摘要
本研究连续记录、分析了低压舱模拟2000m、3000m、4000m、5000m、6000m、7000m高度上8名被试者吸舱内缺氧气体转吸纯氧及吸纯氧转吸舱内缺氧气体两个过程中人体血氧饱和度随时间的变化曲线,结果发现,两个过程的血氧饱和度均按指数规律变化,其数学表达式为:S=(?)-((?)-(?)_o)e^(-Bt),S—瞬时血氧饱和度值(%),(?)—初始状态血氧饱和度稳定值(%),(?)最终状态血氧饱和度稳定值(%),B—常数(不随时间和氧分压水平改变),t—时间。微分方程式为dS/dt=B((?)-S),表示两个过程相一致的动力学特性:血氧饱和度的变化速率同血氧饱和度瞬时值与最终状态稳定值之差成正比。数学表达式和微分方程式同样适用于其他任何两氧分压水平之间,如两不同缺氧水平之间,互相转换过程中血氧饱和度的变化特性。
Oxygen saturation of hemoglobin (S HbO) in blood is an important parameter for human body function during hypoxia. The purpose of this study was to investigate the dynamic change of S HbO during processes from one state of hypoxia to another, so as to predict the hypoxic severity and tolerance to hypoxia of subjects in a hypoxic environment.The experiment was carried out in a decompression chamber simulating altitudes of 0～7000m. The curves of S HbO change in 8 subjects were recorded with a Water's Oxymeter 0-1100A (made in USA).It was found that the cuves of change of S HbO from hypoxic states to 100 O_2 were similar to each other among the 8 subjects, and so were the curves of changes of S HbO from 100 O_2 state to hypoxic states. Statistical analysis demonstrated that S HbO changes exponentially with time, as shown in formulae(1) and (2):S=-(-o)e^(-bt)…………(1)whereS——instantaneous value of S HbO during process from hypoxic states to 100 O_2 state;o——initial and steady value of S HbO at a certain altitude;——final and steady value of S HbO during inhalation of 100 O_2;b——combination constant of HbO;t——time in second;S′ =′+(o′-′)e^(-b′t)…………(2)whereS′——instantaneous value of SHbO during process from 100 O_2 state to hypoxic state;o′——initial and steady value of SHbO at time of inhalation of 100 O_2;′——final and steady value of SHbO at a certain altitude;b′——dissociation constant of HbO.It was obvious from formulae (1) and (2) that S increases exponentially with time when (?)>(?)_0, and that S′ decreases with time when (?)′<(?)o′. If we differentiate the formulae (1)and (2), we can find that their differential equations are the same:dS/dt=b(—S) and dS′/dt= -b′(S′-′) =b′ (′-S′).The general differential equation can be written as dS/dt=B(-S),and the general formula can he written asS=-(-o)e^(-Bt)…………(3)whereS——instantaneous value of S HbO;o——nitial and steady value of S HbO;——final and steady value of S HbO;B——constant of HbO;which indicates that there is a common dynamic characteristic of S Hb0 in the process when concentration of O_2 in inhaled air is changed from any level to another ,and that the change rate of S HbO is proportional to the difference between instaneous value and final—steady value of S HbO.
出处
《航天医学与医学工程》
CAS
CSCD
1992年第3期172-178,共7页
Space Medicine & Medical Engineering
关键词
急性
高空缺氧
血氧饱和度
高空
acute altitude hypoxia, blood oxygen saturation, dynamic characteristics
