AMERICAN JOURNAL OF PERINATOLOGY/VOLUME 9, NUMBER 5/6
Sept/Nov 1992
URINARY ARGININE VASOPRESSIN EXCRETION AND HYPONATREMIA IN THE SICK NEONATES Takatsugu Kojima, M.D., Yuka Isozaki, Yukio Hirata, Shuji Matsuzaki, and Yohnosuke Kobayashi
We attempted to clarify the renal physiologic response to arginine vasopressin (AVP) in the 12 sick neonates: three with respiratory distress syndrome (RDS), three with meconium aspiration syndrome, two with transient tachypnea of the newborn, two with neonatal asphyxia, and two low birthweight infants during the first 2 days of life. Plasma atrial natriuretic factor (ANF), urinary AVP, osmolality, free water clearance and creatinine clearance (Ccr) were measured at 8 to 16 hours of life (stage 1) and 24 to 32 hours of life (stage 2). Urinary AVP was expressed as the ratio of AVP to Ccr (urine AVP/Ccr). These subjects were divided into two groups: group A represented five infants with a urine AVP/ Ccr ratio of 2000 or higher and group B, seven infants with a ratio of less than 2000 at stage 1. Hyponatremia occurred in two infants of group A at stage 2. Number of infants on mechanical ventilation was four in group A and one in group B. There were no significant differences in gestational age, birthweight, Apgar scores at 1 and 5 minutes, blood gas pH and mean arterial blood pressure between groups A and B. A good correlation was observed between logarithm of urine AVP/Ccr ratio and urinary osmolality (p < 0.01). A negative correlation was observed between logarithm of urine AVP/Ccr ratio and free water clearance (p < 0.01). Body weight of infants of group A at stage 2 was greater than at stage 1 (p < 0.05). Higher plasma ANF concentrations were observed in infants of group A at stage 2 when compared with those at stage 1 (p < 0.1). These results suggest that the syndrome of inappropriate excretion of antidiuretic hormone may occur in the early neonatal age.
The posterior pituitary peptide hormone, arginine vasopressin (AVP) is the major antidiuretic hormone in man. Umbilical cord plasma AVP levels are markedly elevated in infants with the evidence of fetal distress and in those delivered vaginally when compared with delivery by cesarean section.1 An increase in plasma AVP concentrations has also been reported in human neonates with respiratory distress syndrome (RDS) and pneumothorax.2 The syndrome of inappropriate excretion of antidiuretic hormone (SIADH) in neonates has been recognized by some authors and has been described in several clinical disorders, including hypoxic-ischemic encephalopathy, intracranial hemorrhage, and pneumothorax.23 Since urinary AVP has been shown to reflect its plasma values closely and the urinary clearance of AVP is approximately 80% of glomerular filtration rate4 (GFR), measurement of urinary excretion of AVP may provide a more accurate estimation of integrated AVP secretion than that of a plasma value.5-6 In the present study we attempted to clarify the physio-
logic effect of AVP on renal function during the first 2 days of life in the sick neonate.
PATIENTS AND METHODS Twelve infants (five boys and seven girls), 32 to 41 weeks of gestation and 1606 to 3650 gm birthweight, were the subjects of the study. Informed consent was obtained from each patient's parents. Apgar scores at 1 and 5 minutes were 4 to 10 (7.9 ± 1.5, mean ± SD) and 4 to 10 (8.8 ± 1.6), respectively. Urine was collected at 8 to 16 hours of life (stage 1) and 24 to 32 hours of life (stage 2), and at the end of urine collection, the urinary bladder was emptied by gently pressing the lower abdomen. These subjects were divided into two groups according to the level of urine AVP/creatinine clearance (Ccr) ratio at stage 1: group A represented five infants with a urine AVP/Ccr ratio of
Department of Pediatrics, Kansai Medical University, Osaka Japan, and Second Department of Internal Medicine, Tokyo Medical and Dental University, School of Medicine, Tokyo, Japan Reprint requests: Dr. Kojima, Department of Pediatrics, Kansai Medical University, Fumizonocho 1, Moriguchi, Osaka 570, Japan Copyright © 1992 by Thieme Medical Publishers, Inc., 381 Park Avenue South, New York, NY 10016. All rights reserved.
