Pond M N, Conway S P
Adult Cystic Fibrosis Centre, Seacroft Hospital, Leeds, UK.
Thorax. 1995 May;50(5):539-42. doi: 10.1136/thx.50.5.539.
Correction of nocturnal hypoxaemia in patients with cystic fibrosis may delay the development of pulmonary hypertension. Descriptive statistics used for nocturnal arterial oxygen saturation (SpO2) lack uniformity. The relationship between SpO2 and spirometric parameters has not previously been explored in a large number of exacerbations in adult patients with cystic fibrosis.
Over a 21 month period overnight SpO2, forced expiratory volume in one second (FEV1), and forced vital capacity (FVC) were recorded on admission and discharge in 120 treatments of pulmonary exacerbations in 47 patients with cystic fibrosis who did not receive supplemental oxygen during recording. Nocturnal SpO2 was related to spirometric parameters for the whole group and individually in 11 patients, each of whom had at least five treatments.
There was a close linear relationship between the percentage of the recording spent with SpO2 < 90% and mean overnight SpO2. Mean SpO2 correlated moderately with percentage predicted FEV1(%FEV1), r = 0.6, and poorly with percentage predicted FVC (%FVC), r = 0.34. The relationship between mean SpO2 and % FEV1 was non-linear at mean SpO2 < 89%, but approximated to linearity above this value. After exclusion of treatments with mean SpO2 < 89% the regression relationship between mean SpO2 and %FEV1 was the same on admission and discharge. Individual correlation coefficients of mean SpO2 versus % FEV1 in the 11 patients with repeated treatments ranged from 0.57 to 0.77. The slopes of the regression lines did not differ, with a pooled slope of 0.116, but the intercepts varied widely.
In patients with cystic fibrosis mean overnight SpO2 can be substituted for percentage of recording < 90%. The relationship between mean SpO2 and percentage predicted FEV1 is non-linear at low values of SpO2 and is not influenced by treatment of pulmonary exacerbations. Patients with cystic fibrosis desaturate at a uniform rate compared with percentage predicted FEV1, but the value of FEV1 at which desaturation first occurs varies between patients. The spirometric values do not accurately predict nocturnal desaturation in a cystic fibrosis population, but FEV1 is a useful guide in individual patients with moderate desaturation.
纠正囊性纤维化患者的夜间低氧血症可能会延缓肺动脉高压的发展。用于夜间动脉血氧饱和度（SpO2）的描述性统计缺乏一致性。此前尚未在大量成年囊性纤维化患者病情加重时探讨SpO2与肺量计参数之间的关系。
在21个月的时间里，对47例囊性纤维化患者的120次肺部病情加重治疗进行了记录，记录内容包括入院时和出院时的夜间SpO2、一秒用力呼气量（FEV1）和用力肺活量（FVC），这些患者在记录期间未接受补充氧气治疗。对整个组以及11例患者（每人至少接受5次治疗）分别分析夜间SpO2与肺量计参数之间的关系。
SpO2 < 90% 的记录时间百分比与夜间平均SpO2之间存在密切的线性关系。平均SpO2与预测FEV1百分比（%FEV1）中度相关，r = 0.6，与预测FVC百分比（%FVC）相关性较差，r = 0.34。平均SpO2 < 89% 时，平均SpO2与%FEV1之间的关系呈非线性，但高于此值时近似线性。排除平均SpO2 < 89% 的治疗后，入院时和出院时平均SpO2与%FEV1之间的回归关系相同。11例接受重复治疗的患者中，平均SpO2与%FEV1的个体相关系数范围为0.57至0.77。回归线的斜率没有差异，合并斜率为0.116，但截距差异很大。
在囊性纤维化患者中，夜间平均SpO2可替代SpO2 < 90% 的记录时间百分比。SpO2较低时，平均SpO2与预测FEV1百分比之间的关系呈非线性，且不受肺部病情加重治疗影响。与预测FEV1百分比相比，囊性纤维化患者的血氧饱和度下降速率一致，但首次出现血氧饱和度下降时的FEV1值在患者之间有所不同。肺量计值不能准确预测囊性纤维化患者群体的夜间血氧饱和度下降情况，但FEV1对中度血氧饱和度下降的个体患者是一个有用的指标。
