Levels of Catecholamines, Arginine Vasopressin and Atrial Natriuretic Peptide in Hypotensive Extremely Low Birth Weight Infants in the First 24 Hours after Birth

Abstract

Background: Extremely low birth weight infants (ELBWI) often suffer from severe hypotension in the early neonatal period. However, few previous studies have ever revealed plasma levels of vasoactive substances which regulate the cardiovascular system in ELBWI. Objective: To study plasma levels of vasoactive substances in ELBWI with hypotension during the first 24 h of life. Methods: 22 ELBWI with hypotension (gestational age 26.4 ± 1.9 weeks; birth weight 751 ± 135 g) were involved in the study. After initial volume therapy, the infants were arbitrarily divided into two groups depending on requirement of dopamine dosage: severe hypotension group (SH; dopamine >10 μg/kg/min, n = 9) and mild hypotension group (MH; dopamine ≤10 μg/kg/min, n = 13). Plasma levels of dopamine, norepinephrine, epinephrine, arginine vasopressin, and atrial natriuretic peptide were measured at admission and at 24 h after birth. Results: Infants in the SH group had higher plasma dopamine than infants in the MH group both at admission (median; range: 14,410; 224–46,770 vs. 7,900; 32–21,220 pg/ml, p < 0.05) and at 24 h (80,920; 494–146,100 vs. 25,680; 10,130–63,180 pg/ml; p < 0.05). The norepinephrine/dopamine ratio (median; range) was lower in the SH group than in the MH group at admission (0.3; 0.0–1.0 vs. 1.1; 0.1–25.1; p < 0.01). Plasma levels of atrial natriuretic peptide or arginine vasopressin were not different between the two groups. Conclusions: ELBWI with SH may have decreased conversion of dopamine to norepinephrine. We speculate that this mechanism may contribute to development of SH in ELBWI.

Vasopressin for Refractory Hypotension in Extremely Low Birth Weight Infants

“…In preterm infants with low blood pressure, plasma vasopressin levels may be consistent with relative vasopressin deficiency in shock conditions. 10,11 …”

Physiology of Transition from Intrauterine to Extrauterine Life

“…Much of this work could be profitably repeated for extremely low birth weight infants to better understand how their catecholamines responses to preterm birth may be dysregulated and to better target therapies. For example, Ezaki and colleagues recently reported that very low birth weight infants with severe hypotension had a decreased conversion of dopamine to norepinephrine (13). …”

Evaluation and Treatment of Hypotension in Premature Infants

“…This suggested that there was successful conversion of NE to E. In infants who did not need high doses of dopamine, there was a similar correlation between conversion of DOA to NE before and 24 hours after administration of dopamine. However, no correlation was found in infants who needed high doses of dopamine, suggesting that the conversion from DOA to NE was limited (Ezaki et al, 2009b) (Fig.7). Therefore, an understanding of the underlying pathological condition is important when administering catecholamines.…”

“…In extremely low birth-weight infants with hypotension, those in need of high doses of dopamine (DOA>10μg/kg/min) already had high levels of endogenous dopamine compared to those needing low doses of dopamine (DOA <10μg/kg/min) (p<0.05) (Ezaki et al, 2009b). The ratio of conversion from NE to E before the use of dopamine and 24 hours after administration were correlated in both infants who needed high doses of dopamine and in those who did not.…”