阻塞性睡眠呼吸暂停低通气综合征患者睡眠时的呼吸中枢反应性与夜间低氧血症的关系

Respiratory control during sleep and the development of nocturnal hypoxia in patients with obstructive sleep apnea hypopnea syndrome

目的 探讨阻塞性睡眠呼吸暂停低通气综合征 (OSAHS)患者夜间低氧血症与呼吸中枢反应性的关系。方法 应用动态脉搏容积血氧饱和度 (SpO2 )仪定量分析了 2 4例白天二氧化碳分压(PaCO2 )≥ 4 5mmHg(高CO2 组 ,1mmHg=0 133kPa)及 39例PaCO2 <4 5mmHg(等CO2 组 )的OSAHS患者夜间低氧血症的严重程度。进一步应用重复呼吸法测定了其中 15例患者 (等CO2 组 11例 ,高CO2 组 4例 )睡眠状态下呼吸中枢的低氧及高CO2 反应性。结果 6 3例患者的睡眠呼吸暂停低通气指数 (AHI)平均为 (5 4± 2 1)次 /h ;夜间动态SaO2 监测发现高CO2 组与等CO2 组比较 ,每小时氧减饱和4 %以上的次数 (ODI4)为 (43± 2 3)次 /hvs (2 9± 18)次 /h ;SaO2 <90 %的时间占总睡眠时间的百分数(SIT90 )为 (39± 32 ) %vs(15± 18) % ,高CO2 组均较等CO2 组高 ;而睡眠时的最低SaO2 (LSaO2 )为 (5 6± 18) %vs (6 6± 16 ) % ,平均SaO2 (MSaO2 )为 (86± 12 ) %vs(93± 5 ) % ,均较等CO2 组低 (P <0 0 1) ,提示其夜间缺氧程度更重。在清醒状态下 ,高CO2 组及等CO2 组患者的高CO2 反应 (ΔP0 1/ΔPaCO2 )、低氧反应 (ΔP0 1/ΔSaO2 )、口腔阻断压 (P0 1)差异均无显著性 (P >0 1)。进入非快动眼睡眠 (NREM)及快动眼睡眠 (REM)后 ,高CO2

Objective It is assumed that the reduced ventilatory control during sleep may be related to the nocturnal hypoxia in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and daytime CO_2 retention. Methods Oxygen desaturation index(ODI_4),sleep time spent when SaO_2 was below 90% (SIT_ 90 ),the lowest SaO_2(LSaO_2) and the mean SaO_2(MSaO_2) during sleep were measured in 24 OSAHS patients with daytime PaCO_2≥45 mm Hg and 39 with PaCO_2<45 mm Hg. Hypoxic(ΔP_ 0.1 /ΔSaO_2) and hypercapnic (ΔP_ 0.1 /ΔPaCO_2) responsiveness were measured in 11 eucapnic and 4 hypercapnic patients during wakefulness,NREM and REM sleep stages. Results Compared with the eucapnic patients,all the hypercapnic patients had more severe hypoxia during sleep ( P< 0.05). Although both groups had similar chemical responsiveness during wakefulness,the hypercapnic patients had lower ΔP_ 0.1 /ΔSaO_2 and ΔP_ 0.1 /ΔPaCO_2 during both REM and NREM sleep ( P< 0.05). Conclusion The depressed chemical responsiveness during sleep plays an important role in the development of nocturnal hypoxia in OSAHS patients with daytime CO_2 retention.