Adult-type pulmonary function tests in infants without respiratory disease.
ABSTRACT A new method that permits the measurement of adult-type maximal expiratory flow-volume curves and fractional lung volumes in sedated infants was recently described. The purpose of this study was to define the normal range for these new measures of pulmonary function in infants and young children. Measurements of forced expiratory flows and fractional lung volume were made on 35 occasions in 22 children (ages 3-120 weeks) without respiratory disease. Maximal expiratory flow-volume curves were measured by the raised lung volume, thoracoabdominal compression technique. Functional residual capacity (FRC) was measured plethysmographically. Measurements of total lung capacity (TLC), residual volume (RV), FRC, forced vital capacity (FVC), and forced expiratory flows at 25, 50, 75, 85, and between 25% and 75% of expired FVC (FEF(25), FEF(50), FEF(75), FEF(85), and FEF(25-75), respectively) all increased in relation to infant length (P<0.001). RV/TLC, FRC/TLC, and FEF(25-75)/FVC declined in relation to increasing length (P<0.001). The forced expiratory flow and fractional lung volume measurements using this method were similar to previously reported estimates using other methods. These estimates represent a reasonable reference standard for infants and young children with respiratory problems.
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Article: Postnatal human lung growth.[show abstract] [hide abstract]
ABSTRACT: Standard morphometric methods were applied to the lungs of 36 boys and 20 girls aged from 6 weeks to 14 years, dying as a result of trauma or after short illnesses. Individual lung units, alveolar dimensions, and number of alveoli per unit area and volume did not differ between boys and girls, but boys had bigger lungs than girls for the same stature. This resulted in a larger total number of alveoli and a larger aveolar surface area in boys than in girls for a given age and stature. There may be more respiratory bronchioles in boys than girls. There was rapid alveolar multiplication during the first two years of life and alveolar dimensions and number of alveoli per unit area and volume did not change much during this period. There was little or no increase in the total number of alveoli after the age of 2 years but the data are hard to interpret. There is a wide scatter of the total number of alveoli in the growing lung, in keeping with the observation that the total number of alveoli is very variable in adults. Prediction data are given for the various morphometric variables studied.Thorax 09/1982; 37(8):564-71. · 8.38 Impact Factor
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ABSTRACT: We studied 15 normal subjects and 15 patients with cystic fibrosis (CF), to determine the within-subject variability of spirometry, moment analysis, and slope ratios, and to calculate the per cent change for significance. Common sources of variability, such as patient and technician training, equipment errors, lung volume history, posture, and circadian variation, were controlled. Flow-time curves were analyzed with a digital computer. The coefficient of variations of spirometry were smallest for forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and peak flow (PF), and were largest for root moments (M) and slope ratios (SR) in both normal subjects and patients with CF. The coefficient of variations of all tests, except PF, were larger in patients with CF than in normal subjects. Significant change was calculated from the sample variance, mean, and the number of trials using a modified equation for sample size. This calculation estimated the degree of change for significance for each participant that was required in subsequent testing.The American review of respiratory disease 01/1981; 122(6):859-66. · 10.19 Impact Factor
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ABSTRACT: Forced expiratory flows at functional residual capacity (VmaxFRC) by the rapid compression technique and functional residual capacity (FRC) by the helium dilution technique were assessed in 112 normal infants with a mean age of 10.7 months (range, 1.0-31.0). In predicting FRC, log transformation was appropriate and body length was the best predicator. For VmaxFRC, age was a better predictor than length, and logarithmic transformation was not required. In(FRC) = -5.465 + 2.49 x In(length) SD = 0.178; r2 = 0.83 VmaxFRC = -397 + 9.36 x (age) SD = 88; r2 = 0.52 There were no gender differences for FRC or VmaxFRC; however, male infants exposed to passive cigarette smoke tended to have lower flows than male infants not exposed (P < 0.07). This study establishes normative values for VmaxFRC and FRC in infants between 1 and 31 months of age, and suggests that passive cigarette smoke exposure has an adverse effect upon forced expiratory flows in male infants.Pediatric Pulmonology 06/1993; 15(6):357-61. · 2.38 Impact Factor