超声流量仪对不同孕周新生儿潮气呼吸正常值的测定

Detection of normal values of tidal breathing parameters by ultrasonic flow meter in infants at different gestational ages

摘要:

目的：建立正常足月儿及不同孕周早产儿潮气呼吸正常值并分析其差异。方法：对55例足月儿、30例晚期早产儿和25例出生胎龄<34周早产儿，在生后1、14日及28日龄，用超声流量仪进行潮气呼吸检测。结果：新生儿期各孕周潮气呼吸功能参数呈正态分布。在第1、14天及28天呼气达峰时间/呼气时间，呼气达峰容积/呼气量，75%、50%、25%潮气量时呼气流速（tidal expiratory flow at 75% remaining tidal volume，TEF75；tidal expiratory flow at 50% remaining tidal volume，TEF50；tidal expira－tory flow at 25% remaining tidal volume，TEF25）值逐渐升高，而呼吸频率（respiratory rate，RR）值则逐渐下降；RR与TEF75、TEF25的相关性在足月儿组为显著相关（r=0.469，0.539，均P<0.01），在早产儿组为不相关（r=0.190，0.220，均P >0.05）。而晚期早产儿组则RR只与TEF25有相关性（r=0.231，P<0.05），而与TEF75无相关性（r=0.130，P >0.05）；纠正胎龄40周时，早产儿组潮气呼吸参数TEF25、TEF50、TEF75、潮气量明显低于足月儿组，RR明显高于足月儿组（均P<0.05），晚期早产儿组同足月儿比较，上述潮气呼吸参数差别无统计学意义（均P >0.05）。结论：新生儿肺功能参数随日龄逐渐改善，在纠正胎龄40周时，小于34周早产儿潮气呼吸参数仍不能达到足月儿组水平。而RR与TEF25、TEF75在足月儿具有相关性，早产儿则未能体现，新生儿潮气呼吸肺功能的测定及相关性分析有助于评估新生儿特别是早产儿的肺发育。不同孕周新生儿潮气呼吸各项指标可作为临床参考正常值。

Abstract:

Objective：To investigate normal values of tidal breathing parameters in infant at different gestational ages without respira－tory complications and to analyze their differences. Methods：Totally 25 preterm infants less than 34 gestational weeks，30 late preterm infants and 55 healthy full term infants were studied on 1，14，28 d after birth. Tidal breathing parameters were measured by ultrason－ic flow meter. Results：Values of tidal breathing parameters were normally distributed. Ratio of time to peak expiratory flow/expiratory time，ratio of volume to peak expiratory flow/expiratory volume，tidal expiratory flow at 75% remaining tidal volume（TEF75），tidal expi－ratory flow at 50% remaining tidal volume（TEF50），tidal expiratory flow at 25% remaining tidal volume（TEF25） were gradually in－creased on 1，14，28 d after birth in three groups，but respiratory rate（RR） was gradually decreased. Prominence correlation of RR and TEF75，TEF25 was found in full term infants（r=0.469，P<0.01；r=539，P<0.01）；correlation of RR and TEF25（r=0.231，P<0.05） and correlation of RR and TEF75（r=0.130，P >0.05） were found in late preterm infants. There was no correlation of RR and TEF25，TEF75 in preterm infants born less than 34 gestational weeks（r=0.190，P >0.05；r=0.220，P >0.05）. At a matched post men－strual age of 40 weeks，preterm group had lower TEF25，TEF75，TEF25 and tidal volume per kilogram，higher RR compared with those in full term group（P<0.05）；there were no difference in above parameters between late preterm group and full term group（P >0.05）. Conclusions：Lung function of infants in the three groups is improved with the increase of gestational days. At the corrected ges－tational age 40 weeks，preterm infants less than 34 weeks fail to achieve catch-up growth in tidal breath parameters. Correlation of RR and TEF75，TEF25 is found in full term infants not in preterm infants. Infant lung function tests and correlation analysis are very im－portant ways to assess lung development，especially for preterm infant. Tidal breathing parameters in infants at different gestational ages could be used as clinical references.