The clincal significace of pulmonary function detection in normal toddler

Abstract

Objective To explore the development of pulmonary function of normal toddlers between 1 and 3 years old.Methods Totally 115 normal toddlers were divided into 2 groups according to their age,i.e,1 ～ 2 years old,2～3 years old.The indicator of small and big airway examine respiratory system static compliance,total airway resistance and functional residual volume were observed.Results No significant difference was found between male and female toddler( P ＞0.05 ).Between the two groups,the difference of respiratory rate was not significant( 27 vs 26,t =1.512,P ＞0.05 ).The values of tidal volumes in the 2 ～ 3 years group was notably higher than in the 1 ～ 2 years group(0.123 vs 0.091,t =8.586,P ＜ 0.01 ),but the values of tidal volumes per kilogram body weight was not significantly different (0.0091 vs 0.0087,t =1.958,P ＞ 0.05 ).The peak tidal expiratory flow in the elder group was similarly distinctly higher than that in the other group.The measured tidal breathing flow volume loops were both displayed uncharacteristic ellipse.The rations of inspiratory time to total respiratory time,the volume to reach peak tidal expira-tory flow to total expiratory volume,tidal expiratory flow at 25％ remaining expiration to peak expiratory flow and mid-tidal expiratory flow to mid-tidal inspiratory flow were not significantly different between two groups (P ＞ 0.05 ).Butthe ratio of peak tidal flow to tidal volume( 1.257 vs 1.095,t =2.099,P ＜ 0.05 ) and the respiratory system resistances( 2.698 vs 2.071,t =3.762,P ＜0.01 )were evidently lower in the elder group than in the younger.The respiratory system compliances(0.353 vs 0.254,t =4.296,P ＜0.01 ) and functional residual capacities(0.272 vs 0.212,t =8.469,P ＜0.01 ) were significantly higher in the elder group than that in the younger,but the values per kilogram body weight was not significantly different( P ＞0.05 ).It was shown that the values of tidal volume,peak tidal expiratory flow,respiratory system static compliance,residual volume were significantly different(0.0198 vs 0.0198,t =0.000,P ＞0.05),between two groups.The values of each parameter mentioned above were increased with age,and were positively correlated with body weight(γ=0.457,0.849,0.572,0.319 all P＜0.01 ).Conclusion Tidal breathing flow volume loop could show functions of small and large airways and partially replace the maximum expiratory flow loop.The parameters were stable in toddlers and could be used as reasonable index to evaluate the pulmonary function changes in pulmonary diseases.The ventilatory function,residual volume,respiratory system static compliance and peak tidal flow were increased with the age,which coincides with the rule of development of toddlers. Key words: Child ; Respiratory function tests