Effect of Prone Position on Continuous Noninvasive Hemoglobin Measurement

This prospective observational study aims to evaluate whether the prone position affects the agreement between noninvasive hemoglobin (SpHb) measurements and laboratory hemoglobin values in patients undergoing lumbar stabilization surgery under general anesthesia. SpHb provides continuous, noninvasive monitoring of hemoglobin using multi-wavelength pulse CO-oximetry. However, its accuracy may be affected by changes in peripheral perfusion, hemodynamic status, and patient position. The prone position used during spine surgery may alter cardiovascular function and peripheral perfusion and may therefore influence SpHb measurements. In this study, SpHb values obtained in the supine and prone positions will be compared with simultaneously obtained laboratory hemoglobin values. The study will also evaluate the ability of SpHb to follow changes in hemoglobin during surgery. The results may help clarify the clinical usefulness of continuous noninvasive hemoglobin monitoring during surgery performed in the prone position.