Retrospective observational evaluation of postoperative oxygen saturation levels and associated postoperative respiratory complications and hospital resource utilization

Abstract

IntroductionThe clinical importance of postoperative episodic hypoxemia is still unclear, and therefore largely under-studied. As a result, there is limited understanding of its relationship with early postoperative respiratory complications (PRC, defined as intubation within three days of surgery) and hospital resource utilization.Materials and methodsThis single center study was performed using a retrospective observational design. We described population based definitions of desaturation from continuous SpO2 monitoring data captured in the post anesthesia care unit (PACU), namely median SpO2 in PACU, duration of desaturation below median, nadir desaturation, and length of oxygen therapy relative to PACU duration. These measures were evaluated against the occurrence of early PRC in logistic regression models. Measures that were independently associated with early PRC were accepted as the primary study exposures. Stratified logistic regression models were planned if significant interaction occurred with high risk surgical procedures. Models were adjusted by including several patient conditions, procedural, and anesthesia risk factors. Propensity matching on desaturation occurrence was planned to evaluate the relationship with postoperative resource utilization.ResultsAmong 125,740 patients included in the univariate analyses, 351 patients (0.3%) developed early PRC. Nadir desaturation <89% [14.3% of patients; adjusted odds ratio 2.02; 95% CI 1.52, 2.68; p<0.001] and PACU oxygen therapy requirements greater than 60 min [adjusted odds ratio 1.92 (>60 min) to 3.04 (>90 min); p<0.001] were identified as independent predictors of early PRC occurrence. A modest interaction was observed between desaturation and higher surgical risk. Propensity matching for postoperative oxygen requirement was performed in 37,354 matched patients. Matched analysis demonstrated significant increase in day of surgery charges, respiratory charges, total charges, hospital length of stay, reintubation and use of invasive or non-invasive ventilatory support.ConclusionsIn summary, we report that prolonged PACU oxygen therapy and nadir desaturation <89% in PACU as captured in a retrospective database are independently associated with early PRC. This study describes resource implications of PACU desaturation in a large academic medical center in North America.

Post‐operative alarm signs in the rapid response system and hospital mortality after non‐cardiac surgery

“…28 Moreover, even if post-operative hypoxemia does not lead to respiratory arrest, it is known to be associated with various post-operative adverse outcomes. 29,30 We found that among the alarm signs, hypoxemia in patients admitted to the ward after non-cardiac surgery was more often associated with increased post-operative in-hospital mortality, which is consistent with the results of previous studies. 29,30 The findings in our study suggest that total CO 2 and post-operative hypoxemia should be monitored more carefully than other alarm signs.…”

The association of early postoperative desaturation in the operating theatre with hospital discharge to a skilled nursing or long‐term care facility

“…We found that patients who experienced early postoperative desaturation were at higher risk of complications and loss of functional independence that may be explained by a hypoxaemia‐induced decrease in oxygen delivery. Peri‐operative hypoxaemia increases the odds of acute MI , AKI and respiratory complications , all of which we found in our study population after just a brief episode of postoperative desaturation. Hypoxaemia is also known to lead to systematic vasodilation and to have meaningful effects on cellular metabolism, central nervous system and several other organ systems .…”

Automated oxygen administration versus conventional oxygen therapy after major abdominal or thoracic surgery: study protocol for an international multicentre randomised controlled study

“…It has also been demonstrated that the duration of O 2 therapy was an independent risk factor for developing postoperative respiratory complications. Patients who require O 2 for ≥75% of recovery room time (or greater than 90 min) appear to be at greater risk of developing respiratory complications 45. This fact may suggest that some patients are not adequately screened for risk factors such as OSA by standard preanaesthesia testing, and that a device dedicated to continuous monitoring of O 2 administration (either alarms on duration and flow variations) may help to detect such high-risk patients.…”