Primary outcomes for resuscitation science studies: a consensus statement from the American Heart Association

Long-term outcomes in elderly survivors of in-hospital cardiac arrest

BACKGROUND

Little is known about the long-term outcomes in elderly survivors of in-hospital cardiac arrest. We determined rates of long-term survival and readmission among survivors of in-hospital cardiac arrest and examined whether these outcomes differed according to demographic characteristics and neurologic status at discharge.

METHODS

We linked data from a national registry of inpatient cardiac arrests with Medicare files and identified 6972 adults, 65 years of age or older, who were discharged from the hospital after surviving an in-hospital cardiac arrest between 2000 and 2008. Predictors of 1-year survival and of readmission to the hospital were examined.

RESULTS

One year after hospital discharge, 58.5% of the patients were alive, and 34.4% had not been readmitted to the hospital. The risk-adjusted rate of 1-year survival was lower among older patients than among younger patients (63.7%, 58.6%, and 49.7% among patients 65 to 74, 75 to 84, and ≥85 years of age, respectively; P<0.001), among men than among women (58.6% vs. 60.9%, P=0.03), and among black patients than among white patients (52.5% vs. 60.4%, P=0.001). The risk-adjusted rate of 1-year survival was 72.8% among patients with mild or no neurologic disability at discharge, as compared with 61.1% among patients with moderate neurologic disability, 42.2% among those with severe neurologic disability, and 10.2% among those in a coma or vegetative state (P<0.001 for all comparisons). Moreover, 1-year readmission rates were higher among patients who were black, those who were women, and those who had substantial neurologic disability (P<0.05 for all comparisons). These differences in survival and readmission rates persisted at 2 years. At 3 years, the rate of survival among survivors of in-hospital cardiac arrest was similar to that of patients who had been hospitalized with heart failure and were discharged alive (43.5% and 44.9%, respectively; risk ratio, 0.98; 95% confidence interval, 0.95 to 1.02; P=0.35).

CONCLUSIONS

Among elderly survivors of in-hospital cardiac arrest, nearly 60% were alive at 1 year, and the rate of 3-year survival was similar to that among patients with heart failure. Survival and readmission rates differed according to the demographic characteristics of the patients and neurologic status at discharge. (Funded by the American Heart Association and the National Heart, Lung, and Blood Institute.).

Chest Compression Alone Cardiopulmonary Resuscitation Is Associated With Better Long-Term Survival Compared with Standard Cardiopulmonary Resuscitation

Background—

Little is known about the long-term survival effects of type-specific bystander cardiopulmonary resuscitation (CPR) in the community. We hypothesized that dispatcher instruction consisting of chest compression alone would be associated with better overall long-term prognosis in comparison with chest compression plus rescue breathing.

Methods and Results—

The investigation was a retrospective cohort study that combined 2 randomized trials comparing the short-term survival effects of dispatcher CPR instruction consisting either of chest compression alone or chest compression plus rescue breathing. Long-term vital status was ascertained by using the respective National and State death records through July 31, 2011. We performed Kaplan-Meier method and Cox regression to evaluate survival according to the type of CPR instruction. Of the 2496 subjects included in the current investigation, 1243 (50%) were randomly assigned to chest compression alone and 1253 (50%) were randomly assigned to chest compression plus rescue breathing. Baseline characteristics were similar between the 2 CPR groups. During the 1153.2 person-years of follow-up, there were 2260 deaths and 236 long-term survivors. Randomization to chest compression alone in comparison with chest compression plus rescue breathing was associated with a lower risk of death after adjustment for potential confounders (adjusted hazard ratio, 0.91; 95% confidence interval, 0.83–0.99; P =0.02).

Conclusions—

The findings provide strong support for long-term mortality benefit of dispatcher CPR instruction strategy consisting of chest compression alone rather than chest compression plus rescue breathing among adult patients with cardiac arrest requiring dispatcher assistance.

Hyperoxia is associated with increased mortality in patients treated with mild therapeutic hypothermia after sudden cardiac arrest

OBJECTIVE

To determine whether higher levels of PaO2 are associated with in-hospital mortality and poor neurological status at hospital discharge in patients treated with mild therapeutic hypothermia after sudden cardiac arrest.

