The Metabolic Changes in Fresh Versus Old Stored Blood Used in Priming of Extracorporeal Circuit in Cardiopulmonary Bypass for Pediatric Patients - First Results

Introduction. One of the main goal in modern pediatric bypass equipment is to reduce the size of the extracorporeal circuit in order to minimize the prime volume. High priming volume can produce a low hematocrit on CPB in small infants, which results in electrolyte imbalance and decreased tissue oxygenation, therefore the donor blood should be used in the prime. The use of donor blood itself has several disadvantages, including complement activation, induction of a transfusion reaction, infusion of lactate, glucose and potassium, therefore this should be avoided as much as possible. When blood is stored, many alterations occur in its constinuents, in particular an increase in potassium and lactate levels, and decrease in pH, which have been associated with severe complications. Aim of the study. To evaluate the effect of length of storage of packed red blood cells (PRBC) on the concentration of potassium, sodium, lactate, glucose and pH in PRBC used in pediatric cardiac surgery. Materials and methods. From October, 2006 until June, 2009 blood samples were drawn from 78 PRBC used in cardiopulmonary bypass before they were added to the priming solution. All PRBC were splited in two groups depending on the age of blood: 5 days ≥ (Group 1), n=44 and 5 days< (Group 2), n=34. Blood samples were analyzed by GEM PREMIER 3000. Results. Seventy eight PRBC used in pediatric cardiac surgery were included in the study. In 44 blood samples the age of PRBC was under 5 days (Group 1) and in 34 blood samples the age of PRBC was over 5 days (Group 2). The mean storage time of PRBC in Group 1 was 4 +/- 1 days and in Group 2 - 8 +/- 3. The pH value in Group 1 was higher than in Group 2 (6.7 +/- 0.1 vs 6.5 +/- 0.2, P=0.000859). There was a significant difference between both groups in terms of potassium level (6.1 +/- 1.8 vs 9.4 +/- 2.6, P <0.0001) and lactate level (7.2 +/- 1.4 vs 10.1 +/- 1.7, P <0.0001), but no significant difference in terms of sodium level (138.3 +/- 3.9 vs 135.6 +/- 4.7, P=0.056688) and glucose level (346.5 +/- 36.1 vs 336.3 +/- 50.7, P=0.509321). There was an intermediate correlation in both groups in terms of storage time and level of potassium, storage time and level of lactate, pH and level of potassium, pH and level of lactate, and the levels of potassium and lactate. There was a linear increase in the levels of potassium and lactate depending on the storage age of PRBC. Conclusions. It is absolutely crucial to use as fresh packed red blood cells as possible in pediatric cardiac surgery to avoid such unexpected complications as transfusion-induced cardiac arrest due to hyperkalaemia. There are also other metabolic changes such as hyperlactemia and low pH, should be avoided, when performing pediatric cardiopulmonary bypass. The research is going to be continued, possibly starting to evaluate the levels of potassium and acid-base balance, when circulating the priming solution for some time before the initiation of cardiopulmonary bypass.