endothelin-1 and Apnea

Altitude illness remains a major cause of mortality. Reduced chemosensitivity, irregular breathing leading to central apnoeas/hypopnoeas, and exaggerated pulmonary vasoconstriction may compromise oxygenation. All factors could enhance susceptibility to acute mountain sickness (AMS). We compared 12 AMS-susceptible individuals with recurrent and severe symptoms (AMS+) with 12 "AMS-nonsusceptible" subjects (AMS-), assessing sleep-breathing disorders in simulated altitude as well as chemoresponsive and pulmonary vasoconstrictive responses to hypoxia. During exposure to simulated altitude, mean blood oxygen saturation during sleep was lower in AMS+ subjects (81.6 ± 2.6 versus 86.0 ± 2.4%, p<0.01), associated with a lower central apnoea/hypopnoea index (18.2 ± 18.1 versus 33.4 ± 24.8 events · h(-1) in AMS+ and AMS- subjects, respectively; p=0.038). A lower hypoxic (isocapnic) chemoresponsiveness was observed in AMS+ subjects (0.40 ± 0.49 versus 0.97 ± 0.46 L · min(-1)·%; p<0.001). This represented the only significant and independent predictive factor for altitude intolerance, despite a higher increase in pulmonary artery systolic pressure in response to hypoxia, a lower lung diffusing capacity and a higher endothelin-1 level at baseline in AMS+ subjects (p<0.05). AMS+ subjects were more hypoxaemic whilst exhibiting fewer respiratory events during sleep owing to lower hypoxic (isocapnic) chemoresponsiveness. In conclusion, the reduction in peripheral hypoxic chemosensitivity appears to be a major causative factor for altitude intolerance.

Topics: Acute Disease; Adult; Altitude Sickness; Apnea; Endothelin-1; Female; Humans; Hypoxia; Male; Middle Aged; Oxygen; Pulmonary Artery; Pulmonary Diffusing Capacity; Severity of Illness Index; Sleep

To explore the treatment effect of H-UPPP on patients with obstructive sleep apnea hypopnea syndrome (OSAHS).. Seventy-nine patients were enrolled in our study. Among which 49 patients were done with H-UPPP, and the other 30 patients were done with UPPP. AHI and LSaO2 were monitored by polysomnography and plasma endothelins-1 were tested with enzyme linked immunosorbent assay (ELISA) before and after operation.. Forty-one patients were improved with reduced snoring and daytime sleepiness one year after operation in H-UPPP group,and the overall efficiency was 83.7%. Twenty-six patients were improved with reduced snoring and daytime sleepiness one year after operation in UPPP group, and the overall efficiency was 86.7%. There were significant differences of AHI, LSaO2 and ET-1 before and after operation between the two groups. Negative correlation was showed between AHI and LSaO2, also between LSaO2 and ET-1.. Both H-UPPP and UPPP were proved to be effective to patients with OSAHS. The perioperative complications with H-UPPP was less than UPPP.

Topics: Adult; Apnea; Disorders of Excessive Somnolence; Endothelin-1; Female; Humans; Male; Middle Aged; Palate, Soft; Pharynx; Polysomnography; Sleep Apnea, Obstructive; Sleep Stages; Snoring; Uvula