De Angelis G, Sposato B, Mazzei L, Giocondi F, Sbrocca A, Propati A, Gentile J
Unità Operativa, Ospedale C. Forlanini, Roma, Italy.
Eur Rev Med Pharmacol Sci. 2001 Sep-Dec;5(5-6):173-9.
Nocturnal oxygen desaturation during the sleep is very frequent in patients affected by chronic obstructive pulmonary disease (COPD). Hypoventilation, rather than sleeping apnea, is commonly considered as the most relevant factor in the onset of nocturnal oxygen desaturation. On this topic, the Authors have carried on a study on the nocturnal hypoxemia in 70 hospitalized COPD patients with a mean FEV1% of 40 +/- 21 and a mean PaO2 of 67.7 +/- 6.1. Anthropometric features (sex, age, body mass index) and functional respiratory parameters (FEV1, FEV1/VC, PaO2, PaCO2, SaO2, pH) were considered. Moreover all the patients were monitorized with transcutaneous pulse oxymetry, while breathing environmental air, in nighttime. Mean oxyhemoglobinic nocturnal saturation (SaO2 noct.%), minimum registered value of nocturnal SaO2 (min SaO2 noct.%) and the minutes of nighttime SaO2 < or = 90% and < or = 85% (tSaO2 < or = 90% e < or = 85%) were considered. Fiftyfour patients (77.15%) were nocturnal desaturating (NOD), whereas 16 (22.85%) were not desaturating (nNOD). A statistically significant difference was found between the two groups as to the values of FEV1 (p < 0.05), PaCO2, pH, SaO2 noct.%, minimum SaO2 noct.% and tSaO2 < or = 90% and < or = 85% (p < 0.0001). A statistically significant correlation was found between tSaO2 < 90% and BMI (r = 0.44), PaCO2 (r = 0.48) and pH (r = -0.44), as well as between tSaO2 < 85% and PaCO2 (r = 0.57) and pH (r= -0.50), between SaO2 noct.% and BMI (r = -0.45), PaCO2 (r = -0,50), FEV1 (r = 0.44) and pH (r = 0.46) and finally between minimum SaO2 noct.% and PaCO2 (r = -0.47) was found. Eighty percent of the NOD patients had PaO2 < 75 mm Hg and PaCO2 > 44 mm Hg. All the patients with PaCO2 > 50 mm Hg were NOD. In conclusion, all COPD subjects with FEV1 < 49% and daytime PaO2 > 60 mm Hg, particularly when associated to elevated PaCO2 values and high BMI, should undergo a nocturnal pulse oxymetry in order to identify possible nocturnal desaturations. In these patients reduced FEV1, high BMI and/or elevated PaCO2 appear to be predictive indexes of nocturnal desaturation. A PaCO2 > 50 mm Hg is highly indicative for a nocturnal oxygen desaturation.
慢性阻塞性肺疾病（COPD）患者睡眠期间夜间氧饱和度下降非常常见。通气不足而非睡眠呼吸暂停通常被认为是夜间氧饱和度下降发生的最相关因素。关于这个主题，作者对70例住院的COPD患者进行了夜间低氧血症研究，这些患者的平均第一秒用力呼气容积（FEV1）百分比为40±21，平均动脉血氧分压（PaO2）为67.7±6.1。考虑了人体测量特征（性别、年龄、体重指数）和呼吸功能参数（FEV1、FEV1/肺活量（VC）、PaO2、二氧化碳分压（PaCO2）、动脉血氧饱和度（SaO2）、pH值）。此外，所有患者在夜间呼吸环境空气时均采用经皮脉搏血氧饱和度测定法进行监测。考虑了夜间平均氧合血红蛋白饱和度（夜间SaO2%）、夜间SaO2的最低记录值（夜间最低SaO2%）以及夜间SaO2≤90%和≤85%的分钟数（tSaO2≤90%和≤85%）。54例患者（77.15%）出现夜间氧饱和度下降（NOD），而16例（22.85%）未出现氧饱和度下降（非NOD）。两组在FEV1值（p<0.05）、PaCO2、pH值、夜间SaO2%、夜间最低SaO2%以及tSaO2≤90%和≤85%方面存在统计学显著差异（p<0.0001）。发现tSaO2<90%与体重指数（r = 0.44）、PaCO2（r = 0.48）和pH值（r = -0.44）之间存在统计学显著相关性，tSaO2<85%与PaCO2（r = 0.57）和pH值（r = -0.50）之间、夜间SaO2%与体重指数（r = -0.45）、PaCO2（r = -0.50）、FEV1（r = 0.44）和pH值（r = 0.46）之间，以及最后夜间最低SaO2%与PaCO2（r = -0.47）之间均存在统计学显著相关性。80%的NOD患者的PaO2<75毫米汞柱且PaCO₂>44毫米汞柱。所有PaCO₂>50毫米汞柱的患者均为NOD。总之，所有第一秒用力呼气容积<49%且日间PaO₂>60毫米汞柱的慢性阻塞性肺疾病患者，特别是当伴有PaCO₂值升高和高体重指数时，应进行夜间脉搏血氧饱和度测定以确定是否可能存在夜间氧饱和度下降。在这些患者中，FEV1降低、高体重指数和/或PaCO₂升高似乎是夜间氧饱和度下降的预测指标。PaCO₂>50毫米汞柱高度提示夜间氧饱和度下降。
