Frequency of low level bacteremia in infants from birth to two months of age.

BACKGROUND: The frequency of low level bacteremia (< or = 10 colony-forming units/ml) in infants from birth to 2 months of age and the optimal volume of blood and number of blood cultures to be collected have not been well-documented. During 1991 guidelines at this hospital for collection of blood for culture from these infants were revised. METHODS: Blood from each infant with suspected bacteremia was usually inoculated into an Isolator 1.5 Microbial Tube (1.5 ml of blood) and a bottle of anaerobic broth (0.5 to 3.0 ml of blood). The use of a second Isolator tube and the total blood volume recommended for culture (2 to 6 ml) depended on the weight and total blood volume of each infant. RESULTS: Forty-four bacterial pathogens were recovered from the blood of 40 (2.5%) of 1589 infants. Of 34 infants from whose blood the concentration of pathogens could be determined, 23 (68%) had low level bacteremia. Of 50 isolates of pathogens recovered from Isolator cultures, 32 (64%) were detected in counts of < or = 10 colony-forming units/ml. When 2 or 3 blood culture devices were inoculated with a total of 2 to 6 ml of blood from each infant, significantly more cases of bacteremia were detected (34 (3.0%) of 1126 infants had positive blood cultures) than when only one culture device containing < or = 1.5 ml of blood was used (2 (0.5%) of 398 infants had positive blood cultures; P = 0.008). However, when 4 or more culture devices were inoculated with a total of > 6 ml of blood from each infant (5 (7.7%) of 65 infants had positive blood cultures), the difference in recovery of pathogens compared with the culturing of from 2 to 6 ml of blood per infant was not significant (P = 0.089). CONCLUSIONS: Low level bacteremia was common in our infants' patient population. The culturing of up to 6 ml of blood which represented up to 4.5% of an infant's total blood volume was required for detection of the pathogens.

Comparison of two preservation solutions for erythrocyte transfusions in newborn infants.

To determine whether one of the newer preservation solutions for packed red blood cells (PRBC) is safe and effective in the transfusion of the very low birth weight infant, we conducted a randomized trial comparing PRBC preserved with the anticoagulant solution mannitol-adenine-dextrose (AS-1) and PRBC preserved with citrate-phosphate-dextrose-adenine (CPDA-1). Sixteen infants (birth weight 863 +/- 218 gm) with a gestational age of 26 +/- 3 weeks received one to three small-volume replacement transfusions with PRBC, 17 ml/kg, preserved with either AS-1 or CPDA-1 in a double crossover design. Transfusion with AS-1-preserved PRBC resulted in an equivalent increase in hemoglobin concentration when adjustment was made for the difference in the hemoglobin concentration of the transfused PRBC. During the transfusion, the percentage decrease in serum glucose values was greater with the CPDA-1 preservative than with the AS-1 preservative (54% +/- 13% vs 42% +/- 11% at 1 hour; p < 0.001). No other significant difference in blood chemistry values was found. Urine output was unaffected by AS-1 in the posttransfusion period. We conclude that (1) small-volume PRBC transfusions with AS-1 can be used in the very low birth weight infant without apparent detriment, (2) AS-1-preserved cells are as effective as cells preserved with CPDA-1 for increasing hemoglobin concentration, and (3) the higher dextrose content of the AS-1-preserved blood allows for improved glucose homeostasis during transfusion.