Effect of head rotation on cerebral blood velocity in the prone position

TY - JOUR

T1 - Effect of head rotation on cerebral blood velocity in the prone position

AU - Højlund, Jakob

AU - Sandmand, Marie

AU - Sonne, Morten

AU - Mantoni, Teit

AU - Jørgensen, Henrik L

AU - Belhage, Bo

AU - van Lieshout, Johannes J

AU - Pott, Frank C

PY - 2012

Y1 - 2012

N2 - Background. The prone position is applied to facilitate surgery of the back and to improve oxygenation in the respirator-treated patient. In particular, with positive pressure ventilation the prone position reduces venous return to the heart and in turn cardiac output (CO) with consequences for cerebral blood flow. We tested in healthy subjects the hypothesis that rotating the head in the prone position reduces cerebral blood flow. Methods. Mean arterial blood pressure (MAP), stroke volume (SV), and CO were determined, together with the middle cerebral artery mean blood velocity (MCA V mean) and jugular vein diameters bilaterally in 22 healthy subjects in the prone position with the head centered, respectively, rotated sideways, with and without positive pressure breathing (10 cmH 2O). Results. The prone position reduced SV (by 5.4±1.5%; P<0.05) and CO (by 2.3±1.9% ), and slightly increased MAP (from 78±3 to 80±2 mmHg) as well as bilateral jugular vein diameters, leaving MCA V mean unchanged. Positive pressure breathing in the prone position increased MAP (by 3.6±0.8 mmHg) but further reduced SV and CO (by 9.3±1.3% and 7.2±2.4% below baseline) while MCA V mean was maintained. The head-rotated prone position with positive pressure breathing augmented MAP further (87±2 mmHg) but not CO, narrowed both jugular vein diameters, and reduced MCA V mean (by 8.6±3.2% ). Conclusion. During positive pressure breathing the prone position with sideways rotated head reduces MCA V mean ∼10% in spite of an elevated MAP. Prone positioning with rotated head affects both CBF and cerebrovenous drainage indicating that optimal brain perfusion requires head centering.

AB - Background. The prone position is applied to facilitate surgery of the back and to improve oxygenation in the respirator-treated patient. In particular, with positive pressure ventilation the prone position reduces venous return to the heart and in turn cardiac output (CO) with consequences for cerebral blood flow. We tested in healthy subjects the hypothesis that rotating the head in the prone position reduces cerebral blood flow. Methods. Mean arterial blood pressure (MAP), stroke volume (SV), and CO were determined, together with the middle cerebral artery mean blood velocity (MCA V mean) and jugular vein diameters bilaterally in 22 healthy subjects in the prone position with the head centered, respectively, rotated sideways, with and without positive pressure breathing (10 cmH 2O). Results. The prone position reduced SV (by 5.4±1.5%; P<0.05) and CO (by 2.3±1.9% ), and slightly increased MAP (from 78±3 to 80±2 mmHg) as well as bilateral jugular vein diameters, leaving MCA V mean unchanged. Positive pressure breathing in the prone position increased MAP (by 3.6±0.8 mmHg) but further reduced SV and CO (by 9.3±1.3% and 7.2±2.4% below baseline) while MCA V mean was maintained. The head-rotated prone position with positive pressure breathing augmented MAP further (87±2 mmHg) but not CO, narrowed both jugular vein diameters, and reduced MCA V mean (by 8.6±3.2% ). Conclusion. During positive pressure breathing the prone position with sideways rotated head reduces MCA V mean ∼10% in spite of an elevated MAP. Prone positioning with rotated head affects both CBF and cerebrovenous drainage indicating that optimal brain perfusion requires head centering.

U2 - 10.1155/2012/647258

DO - 10.1155/2012/647258

M3 - Journal article

SN - 1687-6962

VL - 2012

SP - 647258

JO - Anesthesiology Research and Practice

JF - Anesthesiology Research and Practice

ER -