Discrepancy in finger pulse oximetry reading related to positioning: a case report

Pulse oximetry is one of the five cardinal vital signs used to monitor patients in the clinical setting, and has contributed significantly to patient safety. Unfortunately, extremes in patient positioning may lead to changes in peripheral perfusion pressures resulting in erroneous pulse oximetry readings. We present a case of a relatively well patient coming for robot-assisted laparoscopic radical prostatectomy who became hypoxic in the Trendelenburg position that spontaneously resolved upon transiting to supine. The reliability of the traditional method of assessing the pulse oximeter value via the plethysmograph is questioned and we discuss other modalities to assist in interpretation of the suspicious pulse oximetry reading.