Is supratentorial pressure difference clinically relevant? Analysis of 55 consecutive cases by bilateral intracranial pressure monitoring.

OBJECTIVE The purpose of this study is to explore the possibilities of an early warning system by measuring intracranial pressure differences in order to prevent secondary insults to the injured brain. METHODS Fifty-five cases with a Glasgow coma scale (GCS) score 8 or below who presented with intracranial hypertension due to various intracranial pathologies underwent bilateral intraparenchymatous intracranial pressure (ICP) monitorization in an attempt to find out the existence of interhemispheric pressure differences. ICP values were recorded every 30 minutes during the first 24 hour interval. Patients were stratified into two groups as diffuse and focal according to the magnitude of their pathologies. Focal cases were also grouped according to lesion size and/or midline shift. RESULTS ICP differences that necessitated changes in the treatment were found at different time intervals in patients with focal lesions, but these did not reach statistical significance within the whole group (p > 0.05). There were significant percentage differences between focal I and II groups in correlation with lesion side and non-lesion side within the first 4.5 hours (p < 0.05). There was a significant difference within the first 3 hours between diffuse and focal II groups (p < 0.05). DISCUSSION In patients with focal lesions, although more pronounced in focal II group, apparent pressure differences between two hemispheres within the first hours of admission were found. These pressure differences were related to the volume of the intracranial pathology. ICP monitorization from the lesion side is reasonable as an early forewarning procedure and this might prevent the development of secondary insults by providing the exact ICP values of the patients.