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

Purpose: To quantify the effects of graded head rotation and elevation on i ntracranial pressure (ICP) in neurosurgical patients, before and after indu ction of general anesthesia. Methods: Patients with supratentorial tumours (n = 12), scheduled for crani otomy with planned ICP monitoring, underwent baseline ICP measurements awak e and supine (0 degrees rotation and elevation). Incremental degrees of hea d rotation (15 degrees) and of head elevation (10 degrees) were performed i ndependently and in combination. Paired measurements of ICP at all levels o f head rotation and elevation were also performed before and after inductio n of general anesthesia (n=6). Results: The baseline ICP was 12.3 +/- 6.4 mmHg (n = 12). Changes of ICP we re 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). Hea d 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 degree s reduced the intracranial hypertension associated with head rotation. No d ifferences were observed between ICP measurements made before or after indu ction of general anesthesia (n=6). Three patients experienced headache with extreme head rotation (<60 degrees) and intracranial hypertension (ICP > 2 0 mmHg). Conclusion: Head rotation of 60 degrees caused an increase in ICP. Concomit ant head elevation to 30 degrees reduced the intracranial hypertension asso ciated with head rotation. Headache with head rotation may provide a useful clinical warning of elevated ICP.