Multicenter controlled trial comparing high-frequency jet ventilation and conventional mechanical ventilation in newborn infants with pulmonary interstitial emphysema.

One hundred forty-four newborn infants with pulmonary interstitial emphysema were stratified by weight and severity of illness, and randomly assigned to receive treatment with high-frequency jet ventilation (HFJV) or rapid-rate conventional mechanical ventilation (CV) with short inspiratory time. If criteria for treatment failure were met, crossover to the alternate ventilatory mode was permitted. Overall, 45 (61%) of 74 infants met treatment success criteria with HFJV compared with 26 (37%) of 70 treated with CV (p less than 0.01). Eighty-four percent of patients who crossed over from CV to HFJV initially responded to the new treatment, and 45% ultimately met success criteria on HFJV. In contrast, only 9% of those who crossed over from HFJV to CV responded well to CV (p less than 0.01), and the same 9% ultimately met success criteria (p less than 0.05). Therapy with HFJV resulted in improved ventilation at lower peak and mean airway pressures, as well as more rapid radiographic improvement of pulmonary interstitial emphysema, in comparison with rapid-rate CV. Survival by original assignment was identical. When survival resulting from rescue by the alternate therapy in crossover patients was excluded, the survival rate was 64.9% for HFJV, compared with 47.1% for CV (p less than 0.05). The incidence of chronic lung disease, intraventricular hemorrhage, patent ductus arteriosus, airway obstruction, and new air leak was similar in both groups. We conclude that HFJV, as used in this study, is safe and is more effective than rapid-rate CV in the treatment of newborn infants with pulmonary interstitial emphysema.

Prostaglandin formation in the isolated human ductus arteriosus, aorta, pulmonary and umbilical arteries.

The prostaglandins comprise a large family of substances that includes primary prostaglandins, prostacyclin and thromboxane, all of which exhibit some vascular activity. The activity of each prostaglandin may be species - and organ - dependent, and the type of prostaglandin produced in a tissue is often dependent on the presence of terminal enzyme systems in that tissue. The prostaglandin endoperoxide PGH2 serves as a common intermediate for the enzymatic production of prostaglandins, thromboxanes and prostacyclin. We have obtained information on the biosynthesis of these compounds by the human ductus arteriosus, aorta, pulmonary and umbilical arteries in vitro. Vascular tissue samples were obtained from two fetuses of 16 to 18 weeks of gestation, two newborns of 26 and 35 weeks of gestation and in nine term infants. The vascular tissue samples were incubated with [1-14C]-arachidonic acid and/or [1-14C]-prostaglandin endoperoxide (PGH2). The study demonstrates the formation of prostaglandins and prostacyclins from all the vascular tissues and the formation of thromboxanes from the umbilical artery. The study implies that the above vessels contain "prostaglandin synthetase" enzymes as early as 16 weeks of gestation.

Myofibrillar protein degradation in premature infants with respiratory distress as assessed by 3-methylhistidine and creatinine excretions.

The skeletal muscle content of 3-methylhistidine has been measured in two fetuses and four infants of 15 to 38 wk of gestation. The average concentration of skeletal muscle 3-methylhistidine is 1.11, 2.64, and 3.28 (mumol/mixed protein) for fetuses of 15 to 18 of gestation and infants of 26 to 32 and 37 to 38 wk of gestation, respectively. Myofibrillar protein degradation has been measured by the rate of 3-methylhistidine excretion in premature infants suffering from respiratory distress and weighing between 1310 and 2420 g. In 26 balance studies in six infants, total muscle protein breakdown varied from 0.92 to 1.58 g day-1 kg-1 body weight. Calculated fractional catabolism of myofibrillar protein varied from 0.38 to 1.07% per day. A trend toward a higher rate of myofibrillar protein degradation is noted during the infants' acute illness and during their rapid growing phase.