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ABSTRACT
AMERICAN JOURNAL OF PERINATOLOGY/VOLUME 9, NUMBER 5/6
Ccr = Ucr x V/Scr (ml/min/kg), CH2O = V - (Uosm x V/Posm) where Ucr indicates urinary creatinine concentration (mg/ dl); V, urinary volume (ml/min/kg); Scr> serum creatinine concentration (mg/dl); Uosm, urinary osmolality (mOsm/ liter); Posm, plasma osmolality (mOsm/liter). Plasma ANF and urinary AVP were measured by the radioimmunoassay method.7-8 Creatinine and electrolytes in plasma and urine were determined using an autoanalyzer (Beckman Astra-8). Plasma and urinary osmolality were determined using a Fiske osmometer. Urinary AVP was expressed as a ratio of pg/ml of AVP to Ccr (urine AVP/Ccr ratio). Data were expressed as mean ± SD and the paired t test was used to determine significance and p < 0.05 was considered significant.
Table 1. Characteristics and Clinical Diagnosis of Infants in Groups A and B on Admission
(No. m/f) Gestational age (wk) Birthweight (gm) Apgar score 1 min 5 min Blood gas pH Mode of delivery Vaginal Cesarean Clinical diagnosis RDS MAS TTN
Asphyxia LBWI Assisted ventilation Mechanical ventilation N-CPAP
Group A (n = 5, 213)
Group B (n = 7, 3/4)
36.1 ± 3.0 2,847 ± 569
36.6 ± 2.6 2,317 ± 589
7.2 ± 2.1 8.2 ± 2.2 7.26 ± 0.09
8.1 ± 1.1 9.0 ± 1.0 7.25 ± 0.07
2
3
3
4
2 2 0 1 0
1 1 2
4
1
0
2
1 2
Data was presented as mean ± SD. Croup A: urine AVP/Ccr ratio of ^2,000 at stage 1 Group B: urine AVP/Ccr ratio of
Sept/Nov 1992
URINARY ARGININE VASOPRESSIN EXCRETION AND HYPONATREMIA IN THE SICK NEONATES Takatsugu Kojima, M.D., Yuka Isozaki, Yukio Hirata, Shuji Matsuzaki, and Yohnosuke Kobayashi
We attempted to clarify the renal physiologic response to arginine vasopressin (AVP) in the 12 sick neonates: three with respiratory distress syndrome (RDS), three with meconium aspiration syndrome, two with transient tachypnea of the newborn, two with neonatal asphyxia, and two low birthweight infants during the first 2 days of life. Plasma atrial natriuretic factor (ANF), urinary AVP, osmolality, free water clearance and creatinine clearance (Ccr) were measured at 8 to 16 hours of life (stage 1) and 24 to 32 hours of life (stage 2). Urinary AVP was expressed as the ratio of AVP to Ccr (urine AVP/Ccr). These subjects were divided into two groups: group A represented five infants with a urine AVP/ Ccr ratio of 2000 or higher and group B, seven infants with a ratio of less than 2000 at stage 1. Hyponatremia occurred in two infants of group A at stage 2. Number of infants on mechanical ventilation was four in group A and one in group B. There were no significant differences in gestational age, birthweight, Apgar scores at 1 and 5 minutes, blood gas pH and mean arterial blood pressure between groups A and B. A good correlation was observed between logarithm of urine AVP/Ccr ratio and urinary osmolality (p < 0.01). A negative correlation was observed between logarithm of urine AVP/Ccr ratio and free water clearance (p < 0.01). Body weight of infants of group A at stage 2 was greater than at stage 1 (p < 0.05). Higher plasma ANF concentrations were observed in infants of group A at stage 2 when compared with those at stage 1 (p < 0.1). These results suggest that the syndrome of inappropriate excretion of antidiuretic hormone may occur in the early neonatal age.
