Brain death after decompressive craniectomy: Incidence and pathophysiological mechanisms

Area of Science:

• Neurology
• Critical Care Medicine
• Neurosurgery

Background:

• Decompressive craniectomy (DC) is a neurosurgical procedure to reduce intracranial pressure (ICP).
• Patients undergoing DC are often presumed not to meet criteria for brain death (BD).
• This presumption stems from the belief that ICP may not reach levels critical enough to cause irreversible cerebral perfusion failure.

Purpose of the Study:

• To investigate the incidence of brain death (BD) in patients who have undergone decompressive craniectomy (DC).
• To analyze the pathophysiological mechanisms leading to BD after DC.
• To determine if DC excludes the possibility of BD.

Main Methods:

• Retrospective chart review of patients who underwent DC between 2010 and 2016.
• Analysis of intracranial pressure (ICP) and cerebral perfusion pressure (CPP) trends prior to BD diagnosis.
• Review of radiological tests used to demonstrate loss of cerebral perfusion in BD.

Main Results:

• Brain death (BD) was diagnosed in 12 out of 164 (7.3%) patients following DC.
• The mean latency between DC and BD diagnosis was 69.4 hours.
• ICP levels rose significantly, and CPP decreased to critically low levels (-9.9 mmHg) preceding BD, with radiological evidence of lost cerebral perfusion in some cases.

Conclusions:

• Decompressive craniectomy (DC) does not exclude the diagnosis of brain death (BD).
• Severely reduced cerebral perfusion pressure (CPP) consistently precedes BD, even after DC.
• These findings underscore the critical role of cerebral perfusion failure in the pathophysiology of brain death.