The effect of red blood cell transfusion on oxygen consumption in the pediatric patient.

The study used a one-group, pretest/posttest design to determine the effect of red blood cell transfusion on oxygen consumption (VO2) and if the change in VO2 was related to the volume of red blood cells transfused. The SensorMedics 2900 metabolic cart was used to measure VO2 by indirect calorimetry. VO2 was measured before and after red blood cell transfusion. A convenience sample of 17 pediatric hematology-oncology outpatients, with a hematocrit of less than 26%, was evaluated on 23 separate occasions. Patient age ranged from 5 to 19 years. Data were obtained from 4 patients more than once. An average of the measurements was used in all calculations. Six patients carried the diagnosis of acute lymphoblastic leukemia, and 1 patient had hepatocellular carcinoma. The remainder of the patients was evenly distributed among the following five diagnoses: (a) medulloblastoma, (b) Ewing's sarcoma, (c) Fanconi's anemia, (d) rhabdornyosarcoma, and (e) Wilm's tumor. Baseline hematocrit averaged 23% (15.5% to 25.7%). Patients received an average of 10.3 cc/kg (4.5 cc/kg to 16.33 cc/kg) of packed red blood cells. The mean increase in VO2 was 23.37 ml/min/m2 or a 17% (0% to 34%) increase from the initial VO2. No significant correlation was found between the volume of red blood cells administered and the change in VO2 per body surface area. There was also no significant change in systolic blood pressure or respiratory rate from the 3 pre- to posttransfusion VO2 measurement. Three patients had a decrease in heart rate by an average of 8.8%, and the remaining had an average increase in heart rate of 13.2%. Seven patients who demonstrated an increase in VO2 of less than 10% were compared to patients with a greater than 10% change. No significant difference was found in age, height, weight, initial hematocrit, or volume of red blood cells transfused between these two groups. In summary, a significant change in VO2 was noted before and after a red blood cell transfusion. These findings demonstrate that VO2 was dependent on the supply of oxygen in this subset of pediatric patients. Recommendations, thus, are made to guide the decision to initiate transfusions earlier in patients with chronic anemia.