慢性阻塞性肺疾病患者夜间低氧血症相关预测因素的分析

目的研究慢性阻塞性肺疾病(COPD)患者睡眠时低氧血症发生的可预测因素。方法分析和比较28例COPD患者与20例正常对照者的肺功能、白天动脉血气及夜间血氧水平。结果 COPD患者夜间平均血氧饱和度(MSaO2)、夜间最低血氧饱和度(LSaO2)较正常对照组明显下降(P<0.05)。COPD患者睡眠时动脉血氧饱和度(SaO2)<90%的时间占睡眠时间百分比(T90)亦显著高于正常对照(P<0.01)。日间SaO2、一秒钟用力呼气容积(FEV1)绝对值与夜间MSaO2相关(r值依次0.704、0.435,P<0.01)。建立了夜间血氧水平的预测公式:MSaO2(%)=0.536×日间SaO2(%)+2.35×FEV1绝对值(L)+38.805。日间SaO2、FEV1绝对值与夜间睡眠时血氧饱和度分布有关。结论 COPD患者睡眠时血氧饱和度较正常人出现明显下降,此时的血氧水平和分布可以通过日间SaO2、FEV1绝对值进行预测。

Analysis of predictive factors of nocturnal hypoxemia in chronic obstructive pulmonary disease

Objective To study the predictive factors of nocturnal hypoxemia in patients with chronic obstructive pulmonary disease(COPD).Methods Pulmonary function test was performed,daytime arterial blood gases were analyzed and nocturnal oxygen level were monitored both in 28 COPD patients and 20 normal controls.Results Compared with normal controls,the extents of nocturnal mean oxyhemoglobin saturation(MSaO 2) and lowest nocturnal oxygen saturation(LSaO 2) were significantly decreased in COPD patients(P <0.05).The percentage of the time that oxyhemoglobin saturation(SaO 2) lower than 90% during sleep(T90) in COPD patients were found increased than those in normal controls(P < 0.01).Daytime SaO 2 and absolute value of FEV 1 were related to the nocturnal MSaO 2(r =0.704,0.435,P <0.01).Predictive formula of nocturnal oxyhemoglobin level was derived as follow: MSaO 2(%) = 0.536 × SaO 2(%) + 2.35 × FEV 1(L) + 38.805.Daytime SaO 2 and absolute value of FEV 1 were also found correlated with nocturnal oxygen distribution.Conclusion Hypoxemia is worse in COPD patients than that in normal contorls at night,and the level and the distribution of nocturnal oxygen can be predicted by daytime SaO 2 and absolute value of FEV 1.