Fentanyl-induced chest wall rigidity and laryngospasm in preterm and term infants.

OBJECTIVE: To assess the occurrence of muscle rigidity after fentanyl administration in premature and term neonates. DESIGN: Prospective case series, observational study. SETTING: A university hospital neonatal intensive care unit. PATIENTS: 8/89 preterm and term infants (25-40 wks gestational age) who received fentanyl for perioperative analgesia and sedation or intensive care procedures. INTERVENTIONS: Mechanical or bag mask ventilation and antagonization with naloxone. MEASUREMENTS AND MAIN RESULTS: We observed chest wall rigidity in 8 patients after low dosage of fentanyl (3-5 microg/kg body weight). All patients presented with respiratory distress, hypercapnia, and hypoxemia leading to bradycardia. In two patients, laryngospasm was noted and associated with muscle rigidity, thus making intubation impossible. Naloxone (20-40 microg/kg body weight) reversed the laryngospasm and muscle rigidity immediately, allowing restitution within 1 min. In our patient population, we found fentanyl-induced chest wall rigidity in 4% of neonates after fentanyl administration. CONCLUSION: Even low doses of fentanyl can lead to thoracic rigidity in neonates. Additionally, we observed laryngospasm in two patients and speculate that it might be a variant of muscle rigidity.

Oestrogen formation in genital and non-genital skin fibroblasts cultured from patients with hypospadias.

OBJECTIVE: Hypospadias is the most common birth defect in males. In most cases the aetiology is unknown. Since penile development is androgen dependent and oestrogen can modify androgen action, we compared the formation of oestrogen in penile tissue from patients with hypospadias to those with normal penile development. DESIGN AND PATIENTS: Oestrogen formation was assessed in fibroblast monolayers grown from biopsies of genital and non-genital skin from 11 males with normal genital development (controls) and 18 males with severe hypospadias utilizing the incorporation of tritium into H2O resulting from the aromatization of 1 beta-3H-androstenedione. RESULTS: In paired fibroblast strains from genital and non-genital skin of nine males with hypospadias, oestrogen formation was significantly (P < 0.025) lower in non-genital skin. Rates of oestrogen formation were also higher in a subset of foreskins from subjects with hypospadias than in normal controls and the remaining hypospadias subjects. In addition, oestrogen formation in this subset of fibroblast strains from patients with hypospadias was markedly enhanced by incubation of intact monolayers with either cholera toxin or forskolin, agents known to stimulate cAMP formation. Oestrogen formation in the remaining cell strains (controls and hypospadias) was also enhanced in most instances by cholera toxin and forskolin, although to a much lower degree. Thus, we identified in the hypospadias group a subgroup of fibroblast strains in which unstimulated and stimulated oestrogen formation was markedly higher than in other strains examined. CONCLUSIONS: Since oestrogen can modify certain androgen effects within cells and since formation of the male genitalia during embryogenesis is mediated by androgens, elevated oestrogen formation in male genital tissue might be a causative factor of hypospadias in some instances.

Agenesis of the ductus venosus and its correlation to hydrops fetalis.

Absence of the ductus venosus is a rare vascular anomaly. We report a late onset of a hydrops fetalis seen in a fetus at 34 completed weeks of gestation. A persistence of the cranial parts of the left and right umbilical veins and of the paired cranial vitelline veins with an absent ductus venosus led to a bilateral hydrothorax, ascites and skin-edema. Postnatally the hydrops resolved within 7 days most probably due to the change from the fetal to the adult circulation. The abnormal venous system was confirmed by angiography. Agenesis of the ductus venosus can manifest in two different morphologic patterns: The umbilical vein drains exclusively into the left branch of the intrahepatic portal vein or the umbilical vein drains into the inferior vena cava or directly into the right atrium by-passing the liver completely. In both patterns, the preferential direction of the flow towards the foramen ovale is not present. While the first pattern leads to hyperperfusion of the liver parenchyma, the latter would result in reduced perfusion and oxygenation. Our findings suggest that agenesis of ductus venosus might induce hydrops fetalis. We conclude, that in every case of hydrops fetalis the venous system should be evaluated by ultrasonography prenatally and/or immediately postnatally.

Measurements of sodium and potassium in newborns and prematures by ion-selective electrodes and flame photometry: influence of lipid and protein content of blood.

The alternative use of flame photometry and ion selective electrodes for electrolyte determinations in neonatology led to the question how the two methods agree. 104 routine blood samples were taken as matched pairs for a comparison of sodium and potassium determinations. Pre-analytical error was avoided by the mode of blood collection. The influence of the protein and lipid content of blood on the differences between the methods was determined by calculating its water content and making a post-correction of the flame values. Thus the differences for sodium could be reduced, whereas the differences for potassium slightly increased. As long as the imprecision of sodium determination is a meaningful methodological problem, the influence of the protein and lipid content of neonatal blood is not the main factor for differences between ISE and flame photometry.

CT imaging of pulmonary lobar interstitial emphysema in a spontaneous breathing preterm infant.

Pulmonary interstitial emphysema (PIE) is a well-recognized severe complication of neonatal respiratory distress syndrome (RDS). However, its occurrence under spontaneous breathing conditions has been described rarely. We present a case of PIE of the left upper lung lobe in an extremely low birth weight infant. Recurrent episodes of spontaneous pneumothorax led to the diagnosis, which was confirmed by histopathology. Plain chest X-ray did not show typical signs of PIE, whereas extra-alveolar air accumulation could be visualized by helical computed tomography (CT)-scan. We stress the role of predispositional factors increasing the risk of PIE development in spontaneous breathing preterm infants.