Immediate Post-op Desaturation After Extubation Predicts Poor Outcomes

Author: Michael Vlessides

Anesthesiology News

Very early postoperative desaturation after extubation may have a more profound effect on outcomes than commonly believed. According to a data analysis of more than 70,000 patients, researchers at Massachusetts General Hospital concluded that the phenomenon is associated with a host of adverse postoperative events, including higher cost of care, prolonged hospital stay, and greater risks for adverse discharge, ICU admissions and respiratory complications.

“Anesthesiologists are well aware that desaturation in patients recovering from anesthesia should be avoided,” said Paul Rostin, cand.med., a medical student now at Christian-Albrechts University in Kiel, Germany. “Nevertheless, these events sometimes occur. So this study aimed to determine whether short periods of desaturation right after extubation, while patients are still in the operating room, translate into poor outcomes.”

Although the predictive value and clinical implications of postoperative desaturation in the recovery room have been the subject of recent research (PloS One 2017;12[5]:e0175408; Journal of Clinical Anesthesia 2013;25[8]:612-617), the association between postoperative desaturation immediately after extubation and outcomes has yet to be evaluated.

The investigators conducted multivariable logistic and negative binomial regression analyses adjusted for a wide variety of case- and patient-related characteristics. “Our primary outcome was ‘adverse discharge,’ which describes patients who came from home with good functional capacity but were then discharged to a skilled nursing facility or a long-term care facility,” Rostin said in an interview with Anesthesiology News.

Total Desaturation Time Duration Dependent

As Rostin reported at the 2018 annual meeting of the International Anesthesia Research Society (abstract PA136), nadir desaturation below 90% for at least one minute in the first 10 minutes of extubation was associated with a 36% greater odds of discharge to a skilled nursing home or long-term care facility (odds ratio [OR], 1.36; 95% CI, 1.20-1.54; P<0.001) (Table). Moreover, the effect was time dependent, with the odds of an adverse discharge event increasing with the number of minutes of desaturation.

“We then tried to identify the possible mechanism of the association between desaturation in the [operating room] and adverse discharge. We found that desaturation was associated with an increased risk of respiratory complications within the first three days after surgery, along with a greater risk of postoperative ICU admission. Both of these adverse outcomes again demonstrated a duration-dependent relationship with total desaturation time. Thirty-day mortality did not differ significantly between patients with and without desaturation events.”

Given these results, it is not surprising that desaturation was also associated with higher costs (incidence rate ratio [IRR], 1.07; 95% CI, 1.05-1.09; P<0.001) and prolonged hospital stay (IRR, 1.07; 95% CI, 1.05-1.09; P<0.001)

“We also performed a provider variability analysis,” Rostin said. “We found that after [adjusting for] confounding for patient and procedural factors, some providers had an adverse discharge likelihood as high as 4.7%, while others had a likelihood as low as 3.7%, which is a relative difference of approximately 25%.”

The analysis found several other predictors of immediate post-extubation desaturation, insights the researchers said may ultimately help improve patient care. “Some of these predictors, like [body mass index], can’t be modified in the short term,” Rostin said. “Others, however, can actually be mitigated or prevented.” These predictors include intraoperative hypertension, use of long-acting opioids, lack of preoxygenation prior to extubation, and fraction of inspired oxygen (FiO₂) ratios greater than 61% throughout the course of the case. “We’re convinced that when some of those things are addressed, we might be able to reduce the likelihood of adverse discharge events,” he added.

Rostin’s co-investigator and mentor Matthias Eikermann, MD, PhD, focused on FiO₂ ratio as a key factor in the mix. “We published a paper last year [Br J Anaesth 2017;119(1):140-149] showing an association between high FiO₂ levels and negative postoperative outcomes,” said Dr. Eikermann, the vice chair of faculty affairs in the Department of Anesthesia, Critical Care and Pain Medicine at Beth Israel Deaconess Medical Center, in Boston. “We know that anesthesiologists tend to hyperoxygenate patients to be on the safe side, and that might not always be a good idea.”

In the end, the researchers believe these results help illustrate the importance of postoperative vigilance by all medical professionals.

“Anesthesiologists and surgeons might want to be more aware of those first few minutes right after extubation,” Rostin said. “That may go a long way toward improving patient care.”

Dr. Eikermann agreed. “I think what this study shows is that we can do better when it comes to immediate outcomes. We’re all interested in long-term outcomes, but maybe the things that we control in the immediate period after extubation have effects on those long-term outcomes as well.”

For D. John Doyle, MD, PhD, the study helped demonstrate that anesthesiologists need to be practiced in a number of skill s to ensure patient safety. “This is a notable study that tells us that the art of extubation is every bit as important as the art of intubation,” said Dr. Doyle, a consultant anesthesiologist at the Cleveland Clinic Abu Dhabi, in the United Arab Emirates, and member of the editorial advisory board of Anesthesiology News. “My experience in this matter is that a low-level remifentanil infusion can often be very helpful to suppress stress and coughing responses during extubation, especially in [ear, nose and throat] cases.”