From the Guidelines
Pickwickian syndrome, also known as obesity hypoventilation syndrome (OHS), should be diagnosed and treated with a combination of weight loss interventions, positive airway pressure (PAP) therapy, and supplemental oxygen as needed, with the goal of achieving sustained weight loss of 25-30% of actual body weight and resolving hypoventilation. The diagnosis of OHS is made by the combination of obesity (body mass index [BMI] > 30 kg/m2), sleep-disordered breathing (SDB), and awake daytime hypercapnia (awake resting PaCO2 > 45 mm Hg at sea level), after excluding other causes for hypoventilation 1.
Diagnosis
The diagnosis of OHS requires a sleep study (polysomnography or respiratory polygraphy) to establish the presence of SDB and a measurement of arterial blood gases during wakefulness to establish the presence of hypercapnia 1. Serum bicarbonate level can be used to screen for OHS in obese patients with sleep-disordered breathing, with a level < 27 mmol/L suggesting a low probability of OHS 1.
Treatment
Treatment of OHS typically involves weight loss through diet and exercise, with bariatric surgery considered for severe cases 1. Continuous positive airway pressure (CPAP) therapy is often prescribed, starting at 8-12 cmH2O and adjusted based on response, with bi-level positive airway pressure (BiPAP) may be needed for some patients, with typical settings of 12-16 cmH2O for inspiratory pressure and 4-6 cmH2O for expiratory pressure. Supplemental oxygen might be required if oxygen saturation remains low despite CPAP/BiPAP 1. Medications like acetazolamide (250mg twice daily) may help stimulate breathing in some cases. Regular follow-up with pulmonary function tests and sleep studies is essential to monitor progress.
Key Considerations
The condition is serious as chronic hypoxemia and hypercapnia can lead to pulmonary hypertension, right heart failure, and increased mortality if left untreated 1. Addressing both the obesity and breathing components is crucial for effective management. Weight-loss interventions that produce sustained weight loss of 25-30% of actual body weight are suggested to achieve resolution of hypoventilation 1.
From the Research
Diagnosis of Pickwickian Syndrome
- Pickwickian syndrome, also known as obesity-hypoventilation syndrome (OHS), is a respiratory consequence of morbid obesity, characterized by mechanical impairment of ventilation resulting in greatly compromised gas exchange 2.
- The syndrome is associated with deposits of adipose tissue around the abdomen and diaphragm, which can be completely reversible with weight loss 2.
- Diagnosis of OHS involves assessing the patient's respiratory function, including gas exchange, and evaluating the presence of sleep-disordered breathing, such as obstructive sleep apnea (OSA) 3, 4.
Treatment of Pickwickian Syndrome
- Treatment of OHS typically involves a combination of weight loss and positive airway pressure (PAP) therapy, such as non-invasive positive pressure ventilation (NPPV) or continuous positive airway pressure (CPAP) 3, 4, 5.
- The choice of PAP therapy may depend on the severity of the patient's condition, with CPAP being recommended as the first-line treatment for stable ambulatory patients with OHS and coexistent severe OSA 4.
- NPPV may be more effective for patients with more severe hypercapnia or those who require more ventilatory support 6.
- Weight loss is a crucial component of long-term management, as it can help improve respiratory function and reduce the need for PAP therapy 3, 2, 5.
- Monitoring of the patient's condition, including transcutaneous pressure of carbon dioxide (PtcCO₂) levels, is essential to determine the effectiveness of treatment and adjust the therapy as needed 3.