The relationship between magnesium, epinephrine and norepinephrine blood concentrations during CABG with normovolemic hemodilution.

The effects of procedures with extracorporeal circulation on the disturbance of relationships between blood magnesium (Mg), epinephrine, and norepinephrine levels have not been explicitly explained. It is assumed that both hypomagnesemia and increased concentration of the above mentioned hormones exert adverse effects on the myocardium often causing life threatening disorders. This problem is particularly important in cases of stunned myocardium, observed after extracorporeal circulation procedures. The complex nature of the procedures and the intraoperative normovolemic hemodilution (NH) employed are likely to alter Mg, epinephrine, and norepinephrine concentrations, as well as the above mentioned relations. The aim of the study was to evaluate the changes in blood Mg, epinephrine and norepinephrine concentrations in patients undergoing extracorporeal circulation and normovolemic hemodilution. The study encompassed 16 men operated on for stable coronary disease (I or II degrees according to the Canadian Scale). The patients were divided into two groups according to body weight: A) patients weighing less than 75 kg and B) patients weighing more than 75 kg. The degree of NH caused by constant volume of priming (1800 mL) was determined on the basis of hematocrit measurements and in relation to body weight. The examinations were conducted in 5 stages: 1) after radial artery cannulation before anaesthesia and surgery, 2) during hemodilution and deepest hypothermia, 3) after surgery before sending the patient to Intensive Postoperative care Unit, 4) in the first postoperative day, 5) in the second postoperative day. The observations showed an increase in epinephrine levels in group A in the second stage and of norepinephrine levels in stage 4. Decreased blood Mg levels were noted in all the patients in the second stage, however in group A significantly lower values were also observed in stage 3. Moreover, the correlation between Mg level changes and blood epinephrine and norepinephrine levels were observed. The study revealed significant effects of extracorporeal circulation procedures on adrenergic reactions as well as blood magnesium concentrations. It seems that the degree of NH is the main factor determining blood levels of Mg, epinephrine and norepinephrine during the use of a heart-lung apparatus, which may be particularly relevant in patients with impaired heart function and low body weight.

The degree of lymphocytic mitochondrial transmembrane potential and blood magnesium concentrations during coronary artery bypass grafting.

UNLABELLED: Magnesium (Mg) plays an important role in lymphocyte function. Low blood concentration of Mg may result in intralymphocyte imbalance and in turn may be associated with intensified apoptosis of peripheral blood lymphocytes. Due to its multistage character; extracorporeal circulation (ECC) may augment Mg disorders adding to the above mentioned pathology. The aim of this study was to assess the correlation between lymphocyte apoptosis and Mg concentration in the blood during the course of coronary artery bypass grafting (CABG) and in the early postoperative period. METHOD: Twenty male patients undergoing CABG with ECC under general anaesthesia were included in the study. For detection of apoptotic lymphocytes in the circulation, inner mitochondrial transmembrane potential (deltapsim) was measured with the use of chloromethyl-X-rosamine (CMXRos) and flow cytometry. Spectrophotometry was used for Mg blood concentration measurements. Peripheral blood samples were obtained in seven stages: 1) just before anaesthesia, 2) 2 hours after the beginning of surgery, 3) immediately after surgery, 4) 12 hours after the beginning of surgery, 5) 24 hours after the beginning of surgery, 6) 36 hours after the beginning of surgery, 7) 54 hours after the beginning of surgery. RESULTS: The statistically significant increases of lymphocyte apoptosis were noted in stages from 2 to 7. Blood Mg concentrations decreased in stages 2 and 3. There was negative correlation between Mg blood concentration in stages 2 and 3 and the intensity of lymphocyte apoptosis in the stage 5. CONCLUSIONS: 1) CABG with extracorporeal circulation was associated with a decrease of magnesium concentration in the blood and an increase of lymphocyte apoptosis intensity. 2) The decrease of magnesium blood concentration may increase the degree of lymphocyte apoptosis. 3) Lymphocyte apoptosis after extracorporeal circulation has a two-phase course.