Arterio-venous differences in cord levels of catecholamines, glucose, lactate and blood gases.

BACKGROUND: Norepinephrine (NE) and epinephrine (EPI) levels are higher in cord arterial blood relative to venous blood, consistent with active mechanisms of placental-maternal clearance. There are no contemporary studies of cord arteriovenous blood levels of sulfated and non-sulfated catechols. AIM: To assess the arteriovenous differences in cord blood levels of dopamine (DA), the sulfated catecholamines and their sulfated and non-sulfated metabolites. To correlate levels of oxygen, H+/CO2, and glucose with cord catecholamine levels. METHODS: Fifty-seven term infants, delivered by elective cesarean section, were recruited. Cord arterial and venous blood was sampled; levels of glucose, lactate, blood gases, six catechols and their sulfated conjugates were measured. RESULTS: With one exception (DOPA sulfate), mean cord arterial levels of sulfated and non-sulfated catechols were significantly higher than venous levels. Arterial lactate and glucose levels were independently associated with NE levels, but only lactate was associated with levels of EPI and DA. CONCLUSION: This study establishes that in vivo metabolic parameters of hypoxia, respiratory and metabolic acidosis are associated with catecholamine levels, a key relationship for perinatal adaptation and homeostasis, and findings that are consistent with in vitro studies of the regulators of catecholamine secretion.

Cohort study of the decision to delivery interval and neonatal outcome for emergency operative vaginal delivery.

OBJECTIVE: The purpose of this study was to assess whether a target decision to delivery interval (DDI) is appropriate for 'emergency' operative vaginal delivery and whether this would reduce adverse neonatal outcomes. STUDY DESIGN: We performed a retrospective cohort study of 1021 singleton term babies who experienced operative delivery for 'fetal distress' in the second stage of labor between 1998 and 2003 in Dundee, Scotland. RESULTS: The mean DDI in a labor room was 14.5 minutes (SD 9.5) compared to 30.0 minutes (SD 14.6) in an operating room. Shorter DDIs were associated with use of local rather than regional or general anesthesia. There were no significant differences in rates of low Apgar score (< 7 at 5 min) OR 0.99 (95% CI 0.27, 3.71), fetal acidosis (pH < 7.10) OR 1.24 (0.78, 1.99), neonatal resuscitation OR 1.00 (95% CI 0.65, 1.53), or admission to NICU OR 0.53 (95% CI 0.27, 1.03) for babies delivered within 15 minutes compared to greater than 15 minutes. The outcomes were similar for a 30-minute threshold. The DDIs for forceps and vacuum deliveries were similar as were neonatal outcomes. CONCLUSION: A DDI of 15 minutes is an achievable target for operative vaginal delivery in a labor room with 30 minutes for delivery in an operating room; however, setting arbitrary limits is unlikely in itself to prevent adverse neonatal outcomes.

Glucose homeostasis in the newborn.

Hepatic glucose production by glycogenolysis and gluconeogenesis is essential to maintain blood glucose levels, and the glucose-6-phosphatase system catalyses the terminal step of both pathways. Developmental delays in the postnatal up-regulation of hepatic glucose-6-phosphatase enzyme activity are common in preterm infants. Two groups of infants have been identified with failure of developmental regulation of glucose homeostasis. Firstly, up to 20% of preterm infants about to be discharged home are at risk of hypoglycaemia if a feed is delayed. Cortisol, corticotrophin and epinephrine levels are higher in the infants with severe and persistent hypoglycaemia, but insulin, glucagon and human growth hormone do not differ from normoglycaemic infants. Secondly, preterm infants with an inadequate glycaemic response to glucagon (30% at the time of discharge home) have relative fasting hyperglycaemia, hyperinsulinaemia, increased insulin:glucagon ratios and a lower insulin sensitivity index. Hormonal dysfunctions in preterm infants may contribute to failures in postnatal expression of hepatic enzymes.