Can anesthesiologic strategies for caesarean section influence newborn jaundice? A retrospective and prospective study.

RATIONALE AND OBJECTIVES: Neonatal jaundice is a frequent problem in neonatology and can be influenced by many factors. Our study arose from the clinical observation that among all newborns delivered by caesarean section in our center, some had a more intense physiological jaundice. We began by reviewing clinical anesthesiological case-sheets to ascertain whether this difference was linked to the use of different anesthesiologic strategies. We then performed a prospective study on healthy preterm and term newborns to verify this hypothesis. STUDY DESIGN: We retrospectively considered all healthy term newborns with weight > 2,400 g delivered by caesarean section from January 1998 to May 1999. In the prospective studies we included healthy term and preterm newborns consecutively delivered by caesarean section from May 1999 to December 1999. We excluded preterm newborns with gestational age < 31 weeks and with weight < 1,400 g. RESULTS: Both in retrospective and in prospective studies anesthetic agents employed were isoflurane (A), sevoflurane (B), or bupivacaine (C). The statistical comparison of the three groups in retrospective study confirmed the clinical observation: the total bilirubin levels were significantly higher in the isoflurane group than in the sevoflurane group (p = 0.0000) and bupivacaine group (p = 0.0002). Analysis of data from the prospective study on term newborns confirmed our previous results. In preterm infants total bilirubin is statistically higher in group A starting from 96 h postdelivery. CONCLUSIONS: It is likely that anesthetic technique can be included among factors with possible influence on neonatal jaundice.

Immunophenotypic changes of fetal cord blood hematopoietic progenitor cells during gestation.

We measured cell surface expression of CD34, HLA-DR, CD38, CD19, CD33, CD71, and CD45 antigens in the hematopoietic progenitor cells of fetal cord blood to investigate immunophenotypic changes at different gestational ages. These antigens were identified by flow cytometry in 11 fetuses (gestational age 19-24 wk, in 12 preterm (25-28 wk) and in ten newborn infants born at term. The frequency and number of CD34+ cells were higher in the blood of the 11 fetuses; in addition, a statistically significant inverse correlation between number of CD34+ cells and advancing gestational age was noted. The numbers of CD34+ CD19+, CD34+ CD33+, and CD34+ CD45+ coexpressing cells were significantly higher in the fetuses, whereas CD34+ CD38+ cells were more represented in the neonates at term. Gestational age was inversely correlated with the number of CD34+ CD19+ and CD34+ CD33+ coexpressing cells. A positive correlation between gestational age and CD34+ CD38+ cells was noted. The number of CD34- CD19+, CD34- CD38+, and CD34- CD45+ cells was higher in term infants; furthermore, a significant correlation between advancing gestational age and CD34- CD38+ or CD34- CD45+ cells was demonstrated. The proliferative capacity was also higher at lower gestational ages. These data suggest that the development and lineage commitment of fetal cord blood hematopoietic progenitor cells are very active during the last two trimesters of pregnancy. The most significant changes of hematopoietic cells maturation seem to occur within 25 wk of gestation.

Leukocyte counts in relation to the method of delivery during the first five days of life.

The goal of the present study was to evaluate total and differential leukocyte counts during the first 5 days of life in relation to the method of delivery. We included 203 healthy term infants; of these, 114 were born by vaginal delivery, and 89 by elective cesarean section. Total and differential leukocyte counts were evaluated at the following intervals: 0-6, 7-12, 13-24, 25-48, 49-72, 73-96, and 97-120 h after birth. The cord serum cortisol level was measured as an indicator of the degree of delivery-related stress. Mean leukocyte and neutrophil counts were higher in infants born by vaginal delivery in cord blood and up to 12 h of life. No significant differences were observed in the immature: total neutrophil ratios between the two groups of infants. The cord serum cortisol level was higher in vaginally delivered infants. A significant correlation was found between cortisol and leukocyte, neutrophil, or lymphocyte counts. The method of delivery produces significantly different total leukocyte and neutrophil counts during the first 12 h after birth; after this time, there appears to be no more variation of leukocyte counts during the first 5 days of life.

Effects of adenosine on NANC bronchoconstriction in anaesthetized guinea-pigs.

The present work assesses the effects of the acute administration of adenosine on tachykinergic bronchoconstriction induced in different ways (exogenously administered capsaicin or substance P and vagal electrical stimulation) in anaesthetized and curarized guinea-pigs. Adenosine (30-3000 micrograms kg-1, i.v.) enhanced significantly and dose-relatedly the airway narrowing induced by a single dose of capsaicin (0.5-2 micrograms kg-1, i.v.), both in normal and in vagotomized animals. A smaller and less dose-dependent enhancement by the nucleoside of the pulmonary resistance increase induced by substance P (5-15 micrograms kg-1, i.v.) was observed. This effect was almost completely prevented by the H1 antagonist diphenhydramine (1 mg kg-1, i.v.), which also unmasked an inhibitory action of adenosine at the highest doses. Diphenhydramine, on the contrary, did not significantly modify the potentiation by adenosine of capsaicin-mediated bronchoconstriction. Finally, the nucleoside dose-dependently inhibited the atropine-resistant bronchospasm following vagal electrical stimulation. The use of the selective adenosinic agonists R-N6-[2-phenylisopropyl]adenosine (1-100 micrograms kg-1, i.v.) and 5'-N-methylcarboxamidoadenosine (1-100 micrograms kg-1, i.v.) before the administration of capsaicin, revealed the ability of the first to reproduce the enhancement induced by adenosine, while the second had an inhibitory effect. It is concluded that adenosine has both excitatory and inhibitory modulatory effects on airway responsiveness to excitatory non-adrenergic non-cholinergic (e-NANC) stimuli. The excitatory effects, revealed with substance P and capsaicin, support the hypothesis that adenosine may play a role as an asthma mediator.