We have read the recently published article by Loma-Osorio et al.1 with interest and wish to make some comments.
The population studied represents a group of patients who present with out-of-hospital cardiac arrest, all of cardiac etiology, whereas most series refer to around 75%.2 Similarly, the authors choose the concept of out-of-hospital sudden death—the Spanish language term—instead of the more widely-used English-language term: out-of-hospital cardiac arrest. Sudden death and cardiac arrest are normally used as synonyms, as they are concepts with arbitrarily established limits on the same phenomenon. Sudden death has an epidemiologic focus and cardiac arrest, a clinical orientation. We consider the variables analyzed should have been those of Utstein's template (2004),3 to facilitate comparison with similar series. Similarly, the treatments administered by participating centers were not homogeneous, despite recommendations to that effect.4
Several aspects of the results have drawn our attention. As the number of non-cardiac cases excluded is not given, the high percentage of patients with shockable rhythm (64.4%) is remarkable when other series report 30% to 40% in patients who recovered spontaneous circulation.2 The 38% incidence of events at home is far removed from that of other series in which this occurs in over 65% of cases.2 Furthermore, it would have been interesting to have known about the time intervals involved: emergency service response times, time-to-activation, time-to-consulting room, start of life support measures, and spontaneous circulation recovery, which should have been presented as medians, not means. Other issues that need clarifying are the criteria for the use of hypothermia (applied in 86 patients when 131 presented in shockable rhythm and 95.6% were in coma); cardiac catheterization, whether urgent or elective; and how many patients with non-ST segment elevation acute myocardial infarction were involved. The excellent neurological results are remarkable given that initially a high percentage of patients were in coma. This would suggest severity was not high and that a substantial number of pharmacologic cases were included. Finally, in the logistic regression model, introducing variables that interact—such as shockable rhythm and use of hypothermia or shock, pH and time of life support measures-spontaneous circulation recovery—would distort the predictive value of the model.
In the conclusions, despite excellent neurological results, the authors emphasize the need to implement the first links in the chain to survival, having reported improved survival due to improved interventions at these stages.5 The action taken in all cases of out-of-hospital cardiac arrest attended, whether the patient recovers or not, needs to be evaluated.
American Heart Association recommendations for 2010 introduce a fifth link in the chain of survival, corresponding to post-arrest care, demonstrating the need to progress in its development, as optimal care should include much more than therapeutic hypothermia.6 It would also be of great interest to know the characteristics and results not only of patients of cardiac etiology, but also of those with any etiology, and to evaluate the in-hospital protocols used.
Finally, close collaboration and coordination between emergency and other hospital services is essential. Attention must be unified, with the participation of a multidisciplinary, multiprofessional team of emergency room physicians, cardiologists, intensive care specialists, neurologists, neurophysiologists, rehabilitation physicians, nurses and physiotherapists,6 independent of primary disease type, local hospital culture or the closed compartments of medical specialties, in a change of culture affecting the specialties involved in attending these patients and putting professional exclusiveness and territorial concerns aside.
