MECHANICAL AUTOLOGOUS TRANSFUSION DURING ORTHOPEDIC-SURGERY IN CHILDREN

The use of autotransfusion devices is an established method of reducin g the need for homologous transfusions in surgery [3, 11, 13], but tec hnical factors still contraindicate the washing and concentration of b lood volumes smaller than 300 mi. Therefore, haemoconcentration of sma ll volumes of salvaged blood, as usually found in paediatric surgery, is considered to be a complicated and questionable practice [5]. Where as these amounts of blood loss are easily tolerated by adults, they ma y necessitate homologous transfusions in paediatric surgery. In a pros pective study, we investigated whether a simple technical modification in the processing of salvaged blood could facilitate the use of autot ransfusion devices, especially in children. Patients and methods. Intr aoperative blood salvage was performed in children 6 months to 10 year s old undergoing surgery for hip dysplasia. Autotransfusion (Dideco ST AT) was started when the blood loss was estimated to be more than 20% of the total blood volume (TBV). As a reference, we used a formula bas ed on body weight [10]: for children up to the age of 6 years 80 ml/kg blood volume and for children up to 10 years 75 ml/kg. The total volu me of salvaged fluid including blood, anticoagulant solution, and surg ical irrigation was collected in a reservoir and transferred to the au totransfusion set, after which the reservoir was rinsed with 500 ml 0. 9% saline solution in order to save the remaining blood. After process ing, the blood was stored in the retransfusion bag. By adding the same volume of plasma expander (6% hydroxyethyl starch [HES], molecular we ight 450000), spontaneous sedimentation of the washed autologous eryth rocytes (RBCs) for 10-15 min led to a concentrate of RBCs. After 10 mu filtration, the RBC suspension was retransfused (Figs. 1-3). Results. Within 12 months, autotransfusion was performed during 6 out of 15 su rgical procedures according to the method described above. The calcula ted blood loss averaged 25.6% of TBV, of which 21.4% (=272 ml) could b e processed by the autotransfusion device (Table 3). The mean values o f 2.6 g/dl haemoglobin (Hb) and 6.8% haematocrit (HCt) in the salvaged blood increased to 9.4 g/dl and 27.3% in the processed RBC concentrat es. After adding 6% HES solution, spontaneous sedimentation of the RBC s led to values of Hb 22.1 g/dl and HCt 59.8%. An average of 59.5 ml ( 22-99 mi) sedimented RBCs was retransfused to the patients, including 11.6 ml 6% HES solution (Table it). In this manner, the need for homol ogous transfusions could be avoided in these patients both during and after surgery. Conclusions. This study shows that the use of blood sal vaging in paediatric surgery is indicated under certain conditions. Wi th the aid of the simple modification described above, we solved the m ain problem in paediatric autotransfusion by concentrating RBC suspens ions with low Hb and Hct values after using the autotransfusion device .