Head elevation reduces head-rotation associated increased ICP in patients with intracranial tumours.

Abstract

To quantify the effects of graded head rotation and elevation on intracranial pressure (ICP) in neurosurgical patients, before and after induction of general anesthesia. Patients with supratentorial tumours (n=12), scheduled for craniotomy with planned ICP monitoring, underwent baseline ICP measurements awake and supine (0 degrees rotation and elevation). Incremental degrees of head rotation (15 degrees) and of head elevation (10 degrees) were performed independently and in combination. Paired measurements of ICP at all levels of head rotation and elevation were also performed before and after induction of general anesthesia (n=6). The baseline ICP was 12.3 +/- 6.4 mmHg (n=12). Changes of ICP were proportional to the degree of head rotation or elevation. Head rotation of 60 degrees maximally increased ICP to 24.8 +/- 14.3 mmHg (P < 0.05). Head elevation above 20 degrees reduced ICP with a maximal reduction to -0.2 +/- 5.5 mmHg at 40 degrees elevation (P < 0.01). Head elevation to 30 degrees reduced the intracranial hypertension associated with head rotation. No differences were observed between ICP measurements made before or after induction of general anesthesia (n=6). Three patients experienced headache with extreme head rotation (<60 degrees) and intracranial hypertension (ICP > 20 mmHg). Head rotation of 60 degrees caused an increase in ICP. Concomitant head elevation to 30 degrees reduced the intracranial hypertension associated with head rotation. Headache with head rotation may provide a useful clinical warning of elevated ICP.