Long-Term Survival and Neurological Outcomes After Mild Therapeutic Hypothermia

Background: Current guidelines recommend applying therapeutic Hypothermia (TH) early after resuscitation of cardiac arrest patients who remain unresponsive. In the last decade several trials and meta-analysis failed to prove significant benefit of either survival or neurological outcome.

Method: We conducted a retrospective cohort study. Data was collected from January 2000 and October 2017. Patients were classified into 2 groups, before initiatation therapeutic hypothermia (2000-2008) and after (2008-2017). Primary end points were all cause mortality and favorable neurological outcome asses by Cerebral performing category scale (CPCS).

Results: A total of 92 patients were included in the study. 57 (63%) patients were in the TH Group and 34 (37%) in Non TH group. Mean age was 60 years. Patients earlier to hypothermia era were older (p<.01), with less clear evidence of coronary ischemic cause (p<.01) and with non-significant less favorable neurological outcome at discharge (mean CPCS 2.47 vs 3.58, respectively, p<.16). About third of the patients in the TH group had experienced post procedure respiratory tract related infection (35%, p<.10). There was a mildly improve in neurological outcome in the TH group (p<.03). There was no statistically significant difference in survival or major cardiovascular events between the 2 groups (Log rank chi-sq=2.30, p>.13). Primary arrhythmia was independed prognostic factor for short and long term mortality in both groups, where asystole indicated poor outcome.

Conclusion: Therapeutic hypothermia is an expensive treatment that requires considerable resources and its effectiveness is questionable. Compared to Non Therapeutic era, our experience demonstrated a modest neurological outcome, with non-significant change in mortality or major cardiovascular events.