REDOX POTENTIAL MEASUREMENTS OF PLASMA IN PATIENTS UNDERGOING CORONARY-ARTERY BYPASS GRAFT AND ITS CLINICAL-SIGNIFICANCE

The apparent redox potentials (E-m) of plasma as a marker of oxidant i njury during coronary artery bypass graft (CABG) is determined, and th eir clinical significance is discussed. We measured plasma E-m of norm al volunteers (n = 20) and samples drawn at different time points from patients undergoing elective CABG (n = 60) directly and by adding 5 m u l (20 mM) oxidants or reductants with known redox potential to plasm a (95 mu l), using a micro Pt/AgCl combination redox electrode. The E- m value stays elevated up to 30 min during the surgery, after the admi nistration of protamine it came down toward a more reduced state. Simi lar changes are seen with the lactate pyruvate ratio. Smaller changes of E-m than normal are observed in plasma samples from patients treate d with Aprotinin (antiprotease), Carmeda (heparin-coated) circuit and aspirin reflecting their protective effect. Redox potential (E-m) meas urements appear to be effective and useful in monitoring redox shifts wherever oxidative stress needs to be monitored. (C) 1998 Elsevier Sci ence Inc.