The Effect of Positive End-Expiratory Pressure on Intracranial Pressure and Cerebral Hemodynamics

Abstract

Background: Lung protective ventilation has not been evaluated in patients with brain injury. It is unclear whether applying positive end-expiratory pressure (PEEP) adversely affects intracranial pressure (ICP) and cerebral perfusion pressure (CPP). We aimed to evaluate the effect of PEEP on ICP and CPP in a large population of patients with acute brain injury and varying categories of acute lung injury, defined by PaO2/FiO2.

Method: Retrospective data were collected from 341 patients with severe acute brain injury admitted to the ICU between 2008 and 2015. These patients experienced a total of 28,644 paired PEEP and ICP observations. Demographic, hemodynamic, physiologic, and ventilator data at the time of the paired PEEP and ICP observations were recorded.

Results: In the adjusted analysis, a statistically significant relationship between PEEP and ICP and PEEP and CPP was found only among observations occurring during periods of severe lung injury. For every centimeter H2O increase in PEEP, there was a 0.31 mmHg increase in ICP (p = 0.04; 95 % CI [0.07, 0.54]) and a 0.85 mmHg decrease in CPP (p = 0.02; 95 % CI [-1.48, -0.22]).

Conclusion: Our results suggest that PEEP can be applied safely in patients with acute brain injury as it does not have a clinically significant effect on ICP or CPP. Further prospective studies are required to assess the safety of applying a lung protective ventilation strategy in brain-injured patients with lung injury.

Keywords: Acute brain injury; Acute respiratory distress syndrome; Cerebral perfusion pressure; Intracranial hypertension; Intracranial pressure; Mechanical ventilation.

Conflict of interest statement

Conflict of interest The authors declare that they have no conflict of interest.

Figures

Fig. 1

Assembly of the study cohort

Fig. 2

Univariate analysis of the relationship between ICP and PEEP at varying strata of lung injury. Depicted above are the results from the univariate GEE model of the relationship between PEEP and ICP, accounting for repeated measures per subject. Results are stratified by severity of lung injury defined by PaO2/FiO2

Fig. 3

Univariate analysis of the relationship between CPP and PEEP and varying strata of lung injury. Depicted above are results from the univariate GEE model of the relationship between PEEP and CPP, accounting for repeated measures per subject. Results are stratified by severity of lung injury defined by PaO2/FiO2