[Perioperative management of patients on maintenance hemodialysis: serum potassium and hemodynamic changes during...

Serum potassium and hemodynamic changes were studied during anesthesia in 32 patients on chronic hemodialysis (HD) who received the last HD either 24 hours (12 patients; Group A) or 3 hours (20 patients; Group B) prior to surgery. Preanesthetic removal of body water by HD in Group A (2,400 +/- 1,100 ml) was significantly greater than that of Group B (1,200 +/- 500 ml). Preanesthetic serum potassium values were 4.7 +/- 0.6 and 4.1 +/- 0.4mEq.l-1 in Groups A and B respectively. Anesthesia was induced and maintained with N2O-O2 plus halothane or enflurane. Six patients in Group A (50%) developed hypotension during anesthesia. In contrast, hypotension was noted in only one patient (5%) in Group B. On the other hand, in Group B, 3 patients (15%) developed hyperkalemia (serum K greater than 6mEq.l-1), although no patient had hyperkalemia in Group A. The excessive removal of body water by preoperative HD should be avoided because hypotension often develops during anesthesia. Since the risk of hyperkalemia is not low, we should measure serum potassium during anesthesia when HD is performed immediately before anesthesia and removal of body water appears to be inadequate even if preanesthetic serum potassium value is normal.