小于胎龄儿婴儿期肺功能初步探讨

目的 比较小于胎龄儿（SGA）和适于胎龄儿（AGA）婴儿期肺功能的差异。方法 2010 年 7 月至 2013 年 7 月在深圳市儿童医院NICU住院的胎龄<36周、无明显影响肺功能疾病的SGA为SGA组；出生体重与SGA组匹配的AGA为AGA组。两组均于纠正胎龄12月龄随访时行潮气呼吸和功能残气量检测，比较两组肺功能参数的差异。多元线性回归分析SGA组影响小气道功能的因素。结果 SGA 组 20 例（男 12 例，女 8 例），AGA 组 30 例（男 17 例，女 13 例）进入分析。两组在出生体重和身长，机械通气天数等基线数据差异无统计学意义（P>0.05）；SGA 组胎龄和用氧天数高于 AGA 组，SGA组随访时体重和身长均低于 AGA 组（P＜0.05）。①在纠正胎龄12 月龄随访时两组呼吸频率、潮气量、每公斤潮气量、分钟通气量和功能残气量的差异均无统计学意义（P>0.05）； 呼气达峰时间、呼气达峰容积、呼气达峰时间比、呼气达峰容积比，75%、50%和25%潮气量时呼气流速，SGA 组均低于 AGA 组（P＜0.05）。②两组NICU出院至肺功能检测期间下呼吸道感染≥3次的比例，SGA组为90%（18/20），AGA组为50%（15/30），差异有统计学意义。③多元线性回归显示，SGA组25%潮气量时呼气流速与检测肺功能随访时身长、体重呈正相关，与吸氧天数呈负相关。结论 SGA 婴儿期肺容积参数与出生体重相近的AGA相近，但气道阻力高于AGA，可能与SGA生后肺发育迟缓相关。

Preliminary study of lung function in small for gestational age infancy

Objective To compare the differences in lung function between small for gestational age infants(SGA) and appropriate for gestational age infants (AGA). Methods From July 2010 to July 2013, hospitalized SGA infants in Shenzhen Children's Hospital Neonatal Intensive Care Unit(NICU) were grouped as SGA group,with gestational age <36 weeks. SGA group had no disorders with significant effect on lung function. AGA group was matched with the gestational age, birth weight in aspects of SGA group. Tidal breathing function was tested and functional residual capacity(FRC) was measured by multiple breath washout measurements in both groups at 12 corrected gestational months. Differences in lung function parameters were compared and the factors affecting small airway function of SGA group were analyzed. Results The study included 20 cases in SGA group(12 males, 8 females), 30 cases in AGA group (17 males, 13 females). There were no significant differences in birth weight, birth length, the number of days of mechanical ventilation between two groups(P>0.05); In SGA group gestational age and the number of days with oxygen-dependent were higher than those in AGA group. In SGA group, weight and height during pulmonary function testing were lower than AGA group (P<0.05). ①Respiratory rate (RR),tidal volume (VT), tidal volume per kilogram(VT/kg),minute ventilation (MV) and FRC were not significantly different between two groups at 12 corrected gestational months(P>0.05). Time to peak expiratory flow (TPEF),volume to peak expiratory flow (VPEF),the ratios of time to peak expiratory flow and expiratory time(TPEF/TE),the ratios of volume to peak expiratory flow and expiratory volume (VPEF/VE) ,tidal expiratory flow 75% remaining tidal volume (TEF75), tidal expiratory flow 50% remaining tidal volume (TEF50) and tidal expiratory flow 25% remaining tidal volume (TEF25) were lower in SGA group than those in the AGA group (P<0.05). ②In two groups, the ratio of lower respiratory tract infection ≥ 3 times during the time from discharged to pulmonary function testing was 90%(18/20) for SGA group versus 50(15/30) for AGA group with significant difference. ③ Multiple linear regression showed a positive correlation between TEF25 and height, weight in SGA group when pulmonary function were tested, and there was a negatively correlation between the oxygen-dependent days and TEF25. Conclusion In infancy, the lung volume parameters of SGA were close to those of AGA who had the same weight.However, the airway resistance of SGA was higher than those of AGA, the increases of airway resistance of SGA was related with developmental retardation after boring