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Occlusion of a major artery may occur in a newborn as a result of catheter placement, particularly an indwelling catheter, in the heart or umbilical artery. Primary occlusion of a major artery (unrelated to catheterization) is a rare occurrence. Two cases are presented describing arterial occlusion in male infants. In both cases the condition was diagnosed within days of birth, one baby had occlusion of the right femoral (thigh) artery, the other had occlusion of the left iliac artery (the groin area). Both infants were born at full term after uncomplicated pregnancies, and their mothers were in good health. In the first case, a slight decreased in the fetal heart rate was noted one week before birth. Soon after birth the infant appeared to have complete lack of blood flow to the left leg, which was cold and sensitive to touch. In the second case, the baby was observed to have a temporary loss of color in the right leg when he was four days old; this occurred with increasing frequency and by the seventh day he had no pulse in the right foot. In both cases Doppler studies (an ultrasound technique used to monitor blood flow) were used for diagnosis and monitoring; angiography (X-ray examination of the blood vessels following injection of radiopaque contrast dye) confirmed arterial occlusion and the success of treatment. Despite the usual recommendation that occlusion of a major artery be treated with emergency surgery, these infants were successfully treated medically by continuous infusion of urokinase (a thrombolytic agent) and verapamil (a vasodilator). In one case it was necessary to deliver the urokinase directly to the area of obstruction. Good blood supply to the leg was confirmed by Doppler. The causes of this condition are not clearly known. (Consumer Summary produced by Reliance Medical Information, Inc.)

Surfactants were labeled in vivo with 3H choline and the large aggregates of the surfactant were recovered by alveolar wash and centrifugation. The labeled natural surfactants from rabbit, sheep, cat, and pig were injected into the airways of 3-day-old rabbits, and the percent recoveries of the labeled surfactant-associated phosphatidylcholine were measured in alveolar washes, lung tissue after alveolar wash, and in the lungs (alveolar wash plus lung tissue). The rabbit surfactant-associated phosphatidylcholine was cleared from the lungs at a constant 15.6 ± 1.8 per 24 h (mean ± SE) of the injected doses of surfactant that contained from 0.41 to 10.2 µmol phosphatidylcholine. At all times following injection, approximately 50 of the labeled phosphatidylcholine remaining within the lungs was recovered in the alveolar wash and 50 with the lung tissue. The percent clearances for sheep, cat, and pig surfactant phosphatidylcholine in rabbits were 12.5, 16.6, and 16.3 per 24 h, respectively, values not different from that measured for rabbit surfactant. The results documented a slow clearance of exogenously administered surfactant phosphatidylcholine as a fixed percent of the injected dose that was unchanged by species source of the surfactant.

Premature rabbits delivered by cesarean section at 28 d of gestation were each given intratracheally 75 mgkg of a radiolabeled preparation of either natural rabbit surfactant, natural calf surfactant, or surfactant-TA. Each newborn rabbit was ventilated for up to 6 h in a ventilatorplethysmograph with individual adjustments of peak inspiratory pressures to attain tidal vol of 12-15 mLkg body wt. Dynamic compliances were about 0.7-0.9 mLcm H2O · kg after treatment with the three surfactants and did not deteriorate during the 6-h study. Rabbits were randomly studied at 0.5, 1.5, 3, 4.5, and 6 h of age for the recovery of the labeled surfactant phosphatidylcholine in the total lungs (alveolar wash plus postlavage lung tissue). The labeled phosphatidylcholine was cleared from the total lungs of rabbits treated with natural rabbit or calf surfactants at comparable rates of about 256 h. In contrast, the clearance rate of surfactant-TA phosphatidylcholine from the total lungs was not significantly different from 0. Lipids from rabbit surfactant that had been administered intratracheally were only minimally present in the blood and liver. In other similarly treated rabbits, the lipids from radio labeled rabbit surfactant and liposomes of dipalmitoyphosphatidylcholine that had been injected intravenously were recovered in blood and liver in substantial quantities. These studies documented significant losses of rabbit and calf surfactant phosphatidylcholine but not surfactant- TA phosphatidylcholine from the lungs of preterm ventilated rabbits. The losses were not explained by surfactant losses to the vascular compartment

Rabbit fetuses were delivered by hysterotomy on day 27 or 28 of gestation. Immediately after birth, the animals were tracheotomized and received by intravenous injection 0.2 µCi radiolabeled albumin and 11 mg iron dextran in 0.2 ml saline. The newborn rabbits then were ventilated artificially with a tidal vol of 12 mlkg for 5–20 min. One group of nonventilated animals served as controls. At the end of the experiment, one lung was lavaged via the airways and the other was fixed for histologic examination. The recovery of labeled albumin and iron dextran in the lavage fluid was quantified. Iron dextran complexes were easily identified in the lung sections by staining with Prussian blue. Iron dextran accumulated in the airspaces of animals delivered on day 27 (about 4 of the injected dose during 10–20 min of ventilation). The albumin leakage was slightly higher than that of the dextran, a result consistent with different mol wt of the markers. The vol density of leaking alveoli in histologic sections increased with time, from 0 at birth to a mean value of 0.36 after 20 min of ventilation. The leakage starts as a focal event, gradually involving more and more terminal airspaces. In the histologic sections, there was no indication of a significant leakage at the bronchiolar level, although the epithelium of terminal and preterminal airways was clearly injured in all ventilated animals.