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What Is the Ideal Head Position for Patients with Large Strokes?

Although head elevation can reduce increased intracranial pressure in patients with large strokes, this study suggests that the optimal head position should be determined cautiously for each patient.

Neurointensivists have been greatly interested in the preferred degree of head elevation in patients with raised intracranial pressure (ICP). Elevating the head and torso is one of the few easily instituted methods of reducing ICP; the ICP probably drops due to drainage of cerebral venous blood and CSF. Although this maneuver can reduce elevated ICP, often it also reduces blood pressure and, thereby, reduces cerebral perfusion pressure (CPP). Indeed, on this basis, the current preference in critical care is to protect cerebral perfusion by nursing patients with intracranial hypertension in the supine position. These researchers prospectively investigated the effects of elevating the upper body to varying degrees in 18 patients with large hemispheric stroke.

Blood pressure, CPP, and ICP all fell as the head and upper body were elevated progressively from supine (0 degrees) to 15 degrees and then to 30 degrees. Initial ICP was, on average, only 13 mm Hg and fell to 11 mm Hg at 30 degrees of elevation. Blood pressure, measured through a radial-artery or femoral-artery catheter (and a transducer at the level of the foramen of Monro), fell to a greater extent, from a mean of 90.0 mm Hg at baseline (no elevation) to a mean of 76.1 mm Hg at 30 degrees of elevation. The investigators concluded that the supine position was probably preferable with regard to perfusion pressure but that optimal body position should be established individually and that, in any case, routine use of 30-degree elevation could not be endorsed.

Comment: The authors carefully emphasized that their data do not apply to the group of greatest interest and controversy: those with large strokes and massive brain edema. No firm conclusions can be drawn regarding this group, except that one must be cautious with upper-body elevation, because the one consistent result is a drop in mean arterial blood pressure. Another caution in interpreting these results is that it is unproved that leveling the blood-pressure transducer to the cranium will reflect ICP. Also, a 15-mm-Hg drop in blood pressure with modest head elevation suggests that many of these patients were volume-depleted or, possibly, deconditioned from prolonged bed rest.

Perhaps the more interesting conclusion, applicable to stroke patients in general, is that ostensibly benign maneuvers such as raising the head of the bed or getting a patient into a chair can greatly reduce blood pressure. In cerebral vascular occlusive disease, there is every reason to believe that this result would be harmful.

— Allan H. Ropper, MD

Dr. Ropper is Chairman of Neurology, Tufts Medical School, and Chief, Department of Neurology, St. Elizabeth's Medical Center, Boston.

Published in Journal Watch Neurology April 12, 2002

Citation(s):

Schwarz S et al. Effects of body position on intracranial pressure and cerebral perfusion in patients with large hemispheric stroke. Stroke 2002 Feb; 33:497-501.

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