1-2岁和-3岁肺炎支原体肺炎肺功能的前瞻性对照研究

目的观察1～3岁肺炎支原体（MP）肺炎患儿的肺功能改变情况并探讨其临床意义。方法前瞻性选择2005年1月至2006年12月在广州市妇女儿童医疗中心儿童医院住院治疗的1～3岁MP肺炎患儿为研究对象，按年龄分为1～2岁和～3岁组。采用凝集法检测患儿血清特异性抗体MP-IgM的浓度，滴度≥1：160为阳性，提示MP现症感染。采用美国森迪公司2600幼儿肺功能仪测定MP肺炎患儿急性期肺功能，并以120名1～3岁（1～2岁组62例，～3岁组58例）健康儿童的肺功能数据作为正常对照组。结果研究期间77例MP肺炎患儿入组，1—2岁43例、～3岁34例。1～2岁和～3岁MP肺炎亚组急性期潮气呼吸流速-容量（TBFV）环形态特点均表现为TBFV环变窄，呼气曲线升支陡、高峰提前、峰值增高，降支凹陷；1～2岁MP肺炎亚组急性期呼吸频率（RR）、潮气呼气峰流速（PTEF）较同龄正常对照亚组增加（P〈0．05）；吸气时间／总呼吸时间（Ti／Tt）、到达PTEF时的呼出气量／潮气量（％V—PF）、呼出75％潮气量时的呼气流速／PTEF（25／PF）、潮气呼气中期流速／潮气吸气中期流速（ME／MI）、每千克体重功能残气量（FRC／kg）和每千克体重顺应性（Crs／kg）较同龄正常对照亚组减少（p〈0．05）。～3岁MP肺炎亚组急性期PTEF较同龄正常对照亚组增加（P〈0．05），Ti／Tt、％V—PF和25／PF较同龄正常对照亚组减少（P〈0．05）。1～2岁和～3岁MP肺炎亚组的临床表现与其肺功能检测的结果较吻合。1～2岁和-3岁MP肺炎亚组咳痰分别为22例（51．2％）和9例（26．5％），肺部闻及湿啰音分别为19例（44．2％）和8例（23．5％），胸部X线检查见斑片状影分别为36例（83．7％）和14例（41．2％），差异均有统计学意义（P均〈0．05）；1～2岁和～3岁MP肺炎亚组发热、喘息或呼吸困难发生率差异均无统计学意义。结论肺功能检测是监测幼儿MP肺炎急性期肺功能改变的较理想方法。1～2岁MP肺炎患儿急性期肺功能改变较大，呈现大、小气道阻力增高，FRC／kg和Crs／kg下降，RR增加；而-3岁MP肺炎患儿急性期肺功能改变相对较小，仅呈现小气道阻力增高改变。

Prospective controlled trial of the pulmonary function between 1 to 2 years old and elder than 2 years old toddlers with pneumonia caused by M. pneumoniae

Objective To observe the alteration of pulmonary function in toddlers with pneumonia caused by M. pneumoniae （MP）. Methods We detected the concentration of serum specific antibody against MP（IgM） with the agglutination test to support the diagnosis of MP infection, and a titer of 1：160 or greater was considered as positive. The reagents were purchased from the Fujitsu Corporation of Japan. The pulmonary function of 77 hospitalized toddlers with pneumonia caused by MP who fulfilled the exclusion criteria was tested respectively during acute phase and compared with the 120 healthy toddlers . There were three exclusion criteria. One was cough lasting more than 2 weeks upon hospitalization, another was multiple infections, and the other was the children who combined with asthma . In these two groups, younger than 2 years old toddlers were compared with elder than 2 years old ones. Pediatric pulmonary function laboratory type 2600 （Sensor Medics Corporation, USA） was used to detect tidal flow volume curve,which could partially replace the maximum expiratory flow volume curve. Parameters showing small airway function were ratio of the volume to reach peak tidal expiratory flow to total expiratory volume（ % V-PF） ,ratio of tidal expiratory flow at 25% remaining expiration to peak expiratory flow （ 25/PF ） , and ratio of inspiratory time to total respiratory time （ Ti/Tt ）. Parameter showing large airway function was ratio of mid-tidal expiratory flow to mid-tidal inspiratory flow（ME/MI）. Passive expiratory flow volume technique was used to examine respiratory system static compliance and total airway resistance. Open nitrogen washout method was used to measure functional residual volume. Results In the toddlers from 1 to 2 years of age, during the acute phase of pneumonia caused by MP, the respiratory rate （RR） and peak tidal expiratory flow （PTEF） were significantly increased, Ti/ Tt, % V-PF,25/PF, ME/MI, functional residual capacity per kilogram （FRC/kg） and respiratory system compliance per kilogram （Crs/kg） were significantly decreased comparing with those normal toddlers. In the toddlers from 2 to 3 years of age, PTEF was significantly increased, Ti/Tt, % V-PF and 25/PF were significantly decreased, but there was no significant difference in Crs/kg and FRC/kg. During acute phase, the tidal breathing flow-volume （TBFV） loops both displayed a concave expiratory curve. And the results of the pulmonary function testing in 1 - 3 years old toddlers with pneumonia caused by MP were coincided with their clinical manifestations. The younger group was more severe than the elder group, and the difference was significant （ P 〈 0.05 ） . In the younger group,more patients （51.2%） had productive cough than in the elder group（26.5% ）. More patients had moist rales in lungs and spot-patchy shadows in chest X-ray in the younger （ in order,44.2% , 83.7% ） than the elder （23.5% ,41.2% ）. The clinical signs of fever and wheezing/dyspnea were similar in these two groups. Conclusions Higher resistance in small and large airway and higher RR ,lower FRC/kg and Crs/kg could be seen in the toddlers from 1 to 2 years of age with pneumonia caused by MP. And only the resistance in small airway was higher in the toddlers from 2 to 3 years of age. Pulmonary function test was a valuable way for surveillance of the alteration during acute phase in toddlers with pneumonia caused by MP.