 40 (24.4%) died in ICU and 19 (11.6%) survived to hospital discharge. Patients who achieved ROSC and had esophageal temperature measured pre-hospital (n = 29) had a mean pre-hospital temperature of 33.9 °C (95% CI 33.2-34.5). All patients arriving in the ED post OHCA had a relatively low esophageal temperature (34.3 °C, 95% CI 34.1-34.6). Patients surviving to hospital discharge were warmer on admission to ICU than patients who died in hospital (35.7 °C vs 34.3 °C, p < 0.05). Patients surviving to hospital discharge also took longer to reach T_targ than non-survivors (2 h 48 min vs 1 h 32 min, p < 0.05).

Conclusions

Following OHCA all patients have esophageal temperatures below normal in the pre-hospital phase and on arrival in the Emergency Department. Patients who achieve ROSC following OHCA and survive to hospital discharge are warmer on arrival in ICU and take longer to reach target MTH temperatures compared to patients who die in hospital. The mechanisms of action underlying esophageal temperature and survival from OHCA remain unclear and further research is warranted to clarify this relationship.     

Severe QTc prolongation under mild hypothermia treatment and incidence of arrhythmias after cardiac arrest--a prospective study in 34 survivors with continuous Holter ECG

Background

Mild hypothermia treatment (32-34 °C) in survivors after cardiac arrest (CA) is clearly recommended by the current guidelines. The effects of cooling procedure towards QT interval have not been evaluated so far outside of case series. In a prospective study 34 consecutive survivors after cardiac arrest were continuously monitored with Holter ECG over the first 48 h.

Patients and methods

A total of 34 patients were analysed and received mild therapeutic hypothermia treatment (MTH) according to the current guidelines and irrespective of the initial rhythm. At admission to hospital and in the field in case of OHCA, a 12-lead ECG was performed in all patients.

Results

During cooling the incidence of ventricular tachycardia was low (8.8%) and in none of the patients Torsade de pointes occurred. The QTc interval was within normal range at first patient contact with EMS in the field (440.00 ms; IQR 424.25-476.75; n = 17) but during hypothermia treatment the QTc interval was significantly prolonged at 33 °C after 24 h of cooling (564.47 ms; IQR 512.41-590.00; p = 0.0001; n = 34) and decreased after end of hypothermia to baseline levels (476.74 ms; 448.71-494.97; p = 0.15).

Conclusion

The QTc interval was found to be significantly prolonged during MTH treatment, and some severe prolongations >670 ms were observed, without a higher incidence of life-threatening arrhythmias, especially no Torsade des pointes were detected. However, routine and frequent ECG recording with respect to the QTc interval should become part of any hypothermia standard operation protocol and should be recommended by official guidelines.     

Examining the contextual effects of neighborhood on out-of-hospital cardiac arrest and the provision of bystander cardiopulmonary resuscitation

Objective

To understand the association between neighborhood and individual characteristics in determining whether or not bystanders perform cardiopulmonary resuscitation (CPR) in cases of out-of-hospital cardiac arrest (OHCA).

Methods

Between October 1, 2005 to November 30, 2008, 1108 OHCA cases from Fulton County (Atlanta), GA, were eligible for bystander CPR. We conducted multi-level non-linear regression analysis and derived Empirical Bayes estimates for bystander CPR by census tract.

Results

279 (25%) cardiac arrest victims received bystander CPR. Provision of bystander CPR was significantly more common in witnessed events (odds ratio [OR] 1.64; 95% confidence interval [CI] 1.21-2.22, p < 0.001) and those that occurred in public locations (OR 1.67; 95% CI 1.16-2.40, p < 0.001). Other individual-level characteristics were not significantly associated with bystander CPR. Cardiac arrests in the census tracts that rank in the highest income quintile, as compared to the lowest income quintile were much more likely (OR 4.98; 95% CI 1.65-15.04) to receive bystander CPR.

