Validation of the deuterium dilution technique for the measurement of fluid intake in infants.

The validity of the deuterium dilution technique as a method of measuring fluid intake was investigated by comparing values obtained with this technique and direct measurements of milk intake in 10 exclusively bottle-fed infants recovering from protein-energy malnutrition. Values for total body water were derived from body weight and length using Friis-Hansen's formula. During a 15-d period, average daily milk intake, measured with the deuterium technique, ranged between 519 and 963 ml and was similar to values obtained by direct measurement (range 531-1002 ml). Correlation between both sets of values was highly significant (r = 0.97; P less than 0.001). The data indicate that the deuterium dilution method provides good estimates of daily fluid intake in young infants.