The effects of achieving hypothermia early in a heterogeneous population of patients with cardiac arrest

Abstract

In a recent article Wolff et al. (2009) present highly interesting results bearing on how timing of therapeutic hypothermia might affect outcome. However, some of their analyses are unadjusted for heterogeneities in the patient population, while others indicate a statistical model break-down. Moreover, the time from cardiac arrest to return of spontaneous circulation is recorded but not included as a potential covariate in the multivariate logistic regression, which is unfortunate considering that many studies have found it to be an important predictor of outcome. It is well-known that in observational studies it is important to adjust for all important covariates, not only statistically significant ones. Hence, we caution against drawing firm conclusions from this study.