To the Editor:
I have read the very interesting and detailed article by Ramachandran et al. recently published in Anesthesiology,1 dealing with perioperative cardiopulmonary arrest and the possibility of its prediction through a retrospective database analysis. The authors showed results on the influence (predictors) of perioperative diseases, type of cardiac rhythm when pulseless activity was detected, event location (operating room, postanesthesia care unit, intensive care area, telemetry, or general ward), and other patient characteristics. Although designed to study the survival to hospital discharge as the primary outcome, and the neurological outcome (intact or affected by neurological disability) as the secondary one, I was suprised by the fact that several items usually (and in my opinion obligatory) included in anesthesia-related mortality and morbidity studies, as those cited by the authors2–4 and others,5–8 as are the surgical procedure (even grossly classified), any kind of risk stratification or score (American Society of Anesthesiologists’ physical status, etc.), and, perhaps the most important, the type of anesthetic procedure the patient was subjected to, were not included in the analysis or not showed. Otherwise, the exclusion of these informative data was not clearly explained. These are important because it could explain some of the findings of the study, as the relatively high survival rates, with good neurological outcomes of asystolic arrests, and, in part, the better outcome of cardiac arrests occurring in the operating room or in the postanesthesia care unit: for instance, asystolic cardiac arrests due to spinal anesthesia have been described as with easier resuscitation and good outcomes,2,9 and those can occur in younger patients having better physical status. Another example would be that general anesthesia is frequently chosen in the more severe patients and in high-risk surgeries, and consequently, worse prognostic should be expected if a cardiopulmonary arrest occurs.2
The author declares no competing interests.