The clinical and polysomnographic features in complex sleep apnea syndrome

Aim: Complex sleep apnea syndrome (CompSAS) is characterized by the onset of central apneas or a Cheyne-Stokes breathing pattern in some patients with obstructive sleep apnea syndrome (OSAS) who were treated with continuous positive airway pressure (CPAP). The etiology of CompSAS is unclear, but derangement of respiratory control has been proposed. We sough.: to compare clinical and polysomnography (PSG) features of patients with CompSAS and OSAS. Materials and methods: Records of PSG were evaluated in a total of 270 patients, retrospectively. CPAP titration was prescribed in patients with an apnea-hypopnea index (AHI) of >= 15. Patients who developed a central AHI of >= 5 following titration PSG were diagnosed with CompSAS. Results: There were 71 patients with OSAS and 12 with CompSAS. The mean ages and body mass indexes (BMIs) were similar between the 2 groups. The incidences of diagnostic AHI, congestive heart failure (CHF), and chronic renal failure (CRF) were higher in patients with CompSAS. The average and minimum oxygen saturation levels were lower in patients with CompSAS and those with diagnostic PSGs. Conclusion: According to our results, lower oxygen saturation may cause instability of respiratory control in these patients and may be responsible for the pathophysiology of CompSAS.