DESIGN

Retrospective analysis of a prospective cohort.

PATIENTS

A total of 170 consecutive patients treated with therapeutic hypothermia in the cardiovascular care unit of an academic tertiary care hospital.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 170 patients, 77 (45.2%) survived to hospital discharge. Survivors had a significantly lower maximum PaO2 (198 mm Hg; interquartile range, 152.5-282) measured in the first 24 hrs following cardiac arrest compared to nonsurvivors (254 mm Hg; interquartile range, 172-363; p = .022). A multivariable analysis including age, time to return of spontaneous circulation, the presence of shock, bystander cardiopulmonary resuscitation, and initial rhythm revealed that higher levels of PaO2 were significantly associated with increased in-hospital mortality (odds ratio 1.439; 95% confidence interval 1.028-2.015; p = .034) and poor neurological status at hospital discharge (odds ratio 1.485; 95% confidence interval 1.032-2.136; p = .033).

CONCLUSIONS

Higher levels of the maximum measured PaO2 are associated with increased in-hospital mortality and poor neurological status on hospital discharge in patients treated with mild therapeutic hypothermia after sudden cardiac arrest.

Increasing arterial oxygen partial pressure during cardiopulmonary resuscitation is associated with improved rates of hospital admission

AIM

As recent clinical data suggest a harmful effect of arterial hyperoxia on patients after resuscitation from cardiac arrest (CA), we aimed to investigate this association during cardiopulmonary resuscitation (CPR), the earliest and one of the most crucial phases of recirculation.

METHODS

We analysed 1015 patients who from 2003 to 2010 underwent out-of-hospital CPR administered by emergency medical services serving 300,000 inhabitants. Inclusion criteria for further analysis were nontraumatic background of CA and patients >18 years of age. One hundred and forty-five arterial blood gas analyses including oxygen partial pressure (paO2) measurement were obtained during CPR.

RESULTS

We observed a highly significant increase in hospital admission rates associated with increases in paO2 in steps of 100 mmHg (13.3 kPa). Subsequently, data were clustered according to previously described cutoffs (≤ 60 mmHg [8 kPa]], 61-300 mmHg [8.1-40 kPa], >300 mmHg [>40 kPa]). Baseline variables (age, sex, initial rhythm, rate of bystander CPR and collapse-to-CPR time) of the three compared groups did not differ significantly. Rates of hospital admission after CA were 18.8%, 50.6% and 83.3%, respectively. In a multivariate analysis, logistic regression revealed significant prognostic value for paO2 and the duration of CPR.

CONCLUSION

This study presents novel human data on the arterial paO2 during CPR in conjunction with the rate of hospital admission. We describe a significantly increased rate of hospital admission associated with increasing paO2. We found that the previously described potentially harmful effects of hyperoxia after return of spontaneous circulation were not reproduced for paO2 measured during CPR.

CLINICAL TRIAL REGISTRATION

n/a.

Randomised comparison of the effectiveness of the laryngeal mask airway supreme, i-gel and current practice in the initial airway management of prehospital cardiac arrest (REVIVE-Airways): a feasibility study research protocol

INTRODUCTION

Effective cardiopulmonary resuscitation with appropriate airway management improves outcomes following out-of-hospital cardiac arrest (OHCA). Historically, tracheal intubation has been accepted as the optimal form of OHCA airway management in the UK. The Joint Royal Colleges Ambulance Liaison Committee recently concluded that newer supraglottic airway devices (SADs) are safe and effective devices for hospital procedures and that their use in OHCA should be investigated. This study will address an identified gap in current knowledge by assessing whether it is feasible to use a cluster randomised design to compare SADs with current practice, and also to each other, during OHCA.

METHODS AND ANALYSIS

The primary objective of this study is to assess the feasibility of a cluster randomised trial to compare the ventilation success of two newer SADs: the i-gel and the laryngeal mask airway supreme to usual practice during the initial airway management of OHCA. The secondary objectives are to collect data on ventilation success, further airway interventions required, loss of a previously established airway during transport, airway management on arrival at hospital (or termination of the resuscitation attempt), initial resuscitation success, survival to intensive care admission, survival to hospital discharge and patient outcome at 3 months. Ambulance paramedics will be randomly allocated to one of the three methods of airway management. Adults in medical OHCA attended by a trial paramedic will be eligible for the study.

