Despite the increase in evidence-based guidelines for advanced cardiac life support and resuscitation care during the past decade, it is not clear whether survival and neurologic function after in-hospital cardiac arrest have improved. In the November issue of The New England Journal of Medicine, investigators with the American Heart Association’s Get with the Guidelines® (GWTG)-Resuscitation used clinical registry data to examine trends in rates of survival to hospital discharge. 

The GWTG-Resuscitation registry included 113,514 adults with cardiac arrest at 553 hospitals during the period 2000-2009. After arrests in the emergency department, operating room and procedural areas were excluded, 84,625 patients at 374 hospitals constituted the final study population. The primary outcome was survival to discharge; secondary outcomes included neurologic disability. Advanced multivariable regression techniques were used to analyze the cohort. Regression models adjusted for age, sex, race, coexisting conditions, therapeutic interventions at the time of arrest, and hospital characteristics.

Of all arrest patients, 67,125 (79.3%) had asystole or pulseless electrical activity, and 17,490 (20.7%) patients had ventricular fibrillation or pulseless ventricular tachycardia.  Overall survival to discharge was 17%. Survival increased from 13.7% in 2000 to 22.3% in 2009 (adjusted rate ratio per year, 1.04; 95% confidence interval, 1.03 to 1.06; P<0.001 for trend). Rates of acute resuscitation survival improved from 42.7% in 2000 to 54.1% in 2009 (P<0.001 for trend). Clinically significant neurologic disability rates declined over time from 32.9% in 2000 to 28.1% in 2009 (P=0.02 for trend). The authors concluded that both survival and neurological outcomes improved substantially from 2000 to 2009.

The results from this study may be attributed to improved protocols that emphasize high-quality chest compressions with fewer interruptions, as well as other post-resuscitation care such as therapeutic hypothermia and early cardiac catheterization. However, as with all large observational studies, the results may be explained by a decrease in the baseline risk over time, reporting bias from hospitals involved with the GWTG-Resuscitation registry and other residual confounders. While improved survival for in-hospital cardiac arrest is encouraging, confirmatory studies are indicated to identify the specific aspects responsible for this positive trend.

Concise Critical Appraisal is a regular feature authored by SCCM member Samuel M. Galvagno Jr., DO, PhD. Each installment highlights journal articles most relevant to the critical care practitioner.