Pulse oximetry and postoperative hypothermia. An evaluation of the Nellcor N-100 in a cardiac surgical intensive care unit.

The accuracy of the Nellcor N-100 pulse oximeter was evaluated in hypothermic patients (core temperature less than or equal to 35.0 degrees C) after cardiac surgery. The pulse oximeter overestimated oxygen saturation in comparison to values obtained by direct in vitro oximetry with a mean bias of 0.6% saturation. The 95% predictability limits for individual measurements were +/- 3.9% oxygen saturation. No demonstrable loss of accuracy was caused by skin pigmentation, the concurrent administration of low doses of dopamine or vasodilators, or the intra-operative intravascular administration of Patent Blue V dye.