Urinary Arginine Vasopressin: Pattern of Excretion in the Neonatal Period

Abstract

ABSTRACT. The pattern of arginine vasopressin (AVP) secretion in the immediate neonatal period is unclear. Plasma concentrations of AVP are reflected by its urinary excretion, thus providing a noninvasive method for studying the pattern of AVP release in the neonate. In these studies, we determined the pattern of urinary AVP excretion (pU/ mg creatinine) during the first 2-4 days after birth in 78 neonates, 53 of whom had various prenatal and/or neonatal complications. In well term ( n = 12) and preterm (n = 13) infants mean urinary AVP excretion decreased gradually during the first 24-36 h after birth. Although term and preterm infants with perinatal asphyxia had highest initial levels of urinary A V P (>200 pU/mg creatinine) and a significant negative correlation with the 1-min Apgar score was obtained, their pattern of excretion was similar to respective controls. After delivery, elevated values for urinary AVP excretion were found among infants with neonatal courses complicated by intracranial hemorrhage, hypoxic encephalopathy, and pneumothorax. Urine osmolality did not correlate linearly with urinary AVP levels, but rather attained a maximum value of -400 mosmol/kg at urinary AVP levels <200 pU/mg creatinine and then plateaued. It is concluded that the decrease in urinary AVP excretion observed soon after birth generally reflects diminution of the hypersecretion of AVP during parturition; neonates with evidence of intrapartnm asphyxia initially have increased urinary AVP excretion; however, the pattern of excretion is similar to normal infants. During the neonatal period insults such a s pneumothorax and intracranial hemorrhage may cause hypersecretion of this hormone. (Pediatr Res 20: 103-108, 1986) Abbreviations AVP, arginine vasopressin HMD, hyaline membrane disease Cr, creatinine PV-IVH, periventricular-intraventricular hemorrhage Investigations of AVP, or antidiuretic hormone, during the perinatal period have been focused on both its renal and extrarenal actions. Although its potent pressor effect may be more important than its antidiuretic action during this period of adaptation (I), these and other physiologic roles for AVP remain

The Role of Arginine-Vasopressin in the Regulation of Water Metabolism in Preterm Infants in the First Days of Life

“…Our findings are confirmed by one other study [17], This group, however, used the AVP radioimmunoassay which we devel oped and so further studies with different radioimmunoassay systems should be per formed. In general it can be said that se verely ill newborns with RDS have a great risk of overhydration because of nonosmotic release of AVP.…”

“…Many data have been collected in the last few years to gain a better under standing of the pathophysiology of water me tabolism [8,17]. Renal function, changes in body composition and hormonal influences have been studied to define the term ade quate in regard to fluid management in pre term infants.…”

A Comparison of Arginine Vasopressin Levels and Fluid Balance in the Perinatal Period in Infants Who Did and Did Not Develop Chronic Oxygen Dependency

“…Fetal stress as indicated by meconiumpresent in the amniotic fluid is associated with elevated cord AVP levels [10], but the effect of birth on asphyxia in elevating AVP levels [11] only lasts for the first 2 days [12]. The type of delivery also influences AVP levels [13], vaginal delivery versus caesarean section being associated with higher levels [14].…”

“…In one series [17], comparison of results from three groups of preterm infants demonstrated that those with RDS were unable to excrete the administered fluid, gained weight and developed hyponatraemia. In animal models positive pressure ventilation is also a stimulus for AVP release [18], but the effect of ventilation on AVP levels in the human is debated [3,11,[19][20][21]. In one study [3] continuous sequential urinary arginine vasopressin measurement in 14 preterm ventilated infants demonstrated that AVP levels increased during deterioration of the respiratory illness, mask ventilation and the development of bilateral pneumothoraces or severe intraventricular haemorrhage [3].…”

Renal Response to Vasopressin in Premature Infants: What Is New?

“…A VP Release Recent studies on the pattern of AVP secretion in the immediate neonatal period have shown higher cord plasma AVP con centrations in newborn infants born vaginally than in those delivered by cesarean sec tion [9] and perinatal complication such as asphyxia [27], hypoxic-ischemic encephalop athy [12], intracranial hemorrhage [1], se vere respiratory distress [38], pneumotho rax, pneumonia, atelectasis [20,30], and meningitis [19] have been reported to be associated with elevated plasma and urinary AVP concentrations. The inappropriate se cretion of AVP related to perinatal pathol ogy is thought to be an important cause of the early type of hyponatremia which fre quently occurs in the first week of life [18].…”