Does prone positioning increase intracranial pressure? A retrospective analysis of patients with acute brain injury and acute respiratory failure.

Purpose: The objective of our trial was to obtain more comprehensive data on the risks and benefits of kinetic therapy in intensive care patients with intracerebral pathology.

Methods: Standardized data of prone positioning in our NeuroIntensive Care Unit were collected from 2007 onward. A post hoc analysis of all available data was undertaken, with special consideration given to values of intracranial pressure (ICP), cerebral perfusion pressure (CPP) and oxygenation in correlation to prone (PP), or supine positioning (SP) of patients. Cases were considered eligible if kinetic therapy and ICP were documented. Prone positioning was performed in a 135° position for 8 h per treatment unit.

Results: A total of 115 patients treated with prone positioning from 2007 to 2013 were identified in our medical records. Of these, 29 patients received ICP monitoring. Overall, 119 treatment units of prone positioning with a mean duration of 2.5 days per patient were performed. The mean baseline ICP in SP was 9.5 ± 5.9 mmHg and was increased significantly during PP (p < 0.0001). There was no significant difference between CPP in SP (82 ± 14.5 mmHg) compared to PP (p > 0.05). ICP values >20 mmHg occurred more often during PP than SP (p < 0.0001) and were associated with significantly more episodes of decreased CPP <70 mmHg (p < 0.0022). The mean paO(2)/FiO(2) ratio (P/F ratio) was increased significantly in prone positioning of patients (p < 0.0001).

Conclusions: The analyzed data allow a more precise understanding of changes in ICP and oxygenation during prone positioning in patients with acute brain injury and almost normal baseline ICP. Our study shows a moderate, yet significant elevation of ICP during prone positioning. However, the achieved increase of oxygenation by far exceeded the changes in ICP. It is evident that continuous monitoring of cerebral pressure is required in this patient group.