Conclusion

Cardiac arrest victims in the highest income census tracts were much more likely to receive bystander CPR than in the lowest income census tracts, even after controlling for individual and arrest characteristics. Low-income neighborhoods may be particularly appropriate targets for community-based CPR training and awareness efforts.     

Out-of-hospital cardiac arrests in young adults in Melbourne, Australia

Background

Characteristics and outcomes of out-of-hospital cardiac arrest (OHCA) in young adults are not well described in Australia.

Methods

A 10-year retrospective case review of all OHCA in young adults (aged 16-39) and not witnessed by EMS, was performed using data from the Victorian Ambulance Cardiac Arrest Registry (VACAR).

Results

Between 2000 and 2009 there were 30,006 adult cardiac arrests of which 3912 (13%) were in this age group. The median (IQR) age was 30 (25-35) years for both sexes with a 3:1 male to female ratio. Overdose was the most common precipitant (33.5%) followed by presumed cardiac (20%). Bystander CPR occurred in 21.2%, EMS median response time was 7 min and resuscitation was attempted in 36% of OHCAs. The presenting rhythm was asystole in 84.6%, PEA in 8.8% and VF/VT in 6.6%. Survival to hospital discharge, for all cause OHCA where resuscitation was attempted, was similar for young adult and older adults (8.8% vs 8.4%, p = 0.2). However, for presumed cardiac aetiology OHCA, young adults had a greater proportion of survivors (14.8% vs 9.0%, p < 0.001). Cardiac arrest with shockable rhythm (VF/pulseless VT) had a survival rate of 31.2% for young adults compared to 18.5% for older adults (p < 0.001).

Conclusion

Survival to hospital discharge rates from OHCA due to a ‘presumed cardiac’ precipitant in young adults is much better than older adults, however, all cause OHCA survival is similar. Multi agency novel upstream preventive strategies aimed at tackling drug overdose may reduce this aetiology of OHCA and save lives.     

Improved outcome of extracorporeal cardiopulmonary resuscitation for out-of-hospital cardiac arrest – A comparison with that for extracorporeal rescue for in-hospital cardiac arrest

Purpose

The aim was to investigate the effects of extracorporeal cardiopulmonary resuscitation (ECPR) for out-of-hospital cardiac arrest (OHCA) and compare the results with those of in-hospital cardiac arrest (IHCA).

Methods

We analyzed our extracorporeal membrane oxygenation (ECMO) results for patients who received ECPR for OHCA or IHCA in the last 5 years. Pre-arrest, resuscitation, and post-resuscitative data were evaluated.

Results

In the last 5 years, ECPR was used 230 times for OHCA (n = 31) and IHCA (n = 199). The basic demographic data showed significant differences in age, cardiomyopathy, and location of the initial CPR. Duration of ischemia was shorter in the IHCA group (44.4 ± 24.7 min vs. 67.5 ± 30.6 min, p < 0.05). About 50% of each group underwent a further intervention to treat the underlying etiology. ECMO was maintained for a shorter duration in the OHCA patients (61 ± 48 h vs. 94 ± 122 h, p < 0.05). Survival to discharge was similar in the two groups (38.7% for OHCA vs. 31.2% for IHCA, p > 0.05), as was the favorable outcome rate (25.5% for OHCA vs. 25.1% for IHCA, p > 0.05). Survival was acceptable (about 33%) in both groups when the duration of ischemia was no longer than 75 min.

Conclusions

In addition to having a beneficial effect in IHCA, ECPR can lead to survival and a positive neurological outcome in selected OHCA patients after prolonged resuscitation. Our results suggest that further investigation of the use of ECMO in OHCA is warranted.     

Hypokalemia during the cooling phase of therapeutic hypothermia and its impact on arrhythmogenesis

Background

Mild to moderate therapeutic hypothermia (TH) has been shown to improve survival and neurological outcome in patients resuscitated from out-of-hospital cardiac arrest (OHCA) with ventricular fibrillation (VF) as the presenting rhythm. This approach entails the management of physiological variables which fall outside the realm of conventional critical cardiac care. Management of serum potassium fluxes remains pivotal in the avoidance of lethal ventricular arrhythmia.

