Effect of thiopental or propofol continuous infusion on serum potassium disturbance in patients with increased intracranial pressure

Abstract

Introduction: Thiopental continuous infusion is associated with hypokalemia and rebound hyperkalemia. However, the effect of propofol continuous infusion on serum potassium levels has not been investigated extensively. We retrospectively compared the effects of thiopental and propofol on serum potassium levels during continuous infusion.

Methods: We reviewed the medical records of 60 consecutive patients who received coma therapy or deep sedation for intracranial pressure control using either thiopental (n=37) or propofol (n=23) between January 2010 and January 2012.

Results: Thirty-three (89.2%) patients in the thiopental group and nineteen (82.6%) patients in the propofol group had hypokalemia (serum potassium <3.5 mmol/L) following the induction of therapy (p=0.468). The incidence of moderate to severe hypokalemia (serum potassium <3.0 mmol/L) following the induction of therapy was significantly higher in the thiopental group than in the propofol group (51.4 vs. 13.0%, p=0.003). The lowest serum potassium level averaged 2.9 ± 0.6 mmol/L in the thiopental group and 3.2 ± 0.4 mmol/L in the propofol group (p<0.05). The patients in the thiopental group required greater potassium replacement than the propofol group patients (0.08 ± 0.04 vs. 0.02 ± 0.01 mEq/kg/hr, p<0.001). On multivariate analysis, thiopental (odds ratio, 95% confidence interval, 7.31 [1.78-27.81]

p=0.005) was associated with moderate to severe hypokalemia during continuous infusion. The incidence of rebound hyperkalemia (serum potassium >5.0 mmol/L) after the cessation of therapy was higher in the thiopental group than in the propofol group (32.4 vs. 4.3%

p<0.05). The average peak serum potassium concentration was 4.8 ± 1.1 and 4.2 ± 1.1 mmol/L in the thiopental and propofol groups, respectively (p<0.05). On multivariate analysis, thiopental (8.821 [1.000-77.811]

p=0.049) and duration of continuous infusion (1.021 [1.004-1.039]

p=0.016) were associated with rebound hyperkalemia once therapy was discontinued.

Conclusions: When continuous infusion was used to relieve intracranial hypertension, propofol was less frequently associated with moderate to severe hypokalemia after induction and rebound hyperkalemia following the cessation of continuous infusion than thiopental.