Obstructive Sleep Apnoea (OSA) Patterns in Bariatric Surgical Practice and Response of OSA to Weight Loss after Laparoscopic Adjustable Gastric Banding (LAGB)

Abstract

Introduction: This study aims to evaluate the incidence of Obstructive Sleep Apnoea (OSA) in severely obese Asians and to study the impact of weight loss on OSA. Materials and Methods: We report the results of routine preoperative Polysomnograms in 350 Asian patients undergoing bariatric surgery in our institute. Polysomnograms were repeated in 75 randomly selected patients with moderate to severe OSA after target weight loss with the laparoscopically placed adjustable gastric band (LAGB). Results: The prevalence of OSA in obese Asians is high. Moderate OSA was found in 46% of patients and severe OSA was found in 33%. Severe OSA was significantly more in the Chinese (46%) compared to the Malays (29%) or Indians (21%) (P = 0.035). We identified other risk factors for severe OSA (male sex, higher body mass index and the presence of hypertension) but were unable to select identifying parameters for very low (<5%) likelihood of severe OSA such that routine sleep studies prior to bariatric surgery could be omitted. Apnoea Hypoapnoea Index (AHI) showed improvement of 50% at 20 kg excess weight loss with the cure of OSA in preoperatively severe cases (P <0.005). Mild to moderate cases reported similar improvements although a direct correlation could not be established. Desaturation events, apnoea episodes, work of breathing and subjective assessment of sleepiness scores and quality of life (QOL) showed improving trends, albeit not statistically significant. Similar improvements were seen in sleep architecture with increased rapid eye movement (REM) and stage 3 sleep. Conclusions: The incidence of OSA in Asians undergoing bariatric surgery is high. Routine sleep studies in Asian patients are justified. Weight loss brought about a significant improvement in AHI and continuous positive airway pressure requirements. LAGB placement should be considered a broadly effective therapy for sleep apnoea in the severely obese patient. Introduction: This study aims to evaluate the incidence of Obstructive Sleep Apnoea (OSA) in severely obese Asians and to study the impact of weight loss on OSA. Materials and Methods: We report the results of routine preoperative Polysomnograms in 350 Asian patients undergoing bariatric surgery in our institute. Polysomnograms were repeated in 75 randomly selected patients with moderate to severe OSA after target weight loss with the laparoscopically placed adjustable gastric band (LAGB). Results: The prevalence of OSA in obese Asians is high. Moderate OSA was found in 46% of patients and severe OSA was found in 33%. Severe OSA was significantly more in the Chinese (46%) compared to the Malays (29%) or Indians (21%) (P = 0.035). We identified other risk factors for severe OSA (male sex, higher body mass index and the presence of hypertension) but were unable to select identifying parameters for very low (<5%) likelihood of severe OSA such that routine sleep studies prior to bariatric surgery could be omitted. Apnoea Hypoapnoea Index (AHI) showed improvement of 50% at 20 kg excess weight loss with the cure of OSA in preoperatively severe cases (P <0.005). Mild to moderate cases reported similar improvements although a direct correlation could not be established. Desaturation events, apnoea episodes, work of breathing and subjective assessment of sleepiness scores and quality of life (QOL) showed improving trends, albeit not statistically significant. Similar improvements were seen in sleep architecture with increased rapid eye movement (REM) and stage 3 sleep. Conclusions: The incidence of OSA in Asians undergoing bariatric surgery is high. Routine sleep studies in Asian patients are justified. Weight loss brought about a significant improvement in AHI and continuous positive airway pressure requirements. LAGB placement should be considered a broadly effective therapy for sleep apnoea in the severely obese patient.

Characteristics of hypertension in obstructive sleep apnea: An Asian experience

“…[6][7][8] As in Western countries, the prevalence of OSA is high in Asia. 9,10 The termination of an episode of apnea or hypopnea in OSA causes an acute and transient rise in BP. Conventionally, ambulatory blood pressure monitoring (ABPM) is the gold standard for measuring nighttime BP.…”

“…The repetitive episodes of breathing cessation due to upper airway collapse during sleep in individuals with OSA confer a risk of hypertension and are also associated with organ damage and CVD events 6‐8 . As in Western countries, the prevalence of OSA is high in Asia 9,10 . The termination of an episode of apnea or hypopnea in OSA causes an acute and transient rise in BP.…”

Bariatric surgery—what the ophthalmologist needs to know

“…It was also noted that minimum oxygen saturation, sleep efficiency, and rapid eye movement (REM) latency improved, as well as a reduced need for continuous positive airway pressure. These findings are reinforced by other studies that found that AHI episodes (which are episodes of hypoventilation during the night -normal range is up to 5 episodes per hour) reduced along with a lower percentage of non-REM and higher REM stages [61,62]. It may be correlated that ophthalmological conditions associated with OSA will improve with bariatric surgery as well, but there is no current evidence showing this.…”