Sleep-Disordered Breathing and Postoperative Outcomes After Bariatric Surgery: Analysis of the Nationwide Inpatient Sample

Sleep-disordered breathing (SDB) is increasingly recognized as a possible risk factor for adverse perioperative outcomes and although clinicians may expect SDB to be associated with increased risk of adverse postoperative outcomes after bariatric surgery, rates of postoperative complications after bariatric surgery have not been systematically compared in patients with and without SDB in a large, nationally representative sample.

To that end, we analyzed the Nationwide Inpatient Sample (NIS) database to quantify the impact of the diagnosis of SDB on in-hospital death, total charges, LOS, respiratory outcomes, and cardiac outcomes in 91,028 adult patients undergoing bariatric surgeries from 2004 to 2008. We found the prevalence of SDB to be 36% among patients undergoing elective bariatric surgery in the NIS database. After adjusting for important confounders, SDB was independently associated with significantly increased odds ratio of emergent endotracheal intubation, noninvasive ventilation, and atrial fibrillation. Moreover, emergent intubation occurred significantly earlier in the postoperative course in patients with SDB. These findings differ from what has been previously reported by Weingarten et al and the Longitudinal Assessment of Bariatric Surgery consortium who found that SDB was not associated with an increased likelihood of pulmonary complications in patients undergoing bariatric surgery. These 2 studies were performed in tertiary care academic centers whereas 42% of our patients had their surgery performed in a non-teaching hospital. Academic centers may have used multidisciplinary perioperative processes and pathways to identify and treat SDB more often than non-teaching hospitals.

Despite the increased association of SDB with postoperative complications, in our cohort the diagnosis of SDB was negatively associated with in-hospital mortality and resource use. SDB was independently associated with decreased mortality, total charges, and length of stay. Although non-SDB patients had an overall lower risk of emergent intubation compared to SDB patients, their outcomes were significantly worse when they did get emergently intubated. Other studies have demonstrated that SDB is not a risk factor for death in the postoperative bariatric setting, but why this association was in the opposite direction of what we expected is unclear. Our findings that SDB was not associated with increased length of stay and in-hospital mortality are in line with a recent single-center study by Lockhart et al of approximately 15, 000 presurgical patients.

In summary, using a large nationally representative database, we found that in patients undergoing bariatric surgery, SDB is independently associated with significant postoperative complications but not with increased in-hospital mortality, total charges, and length of stay.

Sleep-Disordered Breathing and Postoperative Outcomes After Elective Surgery: Analysis of the Nationwide Inpatient Sample

In 2006 the American Society of Anesthesiologists (ASA) recommended screening patients prior to surgery for sleep-disordered breathing (SDB) and implementing treatment if clinically significant SDB is present. Interestingly, these recommendations were made despite the lack of significant empirical evidence in the perioperative diagnosis and management of SDB. Since the ASA practice guidelines were published there has been a growing interest in the perioperative care of patients with SDB. To date, most studies have focused on developing effective screening tools in the preoperative population, or have outlined adverse postoperative outcomes in patients with SDB. Most studies, however, are retrospective in nature and represent single center experiences. Since overall postoperative complications are uncommon after elective surgery, analysis of large and nationally representative databases is necessary to ascertain if indeed SDB is associated with increased risk of adverse postoperative outcomes. Importantly, there are no studies examining whether SDB is associated with increased total charges or in-hospital mortality.

A cohort of 1,058,710 hospitalized adult patients undergoing elective surgeries from 2004 to 2008 from the Nationwide Inpatient Sample database was analyzed to determine the impact of the diagnosis of SDB on postoperative outcomes in 4 specific categories of elective surgery: orthopedic, prostate, abdominal and cardiovascular surgeries. The analysis demonstrated that the overall rate of postoperative complications were low and the diagnosis of SDB was independently associated with increased risk of emergent endotracheal intubation, need for noninvasive ventilation and atrial fibrillation in all 4 surgical cohorts. However, SDB was not independently associated with clinically significant increases in in-hospital death, LOS, or total charges in this nationally representative large cohort of patients undergoing various types of elective surgery. Indeed, in patients undergoing elective orthopedic, abdominal, and cardiovascular surgeries, the diagnosis of SDB was independently associated with a significant decrease in in-hospital mortality. Emergent intubation occurred significantly earlier in the postoperative course in patients with SDB. In the subgroup of patients that required emergent intubation, LOS, total charges, pneumonias, and in-hospital death were significantly higher in patients without SDB.

It is important to note that despite the growing awareness of increased postoperative complications in patients with SDB, there is a paucity of well-controlled prospective studies examining the impact of treatment on postoperative outcomes. Because of overall low rates of complications, only large multicentric prospective randomized controlled trials will be able to asses the impact of SDB treatment on patient outcomes during the postoperative period. This is an important and clinically relevant question that needs to be addressed by our scientific community. The urgency for further clinical research cannot be overemphasized given that implementation of systematic screening, postoperative monitoring, and perioperative therapy with CPAP would impose a significant cost burden with such a large volume of elective surgeries performed globally.