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.