Pulse oximetry became the standard of care in the postanesthesia care unit (PACU) with the expectation that it would be used to guide patient care decisions related to oxygenation. While health care providers have traditionally placed a great deal of confidence in the use of supplemental oxygen, it is not an adequate safeguard against hypoxemia. Kavanagh et al.  noted that although it reduces the incidence of desaturation it does not affect the degree or duration. It also does not affect patient outcomes such as the incidence of myocardial ischemia.
Our recommendation to use the objective data supplied by the pulse oximeter as a guide for oxygen use is in line with what others, such as DiBenedetto et al. , have recommended. The difference in the recommendations was that we chose a pulse oximeter reading of 92% to indicate those at risk for hypoxemia, while DiBenedetto and colleagues recommended a pulse oxymetry reading below 94%. Their use of a more stringent criterion may be due to the difference in populations. DiBenedetto and colleagues studied all patients admitted to the PACU, which would likely include patients having had thoracic and upper abdominal surgery, a group not included in our study. Unfortunately, there is no description in their research report of the type of surgery performed with their sample. Another difference between the two studies is that their patients were breathing room air while being transported to the PACU, whereas ours received supplemental oxygen during transport.
As a result of our study, the policy for oxygen administration in the PACU where the study was done has been changed. Now when patients are admitted to the PACU only those whose preoperative workup would indicate them to be at high risk for hypoxemia are given supplemental oxygen. For most patients, the pulse oximeter reading is used along with other clinical variables, such as vital signs, wakefulness, and the like, to determine the need for oxygen. Oxygen is therefore administered only to those who require it. Over a 9-month period there have not been any untoward incidents attributable to this change in policy. Oxygen has, however, continued to be provided during transport.
Prior to the start of our study we noted that many patients objected to the application of the high-flow, high-humidity face tent which at that time was routinely used in the unit. Many of the patients were observed removing the face tent immediately after it was applied, which we considered wasteful. Changing the PACU oxygen administration policy has reserved the use of these high-cost oxygen administration devices to only those patients who require increased humidification, reducing hospital waste and costs.
Audrey G. Gift, PhD, RN, FAAN
University of Pennsylvania School of Nursing, Philadelphia, PA 19104-6096
Kaye Whitmore, RN
University of Maryland Medical System, Baltimore, MD 21201
1. Kavanagh BP, Cheng DCH, Sandler AN, et al. Supplemental oxygen does not reduce myocardial ischemia in premedicated patients with critical coronary artery disease. Anesth Analg 1993;76:950-6.
2. DiBenedetto RJ, Graves SA, Gravenstein N, Konicek C. Pulse oximetry monitoring can change routine oxygen supplementation practices in the postanesthesia care unit. Anesth Analg 1994;78:365-8.