Prevalence of troponin elevations in patients with cardiac arrest and implications for assessing quality of care in hypothermia centers.

The prevalence of troponin elevations in patients with cardiac arrest (CA) using newer generation troponin assays when the ninety-ninth percentile is used has not been well described. We studied patients admitted with CA without ST elevation myocardial infarction (MI). Treatment included a multidisciplinary protocol that included routine use of hypothermia for appropriate patients. Serial assessment of cardiac biomarkers, including troponin I was obtained over the initial 24 to 36 hours. Patients were classified into 1 of 5 groups on the basis of multiples of the ninety-ninth percentile (upper reference limit [URL]), using the peak troponin I value: <1×, 1 to 3×, 3 to 5×, 5 to 10×, and >10×. Serial changes between the initial and second troponin I values were also assessed. A total of 165 patients with CA (mean age 58 ± 16, 67% men) were included. Troponin I was detectable in all but 2 patients (99%); all others had peak troponin I values that were greater than or equal to the URL. Most patients had peak troponin I values >10× URL, including patients with ventricular fibrillation or ventricular tachycardia (85%), asystole (50%), and pulseless electrical activity (59%). Serial changes in troponin I were present in almost all patients: ≥20% change in 162 (98%), ≥30% change in 159 (96%), and an absolute increase of ≥0.02 ng/ml in 85% of patients. In conclusion, almost all patients with CA who survived to admission had detectable troponin I, most of whom met biomarker guideline criteria for MI. Given the high mortality of these patients, these data have important implications for MI mortality reporting at CA treatment centers.

Impact of resuscitation system errors on survival from in-hospital cardiac arrest.

BACKGROUND: An estimated 350,000-750,000 adult, in-hospital cardiac arrest (IHCA) events occur annually in the United States. The impact of resuscitation system errors on survival during IHCA resuscitation has not been evaluated. The purpose of this paper was to evaluate the impact of resuscitation system errors on survival to hospital discharge after IHCA. METHODS AND RESULTS: We evaluated subjective and objective errors in 118,387 consecutive, adult, index IHCA cases entered into the Get with the Guidelines National Registry of Cardiopulmonary Resuscitation database from January 1, 2000 through August 26, 2008. Cox regression analysis was used to determine the relationship between reported resuscitation system errors and other important clinical variables and the hazard ratio for death prior to hospital discharge. Of the 108,636 patients whose initial IHCA rhythm was recorded, resuscitation system errors were committed in 9,894/24,467 (40.4%) of those with an initial rhythm of ventricular fibrillation or pulseless ventricular tachycardia (VF/pVT) and in 22,599/84,169 (26.8%) of those with non-VF/pVT. The most frequent system errors related to delay in medication administration (>5 min time from event recognition to first dose of a vasoconstrictor), defibrillation, airway management, and chest compression performance errors. The presence of documented resuscitation system errors on an IHCA event was associated with decreased rates of return of spontaneous circulation, survival to 24h, and survival to hospital discharge. The relative risk of death prior to hospital discharge based on hazard ratio analysis was 9.9% (95% CI 7.8, 12.0) more likely for patients whose initial documented rhythm was non-VF/pVT when resuscitation system errors were reported compared to when no errors were reported. It was 34.2% (95% CI 29.5, 39.1) more likely for those with VF/pVT. CONCLUSIONS: The presence of resuscitation system errors that are evident from review of the resuscitation record is associated with decreased survival from IHCA in adults. Hospitals should target the training of first responders and code team personnel to emphasize the importance of early defibrillation, early use of vasoconstrictor medication, and compliance with ACLS protocols.