More patients became hypoxic after the anesthesiologist had left the PACU. (Image source: Thinkstock)

More patients became hypoxic after the anesthesiologist had left the PACU. (Image source: Thinkstock)

When are patients at risk for hypoxia in the PACU? The answer can help ascertain when an anesthesiologist should staff the area. Dr. Richard H. Epstein, Department of Anesthesiology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, and colleagues from the Division of Management Consulting, Department of Anesthesia, University of Iowa, Iowa City, Iowa, and the Departments of Anesthesiology, Bioinformatics, and Surgery, Vanderbilt University, Nashville, Tennessee, retrieved online information from the Vanderbilt University adult PACU to examine all unique hypoxemic episodes in the PACU that occurred from October 3, 2008, through April 14, 2013. The results of this analysis are published in this month’s issue of Anesthesia and Analgesia and discussed in the article titled “Anesthesiologist Staffing Considerations Consequent to the Temporal Distribution of Hypoxemic Episodes in the Postanesthesia Care Unit.”

Roughly 11% of patients were hypoxic (SpO2 < 90% for at least 2 min) in the PACU. The hypoxemia remained unresolved at 3, 5, and 10 min after onset in 41%, 33% and, 26% of episodes, respectively, suggesting ineffective treatment in a significant proportion of cases. These episodes of hypoxemia took longer to resolve than similar episodes in the operating room (episodes remained unresolved at 3 and 5 min after onset in 23% and 9%, respectively, based on a previous report.

Fewer than 50% of these episodes occurred < 30 min after PACU arrival. The 30 min time point is significant since this is the time the anesthesiologist who dropped off the patient would be bringing the next patient into the operating room. As expected, patients who received an opioid in either the operating room (OR) or the PACU had higher incidences of hypoxemia in the PACU. For those who were also paralyzed intraoperatively and who received an opioid in the either the OR or the PACU, the incidence of hypoxia was higher than if paralysis was not used. Of those patients who were intubated, the majority of intubations occurred ≥30 min after PACU arrival.

Based on the study findings, PACU nurses should know whom to immediately call when a patient is hypoxic. Admittedly, in this study, an anesthesiology resident was available most of the time. Whether findings would be different if an anesthesiology attending was present is not clear. It is also unclear whether study findings would be similar for children. In the accompanying editorial titled “Operational Realities in the Postanesthesia Care Unit: Staffing and Monitoring for Safe Postoperative Care,” Dr. Jenny Freeman and Dr. Charles Weissman, Department of Anesthesia and Critical Care, Hadassah Hebrew University Medical Center, Hebrew University Hadassah School of Medicine, Jerusalem, Israel, note that the dearth of research on clinical and operational aspects of the PACU is surprising, yet the use of computerized patient data management systems in the PACU will provide much-needed information. They write that “studies are needed that track long-term patient outcomes and examine how these outcomes correlate with the length and severity of desaturation events, so that insightful conclusions can be drawn regarding the potential impacts of particular desaturation events.” In addition, they point out that if ventilation is also monitored, earlier determination of respiratory compromise might be made. Finally, the authors recommend we focus our efforts on individualizing treatment plans rather than “drawing additional resources to resolve respiratory compromise once it has occurred.”