Occult Hypoxemia During Aeromedical Transport: Detection by Pulse Oximetry

Abstract The use of pulse oximetry as an adjunct to clinical evaluation of oxygenation during aeromedical transport by helicopter and fixed-wing aircraft was evaluated. As evidenced by an oxygen saturation of 90% or less, 29 of 150 patients (29%) were hypoxemic in the presence of the flight team. Airway interventions were carried out by the flight team in 17 of these 29 hypoxemic patients. In 11 of these 17 instances, desaturation noted by pulse oximeter was the first evidence that airway interventions were indicated. In the other 12 cases of hypoxemia, no new airway interventions were carried out despite oximeter evidence of desaturation. Three of these patients subsequently required aggressive airway interventions following their arrival at the receiving emergency department. Of the 32 patients transported by fixed-wing aircraft, 27% had evidence of unsuspected hypoxemia detected only by the pulse oximeter. The hypoxemia seemed related to increasing altitude in eight of this latter group. Pulse oximetry is a valuable and feasible technique for monitoring patients during aeromedical transport. Its use may allow detection of physiologic hypoxemia before such becomes apparent clinically.