The effect of patient-controlled intravenous analgesia on postoperative hypokalemia in patients undergoing laparoscopic cholecystectomy.

PURPOSE

We investigated whether hypokalemia developed during the postoperative period and whether the use of intravenous patient-controlled analgesia (IV-PCA) could decrease the incidence of postoperative hypokalemia in patients who underwent laparoscopic cholecystectomy.

METHODS

Sixty patients undergoing laparoscopic cholecystectomy were randomly assigned to either IV-PCA (n = 30) or control (n = 30) groups. We measured serum potassium concentration at the outpatient department (T1), at 8:00 a.m. on the day of surgery (T2), at 6 h after the end of surgery (T3), and at 8:00 a.m. on the first (T4), second (T5), and third (T6) postoperative days. Serum potassium concentration, incidence of hypokalemia, mean blood pressure, heart rate, respiratory rate, and the patient-reported visual analogue scale score were compared within each group and between groups at each time point.

RESULTS

Serum potassium concentrations in all patients showed a significant decrease at T2-T4 compared to the preoperative concentration (T1). Serum potassium concentrations at T3 and T4 in the IV-PCA group were significantly higher than those in the control group. Also, the incidence of hypokalemia at T3 and T4 was significantly lower in the IV-PCA group. Mean blood pressure and heart rate were significantly lower in the IV-PCA group than in controls at T3 and T4.

CONCLUSIONS

The results show that hypokalemia developed during the perioperative period and the use of IV-PCA in patients undergoing laparoscopic cholecystectomy effectively decreased the degree and incidence of postoperative hypokalemia on the day of the operation and postoperative day one.