Methods

We retrospectively analyzed potassium variability with TH and performed correlative analysis of QT intervals and the incidence of ventricular arrhythmia.

Results

We enrolled 94 sequential patients with OHCA, and serum potassium was followed intensively. The average initial potassium value was 3.9 ± 0.7 mmol l⁻¹ and decreased to a nadir of 3.2 ± 0.7 mmol l⁻¹ at 10 h after initiation of cooling (p < 0.001). Eleven patients developed sustained polymorphic ventricular tachycardia (PVT) with eight of these occurring during the cooling phase. The corrected QT interval prolonged in relation to the development of hypothermia (p < 0.001). Hypokalemia was significantly associated with the development of PVT (p = 0.002), with this arrhythmia being most likely to develop in patients with serum potassium values of less than 2.5 mmol l⁻¹ (p = 0.002). Rebound hyperkalemia did not reach concerning levels (maximum 4.26 ± 0.8 mmol l⁻¹ at 40 h) and was not associated with the occurrence of ventricular arrhythmia. Furthermore, repletion of serum potassium did not correlate with the development of ventricular arrhythmia.

Conclusions

Therapeutic hypothermia is associated with a significant decline in serum potassium during cooling. Hypothermic core temperatures do not appear to protect against ventricular arrhythmia in the context of severe hypokalemia and cautious supplementation to maintain potassium at 3.0 mmol l⁻¹ appears to be both safe and effective.     

Feasibility and safety of combined percutaneous coronary intervention and therapeutic hypothermia following cardiac arrest

Review

Mild therapeautic hypothermia (MTH) has been associated with cardiac dysrhythmias, coagulopathy and infection. After restoration of spontaneous circulation (ROSC), many cardiac arrest patients undergo percutaneous coronary intervention (PCI). The safety and feasibility of combined MTH and PCI remains unclear. This is the first study to evaluate whether PCI increases cardiac risk or compromises functional outcomes in comatose cardiac arrest patients who undergo MTH.

Methods

Ninety patients within a 6-h window following cardiac arrest and ROSC were included. Twenty subjects (23%) who underwent PCI following MTH induction were compared to 70 control patients who underwent MTH without PCI. The primary endpoint was the rate of dysrhythmias; secondary endpoints were time-to-MTH induction, rates of adverse events (dysrhythmia, coagulopathy, hypotension and infection) and mortality.

Results

Patients who underwent PCI plus MTH suffered no statistical increase in adverse events (P = .054). No significant difference was found in the rates of dysrhythmias (P = .27), infection (P = .90), coagulopathy (P = .90) or hypotension (P = .08). The PCI plus MTH group achieved similar neurological outcomes (modified Rankin Scale (mRS) ≤3 (P = .42) and survival rates (P = .40). PCI did not affect the speed of MTH induction; the target temperature was reached in both groups without a significant time difference (P = .29).

Conclusion

Percutaneous coronary intervention seems to be feasible when combined with MTH, and is not associated with increased cardiac or neurological risk.     

Intraosseous infusion of ice cold saline is less efficacious than intravenous infusion for induction of mild therapeutic hypothermia in a swine model of cardiac arrest

Background

Intravenous (IV) infusion of ice cold saline is an effective method to initiate induction of mild therapeutic hypothermia (MTH) following resuscitation from out-of-hospital cardiac arrest (OOHCA). Intraosseous (IO) infusion of cold saline may be an alternative method to induce MTH.

Objective

The goal of this study was to determine if IO infusion of cold saline is a comparable alternative to IV infusion for inducing MTH in a laboratory swine model of cardiac arrest.

Methods

Ten mixed breed swine were resuscitated from cardiac arrest and randomized post-resuscitation to infusion with ice cold saline using either IO (n = 5) or IV (n = 5) access. The study endpoints were either a goal esophageal temperature of 34 °C or the elapse of a 30 min time period, simulating a long prehospital transport.