The posterior pituitary peptide hormone, arginine vasopressin (AVP) is the major antidiuretic hormone in man. Umbilical cord plasma AVP levels are markedly elevated in infants with the evidence of fetal distress and in those delivered vaginally when compared with delivery by cesarean section.1 An increase in plasma AVP concentrations has also been reported in human neonates with respiratory distress syndrome (RDS) and pneumothorax.2 The syndrome of inappropriate excretion of antidiuretic hormone (SIADH) in neonates has been recognized by some authors and has been described in several clinical disorders, including hypoxic-ischemic encephalopathy, intracranial hemorrhage, and pneumothorax.23 Since urinary AVP has been shown to reflect its plasma values closely and the urinary clearance of AVP is approximately 80% of glomerular filtration rate4 (GFR), measurement of urinary excretion of AVP may provide a more accurate estimation of integrated AVP secretion than that of a plasma value.5-6 In the present study we attempted to clarify the physio-
logic effect of AVP on renal function during the first 2 days of life in the sick neonate.
PATIENTS AND METHODS Twelve infants (five boys and seven girls), 32 to 41 weeks of gestation and 1606 to 3650 gm birthweight, were the subjects of the study. Informed consent was obtained from each patient's parents. Apgar scores at 1 and 5 minutes were 4 to 10 (7.9 ± 1.5, mean ± SD) and 4 to 10 (8.8 ± 1.6), respectively. Urine was collected at 8 to 16 hours of life (stage 1) and 24 to 32 hours of life (stage 2), and at the end of urine collection, the urinary bladder was emptied by gently pressing the lower abdomen. These subjects were divided into two groups according to the level of urine AVP/creatinine clearance (Ccr) ratio at stage 1: group A represented five infants with a urine AVP/Ccr ratio of
Department of Pediatrics, Kansai Medical University, Osaka Japan, and Second Department of Internal Medicine, Tokyo Medical and Dental University, School of Medicine, Tokyo, Japan Reprint requests: Dr. Kojima, Department of Pediatrics, Kansai Medical University, Fumizonocho 1, Moriguchi, Osaka 570, Japan Copyright © 1992 by Thieme Medical Publishers, Inc., 381 Park Avenue South, New York, NY 10016. All rights reserved.
329
Downloaded by: Universite Laval. Copyrighted material.
ABSTRACT
AMERICAN JOURNAL OF PERINATOLOGY/VOLUME 9, NUMBER 5/6
Ccr = Ucr x V/Scr (ml/min/kg), CH2O = V - (Uosm x V/Posm) where Ucr indicates urinary creatinine concentration (mg/ dl); V, urinary volume (ml/min/kg); Scr> serum creatinine concentration (mg/dl); Uosm, urinary osmolality (mOsm/ liter); Posm, plasma osmolality (mOsm/liter). Plasma ANF and urinary AVP were measured by the radioimmunoassay method.7-8 Creatinine and electrolytes in plasma and urine were determined using an autoanalyzer (Beckman Astra-8). Plasma and urinary osmolality were determined using a Fiske osmometer. Urinary AVP was expressed as a ratio of pg/ml of AVP to Ccr (urine AVP/Ccr ratio). Data were expressed as mean ± SD and the paired t test was used to determine significance and p < 0.05 was considered significant.
Table 1. Characteristics and Clinical Diagnosis of Infants in Groups A and B on Admission
(No. m/f) Gestational age (wk) Birthweight (gm) Apgar score 1 min 5 min Blood gas pH Mode of delivery Vaginal Cesarean Clinical diagnosis RDS MAS TTN
Asphyxia LBWI Assisted ventilation Mechanical ventilation N-CPAP
Group A (n = 5, 213)
Group B (n = 7, 3/4)
36.1 ± 3.0 2,847 ± 569
36.6 ± 2.6 2,317 ± 589
7.2 ± 2.1 8.2 ± 2.2 7.26 ± 0.09
8.1 ± 1.1 9.0 ± 1.0 7.25 ± 0.07
2
3
3
4
2 2 0 1 0
1 1 2
4
1
0
2
1 2
Data was presented as mean ± SD. Croup A: urine AVP/Ccr ratio of ^2,000 at stage 1 Group B: urine AVP/Ccr ratio of
