Reliability of flow-volume measurements in children.
Flow-volume curves were measured in a group of 43 healthy children breathing air and a helium-oxygen gas mixture. Analysis of maximal flow at 25, 50 and 75% of forced vital capacity and at 50, 60 und 70% of total lung capacity (TLC) was performed. There is a correlation between maximal flow rates and height; however, the standard deviations are considerable. Maximal flow rates at different lung volumes expressed in units of TLC/s are independent of height. There is a significant correlation between maximal flow rates and airway resistance expressed as percent of predicted values. Flow increment while breathing a helium-oxygen gas mixture is significant at all lung volumes, but the standard deviation is considerable. Technical problems of measuring flow-volume curves are discussed. Results are compared with those published in the literature. The practical value of these lung function parameters in early detection of small-airway obstruction is doubted.
D000293:Adolescent; D000403:Airway Resistance; D001827:Body Height; D002648:Child; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008168:Lung / Q000502:physiology*; D008176:Lung Volume Measurements; D008297:Male; D012123:Pulmonary Ventilation; D012044:Regression Analysis; D012119:Respiration; D012129:Respiratory Function Tests