Results

Four of five pigs in the IV infusion group achieved goal temperature within 30 min compared to 0/5 in the IO infusion group (p = 0.048). The mean esophageal temperature change was significantly higher in the IV group when compared to the IO group (p < 0.001). Post-arrest hemodynamic parameters were similar between the two groups.

Conclusions

IV infusion of ice cold saline is an efficacious method to achieve MTH in this swine model of cardiac arrest. Furthermore, IO infusion of cold saline is not sufficient to induce MTH in the time routinely available in the prehospital setting following OOHCA.     

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.     

Out-of-hospital cardiac arrest frequency and survival: Evidence for temporal variability

Aim

Some cardiac phenomena demonstrate temporal variability. We evaluated temporal variability in out-of-hospital cardiac arrest (OHCA) frequency and outcome.

Methods

Prospective cohort study (the Resuscitation Outcomes Consortium) of all OHCA of presumed cardiac cause who were treated by emergency medical services within 9 US and Canadian sites between 12/1/2005 and 02/28/2007. In each site, Emergency Medical System records were collected and analyzed. Outcomes were individually verified by trained data abstractors.

Results

There were 9667 included patients. Median age was 68 (IQR 24) years, 66.7% were male and 8.3% survived to hospital discharge. The frequency of cardiac arrest varied significantly across time blocks (p < 0.001). Compared to the 0001-0600 hourly time block, the odds ratios and 95% CIs for the occurrence of OHCA were 2.02 (1.90, 2.15) in the 0601-1200 block, 2.01 (1.89, 2.15) in the 1201-1800 block, and 1.73 (1.62, 1.85) in the 1801-2400 block. The frequency of all OHCA varied significantly by day of week (p = 0.03) and month of year (p < 0.001) with the highest frequencies on Saturday and during December. Survival to hospital discharge was lowest when the OHCA occurred during the 0001-0600 time block (7.3%) and highest during the 1201-1800 time block (9.6%). Survival was highest for OHCAs occurring on Mondays (10.0%) and lowest for those on Wednesdays (6.8%) (p = 0.02).

Conclusion

There is temporal variability in OHCA frequency and outcome. Underlying patient, EMS system and environmental factors need to be explored to offer further insight into these observed patterns.     

Use of ice-cold crystalloid for inducing mild therapeutic hypothermia following out-of-hospital cardiac arrest

Objective

Out of hospital cardiac arrest (OHCA) results in a significant mortality and neurological disability in survivors. The application of mild therapeutic hypothermia (MTH) to patients who have suffered an OHCA with a ventricular rhythm results in a significant reduction in mortality and neurological disability in survivors. The optimal timing of this intervention has not been clearly established; however there is emerging evidence to suggest that maximal benefit is gained from initiation at the earliest time point. Despite this, recent surveys have shown a considerable delay in initiating MTH, with variable uptake in emergency departments (EDs), where a number of impediments to delivery have been identified.

Method

We have reviewed the literature to determine what are the barriers to the initiation of MTH in the ED. We also reviewed the literature on the use of ice-cold crystalloids as a practical, simple, effective, and safe method to induce MTH.

Results

Among the several reasons, the perception of a lack of a practical method and logistical constraints are cited as common barriers. However, the available literature on the use of ice-cold crystalloids suggests that this is a safe and effective method of inducing MTH.

Conclusion

ED staff need to be aware that the use of ice-cold fluids is an inexpensive, readily available and easy to perform method of inducing MTH in patients who suffer an out-of hospital cardiac arrest with a ventricular rhythm. We therefore suggest that ice-cold crystalloid is routinely stocked in emergency departments and, unless contraindicated, is used to induce MTH. Optimal post-resuscitation care also includes timely treatment of the cause of the OHCA and maintenance of MTH. Staff education and care bundles may help to facilitate optimal inter-departmental management of the patient.     

The addition of voice prompts to audiovisual feedback and debriefing does not modify CPR quality or outcomes in out of hospital cardiac arrest--a prospective, randomized trial

Aims

Chest compression quality is a determinant of survival from out-of-hospital cardiac arrest (OHCA). ERC 2005 guidelines recommend the use of technical devices to support rescuers giving compressions. This prospective randomized study reviewed influence of different feedback configurations on survival and compression quality.

