With obesity on the rise, associated conditions like Obesity Hypoventilation Syndrome (OHS) and Obstructive Sleep Apnea (OSA) are gaining prevalence in hospitalized patients.
Obesity Hypoventilation Syndrome (OHS)
Several studies have shown that both CPAP and BiPAP as effective home treatment modalities for patients with OHS. Furthermore, AVAPS has been shown to be effective in patients with mild hypercapnia components to OHS.
When hospitalized, bariatric surgery patients with OHS were reported to have higher rates of admission to the ICU and were cited as requiring invasive mechanical ventilation at a higher rate than obese patients without OHS as shown by Flum et al. in their study on perioperative safety in the longitudinal assessment of bariatric surgery published in the New England Journal of Medicine 2009. It is hardly surprising that that CPAP or BiPAP therapies are recommended in the perioperative setting as bariatric interventions expose these patients to higher risks of mortality.
Ideally, patients with OHS should be treated with PAP therapy—or tracheostomy in cases of PAP failure— before undergoing surgical intervention, in order to decrease perioperative morbidity and mortality. Moreover, PAP therapy should be initiated immediately after extubation to avoid postoperative respiratory failure.¹
Obstructive Sleep Apnea (OSA)
The increasing prevalence of obesity worldwide is impacting healthcare significantly. In particular, the incidence of OSA is increasing², which is reflected as a higher proportion within the surgical population than the general population.³
As the risk of morbidity and mortality increases in OSA patients postoperatively, guidelines such as the ’Practice guidelines for the perioperative patents with Obstructive sleep apnea’ have been drafted to ”reduce the risk of adverse outcome in patients with OSA who receive sedation, analgesia or anesthesia for diagnostic or therapeutic procedures.”⁴
Key in these guidelines is the need to screen incoming patients for sleep apnea. Questionnaires such as STOP BANG or Berlin allow anesthesiologists to screen preoperatively with a high degree of confidence. Once identified as being at risk for OSA, the approach to surgery, anesthesia and postoperative treatment is reviewed for these patients. Patients previously diagnosed with sleep apnea and on CPAP at home are often requested to bring their devices into the hospital for use peri-operatively. Some hospitals do not promote use of patients’ home devices for use in the hospital due to risk and infection control issues and prefer to provide therapy with institutionally owned devices. In the case of patients suspected of having but never been diagnosed with OSA, the institution may choose to refer the patient to a sleep lab for consult. If surgery does go ahead without consult, guidelines indicate close surveillance for apneas or desaturations in the postoperative period in these patients. Should recurrent respiratory events occur in the PACU, CPAP or BIPAP may be initiated. As more hospitals adopt special protocols for OSA patients, there is increased use of NIV in the perioperative setting. Usage of NIV on the wards is also reportedly on the rise.