Overview
Definition
A clinical triad consisting of obesity (BMI >= 30), daytime hypercapnia (PaCO2 > 45 mmHg), and sleep-disordered breathing, in the absence of other causes of hypoventilation.
Epidemiology
Prevalence ~8-20% among obese patients with OSA.
Etiology & Risk Factors
- Increased work of breathing from chest wall loading
- Depressed central respiratory drive in setting of leptin resistance
Clinical Symptoms
- Severe daytime sleepiness
- Dyspnea on minimal exertion
- Signs of right-sided heart failure (edema)
- Cyanosis
Clinical Approach
Diagnosis
- Obesity (BMI >= 30)
- ABG showing daytime PaCO2 > 45 mmHg
- Pulmonary function tests showing restrictive pattern without intrinsic lung disease
Management
- Positive airway pressure therapy (CPAP or BiPAP)
- Aggressive weight loss (bariatric surgery often indicated)
- Avoidance of central nervous system depressants
Complications
- Pulmonary hypertension
- Right-sided Heart Failure (cor pulmonale)
- Respiratory failure
- Cardiac arrhythmias