PubMed Health⌕ Search

Biomedical subjects

I D Frantz

Publications and source records attributed to I D Frantz.

At least 91 records · Page 5Linked to original sources
PubMed1976

Respiratory regulation after elastic loading and CO2 rebreathing in normal term infants.

Studies of airway pressure, tidal volume, respiratory duration, and total breath duration before and after elastic loading airway occlusions were carried out on ten full-term, normal infants on two occassions in the first week of life. Using these noninvasive techniques we infer that static compliance and the Hering-Breuer reflex are unchanged during the first week; that infants may increase sensitivity to chemical drive toward the end of the first week; and that there may be a volume related threshold for vagal inhibition of inspiration in some infants.

Carbon Dioxide↗
PubMed1976

Maturational changes of effective elastance in the first 10 days of life.

The effective elastance of the respiratory system (E'rs) is a measure of its ability to resist a change in tidal volume under conditions of changing elastic loads. E'rs was measured while subjects breathed air and 2% CO2 and 4% CO2 in air in two groups of premature infants of different gestational ages at 1 day 3-4 days, and 7-10 days of age. E'rs was shown to decrease with increasing maturation and was independent of changes in control tidal volume. The decrease of E'rs with increased gestational age could be accounted for by differences in calculated thoracic gas volumes in all but one instance, where E'rs was lower in one group on the 3rd day of life. The activity of the Hering-Breuer reflex, as measured by the degree of slowing of inspiratory time after occlusion at FRC, has been previously reported to be normal to increased in similar infants. This suggests that differences related to size account for most of the maturational changes of E'rs in newborns.

Age Factors↗
PubMed1976

Maturational effects on respiratory responses to carbon dioxide in premature infants.

The respiratory responses of 18 premature infants to breathing steady-state levels of carbon dioxide were quantified by conventional minute ventilation measurements and by measuring the pressure generated after end-expiratory airway occlusions. Since no flow or volume changes occur following airway occlusion, the CO2 response obtained by this measurement is independent of vagal stretch receptor influence and mechanical changes in the lungs. When studied at 3-4 days of postnatal age, a group of 29-32-wk gestation infants had a mean slope of ventilatory response to CO2 of 10.8 +/- 5.6 ml-min-1-kg-1-mmHg-1 as compared to 53.5 +/- 10.8 ml-min-1-kg-1-mmHg-1 (P less than 0.005) for a group of 33-36 wk. When these infants were restudied at 7-10 days of age, the slopes were 21.6+/- 6.6 and 58.4 +/- 10.6 ml-min-1-kg-1-mmHg-1 (P less than 0.01), respectively. The mask pressure response paralleled minute ventilation. We conclude that the increase in ventilatory response to carbon dioxide seen with maturation is not due only to changing mechanical features of the lungs, but to increased sensitivity of respiratory centers to carbon dioxide.

Age Factors↗
PubMed1976

Respiratory response to airway occlusion in infants: sleep state and maturation.

The progressive respiratory response to occlusion of the airway at FRC was measured in a group of full-term and premature human infants. The sleep state of the full-term infants was shown to affect the response primarily through variations in the phase of thoracic and abdominal movements. The weakest responses were seen in those infants who demonstrated parodoxical respiration prior to occlusion. Most infants developed paradoxical respiratory movements after occlusion, but this did not affect the strength of the load-compensatory response. An increase in response related to both gestational and postnatal age was observed. This increase could not be accounted for by variations in the amount of paradoxical and in-phase respiration and thus may represent an increase in the sensitivity of infants to chemical stimuli with maturation.

Aging↗
PubMed1975

The progressive response of the newborn infant to added respiratory loads.

The responses of 10 normal full-term infants to 10-sec airway occlusions at functional residual capacity were studied. The responses were quantified by measuring the pressure generated on successive inspiratory efforts following occlusions in room air and 100% oxygen. The response after oxygen breathing was 30-40% less than after air breathing, indicating that hypoxia accounted for part of the response. There was an increase in the response in air from the first to the fourth day of life. Endtidal carbon dioxide tension was shown to increase during the occlusion, but the response remaining after hypoxia was eliminated may not have been due entirely to hypercapnea. We conclude that the compensatory response of the infant to added respiratory loads is in part due to hypoxia, and that the hypoxic response increases over the first week of life.

Airway Obstruction↗
PubMed1975

Necrotizing enterocolitis.

The clinical course of 54 patients with necrotizing enterocolitis has been compared to a matched group of 98 control patients. On the day of life that NEC occurred, all 54 NEC patients and 63% of controls were receiving standard formula feedings, both at 80/cal/kg/day. Stool cultures at the time revealed a significantly increased frequency of Klebsiella in NEC as compared to control patients. Our data suggest that the combined presence of certain intestinal bacteria and enteric feedings, perhaps requiring a background of mucosal ischemia, may be of etiologic significance in the development of NEC and its radiologic hallmark, pneumatosis intestinalis.

Birth Weight↗
PubMed1975

Experimental meconium aspiration: Effects of glucocorticoid treatment.

An animal model of meconium aspiration was developed to determine the efficacy of glucocorticoids in its treatment. Rabbit pups were made to aspirate either meconium or saline prior to the onset of respiration. Cortisol was administered in a random, blind fashion. Slight decrease in respiratory rate and less severe histopathologic changes in the lungs were seen in corticosteroid-treated animals. Survival was significantly decreased, without definite cause, in the glucocorticoid-treated animals whether or not they had aspirated meconium. Because of this decreased survival and the relatively insignificant improvement in clinical course and histopathology found with glucocorticoid treatment, we cannot recommend cortisol for the treatment of meconium aspiration.

Animals↗