Background: Overdose (OD) deaths has risen dramatically over the last decade, resulting in an increased number of resuscitated cardiac arrest patients who remain comatose. The American Heart Association recommends targeted temperature management (TTM) for all comatose patients with return of spontaneous circulation (ROSC) after cardiac arrest. However, the effect of TTM on patients with ROSC after an OD is unclear. The purpose of this study was to determine the effect of TTM on neurologically intact survival in patients with ROSC following cardiac arrest secondary to OD.
Methods: This was a retrospective observational study performed in a major urban Midwest hospital system, collecting data from 2014-2018 with IRB approval. Patients presenting with out-of-hospital cardiac arrest secondary to OD were identified as undergoing TTM (OD-TTM) vs. not undergoing TTM (OD-NoTTM). Survival to hospital discharge and neurologically intact survival (modified Rankin score 0-2) were compared between groups. Comparisons were also made between patients with a primary cardiac cause of their arrest (CARD) vs. OD and between ventricular arrhythmia (VT/VF) vs. PEA/asystole.
Results: Over the study period, 37 patients presented with cardiac arrest from OD, 12 in the OD-TTM (0% VT/VF) group and 25 in the OD-NoTTM group (4% VT/VF). There were 125 patients with cardiac arrest from a primary cardiac cause, with 55 in the CARD-TTM (76% VT/VF) and 70 in the CARD-NoTTM group (40% VT/VF). For OD patients, survival to discharge and neurologically intact survival was no different in the OD-TTM group (8%) vs. OD-NoTTM group (8%), p=1). For the CARD patients, survival to discharge and neurologically intact survival were both improved with TTM (CARD-TTM 47% and 33% respectively vs. CARD-NoTTM 10% and 7% respectively, both p<.05.) There was a significant difference in neurologically intact survival between the CARD-TTM and OD-TTM (33% vs 8%, p<.05).
Conclusion: No significant benefit was seen in patients presenting with ROSC after an OD cardiac arrest undergoing TTM vs. not undergoing TTM.Patients with an OD cardiac arrest have worse outcomes compared to patients with a primary cardiac arrest following ROSC, regardless of TTM treatment. This demonstrates the importance of implementing programs to prevent OD as the most important link to survival in patients with substance use disorder.