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R S Tepper

Publications and source records attributed to R S Tepper.

64 records · Page 4Linked to original sources
PubMed1986

Expiratory flow limitation in infants with bronchopulmonary dysplasia.

We evaluated lung function in 20 infants with bronchopulmonary dysplasia (BPD) during the first year of life. Compared with a group of age- and size-matched controls, the infants with BPD had a significantly (P less than 0.005) lower functional residual capacity (FRC; 25 +/- 4 vs 18 +/- 6 ml/kg) at less than 10 1/2 months after conception, but no significant difference during the remainder of the first year. The partial expiratory flow volume curves in the infants with BPD were markedly concave, with tidal breathing approaching expiratory flow limitation. The infants with BPD had significantly (P less than 0.01) lower absolute and size-corrected flows than did control infants, and 50% of the infants with BPD required rehospitalization because of acute respiratory distress associated with a lower respiratory tract illness. In addition, the slope of the linear regression of maximal expiratory flow at FRC (in milliliters per second) vs length (in centimeters) was significantly lower (P less than 0.001) for the infants with BPD than for normal control infants (2.25 vs 4.52), indicating poor growth of the airways. Oxygen saturation (SaO2 was negatively correlated with maximal expiratory flow at FRC, indicating that measurement of SaO2 alone may not be sufficient in the evaluation of lung function in infants with BPD. We conclude that, although infants with BPD improve clinically during the first year of life, they have abnormal functional airway growth; the decreased expiratory flow reserve helps to explain their high risk for acute respiratory distress during lower respiratory tract illness.

Airway Resistance↗
PubMed1986

Physiologic growth and development of the lung during the first year of life.

Pulmonary function tests were performed on a total of 125 healthy infants younger than 25 postconception (pc) months of age. Maximal expiratory flow at functional residual capacity (VmaxFRC) was measured from partial expiratory flow-volume curves, and functional residual capacity (FRC) was measured by the helium dilution technique. There was a highly significant (p less than 0.01) linear regression for both VmaxFRC and FRC with increasing body length. The highest size-corrected flows (VmaxFRC/FRC) were obtained in the healthy premature (2.7 FRC/s, n = 6) and full-term (2.5 FRC/s, n = 5) infants, and there was a relatively constant value between 13 and 25 pc months of age (1.2 FRC/s), which was similar to those reported in older children and adults. In an age-matched group of infants 10 to 16 pc months of age, females had both higher absolute flows (126 versus 102 ml/s, p less than 0.03) and size-corrected flows (1.4 versus 1.0 FRC/s, p less than 0.001) than did males. These physiologic data support the concepts that neonates have proportionately larger airways relative to their lung volume at FRC, infants have size-corrected flows similar to those in older children and adults, and female infants have proportionately larger airways relative to their lung size than do male infants.

Chloral Hydrate↗
PubMed1984

Noninvasive determination of total respiratory system compliance in infants by the weighted-spirometer method.

The weighted-spirometer method for noninvasive determination of static total respiratory system compliance (Crs) was adapted for use in infants. Ten normal newborns and 5 infants with bronchopulmonary dysplasia (BPD) were studied. The newborns had a mean Crs of 3.8 ml/cm H2O. Their mean specific Crs was 1.13 ml/cm H2O/kg body weight and 0.075 ml/cm H2O/cm body length. These Crs values were similar to those reported by other investigators who used the Hering-Breuer airway occlusion technique. The infants with BPD, who were of the same weight, height, and postconception age as the normal newborns, had significantly (p less than 0.05) lower mean specific Crs (0.60 ml/cm H2O/kg body weight and 0.047 ml/cm H2O/cm body length) relative to the normal newborns. These data suggest that intrinsic changes in lung elastic characteristics may contribute to the reduced lung compliance of infants with BPD. The weighted-spirometer method for measuring Crs is a potential tool for the noninvasive study of the elastic properties of the respiratory system during infancy in health and disease.

Body Height↗
PubMed1983

Ventilation and oxygenation changes during sleep in cystic fibrosis.

Oxygen desaturation during sleep in patients with cystic fibrosis has been attributed to changes in the end-expiratory volume during rapid eye movement (REM) sleep, leading to worsening of the ventilation-perfusion distribution. The purpose of this study was to describe the changes in ventilation during sleep that may contribute to the oxygen desaturation. Six adolescent males with moderate to severe cystic fibrosis were studied. It was concluded that hypoventilation during REM may contribute to oxygen desaturation in patients with cystic fibrosis.

Acid-Base Equilibrium↗
PubMed1979

Inert gas transport in the microcirculation: risk of isobaric supersaturation.

This paper is concerned with the theretical background and implications of isobaric supersaturation and bubble formation in the microcirculation following an abrupt shift from one inspired inert gas to another. The use of more than one inert gas, simultaneously or sequentially, has become common in diving and presents risks as well as potential benefits. A review of microcirculatory model useds, theoretical approaches to decompression, and order of magnitude calculations indicates that present empiricisms are inadequate for predicting such supersaturation phenomena. This is true whether based on the familiar assumption of perfusion-limited behavior or its diffusion-limited counterpart. The "chromatographic" model used here, which considers both perfusion and axial diffusion in tissue cylinders, shows that these combined effects can produce unexpectedly high local supersaturation. The implications include new possibilities for the experimental evaluation of gas transport models as well as practical risks of inert gas shifts in diving and certain diagnostic procedures.

Brain↗