Changes in cerebral hemoglobin indices in obstructive sleep apnea syndrome with nasal continuous positive airway pressure treatment

Abstract

This study examined both the relationship between the changes in the brain tissue hemoglobin indices and SpO(2) during sleep in patients with obstructive sleep apnea syndrome (OSAS) and the effect of nasal continuous positive airway pressure (CPAP) treatment on hemoglobin indices. Polysomnographic recordings and near-infrared spectroscopy (NIRS) were performed during an afternoon nap on 15 OSAS patients before treatment and 12 healthy controls. Oxyhemoglobin (HbO), deoxyhemoglobin (HbD), and total hemoglobin (HbT) on NIRS were analyzed, and the correlation of these variables and peripheral arterial oxygen saturation (SpO(2)) were investigated in the OSAS group before nasal CPAP treatment. In nine OSAS patients, the recordings were also compared between the condition with and without using CPAP. HbO decreased during obstructive respiratory events while HbT and HbD showed adverse increases, and the values of these hemoglobin indices returned to the baseline values at the end of each respiratory event in the OSAS group. The fluctuations in these cerebral hemoglobin indices during sleep were significantly larger in the OSAS group than in the control group. Moreover, in the OSAS group, these changes correlated strongly with the change in SpO(2). When using CPAP, not only respiratory events but also the fluctuations in both the cerebral hemoglobin indices and SpO(2) were almost completely suppressed. Arterial oxygen desaturation is clearly related to cerebral oxygenation, and fluctuations of hemoglobin indices can be suppressed with CPAP.