Utility of daytime polysomnography for in-patients with suspected sleep-disordered breathing

Obstructive sleep apnoea (OSA) is a common medical problem with significant adverse consequences. Delays in diagnosing and treating OSA have increased with increasing demand for sleep services. The aim of the study was to assess the utility of daytime poly-somnography (PSG) in in-patients who were suspected during admission to have sleep disordered breathing.

We compared 80 in-patients who had daytime PSG with a random sample of 180 patients who had overnight PSG. We analyzed demographic data, medical history, PSG results, and results of continuous positive airway pressure (CPAP) titration.

The diagnosis of OSA was made in 70 (87.5%) daytime patients and 180 (100%) overnight patients. The daytime patients were older (53.5 +/-12.2 years vs. 46.8 +/-14 years, p < 0.001) and had a higher body mass index (BMI) than the overnight patients (43.3 +/-13.3 vs. 35 +/-8, p < 0.001). There was no significant difference between the two groups with regard to apnoea-hypopnoea index (AHI) or desaturation and arousal indices. CPAP titration was successful in 89.5% of the daytime patients and 81.5% of the overnight patients. Daytime patients had more medical co-morbidities. Obesity hypoventilation syndrome (OHS) was diagnosed in 31.3% of the daytime group.

Daytime PSG is as useful as overnight PSG in diagnosing OSA and titrating CPAP in in-patients. It is best suited to inpatients, patients with multiple co-morbidities, and patients with OHS.