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Biomedical subjects

W A Hodson

Publications and source records attributed to W A Hodson.

At least 55 records · Page 3Linked to original sources
PubMed1979

Oxygen-induced alteration of ventilation-perfusion relationships in rats.

The effect of oxygen breathing on shunt and ventilation-perfusion ratios (VA/Q) in anesthetized rats was studied using a modification of the multiple inert gas elimination technique. Base-line analyses showed hypoxemia in some animals breathing room air (arterial O2 tensions 48-70 Torr) associated with intrapulmonary shunts ranging from 0 to 22%, and variable low VA/Q lung regions as determined by calculation of the inert gas arterial-alveolar difference curve. Of nine rats that breathed 100% oxygen for 30 min, three showed increases in shunt (0% leads to 19%, 1.5% leads to 16%, 11% leads to 40%). These three animals had larger preexisting low VA/Q regions than the six that developed no shunt (0.48 +/- 0.15 vs. 0.17 +/- 0.03 (mean +/- SD); P less than 0.05). These data are compatible with the theory of absorption atelectasis. This study documents the usefulness of the inert gas elimination technique for studying pulmonary gas exchange problems in small animals.

Animals↗
PubMed1979

Lung development in the fetal primate Macaca nemestrina. III. HMD.

Delivery of M. nemestrina at 80% of normal gestation provides a population of neonates at high risk for hyaline membrane disease (HMD). The diagnosis of HMD was made by the presence of reticulogranular densities and air bronchograms on chest radiographs. Patchy atelectasis was seen in the lungs of animals assigned by clinical and radiographic criteria to the HMD group and not in the normal lungs of animals matched for gestational and postnatal age. Total phospholipid and phosphatidylcholine in whole lung, airway lavage fluid, and surface-active materials were lower in animals with HMD. Amniotic fluid L/S ratios were lower in the group that developed HMD. Pressure-volume measurements indicated decreased distensibility and unstable terminal air spaces in the HMD group. Alveolar-arterial oxygen pressure differences were greater in animals with HMD. There were no differences between HMD and normal groups in body weight, lung weight, percent dry lung weight, gestational age, and postnatal age at death. This primate species, subjected to premature delivery, is a suitable animal model of HMD in human neonates.

Amniotic Fluid↗
PubMed1977

Ventilatory response in the fetal lamb following peripheral chemodenervation.

Carotid infusions of sodium cyanide solution and perfusions of hypoxemic or hypercapnic fetal blood were done before and after peripheral chemoreceptor denervation. Step changes in PaO2 ranged from -11 to -22 Torr; step changes in PaCO2 ranged from +17 to +42 Torr. The cyanide dose was 0.2 mg/kg per loop system. Control perfusions consisted of 25 ml of fetal blood without changes in pH and blood gases. A ventilatory response occurred in the majority of all experimental perfusions regardless of innervation status of the peripheral chemoreceptors. No response occurred with control perfusions. There was a marked variability in the time of onset of ventilatory activity with a delay of greater than 10 s occurring following most perfusions. These studies demonstrate that the fetus has an attenuated ventilatory response to chemical stimuli and that hypoxia stimulates ventilation in the absence of peripheral chemoreceptors.

Animals↗
PubMed1977

Retrolental fibroplasia and factors influencing oxygen transport.

The hospital records of 58 premature infants in whom proliferative retrolental fibroplasia (RLF) developed were matched with the records of 58 infants without RLF for birth weight, gestational age, and duration oxygen therapy. The two groups were compared for factors likely to influence tissue delivery of oxygen by blood. No significant difference was found in incidence of blood transfusions or exchange transfusions, use of phototherapy, or occurrence of acidosis.

Acidosis↗
PubMed1976

Application of the hot-wire anemometer to respiratory measurements in small animal.

A hot-wire anemometer was evaluated to determine its suitability for measurement of small tidal volumes. Used with a constant background flow of gas, the output of the hot-wire anemometer was linear and independent of respiratory frequency, temperature, and humidity. The change in output with CO2 concentration was negligible within the physiologic range. The use of a background flow eliminates the need for one-way valves, minimizes dead space, and maintains the flow velocity past the hot wire within its range of linear response.

Animals↗
PubMed1976

Is continuous transpulmonary pressure better than conventional respiratory management of hyaline membrane disease? A controlled study.

The influence of continuous positive airway pressure (CPAP) and positive end-expiratory pressure (PEEP) on mortality and complication rates in severe hyaline membrane disease (HMD) was evaluated in a randomized, prospective study. Patients were admitted to the study if the Po2 was less than 50 mm Hg with FiO2 greater than 0.6. Twenty-four patients in each of three weight groups were equally divided between treatment and control groups. The treatment regimen included CPAP (6 to 14 cm H2O) for spontaneously breathing patients and PEEP for patients requiring mechanical ventilation for apnea or hypercapnia (Pco2 greater than 65 mm Hg). Control patients received oxygen and were mechanically ventilated if they had apnea, hypercapnia, or Po2 less than 50 mm Hg with FiO2 greater than 0.8. Oxygenation improved after the start of CPAP or PEEP; however, Pco2 rose after CPAP was initiated. There was no significant difference between treatment and control groups in mortality, requirement for mechanical ventilation, or incidence of pulmonary sequelae. The incidence of pulmonary air-leak was increased with Peep. the findings suggest that CPAP and PEEP have not significantly altered the outcome of HMD.

Carbon Dioxide↗