pituitrin and Bronchopulmonary-Dysplasia

Babies with chronic bronchopulmonary dysplasia (BPD) can sometimes develop pallor, systemic and pulmonary edema, oliguria, and hyponatremia not attributable to cardiopulmonary or renal impairment. These signs and symptoms might, however, be explained by inappropriate control of vasopressin secretion. To test this hypothesis, we measured plasma vasopressin and osmolality, serum sodium and potassium concentrations, urine output and osmolality, and free water clearance in 26 normoxic infants with BPD aged 1-4 months. All of these infants required supplemental oxygen (FiO2 0.41 +/- 0.03, mean +/- 1 SE) to maintain O2 saturation of greater than 88%, and six infants also required mechanical ventilation. As controls, 10 infants of similar age but without BPD were also studied. None of the infants had been discharged from the nursery and was receiving any medications, and all were clinically stable when studied. Compared to control infants, infants with BPD had significantly elevated plasma vasopressin concentrations (control 5.2 +/- 0.9 pg/ml; BPD 42.4 +/- 5.1; mean +/- SE, p less than 0.05). Moreover, infants with BPD had hyponatremia and hypotonic plasma, and both urine output and free water clearance were significantly reduced. These data suggest that some infants with chronic BPD have elevated vasopressin levels that are functionally significant. We speculate that excessive stimulation of vasopressin secretion may explain some of the pulmonary and nonpulmonary signs and symptoms in infants with chronic BPD.

Topics: Bronchopulmonary Dysplasia; Diuresis; Humans; Infant, Newborn; Osmolar Concentration; Potassium; Sodium; Vasopressins; Water-Electrolyte Balance

We investigated the antidiuretic hormone (ADH) response in 12 infants with bronchopulmonary dysplasia during acute respiratory distress. All of the infants had hypoxemia with air-trapping in the chest at the time of admission to the hospital. None had documented infection. There was a dramatic increase in the plasma levels of ADH during acute respiratory distress, with a subsequent reduction of levels toward normal when the respiratory distress decreased to the preadmission well state. Three of 12 infants manifested hyponatremia at 24 hours after admission, with two of them exhibiting persistent hypertension for up to three days. The mechanism for elevated ADH levels is air-trapping in the chest, causing pulmonary hypovolemia and decreased left atrial filling and/or decreased transmural pressure of the left atrium.

Topics: Bronchopulmonary Dysplasia; Female; Furosemide; Humans; Hyponatremia; Hypoxia; Infant; Infant, Newborn; Male; Respiratory Distress Syndrome, Newborn; Vasopressins