# The Effects of Cerebral Perfusion Pressure Change on Acute Intraoperative Brain Herniation in Patients With Severe Traumatic Brain Injury

## TL;DR

This study shows that rapid changes in cerebral perfusion pressure during surgery are linked to a higher risk of brain herniation in severe traumatic brain injury patients.

## Contribution

The study identifies specific thresholds of cerebral perfusion pressure change associated with acute intraoperative brain herniation in sTBI patients.

## Key findings

- Changes in cerebral perfusion pressure at craniotomy and durotomy were significantly related to brain herniation.
- Higher CPP change percentages correlated with increased herniation incidence, with 77.8% in the highest change group.
- Significant differences in herniation rates were observed between all three CPP change groups (p<0.05).

## Abstract

Objective

This study examines how rapid changes in cerebral perfusion pressure (CPP) affect acute intraoperative brain herniation (AIBH) in patients with severe traumatic brain injury (sTBI).

Materials and methods

This single-institute retrospective study analyzed patients with sTBI (Glasgow Coma Scale (GCS) ≤ 8) who underwent surgical intervention from January 2017 to January 2019. An external ventricular drain (EVD)/intracranial pressure monitor (ICPm) was placed in all patients preoperatively. Intracranial pressures (ICPs) before the surgery at the time of both craniotomy and durotomy were recorded. CPP, calculated as mean arterial pressure (MAP) - ICP, was recorded as initial (CPPi), at the time of craniotomy (CPPc), and at the time of durotomy (CPPd). Changes in CPPc and CPPd were calculated as (CPPc - CPPi)/CPPi and (CPPd - CPPc)/CPPc, respectively. The effects of the change in CPP on AIBH were categorized into three groups according to the significance of the changes and were analyzed using SPSS version 22.0 (IBM Corp., Armonk, NY).

Results

A total of 98 cases were recruited, including 77 (78.57%) male patients and 21 (21.43%) female patients. Age ranged from 19 years old to 77 years old, with a mean/median of 49.01/50.50 years old. The changes in CPP at the time of both craniotomy and durotomy were all significantly related to AIBH. Changes in CPP were classified into three groups: (1) both were <50%, (2) at least one was ≥50% but <100%, and (3) at least one was ≥100%. The incidence rates of AIBH in the three groups were 27.1% (13/48), 61% (25/41), and 77.8% (7/9), respectively. Significant differences were also observed between each two groups (p<0.05).

Conclusion

Changes in CPP appear to be related to acute intraoperative brain herniation in patients with severe traumatic brain injury undergoing surgical intervention.