低水平、不稳定:人在高原睡眠时的氧合状态

Low Level and Unstable Fluctuation:the State of Oxygenation during Sleep at High Altitude

目的:对比观察移居不同海拔高原不同时间青年脉氧饱和度(SpO_2)的分布区间及其波动情况,探讨移居者觉醒和睡眠期间机体的氧合水平和状态。方法:在海拔1 400m、3 700m和5 380m对63名男性健康青年志愿者进行多导睡眠监测。分组逐秒记录受试者静息清醒时SpO_2在1min内能稳定维持的时间长短、发生波动的次数和幅度作为觉醒状态下的氧合指标,以睡眠仪自动分析后导出的SpO_2及氧减饱和度指数为睡眠期指标进行对比分析。结果:(1)海拔1 400m青年清醒静息时SpO_2为(95.85±0.99)%,(95.25～96.44)%,95%CI,移居高原后显著降低(P<0.001)。但不论是海拔3 700m还是5 380m地区,随着居留时间的延长,SpO_2并无"适应性回升"的迹象;(2)移居海拔5 380m初期青年清醒静息SpO_2的最长持续时间缩短,波动次数增加,波动幅度增大(P<0.05)。随居留时间的延长SpO_2有逐步稳定的趋势,至6个月或1年时基本恢复到平原组水平;(3)与1 400m平原组比较,移居海拔3 700m青年氧减饱和度指数的改变并无统计学差异(P>0.05),但移居海拔5 380m青年氧减饱和度指数显著升高(P<0.01)。结论:高原移居青年长期处于"低水平、不稳定"的氧合状态,该特点可能与夜间频发的周期性呼吸有关,亦关系到机体对高原低氧环境的习服机制与能力。相对于低水平SpO_2的影响,频繁、大幅度波动的不稳定氧合状态对机体产生的影响可能更为深远。日间SpO_2稳定维持的时间长短能在一定程度上对夜间的氧减饱和度指数进行预测:Y=53.354-0.972X。

Objective.This paper is aimed to explore the state of oxygenation during sleep in young healthy migrants at different time and high altitude.Methods：Nocturnal sleep recordings of 63 young volunteers aged between 18 and 25 years were analyzed at the different high level of 1 400m, 3 700m and 5 380m. The time of maintenance, frequency and amplitude of fluctuation of the wake SpO2 in one minute were tested to be the index of oxygenation, which was compared with the oxygen saturation of pulse （SpO2） and analyzed.Results： ①The wake SpO2 of the young at the high altitude of 1 400m is （95.85± 0.99） %, （95.25 ～ 96.44） %, 95 % CI, which was significantly decreased after migrating to the high altitude （P〈0.001）.But whether it is 3 700 meters above sea level or the area of 5 380 meters, there is no in- dication of SpO2 with the extension of resident time;The longest duration of SpO2 shortened and the fluctuation frequency and amplitude increased in the early stage at 5380m altitude （P〈0.05）.With the extension of resident time, SpO2 tended to be stable gradually, and returned to the plain level at 6 months or 1 year;③Comparedwith 1 400m plain group, there was no statistical difference in the changes of the 3 700m young people （P〉0.05）, but their ODI4 is significantly increased at an altitude of 5 380m（P〈0.01）.Conclusions： High altitude migrants have been in a low lev- el, unstable state of oxygenation for a long time. This feature may be related to the occurrence of nocturnal periodic breathing. It is also related to the mechanism and ability of acclimatize to hypoxia. Compared with the infects of the lower level SpO2, the more frequent and unstable oxygenation state with frequent fluctuations may have a greater im- pact on the migrants. The ODI4 on the night can be predicted by the duration of the day＇s stability SpO2 .Y=53.354-0.972X.