While surgical procedures aimed at increasing airway patency do exist, their efficacies vary and many are not validated in morbidly obese patients [26, 27]. For the purpose of this review, we will focus on the medical treatment of OSA.

Continuous positive airway pressure (CPAP) is currently the mainstay in treatment of both obese and nonobese OSA patients (Fig. 51.1). It delivers continuous airway pressure that keeps the upper airway open during sleep, and studies have shown that it improves OSA-related desaturation events, hypertension, and “sleepiness” in those with an established diagnosis of OSA. Conventional nasal CPAP masks can be difficult to tolerate for some patients, and compliance is a constant concern, but numerous types of masks exist, and some may be better tolerated than others. For patients with significant nasal dryness or obstruction, a CPAP facemask can be utilized to improve therapy [28–30]. While no clear consensus exists on the duration of CPAP therapy before considering surgery, the patient should be given ample time to adjust to the system before moving ahead with surgery [10].

Previously, there have been concerns regarding the postoperative use of CPAP and the risk of anastomotic leak after Roux-en-Y gastric bypass based on studies that reported increased complication rates in those using postoperative CPAP [31, 32]. Because of these concerns, some have suggested omitting positive airway pressure therapy in the immediate postoperative period to avoid adverse surgical events. The American Society for Metabolic and Bariatric Surgery (ASMBS) released their position statement in 2012 addressing this issue and concluded that there was no evidence that postoperative CPAP increased the risk of anastomotic leak and that the usage of CPAP immediately after bariatric surgery was appropriate if indicated for pulmonary concerns [10].

The level of postoperative monitoring and care required will ultimately depend on numerous patient- (OSA severity, other comorbidities) and procedure-specific factors (type of surgery, laparoscopic vs. open). Our patients are placed on continuous telemetry including pulse oximetry monitoring while on the surgical ward. Higher-risk patients such as those with severe OSA, numerous other comorbidities, superobesity, or advanced age may be better served with a brief ICU stay depending on the facility and airway expertise available at night. There are numerous published guidelines on the postoperative care of bariatric patients, and institutions vary regarding the protocols they incorporate into practice [33, 34]. The level of monitoring should be at the discretion of the surgeon in consultation with the medical consultants managing the patient. For instance, Grover et al. omitted intensive monitoring for their bariatric patients undergoing laparoscopic RYGB. Their cohort included over 200 patients with OSA, and they reported no increase in overall or pulmonary complications despite non-routine use of intensive monitoring [34]. There is consensus, however, that patients should continue their CPAP therapy postoperatively to avoid potential cardiopulmonary events in a patient already under considerable physiologic stress. Patients are encouraged to bring their own masks from home to ensure they have a properly fitting mask during their admission. It is also helpful to have experienced respiratory therapists who are comfortable with positive pressure therapy in morbidly obese patients. The surgeon and the multidisciplinary team should discuss the perioperative usage of CPAP at length with the patient prior to surgery.

Bariatric surgery is now considered to be the most effective way to achieve durable weight loss and has been shown to improve many obesity-related comorbidities like type 2 diabetes and metabolic syndrome [35–37]. Many studies have also shown that bariatric surgery is capable of improving or resolving OSA, which is not surprising given the fact that even modest weight loss can achieve some degree of improvement. Interestingly, many patients develop clinical improvement or resolution of symptoms of OSA after bariatric surgery, regardless of whether a normal BMI is achieved. In fact, 10–20 % weight loss has been associated with improvement of symptoms and a significant reduction in AHI [38]. It is important to note that not all causes of OSA are obesity related, and bariatric surgery may not improve symptoms of sleep apnea in all patients [39].

Marti-Valeri et al. reported prospective outcomes in 30 subjects who required CPAP (or BiPAP) therapy before RYGB surgery. At 1 year after RYGB, patients experienced significant weight loss and achieved a decrease in mean RDI assessed by PSG (63.6 ± 38.4 preoperatively, 17.4 ± 16.6 postoperatively; p = 0.004) [40]. Dixon and colleagues published their prospective randomized control trial assessing surgical (LAGB, n = 30) vs. conventional weight loss (n = 30) therapy for the treatment of OSA. At 2 years follow-up, the surgical cohort lost significantly more weight and achieved greater AHI reductions (reduction of 25.5 events/h vs. 14 events/h) than the conventional weight loss cohort [41]. Greenberg et al. performed a meta-analysis in 2009 looking at the effects of surgical weight loss on objective measures of OSA. Their analysis included 12 studies (n = 342 patients) that had polysomnography performed before and at least 3 months after bariatric surgery. The cohort achieved a 17.9 kg/m² reduction in BMI, which corresponded to a pooled cohort reduction of 38.2 hypopneic/apneic events per hour [2].

While many patients subjectively notice improvement in their sleep apnea after bariatric surgery and stop using their CPAP at home several months after surgery, we recommend that they continue to follow up with their pulmonologist to have their CPAP titrated down during the rapid weight loss phase. Patients should also undergo a repeat PSG 6–12 months after surgery to determine the need for further CPAP therapy.