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 intracranial pressure (ICP) in neurosurgical patients, before and after induction of general anesthesia. Methods: Patients with supratentorial tumours (n = 12), scheduled for craniotomy with planned ICP monitoring, underwent baseline ICP measurements awake and supine (0°rotation and elevation). Incremental degrees of head rotation (15°) and of head elevation (10°) 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). Results: 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°maximally increased ICP to 24.8 ± 14.3 mmHg (P < 0.05). Head elevation above 20°reduced ICP, with a maximal reduction to -0.2 ± 5.5 mmHg at 40°elevation (P < 0.01). Head elevation to 30°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°) and intracranial hypertension (ICP > 20 mmHg). Conclusion: Head rotation of 60°caused an increase in ICP. Concomitant head elevation to 30°reduced the intracranial hypertension associated with head rotation. Headache with head rotation may provide a useful clinical warning of elevated ICP.