Late hyponatremia in very-low-birth-weight infants: incidence and associated risk factors.

OBJECTIVE: To determine the incidence of late hyponatremia in very-low-birth-weight infants and to identify associated risk factors. Low serum sodium concentration in otherwise healthy premature infants beyond 2 weeks of life is referred to as the hyponatremia. DESIGN: Retrospective cohort review. SETTING/SUBJECTS: The intensive care nursery at St Luke's Hospital Perinatal Center, Kansas City, Mo. Criteria for subject selection were birth weight of 1,500 g or less; survival for more than 21 days; development of late hyponatremia or hospitalization for 42 days or more; and measurement of serum sodium concentration at least once between the 14th and 56th day of life. Of 515 infants admitted to the nursery for the 1992 calendar year, 124 had a birth weight of 1,500 g or less and survived for more than 21 days; however, 16 of these infants were discharged at 42 days of life or less, 11 did not have a serum sodium concentration measurement after the second week of life, and 1 did not have complete medical records. Thus, the final sample was 96 subjects. STATISTICAL ANALYSES: Percentages to determine incidence of late hyponatremia; t test of chi 2 test to determine differences between infants with and without late hyponatremia; multiple logistic regression to determine the strongest indicators of late hyponatremia. RESULTS: Incidence of late hyponatremia was 62.5%. Significant risk factors for late hyponatremia were birth weight of 1,000 g or less (P < .001), feedings of fortified human milk (P < .013), and occurrence of an intraventricular hemorrhage (P < .036). Fortified human milk feeding was a significant risk factor for late hyponatremia in both weight groups (ie, birth weight greater than or less than 1,000 g). CONCLUSION: Despite standard fortification, human milk may contain an insufficient quantity of sodium to met the needs of very-low-birth-weight infants.

Liver test alterations with total parenteral nutrition and nutritional status.

Liver test abnormalities are a well-recognized complication in the parenterally fed population. Numerous etiologies for the development of elevated liver tests have been suggested. However, the etiology and clinical significance remain unclear. The aim of this retrospective study was to determine the extent of liver-associated test (LAT) abnormalities in patients receiving total parenteral nutrition (TPN) and to investigate whether the composition of TPN solutions and the magnitude of malnutrition could be used to predict subsequent LAT abnormalities. Medical records of 78 adult patients who received TPN for at least 2 weeks were reviewed. All subjects had normal LAT results before TPN, were not receiving hepatotoxic drugs, and had no underlying liver disease. Aspartate aminotransferase peaked transiently during week 2 and returned to normal during week 4. Alkaline phosphatase and total bilirubin peaked during weeks 4 and 3, respectively. The average nonprotein kilocalorie distribution was approximately 80% dextrose and 20% lipid. Caloric intake ranged from 7% to 23% above estimated needs. The mean nutritional status score was 22 +/- 15, with a possible range of 0 to 75 (0 indicates no malnutrition). The composition of TPN solutions was not significantly associated with the changes in the three LATs during any week of the 4-week study. The nutritional status score was significantly associated (p less than .05) with the change in alkaline phosphatase during week 1. This study confirms that LAT abnormalities occur during TPN, but the composition of the solution has no significant ability to predict subsequent LAT abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)