The Importance of the Time that Elapses Before Spontaneous Circulation is Established Following an Out-of-Hospital Cardiac Arrest

In order to clarify indications for therapeutic hypothermia, we retrospectively examined patients resuscitated after Out-of-Hospital Cardiac Arrest (OHCA) who recorded an Auditory Brainstem Response (ABR) wave V according to the Utstein-style guidelines. Patients who recorded an ABR wave V immediately after resuscitation from OHCA were kept at 34 °C for 48 hours. The cohort was divided into two groups: A favorable neurological outcome group (F group: N=12) and an unfavorable neurological outcome group (U group: N=14). Favorable neurological outcome was defined as Pittsburgh Cerebral-Performance Scale (CPC) 1 or 2 and unfavorable as CPC 3-5. Data used to compare the groups included whether CA was witnessed, if a bystander initiated cardiopulmonary resuscitation, presence of cardiac etiology, initial cardiac rhythm and elapsed time from emergency call receipt until Return of Spontaneous Circulation (ROSC). Elapsed time from receipt of the emergency call until ROSC was significantly shorter in the F group than in the U group. ROC curve analysis indicated that the cut-off duration was 28 minutes for a favorable neurological outcome. For OHCA patients with an ABR wave V, elapsed time from receipt of emergency call until ROSC may be an important parameter within the Utstein-style guidelines to determine the usefulness of therapeutic hypothermia.