Background: It is unclear how long resuscitation efforts should be continued after non-traumatic cardiac arrest. Classically it had been suggested that cardiopulmonary resuscitation (CPR) should be finished in patients who do not respond after 20–30 minutes of advanced life support. Time is a subjective parameter that is always considered. However, there are currently more cases reported with good neurological prognosis from prolonged resuscitations.
Purpose: We aimed to evaluate the characteristics of patients whom return of spontaneous circulation (ROSC) was achieved beyond 30 minutes of CPR and to determine if there is any parameter that justifies prolonging resuscitation efforts to maximize good neurological outcomes including novel therapies such as extracorporeal-CPR.
Methods: Post hoc analysis from a prospective observational cohort study of successfully resuscitated patients admitted to an intensive cardiac care unit. The variables were consecutively collected according to the updated Utstein definitions. All patients were unconscious at arrival and underwent mild therapeutic hypothermia during 24 hours. Neurological assessment at hospital discharge was determined according to Cerebral Performance Category Scale (CPC). The characteristics in good outcomes survivors (CPC 1–2) and poor or non-survivors (CPC 3–5) over time were compared. The multivariate logistic regression method was used to identify the independent prognostic predictors for the outcomes.
Results: From January 2007 to January 2018 a total of 424 patients were screened. Only 142 (33.5%) patients achieved ROSC after prolonged CPR (defined as >30 minutes). Patients with prolonged efforts were stratified by neurological outcome at hospital discharge, defining by favorable outcome (CPC 1–2) in 45 (31.7%) and poor neurolόgica outcome in 97 (68.3%). Patients survived with CPC 1–2 were significantly younger (55.2 vs 62.1 years, p<0.001), more male percentages (91.1 vs 78.5%, p=0.036), smokers (61.4 vs 43.5%, p=0.05), had a higher frequency of shockable initial rhythm (86.7 vs 55.67%, p<0.001) and lower no-flow time (3.2 vs 8.04 min, p<0.001). There were no differences in the pH levels on arrival, lactate or other biochemical markers such as enolase. The multivariate logistic regression confirmed age, shorter no flow time and shockable rthythm were the variables with better outcomes instead of CPR time.
Adjusted odds ratio (OR) for CPC 1-2
Conclusions: High percentage of patients can still being recovered with a favorable functional outcome after prolonged CPR (beyond 30 minutes). Although there are factors associated with better or worse outcomes, no single factor evaluated predicts outcome with sufficient accuracy to recommend termination or prolongation of CPR. It is probably justified to extend the efforts in patients with younger age, shockable rhythm and shorter no-flow time. More research is needed in this field.
