Yau K I, Fang L J
Department of Pediatrics, College of Medicine, National Taiwan University, Taipei, R.O.C.
J Formos Med Assoc. 1994 Feb;93(2):110-6.
In order to understand the change in the pulmonary mechanics and energetics of breathing in infants, dynamic pulmonary function tests were studied on 84 occasions in 70 normal healthy infants between birth and seven months of age. All of the study infants were born at full-term and had no lower respiratory infections after birth. Airflow and transpulmonary pressure were measured simultaneously and utilized to calculate values of pulmonary mechanics and energetics of breathing. Variables of ventilation (respiratory frequency, tidal volume, minute ventilation, and inspiratory time) had good correlation with age. Lung compliance increased with age. However, when it was expressed in body weight the lung compliance was independent of age (1.34 +/- 0.37 mL/cmH2O/kg for infants studied). Pulmonary resistance did not differ statistically between different age-groups and it correlated with the level of lung compliance (r = 0.3411, p < 0.01). Older infants had a higher flow rate and esophageal pressure change. This might imply that the older the infant is, the more forceful the breath becomes. The work of breathing was higher in infants of older age and in infants with higher inspiratory pulmonary resistance or lower lung compliance (r = 0.6257, 0.3825 and 0.4579, respectively; p < 0.05). This study establishes reference values for the pulmonary mechanics and energetics of breathing in infancy which may be of assistance in the objective evaluation of respiratory status in infants.
为了解婴儿呼吸时肺力学和呼吸能量学的变化，对70名出生至7个月的正常健康婴儿进行了84次动态肺功能测试。所有研究婴儿均为足月出生，出生后无下呼吸道感染。同时测量气流和跨肺压，并用于计算呼吸的肺力学和呼吸能量学值。通气变量（呼吸频率、潮气量、分钟通气量和吸气时间）与年龄有良好的相关性。肺顺应性随年龄增加。然而，以体重表示时，肺顺应性与年龄无关（所研究婴儿为1.34±0.37 mL/cmH₂O/kg）。不同年龄组之间的肺阻力在统计学上没有差异，且与肺顺应性水平相关（r = 0.3411，p < 0.01）。年龄较大的婴儿流速和食管压力变化较高。这可能意味着婴儿年龄越大，呼吸越有力。年龄较大的婴儿以及吸气肺阻力较高或肺顺应性较低的婴儿呼吸功较高（分别为r = 0.6257、0.3825和0.4579；p < 0.05）。本研究建立了婴儿呼吸的肺力学和呼吸能量学的参考值，这可能有助于客观评估婴儿的呼吸状况。
