Quantitative and qualitative evaluation of blood salvaged after extracorporeal circulation (ECC) in paediatric heart surgery. Study of biochemical, morphological and structural variations of RBC after ECC and after salvaging of ECC circuit priming blood.

ABSTRACT

The salvaging of ECC circuit priming blood is essential for reducing the morbidity related to homologous blood transfusions and the importance of this technique is inversely proportionate to the age and weight of the child. In infants, the washing and centrifugation of blood not only drastically reduce the risk of contracting blood-transmitted diseases and cut management costs, but are also of considerable hemodynamic importance, producing a rapid normalization of the patient's hematocrit and hemoglobin and balancing the O2 consumption/demand ratio. The marketing of miniaturized salvagin devices with 55 ml bowls by Dideco has made possible the recovery of small quantities of blood, so as to normalise the hematic crisis and permit the application of total hemodilution in low-weight patients. The salvaged blood shows an average hematocrit of 52.7+/-9.7% (max 68.1%) and an average hemoglobin of 17.6 +/- 2.9 g/dl (max 20.7 g/dl), and maintains its structural components, osmotic resistance, concentration of intraerythrocytic hemoglobin and mean corpuscular hemoglobin all intact. Washing with isoosmotic and isoionic hydroelectrolytic solutions normalizes the ionic situation in the post-operative period and activated blood salvaging after Extracorporeal Circulation. The use of solutions without nutritional substances results however in a considerable fall in the number of enzymes in the intraerythrocytic metabolic glucide chain (G6PDH -40.7 +/- 14.3% p<0.001), (PK -23.8 +/- 20.5% p<0.03). This drop may be responsible for erythrocytic morphological alterations (echinocytic change) and probably for the release of hemoglobin from the red blood cells. Washing with isoionic, isoosmotic solutions containing G5% and adenine could, at least in theory, improve the quality of the salvaged blood, by normalizing the morphology and the volume of the RBC and by increasing the hematocrit.