婴幼儿潮气呼吸肺功能指标的预计公式模型构建与评价

Modeling and evaluation of reference equations for lung function in tidal breathing measurement among infants and young children

目的建立及评价西南地区婴幼儿（0-3岁）潮气呼吸肺功能预计公式。方法采用德国JAEGER体积描记肺功能仪（MasterScreen TM Babybody plethysmograph），对来自西南地区166名0-3岁婴幼儿，进行潮气呼吸肺功能共12个指标的测定。通过SPSS18．0统计软件对数据进行处理，首先对各个肺功能指标与肺功能影响因素作相关性分析。二分类资料对各个肺功能指标的影响通过t检验进行分析。各个肺功能指标作为方程的因变量，以性别（s）、年龄（A）、身长（L）、体质量（w）为自变量，作多元逐步回归，建立线性多元回归方程。将本研究构建的方程与国外文献中相应年龄范围的正常婴幼儿各个肺功能指标的方程进行比较，采用相对预测误差的平均值（％）：∑｜预计值-实测值｜／预计值×100％／n，评价各预计公式的优劣。结果肺功能指标与年龄、体质量、身长及性别相关，婴幼儿呼吸频率与年龄呈直线负相关（r=-0．5），RR=30．30—0．06×A；婴幼儿潮气量与年龄呈直线正相关（r=0．8），VT=20．80＋0．34×A＋4．38×W＋4．91×S；峰流速与潮气量的比与年龄呈直线负相关（r=-0．4），PTEF／VT=130．72—0．27×A-8．98×S；流速指标均与体质量呈直线正相关（r=0．5，0．5，0．6，0．6），PEF=25．62＋6．88×W；TEF75：20．33＋6．99×W；TEF50：23．07＋6．39×W；TEF25=0．07＋2．57×w＋0．55×L。预计公式模型比较后显示，构建的预计模型及NguyenTF的模型对本研究群体有较好的适用性。结论建立的婴幼儿各项潮气呼吸肺功能指标的预计公式适用于中国西南地区3岁以下儿童的相关指标的预测。潮气呼吸肺功能指标与年龄和／或体质量呈线性相关。

Objective To develop and evaluate the reference equation of tidal breathing parameters for Chinese infants and young children up to 3 years old in the Southwest. Methods Pulmonary function tests were measured in 166 infants using the Jaeger BabyBody system with standard protocols. Twelve tidal breathing parameters were analyzed. SPSS software （version 18. 0 ） was used for statistical analyses. Association between each parameter and related variables on lung function were quantified using Pearson correlation. The impact of Dichotomous variables on lung function was analyzed by independent sample t test. Reference equations adjusted for independent variables, i. e. , body weight （W） and length （L）, age （A）, and sex （S） were built using stepwise regression model. A comparison between our estimates and thosepublished reference equations was done by the mean of relative prediction error （RPE%） ,which was defined as RPE% = ∑｜ predicted value-observed value ｜ / predicted value ＊ 100%/n. Results The following equations described the correlation of tidal breathing parameters to the variables W, L, A and S： Vy （tidal volume） = 20.80 ＋ 0. 34 × A ＋ 4.38 × W ＋ 4.91 × S ; RR （ respiratory rate） = 30.30 - 0.06 × A ; PTEF/VT （peak tidal expiratory flow to tidal volume） = 130.72 -0.27 ×A- 8.98 × S; PEF （peak expiratory flow） = 25.62 ＋6.88 × W;TEF75 （tidal expiratory flow when 75% of tidal volume remained in the lungs） =20.33 ＋ 6.99 × W; TEF50 = 23.07 ＋ 6.39 × W ; TEF25 = 0.07 ＋ 2.57 × W ＋ 0.55 × L. Among them, RR and PTEF/ VT were negative linear correlated to age. The correlation coefficient r were - 0.5 and - 0.4, respectively. In contrast, a positive linear relationship was found between VT and age （ r = 0.8 ） as well as expiratory flow （ including both PEF and TEF） and body weight （r = 0.5, 0.5, 0.6, and 0.6 for PEF, TEF75, TEF50, and TEF25）. The RPE% analysis indicated that our developed reference equations and equations reported by Nguyen TT were more applicable to 0 - 3 years＇ old infants and children of our population. Conclusion Our newly defined reference equations for tidal breathing parameters are applicable for infants and young children up to 3 years old in Southwest China by using commercially available equipment. The tidal breathing parameters are linear related to age and/or weight.