ETHICS AND DISSEMINATION

Approval for the study has been obtained from a National Health Service Research Ethics Committee with authority to review proposals for trials of a medical device in incapacitated adults. The results will be made publicly available on an open access website, and we will publish the findings in appropriate journals and present them at national and international conferences relevant to the subject field.

TRIAL REGISTRATION

ISRCTN: 18528625.

Coronary versus carotid blood flow and coronary perfusion pressure in a pig model of prolonged cardiac arrest treated by different modes of venoarterial ECMO and intraaortic balloon counterpulsation

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) is increasingly used in cardiac arrest (CA). Adequacy of carotid and coronary blood flows (CaBF, CoBF) and coronary perfusion pressure (CoPP) in ECMO treated CA is not well established. This study compares femoro-femoral (FF) to femoro-subclavian (FS) ECMO and intraaortic balloon counterpulsation (IABP) contribution based on CaBF, CoBF, CoPP, myocardial and brain oxygenation in experimental CA managed by ECMO.

METHODS

In 11 female pigs (50.3 ± 3.4 kg), CA was randomly treated by FF versus FS ECMO ± IABP. Animals under general anesthesia had undergone 15 minutes of ventricular fibrillation (VF) with ECMO flow of 5 to 10 mL/kg/min simulating low-flow CA followed by continued VF with ECMO flow of 100 mL/kg/min. CaBF and CoBF were measured by a Doppler flow wire, cerebral and peripheral oxygenation by near infrared spectroscopy. CoPP, myocardial oxygen metabolism and resuscitability were determined.

RESULTS

CaBF reached values > 80% of baseline in all regimens. CoBF > 80% was reached only by the FF ECMO, 90.0% (66.1, 98.6). Addition of IABP to FF ECMO decreased CoBF to 60.7% (55.1, 86.2) of baseline, P = 0.004. FS ECMO produced 70.0% (49.1, 113.2) of baseline CoBF, significantly lower than FF, P = 0.039. Addition of IABP to FS did not change the CoBF; however, it provided significantly higher flow, 76.7% (71.9, 111.2) of baseline, compared to FF + IABP, P = 0.026. Both brain and peripheral regional oxygen saturations decreased after induction of CA to 23% (15.0, 32.3) and 34% (23.5, 34.0), respectively, and normalized after ECMO institution. For brain saturations, all regimens reached values exceeding 80% of baseline, none of the comparisons between respective treatment approaches differed significantly. After a decline to 15 mmHg (9.5, 20.8) during CA, CoPP gradually rose with time to 68 mmHg (43.3, 84.0), P = 0 .003, with best recovery on FF ECMO. Resuscitability of the animals was high, both 5 and 60 minutes return of spontaneous circulation occured in eight animals (73%).

CONCLUSIONS

In a pig model of CA, both FF and FS ECMO assure adequate brain perfusion and oxygenation. FF ECMO offers better CoBF than FS ECMO. Addition of IABP to FF ECMO worsens CoBF. FF ECMO, more than FS ECMO, increases CoPP over time.

Implementation of a standardized pathway for the treatment of cardiac arrest patients using therapeutic hypothermia: "CODE ICE"

Out-of-hospital cardiac arrest is common and is associated with high mortality. The majority of in-hospital deaths from resuscitated victims of cardiac arrest are due to neurologic injury. Therapeutic hypothermia (TH) is now recommended for the management of comatose survivors of cardiac arrest. The rapid triage and standardized treatment of cardiac arrest patients can be challenging, and implementation of a TH program requires a multidisciplinary team approach. In 2010, we revised our institution's TH protocol, creating a "CODE ICE" pathway to improve the timely and coordinated care of cardiac arrest patients. As part of CODE ICE, we implemented comprehensive care pathways including measures such as a burst paging system and computerized physician support tools. "STEMI on ICE" integrates TH with our regional ST-elevation myocardial infarction network. Retrospective data were collected on 150 consecutive comatose cardiac arrest victims treated with TH (n = 82 pre-CODE ICE and n = 68 post-CODE ICE) from 2007 to 2011. After implementation of CODE ICE, the mean time to initiation of TH decreased from 306 ± 165 minutes to 196 ± 144 minutes (P < 0.001), and the time to target temperature decreased from 532 ± 214 minutes to 392 ± 215 minutes (P < 0.001). There was no significant change in survival or neurologic outcome at hospital discharge. Through the implementation of CODE ICE, we were able to reduce the time to initiation of TH and time to reach target temperature. Additional studies are needed to determine the effect of CODE ICE and similar pathways on clinical outcomes after cardiac arrest.

