Summary In order to elucidate the mechanism by which phototherapy induces loose stools in newborns, studies were performed on the speed of gut transit by performing the Carmine Red test on normal newborn, on jaundiced newborns before and after phototherapy. A statistically accelerated intestinal transit was observed in jaundiced newborns treated with phototherapy. The increased rate of intestinal transit produced by phototherapy is probably due to the action of the photo‐decomposition derivatives of bilirubin, which are excreted during phototherapy.

One hundred and ten full-term newborns were treated with integral phototherapy (IP) in the first week of life for hyperbilirubinemia (peak bilirubin concentration, 19.5 +/- 2.8 mg/dl). IP was provided by an apparatus which irradiated the infants over the entire skin surface with four visible blue light lamps placed around the body at a mean distance of only 20 cm. The irradiance of the lamps at the skin surface was 0.350 mW/sq cm, in the wavelength range between 425 and 475 nm. The IP resulted in a 48-hour bilirubin decline rate of 0.163 mg/dl/h. After a mean exposure of 78 +/- 32 h, the mean plasma bilirubin level was 8.4 +/- 0.8 mg/dl. One hundred and ten comparable nonjaundiced infants were studied as controls. At 6 years of age, both groups of subjects were called for a follow-up concerning growth, visual, and hearing functions, and neuro-developmental status. The follow-up was completed in 81 children of the IP group (73.6%) and in 89 of the controls (80.6%). There were no significant differences in the studied parameters between the two groups. The study concludes that IP appears to be an effective and safe treatment for jaundiced infants. IP employs less radiant energy from the lamp source than the traditional apparatus, but delivers this energy to a larger skin surface area.

BSP clearance from the plasma was studied during phototherapy in a group of jaundiced newborns. This therapy did not have any influence on the plasma dye disappearance curve. The obtained results are consistent with the hypothesis that this therapy causes the photodegradation of bilirubin, and that the increased excretion of unconjugated bilirubin is not mediated by a generalized enhancement of the hepatic output.

Catheterization of the umbilical artery for the treatment of critically ill neonates provides a convenient method for monitoring blood gas tension and chemistry. The most important complications are thrombotic. Thirty eight aortographs were carried out in infants who underwent umbilical artery catheterization. 17/38 of the aortographs were pathological. Bacterial cultures were positive in 11/17, but only 4 coincided with pathological aortographs. Clinical signs indicating complications due to the presence of the catheter wwere observed in 10 cases. Post-mortem examination of eight subjects--three of whom had pathological aortographs--during the course of the investigation revealed only one case of thrombosis. This baby was considered to have died as a direct result of a thrombotic complication. In our experience the clinical signs of vascular complications and evaluation of the peripheral circulation in the ipsilateral leg remain the most important ways of assessing the indication for catheter-withdrawal.

The process of conjugation and secretion of bilirubin was studied in a group of healthy, full-term, exclusively breast-fed newborns and a control group of exclusively formula-fed infants by means of a reverse-phase high-performance liquid chromatographic analysis of bilirubins present in serum. The serum concentrations of unconjugated bilirubin, esterified bilirubin, and the proportion of diesterified bilirubin (as percent of esterified bilirubin) were not significantly different in breast- and formula-fed infants on the 3rd and 5th days of life. These data suggest that both bilirubin production and conjugation are not different in breast-fed and in formula-fed newborns.