Changes in serum CPK, LDH, and their isoenzymes in the perioperative period in patients undergoing craniotomy.

The perioperative changes in the serum concentration of creatine phosphokinase (CPK) and its isoenzymes MM, MB, and BB and of lactic dehydrogenase (LDH) and its isoenzymes LDH1 to LDH5 were determined during craniotomy in order to distinguish operation-induced changes in these enzymes from those due to acute myocardial infarction and malignant hyperthermia. Twenty-eight male patients, 29 to 76 years of age (mean +/- SD = 58 +/- 13.2 years), undergoing craniotomy for tumor reseaction (n = 26) or cerebral artery aneurysm clipping (n = 2) were included in this study. Ten serial blood samples were obtained from each patient: one sample before and another after induction of anesthesia, and eight samples after the incision, over a period of 70 h. The preinduction serum CPK level of 97 +/- 32 U/L (mean +/- SD) increased gradually and significantly and reached the peak level of 542 +/- 116 U/L 34 h after incision (p <0.05). Whereas all of the CPK isoenzymes increased in terms of U/L after incision, only the MM fraction (expressed as percent of total CPK) increased, and the MB and BB fractions (expressed as percent of total CPK) decreased. The preinduction serum LDH level of 150 +/- 42 U/L (mean +/- SD) increased gradually after incision and reached the peak level of 210 +/- 32 U/L 58 h after incision (p <0.05). LDH2 as a percent of total LDH decreased significantly, but the LDH1/LDH2 ratio did not change. LDH4 and LDH5, as percents of total LDH, increased significantly. The large increases in total serum CPK and the concomitant decrease in MB percent after craniotomy may minimize and/or mask the percentage increase in the MB level following acute myocardial infarction. The perioperative serum CPK level as a marker in the diagnosis of malignant hyperthermia should be interpreted in light of the present results and in conjunction with clinical symptomatology.