Significant Association of Nightly Nasal Continuous Positive Airway Pressure Using Time with Weight Change in Japanese Patients with Obstructive Sleep Apnea-Hypopnea Syndrome

Background: Obstructive sleep apnea syndrome (OSAS) is one of the representative sleep disorders believed to be associated with metabolic syndrome. Nasal continuous positive airway pressure (nCPAP) ventilation is the first choice therapy for OSAS, which has been reported to cause an improvement in body fat mass, hepatocellular damage and hypertension. Study Objectives: We evaluated whether the changes in the body weight observed in patients with OSAS may have potential associations with the sleep time during which the patients are under nCPAP. Method: A total of 194 patients (148 obese and 46 non-obese) in whom nCPAP use was present for more than 70% of the nights were enrolled in this study. Using the electronic records of the night use time for CPAP devices, we examined whether the habitual sleep time during nCPAP is associated with changes in body weight. Results: In the non-obese OSAS group, the patients with night time use of nCPAP devices for 6 to 7 hours showed the greatest and the most sustained decrease in body weight. In the obese patients with OSAS, on the other hand, a U-shaped relationship has been demonstrated between a percent weight gain over 9 years and a minimal weight gain in patients with habitual sleep for 5 to 6 hours. Conclusions: These results suggest that changes in body weight in patients with OSAS are associated with habitual sleep time.

A study on sleep architecture in patients with chronic respiratory failure under long-term oxygen therapy—Focused on the influence of ventilatory failure (high CO₂) elements on the patient’s sleep architecture

Sleep disturbance related symptoms are common in patients with long-term oxygen therapy (LTOT). Essentially, there were only few previous reports about the sleep architecture in patients with respiratory disease, such as chronic obstructive pulmonary disease (COPD). This study aims to clarify the objective sleep state and the elements that affect sleep architecture in Chronic Respiratory Failure (CRF) patients with focus on clinical cases of chronic hypercapnia. 13 subjects with chronic respiratory failure were enrolled in the study. All the subjects were pre-evaluated by pulmonary function test and Arterial blood gas analysis (ABG) including exercise testing. Polysomnography (PSG) test was performed in each subject with supplemental oxygen. The estimated base line PaCO2 value that reflects overall PaCO2 including sleep period was calculated using equation of PaCO2[2.4×(HCOˉ3)-22]from obtained ABG value just before PSG test. 6 subjects were classified as hypercapnic group (base line PaCO2 ≥ 45 mmHg) and 7 subjects were non-hypercapnic group (base line PaCO2 < 45 mmHg). Latency persistent sleep of PSG data was significant higher in patients with hypercapnic than non-hypercapnic (p < 0.01). Periodic Limb Movement was seen in 23.6% of the subjects, however there was no contribution for arousals. Other PSG data include mean SpO2 were no significant difference. This study suggests that patients with estimated hypercapnia had more disturbed sleep architecture especially significant loss of sleep latency than non-hypercapnic patient with chronic respiratory failure under LTOT. Nocturnal PaCO2 level or ventilatory function may contribute to sleep disturbance in patients with estimated hypercapnia during LTOT.