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Biomedical subjects

W F Powers

Publications and source records attributed to W F Powers.

10 recordsLinked to original sources
PubMed1991

Improved neonatal survival following multiple doses of bovine surfactant in very premature neonates at risk for respiratory distress syndrome.

To determine whether multiple doses of bovine surfactant would improve neonatal mortality in very premature neonates, we conducted two multicenter controlled trials under identical protocols; the results were combined for analysis. Four hundred and thirty neonates born between 23 and 29 weeks gestation and weighing 600 to 1250 g at birth were assigned randomly at birth to receive either 100 mg of phospholipids/kg of Survanta, a modified bovine surfactant (n = 210), or a sham air placebo (n = 220) within 15 minutes of birth. Neonates who developed respiratory distress syndrome and required mechanical ventilation with at least 30% oxygen could be given up to three more doses in the first 48 hours after birth. Dosing was performed by investigators not involved in the clinical care of the neonates; nursery staff were kept blinded as to the treatment assignment. Cause of death was determined by a panel of three independent, board-certified neonatologists after blindly reviewing case report forms and autopsy reports. Fewer Survanta-treated neonates died of any cause (11.4% vs 18.8%, P = .031), died of respiratory distress syndrome (1.9% vs 15.6%, P less than .001), and either died or developed bronchopulmonary dysplasia due to respiratory distress syndrome (39.5% vs 49.1%, P = .044). The incidence of respiratory distress syndrome was also lower in Survanta-treated neonates (28.0% vs 56.9%, P less than .001), and the Survanta-treated neonates' oxygenation and ventilatory status were improved significantly at 72 hours. Survanta-treated neonates were also at lowered risk of developing pulmonary interstitial emphysema (23.3% vs 36.9%, P = .002) and other forms of pulmonary air leaks (9.6% vs 20.8%, P .002).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1979

Bed rest in twin pregnancy: identification of a critical period and its cost implications.

Since twin pregnancies often result in poor perinatal outcomes, many physicians advise prolonged bed rest. Recommendations concerning the timing of bed rest conflict and are made with little assessment of costs. This review of twin pregnancies in the North Central Illinois perinatal region establishes that twins are most vulnerable if they are born between 27 and 34 weeks' gestation. If bed rest is to be imposed, it probably should be timed so as to influence this vulnerable period. Intervention (bed rest in the hospital from 27 to 34 weeks' gestation) would cost between $5,720 and $6,909 per twin pregnancy, whereas nonintervention (intensive care nursery charges for infants born before 34 weeks' completed gestation) would cost $1,689 per twin pregnancy. Before intervention can be universally advocated and costs of this magnitude incurred, a prospective controlled trial to determine the efficacy of bed rest in twin pregnancy is mandatory.

Bed Rest↗
PubMed1977

Diminished limb blood flow in infants with transposition of the great vessels: An adaptation to chronic hypoxia?

Calf blood flow was measured by venous occlusion plethysmography using a mercury in rubber strain gauge in infants with transposition of the great vessels. (TGV), and in comparable infants free from cardiopulmonary disease. Resting calf blood flow in the infants with TGV was 3.6 +/- 0.8 ml/100 ml/min, while in the control group flow was 6.8 +/- 2.3 ml/100 ml/min, a highly significant difference. We postulate that newborns with TGV decrease their resting calf flow in response to chronic hypoxia.

Birth Weight↗
PubMed1975

The peripheral hemodynamic effects of continuous positive transpulmonary pressure breathing in neonates free from cardiorespiratory disease.

We applied continuous positive transpulmonary pressure (CPTP) by face mask to 22 spontaneously breathing infants who were free from cardiorespiratory disease, and measured resultant changes in peak esophageal pressure (Pes) and peripheral perfusion (Q1). We measured Pes by balloon and transducer, and Q1 by venous occlusion plethysmography with a mercury-in-rubber strain gauge. Application of 7.6 cm H2O CPTP led to a 13% decrease in Q1 (paired t-test=2.39; P less than .02). Thirty-two percent of the applied CPTP was detected as a change in Pes. The biological significance of a 13% decrease in peripheral perfusion is probably minimal.

Blood Circulation↗
PubMed1975

Limb blood flow following umbilical arterial catheterization.

Stimulated blood flow was measured in the legs of 28 infants who had undergone umbilical arterial catheterization in the neonatal period. Catheter tips were positioned in the region of the aortic bifurcation, and only an isotonic saline/dextrose solution was continuously pumped through the catheter. The catheters were in place for an average of 58.3 hours (range, 4 to 144), and the infants were studied between 29 and 135 days of age (mean, 67 days). Blood flow in both legs was measured simultaneously by venous occlusion plethysmography using a mercury-in-rubber strain gauge. Analysis of peak stimulated blood flow in each leg and simultaneous flow in the opposite leg showed no difference between flow in the leg whose iliac artery had been catheterized in the neonatal period and flow in the opposite leg (paired t-test equal 0.17; P greater.50). No chronic, subclinical flow deficiencies of umbilical arterial catheterization were demonstrable. We see no new reason to curtail the judicious use of the umbilical artery catheter.

Blood Flow Velocity↗