Obesity Hypoventilation Syndrome

Obesity hypoventilation syndrome was framed as an obesity-related condition in 1964, accompanied by cyanosis, somnolence, twitching of the muscles, and breathing on a periodic basis (Falsetti et al. 1964). The syndrome incorporates obesity, breathing problems during sleep, as well as daytime hypercapnia without any neuromuscular, mechanical, or metabolic factors involved. Even though “Pickwickian syndrome” was coined in the 1950s, descriptions of overweight patients experiencing somnolence have existed in medical records since 1889. According to the American Thoracic Society (ATS) clinical practice guideline and the European Respiratory Society (ERS), obesity hypoventilation syndrome refers to hypercapnia (PaCO2 >45 mmHg) occurring during the day in individuals with obesity (BMI >30 kg/m2), regardless of whether they have sleep-disordered breathing. Patients with this syndrome are likely to develop cardiovascular compromises associated with higher mortality rates (Shah et al. 2021). The ethnicity of the patient may influence the clinical features of this condition (Shah et al. 2021). The syndrome is usually diagnosed in the fifth and sixth decades of life (Masa et al. 2019). With the global increase in body mass index (BMI), the probability of obesity hypoventilation syndrome is expected to rise. The estimated prevalence of this syndrome is considered to be approximately 0.4–0.6% of the population (Shah et al. 2021), accounting for about 1 out of every 260 adults in the United States (Masa et al. 2019). Moreover, obesity hypoventilation syndrome is reported to be present in 8–20% of obese patients who attend referral sleep centers for sleep-disordered breathing assessments (Masa et al. 2019).