Duration of resuscitation, regain of consciousness and histopathological severity of hypoxic-ischemic encephalopathy after cardiac arrest.

PURPOSE: To study the histopathologically quantified severity of hypoxic-ischemic encephalopathy (HIE) in deceased cardiac arrest unbiased by death causes and correlated with demographic parameters.

METHODS

We conducted a retrospective, single-centre study including cardiac arrest patients with postmortem brain autopsies. Using the selective eosinophilic neuronal death (SEND), the histopathological severity of HIE was quantified in the cerebral neocortex, hippocampus, basal ganglia, cerebellum, and brainstem, and correlated with demographic parameters.

RESULTS

We included 319 patients with a median time of return from cardiac arrest to spontaneous circulation (tROSC) of 10 min, of whom 62(19.4%) had a regain of consciousness (RoC) before death. The tROSC was significantly correlated with the SEND in all brain regions (p < 0.05, Spearman's rho = 0.14 to 0.29). The SEND in the neocortex, hippocampus, and basal ganglia was significantly correlated with RoC (p < 0.05, Spearman's rho = -0.25 to -0.11). In 9 patients with tROSCs less than 1 min, all had a brainstem SEND less than 30%, and 8(88.9%) had neocortical SEND less than 30%. Among 69 patients with tROSCs greater than 20 min, 47.8-82.6% showed a SEND less than 30% across brain regions.

CONCLUSIONS

We found less SEND and RoC was more likely in patients with shorter tROSCs. A tROSC less than 1 min was mostly associated with SEND less than 30% in all brain regions. Prolonged resuscitations with tROSCs greater than 20 min did not exclude a SEND less than 30% in a relevant proportion of patients. Future histopathological studies are warranted to investigate the impact of modifiable clinical parameters on the severity of HIE.