Red blood cell energy metabolism during cardiopulmonary bypass
Cavaliere, F.; Meo, F.; Scapigliati, A.; Sciarra, M.; Schiavello, R.
Journal of Cardiovascular Surgery 40(5): 653-657
1999
ISSN/ISBN: 0021-9509 PMID: 10596997 Document Number: 505596
Background. During cardiopulmonary bypass (CPB) an intracellular ATP deficit could theoretically play a role in changes of erythrocyte shape and deformability caused by mechanical trauma. We therefore studied erythrocyte energy metabolism in 12 patients undergoing normothermic CPB for myocardial revascularization. Methods. Blood samples were collected prior to and 45 minutes after CPB beginning and analyzed for erythrocyte ATP, ADP, and AMP and their metabolites, erythrocyte NAD and NADP, plasma and whole blood lactate (Lactp and Lactb respectively), and whole blood pyruvate (Pyrb). Results. Values were expressed as mean+-standard deviation or median (lower and higher quartiles) on the ground of a test for normality. During CPB erythrocyte nucleotides and their metabolites did not change significantly (ATP: 60.2+-12.1 vs 68.3+-13.0; ADP: 12.2+-3.6 vs 12.0+-3.1; AMP: 0.43+-24 vs 0.44+-0.26; adenosine: 0.063 (0.034-0.203) vs 0.77 (0.032-0.221); inosine: 0.064 (0.023-0.072) vs 0.075 (0.025-0.111); hypoxanthine: 0.330+-0.272 vs 0.367+-0.223; xanthine: 0.193+-0.090 vs 0.220+-0.095; NAD: 3.149+-0.743 vs 3.358+-0.851; values in muM/mM packed red blood cell hemoglobin) while NADP increased (2.110+-0.390 vs 2.433+-0.288 muM/mM packed red blood cell hemoglobin; p<0.05). Ringer lactate, with which the extracorporeal circuit was primed, caused Lactp to increase (1.87+-0.81 vs 3.27+-1.15 mM/l; p<0.01). Some lactate entered erythrocytes since Lactp/Lactb ratio did not change (1.09+-0.25 vs 1.07+-0.23) and some was transformed into pyruvate since Pyrb increased (62.9 (30.3-73.3) vs 100.5 (61.0-146.9) muM/l; p<0.01). Lactb/Pyrb ratio did not change significantly (22.6 (16.1-40.5) vs 27.9 (17.5-35.2)) so that NAD/NADH ratio and, consequently, the rate of glycolysis were unlikely to change too. Conclusions. Erythrocyte energy metabolism is not affected by CPB, at least during the period of time taken into account in this study.