Nasal continuous positive airway pressure treatment reduces systemic oxidative stress in patients with severe obstructive sleep apnea syndrome

Abstract 

Objective

To evaluate whether nasal continuous positive airway pressure (nCPAP) reduces oxidative stress in patients with severe obstructive sleep apnea (OSA) syndrome.

Materials and methods

Forty-six patients with severe OSA (AHI⩾30) requiring nasal CPAP treatment and 46 controls (subjects without OSA and with mild OSA as defined by an AHI<15) were enrolled. Oxidative stress was evaluated in blood samples with a commercially available automated spectrophotometric assay (D-ROMs test, Diacron, Grosseto, Italy). Blood samples were collected the evening before (10:00 p.m.) and the morning after (07:00 a.m.) a diagnostic polysomnography. Patients with severe OSA syndrome were subsequently submitted to a second polysomnography with nasal CPAP titration the following night. Using the same schedule we collected blood samples from the patients the morning after the nCPAP titration and after two months of nCPAP treatment.

Results

Patients with severe OSA presented higher levels of oxidative stress than patients with AHI<15 in the evening and in the morning (357.57±13.07UCarr vs. 319.28±12.66UCarr, p=0.038, and 371.83±12.83UCarr vs. 328.09±11.76UCarr, p=0.014, respectively). Patients with severe OSA presented a significant reduction the levels of oxidative stress the morning after the nCPAP titration study (371.83±12.83UCarr vs. 298.21±9.62UCarr, p=0.001) and this reduction was further preserved after a period of two months of nCPAP treatment (293.72±6.55UCarr, p=0.001 vs. baseline). Statistically significant correlations were observed between levels of oxidative stress and nocturnal polysomnography (NPSG) markers as oxygen desaturation index (ODI), arousal index (AI), lowest oxygen saturation of hemoglobin, and mean oxygen saturation of hemoglobin.

Conclusions

Patients with severe OSA syndrome presented increased systemic oxidative stress. A single night of nCPAP treatment significantly reduced the levels of oxidative stress in patients with severe OSA syndrome, and this reduction was maintained at least after two months of nCPAP treatment.

Keywords: Oxidative stress, Hydroperoxides, Obstructive sleep apnea syndrome, Continuous positive airway pressure, Polysomnography, Follow-up study