GROWTH OF AIRWAYS AND LUNG PARENCHYMA IN NORMAL INFANTS

人们普遍认为，婴儿期是儿童快速成长的关键时期。 呼吸道和肺实质与早期影响肺功能的事件 可能会产生终生后果。与我们广泛的 年龄较大的儿童和成人的呼吸力学知识，我们的 对出生后头两年的肺发育的了解非常有限。 部分用力呼气动作已被改装用于婴儿， 然而，这项技术受到了质疑，因为还不确定 达到FL时，用力呼气流量只能在 潮汐呼吸范围大，流量变异性大。我们有 开发了一种新的方法，可以测量完全用力的生命 容量动作、肺容量分数和静压容量 婴儿和幼儿的曲线。 本项目的具体目标是应用这些新技术：1) 在一大群婴儿和非常年幼的儿童中测定肺 达到流量限制的体积范围。流量限制将 通过构建等容压力流量(IVPF)曲线来确定 测量经肺压力的食道导管。1b)发展 并验证了一种非侵入性技术，可以取代IVPF曲线 评估FL在这个年龄段的存在。非侵入性的 测试的技术包括：L)外口技术，2) 在体表上叠加振荡压力，以及3)肺 用力呼气喘息的声学分析。2a)确定在 出生后头24个月，呼吸道和肺的相对生长 通过最大流量、肺体积、静态反冲来评估实质 压力和密度依赖。2b)在以下对象之间建立参考数据 O和24个月的生命。3A、B)评价呼吸道发育情况 在生命的前24个月内使用最大值变化的响应性 雾化吸入后的呼气流量和肺容量分数 支气管扩张剂。 这个项目的成果将极大地增加我们对 呼吸系统在前两个阶段的正常机械发育 生命中的岁月。这些信息将为以下工作提供科学依据 了解早期重要呼吸系统疾病的影响 儿童期(哮喘、囊性纤维化、支气管肺发育不良) 生长和成熟。这些数据还将使我们能够更好地 检测呼吸功能障碍并更有效地评估 婴幼儿的治疗性干预。可比性 这些评估婴儿肺功能的新方法中有哪些符合标准 成人和年龄较大的儿童的肺功能测量将允许 研究人员和临床医生更准确地量化 呼吸系统疾病对肺部和呼吸道的纵向影响 从婴儿期到成年期。

It is widely held that infancy is a critical time for rapid growth of the airways and lung parenchyma and that events affecting lung function early in life may have lifelong consequences. In contrast to our extensive knowledge of respiratory mechanics in older children and adults, our understanding of lung growth the first 2 years of life is very limited. Partial forced expiratory maneuvers have been adapted for use in infants, however, the technique is being questioned because there is no certainty that FL is reached, forced expiratory flows can be produced only over the tidal breathing range, and the variability of flow is high. We have developed a new method which allows the measurement of full forced vital capacity maneuvers, fractional lung volumes, and static pressure volume curves in infants and young children. The Specific Aims of this project are to apply these new techniques: 1A) To determine in a large group of infants and very young children the lung volume range over which flow limitation is achieved. Flow limitation will be determined by constructing isovolume pressure flow (IVPF) curves using an esophageal catheter to measure transpulmonary pressure. 1B) To develop and validate a non-invasive technique that can replace IVPF curves in assessing the presence of FL in this age group. The non-invasive techniques tested will include: l) the external orifice technique, 2) superimposing an oscillating pressure at the body surface, and 3) lung sound analysis for forced expiratory wheeze. 2A) To determine during the first 24 months of life the relative growth of the airways and the lung parenchyma as assessed by maximal flows, lung volumes, static recoil pressures, and density dependence. 2B) To establish reference data between O and 24 months of life. 3A,B) To evaluate the development of airway responsiveness during the first 24 months of life using changes in maximal expiratory flows and fractional lung volumes following an aerosolized bronchodilator. The results of this project will greatly increase our knowledge of the normal mechanical development of the respiratory system over the first 2 years of life. Such information will provide the scientific basis for understanding the effects of the important respiratory disorders of early childhood (asthma, cystic fibrosis, bronchopulmonary dysplasia) on lung growth and maturation. These data will in addition allow us to better detect respiratory dysfunction and more efficiently assess the effects of therapeutic interventions in infants and young children. The comparability of these new methods for assessing lung function in infants to standard measures of pulmonary function in adults and older children will allow investigators and clinicians to more precisely quantify the effects of respiratory disease processes on the lungs and the airways longitudinally from infancy through adulthood.