Survival rate in patients after sudden cardiac arrest at the university hospital of northern Norway treated with or without opioids: A retrospective evaluation.

Background: Experimental studies both in vivo and in vitro show significantly increased survival rate in animals and in cortical neurons respectively exposed to acute hypoxia and pre-treated with opioids compared to non-treated counterparts. Thus, the main aim of the study was to examine survival rates in patients after sudden cardiac arrest (SCA) in the hospital who were or were not treated with opioids before and/or during cardiac pulmonary resuscitation (CPR).

Methods: The registry SCA database at the University Hospital of Northern Norway (UNN) for the period of January 2006-December 2009 was used to obtain data for the evaluation. Inclusion criteria were observed SCA at UNN for patients with American Society of Anesthesiologists (ASA) 1-3. Exclusion criteria included ASA four to five patients and unobserved SCA. Study patients were divided into two groups: Those not treated with opioids and those treated with opioids not more then 3 h before and/or during CPR. Survival rate 1, 2, 3 and 28 days post CPR were compared for the two groups.

Results: A total of 117 patients were registered in the SCA database at UNN for the period from January 2006 to December 2009. Sixty seven patients were excluded from the study: 17 patients had an unknown time of SCA dιbut, two patients had only syncope and 48 were ASA four to five patients. A total of 50 ASA one to three patients were included in the study, 33 and 17 patients respectively in the control and opioid-treated groups. The patients who were treated with opioids before or during CPR had a significantly higher 1, 2, 3 and 28 days survival rate as compared to those receiving only conventional CPR. The model was adjusted for duration of CPR (P=0.047) and treatment with adrenaline (P=0.779) in the groups. Adjusted Odds ratio was 0.075 (95% confidence interval (CI): 0.015-0.387). Relative risk of fatal outcome in the opioids group was 0.2944 (95% CI: 0.1549-0.5594).

Conclusion: Significantly higher 1, 2, 3 and 28 days survival rate and reduced duration of CPR were found in the patients additionally treated with opioids compared to ordinary resuscitation. Further prospective, randomized, controlled trials are needed to investigate the effects of early administration of opioids during CPR on survival and brain function in patients with witnessed in-hospital SCA.