Showing papers by "Soumya Swaminathan published in 1993"
TL;DR: It is concluded that exercise-induced hyperpnea can occur in the absence of chemoreceptor function and in the CCHS children, limb movement is an important determinant of the ventilatory response to exercise.
Abstract: The role of the central and peripheral chemoreceptors in the hyperpnea of exercise has been controversial. We studied five children, age 6 to 11 yr, with absent hypercapneic and hypoxic ventilatory responses during wakefulness (congenital central hypoventilation syndrome, CCHS). Each child performed an incremental treadmill exercise test. Maximal oxygen consumption (O2) and minute ventilation (e) at maximal exercise were lower than but not significantly different from these values in a group of nine normal control children of similar age, height, and weight (O2/kg, 33.7 ± 5.0 versus 45.4 ± 2.9 ml/kg/min, mean ± SEM, NS; e 28.3 ± 7.3 versus 43.8 ± 3.9 L/min, NS). Oxygen tension and saturation fell and CO2 tension rose significantly at maximal exercise in CCHS but not in control subjects. In contrast to control subjects, CCHS subjects increased e largely by increasing respiratory frequency (f) rather than tidal volume (Vt). In the oldest child, submaximal exercise tests at 50% O2, with varying pacing rate, ...
103 citations
Journal Article•
TL;DR: This work measured Peak Expiratory Flow Rate (PEFR) in 345 healthy South Indian children aged 4-15 years, using the Wright mini peak flow meter, and a nomogram was constructed relating PEFR to height.
Abstract: PEFR is a simple and reliable way of following patients with bronchial asthma and other obstructive airway diseases. Normal data is available for Caucasian and North Indian children but not for ethnic South Indian children. We, therefore, measured Peak Expiratory Flow Rate (PEFR) in 345 healthy South Indian children aged 4-15 years, using the Wright mini peak flow meter. A nomogram was constructed relating PEFR to height. Prediction equations for PEFR using height alone or height, age and weight were determined for both sexes. The prediction equation for boys based on height alone was PEFR = 4.08 height (cm)--284.55 and for girls was PEFR = 3.92 height (cm)--277.01.
43 citations
TL;DR: The peripheral chemoresponses of infant twin pairs were determined using a single-breath hyperoxic stimulus and closer similarity of response in monozygotic twin pairs is explained by proposed high degree of heritability for the response.
Abstract: The peripheral chemoresponses of infant twin pairs were determined using a single-breath hyperoxic stimulus. A total of 43 twin pairs of comparable gestation and birth weight were studied during sleep at a mean (SD) age of 8 wk (1.4) while alternately breathing either air or 16% oxygen in nitrogen. Infants responded to a single breath of 100% oxygen by a reduction in ventilation; the mean (SEM) reduction in air was 273 ml/min (10.6) and in 16% oxygen 560 ml/min (18.4). Within-pair variances were compared in 14 monozygotic and 28 dizygotic pairs utilizing combined responses (air + 16% oxygen) computed for measurements made in behavioral quiet sleep and in 9 monozygotic and 20 dizygotic pairs for whom data were complete in polygraphically confirmed quiet sleep. The variance of responses within dizygotic twin pairs was greater than in monozygotic pairs when expressed in ml/min: F ratio 4.11 (p = 0.005) for all data and F ratio 7.67 (p = 0.003) in quiet sleep. Expressed in ml/min/kg the difference was less si...
43 citations