Materials and methods

312 patients suffering an OHCA were randomly allocated to two different feedback configurations. In the limited feedback group a metronome and visual feedback was used. In the extended feedback group voice prompts were added. A training program was completed prior to implementation, performance debriefing was conducted throughout the study.

Results

Survival did not differ between the extended and limited feedback groups (47.8% vs 43.9%, p = 0.49). Average compression depth (mean ± SD: 4.74 ± 0.86 cm vs 4.84 ± 0.93 cm, p = 0.31) was similar in both groups. There were no differences in compression rate (103 ± 7 vs 102 ± 5 min(−1), p = 0.74) or hands-off fraction (16.16% ± 0.07 to 17.04% ± 0.07, p = 0.38). Bystander CPR, public arrest location, presenting rhythm and chest compression depth were predictors of short term survival (ROSC to ED).

Conclusions

Even limited CPR-feedback combined with training and ongoing debriefing leads to high chest compression quality. Bystander CPR, location, rhythm and chest compression depth are determinants of survival from out of hospital cardiac arrest. Addition of voice prompts does neither modify CPR quality nor outcome in OHCA. CC depth significantly influences survival and therefore more focus should be put on correct delivery. Further studies are needed to examine the best configuration of feedback to improve CPR quality and survival.

Registration

ClinicalTrials.gov (NCT00449969), http://www.clinicalTrials.gov.     

Feasibility of intra-arrest hypothermia induction: A novel nasopharyngeal approach achieves preferential brain cooling

Aim

In patients with cardiopulmonary arrest, brain cooling may improve neurological outcome, especially if applied prior to or during early reperfusion. Thus it is important to develop feasible cooling methods for pre-hospital use. This study examines cerebral and compartmental thermokinetic properties of nasopharyngeal cooling during various blood flow states.

Methods

Ten swine (40 ± 4 kg) were anesthetized, intubated and monitored. Temperature was determined in the frontal lobe of the brain, in the aorta, and in the rectum. After the preparatory phase the cooling device (RhinoChill™ system), which produces evaporative cooling in the nasopharyngeal area, was activated for 60 min. The thermokinetic response was evaluated during stable anaesthesia (NF, n = 3); during untreated cardiopulmonary arrest (ZF, n = 3); during CPR (LF, n = 4).

Results

Effective brain cooling was achieved in all groups with a median cerebral temperature decrease of −4.7 °C for NF, −4.3 °C for ZF and −3.4 °C for LF after 60 min. The initial brain cooling rate however was fastest in NF, followed by LF, and was slowest in ZF; the median brain temperature decrease from baseline after 15 min of cooling was −2.48 °C for NF, −0.12 °C for ZF, and −0.93 °C for LF, respectively. A median aortic temperature change of −2.76 °C for NF, −0.97 for LF and +1.1 °C for ZF after 60 min indicated preferential brain cooling in all groups.

Conclusion

While nasopharyngeal cooling in swine is effective at producing preferential cerebral hypothermia in various blood flow states, initial brain cooling is most efficient with normal circulation.     

Cardiac arrest due to food asphyxiation in adults: Resuscitation profiles and outcomes

Aim

Food asphyxiation is uncommon but unignorable cause of sudden death in the elderly. Several autopsy studies, which identified those at particular risk, have been conducted on the subject. Resuscitation profiles and outcomes of food asphyxiation victims presenting with out-of-hospital cardiac arrest (OHCA) to the emergency department, however, have rarely been reported.

Methods

Data on adults (≥20 years) presenting with OHCA after witnessed food asphyxiation were retrieved from an institutional database. Clinical variables were evaluated to identify their demographic characteristics. Their outcomes, represented by return of spontaneous circulation (ROSC) and survival rate, were also investigated.

