Introduction: Target temperature management (TTM) is one of the effective therapies for patients with post-cardiac arrest syndrome (PCAS). A low target temperature is traditionally believed to be more effective, but this has not been confirmed in recent studies, even in any patient subgroup. Our previous study suggested the possible effectiveness of low TTM for patients with PCAS when the period from collapse to the return of spontaneous circulation (ROSC) is ≤30 minutes. Therefore, we tested this hypothesis in a nationwide Japanese registry.
Methods: This was a retrospective subanalysis based on a registry of patients who experienced out-of-hospital cardiac arrest (OHCA), which was established by the Japanese Association for Acute Medicine. Witnessed cases of adult OHCA were selected. Univariate and multivariate analyses were used to compare the neurological outcomes of patients treated with low (32-33 °C) or mild (34-36 °C) TTM or no temperature management. The analysis was performed in both the total patients and in patients in whom the interval from collapse to ROSC was ≤30 minutes.
Results: We analyzed 1763 cases of PCAS. There was no significant difference in the neurological outcomes of patients treated with low or mild TTM, with or without an interval from collapse to ROSC of 30 minutes. However, neurological outcomes of patients treated with low or mild TTM differed significantly from no temperature management, with or without an interval from collapse to ROSC of ≤30 minutes.
Conclusions: Even in the subgroup in which the interval from collapse to ROSC was ≤30 minutes, neurological outcomes in the low TTM group did not differ significantly from those in the mild TTM group.