Performance of SAPS II and SAPS III scores in post-cardiac arrest

BACKGROUND

Cardiac arrest is a major public health issue affecting an estimated 300,000 patients in the United States each year. The American Heart Association has recommended the Simplified Acute Physiology Score II and III (SAPS) to assess severity of illness and to predict outcomes in the post-cardiac arrest population. Our objective was to determine if SAPS II and SAPS III scores predict outcomes in post-cardiac arrest patients.

METHODS

We performed an observational study of patients suffering cardiac arrest with return of spontaneous circulation. Data were collected prospectively and recorded in the Utstein style. SAPS II and SAPS III scores were calculated for each subject. Logistic regression was used to assess the relationship between the calculated severity of illness score and in-hospital mortality and poor neurologic outcome.

RESULTS

A total of 274 subjects were identified for analysis. SAPS II was a significant predictor of in-hospital mortality (OR: 1.05, 95% CI: 1.03-1.07) and poor-neurologic outcome (OR: 1.06, 95%CI: 1.04-1.08). SAPS III was a significant predictor of in-hospital mortality (OR: 1.04, 95%CI: 1.02-1.06) and poor neurologic outcome (OR: 1.04, 95%CI: 1.02-1.05). Both scores had moderate ability to discriminate survivors from non-survivors (SAPS II AUC: 0.70; SAPS III AUC: 0.66), and good neurologic outcome from poor neurologic outcome (SAPS II AUC: 0.71; SAPS III AUC: 0.65).

CONCLUSION

SAPS II and SAPS III scores have only moderate discrimination and are not clinically relevant tools to predict outcome in post-cardiac arrest patients. Further study is needed to identify a more reliable severity of illness score in the post-arrest population.

Long-term prognosis following resuscitation from out of hospital cardiac arrest: role of percutaneous coronary intervention and therapeutic hypothermia

OBJECTIVES

The aim of the study was to assess the influence of percutaneous coronary intervention (PCI) and therapeutic hypothermia (TH) on long-term prognosis.

BACKGROUND

Although hospital care consisting of TH and/or PCI in particular patients resuscitated following out-of-hospital cardiac arrest (OHCA) can improve survival to hospital discharge, there is little evidence regarding how these therapies may impact long-term prognosis.

METHODS

We performed a cohort investigation of all persons >18 years of age who suffered nontraumatic OHCA and were resuscitated and discharged alive from the hospital between January 1, 2001, and December 31, 2009, in a metropolitan emergency medical service (EMS) system. We reviewed EMS and hospital records, state death certificates, and the national death index to determine clinical characteristics and vital status. Survival analyses were conducted using Kaplan-Meier estimates and multivariable Cox regression. Analyses of TH were restricted to those patients who were comatose at hospital admission.

RESULTS

Of the 5,958 persons who received EMS-attempted resuscitation, 1,001 (16.8%) were discharged alive from the hospital. PCI was performed in 384 of 1,001 (38.4%), whereas TH was performed in 241 of 941 (25.6%) persons comatose at hospital admission. Five-year survival was 78.7% among those treated with PCI compared with 54.4% among those not receiving PCI and 77.5% among those treated with TH compared with 60.4% among those not receiving TH (both p < 0.001). After adjustment for confounders, PCI was associated with a lower risk of death (hazard ratio [HR]: 0.46 [95% confidence interval [CI]: 0.34 to 0.61]; p < 0.001). Likewise, TH was associated with a lower risk of death (HR: 0.70 [95% CI: 0.50 to 0.97]; p = 0.04).

CONCLUSIONS

The findings suggested that effects of acute hospital interventions for post-resuscitation treatment extend beyond hospital survival and can positively influence prognosis following the arrest hospitalization.