Results

Sixty-nine food asphyxiation victims presenting with OHCA were identified during the 4-year period. Food asphyxiation occurred most frequently in the age group of 71-80 years, followed by that of 81-90 years. The majority of victims had medical conditions that adversely affected mastication/swallowing, such as dementia. Bystander cardiopulmonary resuscitation (CPR) was performed only in 26%, although bystanders often attempted to clear the airway without performing CPR. Despite the high ROSC rate of 78%, only 7% survived to discharge. Asphyxiation-ROSC interval might play a crucial role in determining the outcomes: the interval was ≤10 min in all survivors, while it was longer than 10 min in all non-survivors.

Conclusion

Because of their advanced age and debilitating general condition, it may be difficult to substantially improve the outcomes of food asphyxiation victims. Effort should be directed to prevent food asphyxiation, and public education to perform standard CPR for food asphyxiation victims including the Heimlich manoeuvre is warranted.     

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.     

Clinical predictors of survival in patients treated with therapeutic hypothermia following cardiac arrest

Introduction

Therapeutic hypothermia has been shown to provide neuroprotection and improved survival in patients suffering a cardiac arrest. We report outcomes of consecutive patients receiving therapeutic hypothermia for cardiac arrest and describe predictors of short and long-term survival.

Methods

Eighty patients receiving therapeutic hypothermia between January 2005 and December 2008 were identified and categorized as those who survived and died. Outcomes and predictors of survival were determined.

Results

Forty-five patients (56%) survived to hospital discharge and were alive at 30 days and among survivors 41 (91%) were alive 1 year after discharge. Survivors were younger, were more likely to present with VF, required less epinephrine during resuscitation, were more likely to have preserved renal function, and were less likely to be taking beta-blockers and ACE inhibitors. Predictors of survival included VF on presentation (OR 14.9, CI 2.7-83.2, p = 0.002), pre-cardiac arrest aspirin use (OR 9.7, CI 1.6-61.1, p = 0.02), return of spontaneous circulation <20 min (OR 9.4, CI 2.2-41.1, p = 0.003), absence of coronary artery disease (OR 5.3, CI 1.1-24.7, p = 0.002) and preserved renal function.

Conclusion

Therapeutic hypothermia is useful in the treatment of patients suffering a cardiac arrest. Several clinical factors may aid in predicting patients who are likely to survive after a cardiac arrest.     

Prognostic indicators and outcome prediction model for patients with return of spontaneous circulation from cardiopulmonary arrest: the Utstein Osaka Project

Objective

To determine the most important indicators of prognosis in patients with return of spontaneous circulation (ROSC) following out-of-hospital cardiopulmonary arrest (OHCA) and to develop a best outcome prediction model.

Design and patients

All patients were prospectively recorded based on the Utstein Style in Osaka over a period of 3 years (2005-2007). Criteria for inclusion were a witnessed cardiac arrest, age greater than 17 years, presumed cardiac origin of the arrest, and successful ROSC. Multivariate logistic regression (MLR) analysis was used to develop the best prediction model. The dependent variables were favourable outcome (cerebral-performance category [CPC]: 1-2) and poor outcome (CPC: 3-5) at 1 month after the event. Eight explanatory pre-hospital variables were used concerning patient characteristics and resuscitation. External validation was performed on an independent set of Utstein data in 2007.

Results

Subjects comprised 285 patients in VF and 577 patients with pulseless electrical activity (PEA)/asystole. The percentage of favourable outcomes was 31.9% (91/285) in VF and 5.7% (33/577) in PEA/asystole. The most important prognostic indicators of favourable outcome found by MLR were age (p = 0.10), time from collapse to ROSC (TROSC) (p < 0.01), and presence of pre-hospital ROSC (PROSC) (p = 0.15) for VF and age (p = 0.03), TROSC (p < 0.01), PROSC (p < 0.01), and conversion to VF (p = 0.01) for PEA/asystole. For external validation data, areas under the receiver-operating characteristic curve were 0.867 for VF and 0.873 for PEA/asystole.

Conclusions

A model based on four selected indicators showed a high predictive value for favourable outcome in OHCA patients with ROSC.     

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.