Comparative dose response using the intravenous versus enteral route of administration for potassium replenishment

Objective To compare the change in potassium concentration (dose–response) using the intravenous versus enteral route for potassium replenishment. Research Methodology/Design Cross-sectional analysis of individual potassium chloride doses with resulting changes in plasma potassium concentrations in intensive care patients. Potassium chloride was administered according to potassium replenishment protocols. For inclusion, doses were required to have pre- and post-dose plasma potassium concentrations obtained within 8 hours of administration. Setting Medical and surgical intensive care units of a United States Veterans Affairs Medical Center. Main Outcome Measures The primary outcome was the dose–response slope for intravenous versus enteral potassium administration as estimated by linear regression analysis. Multivariable linear regression was employed to adjust for potential confounders. Results The sample had 278 potassium chloride doses administered to 142 patients. The potassium concentration change per 20 mmol of potassium chloride was similar for intravenous and enteral routes, 0.25 mmol/L (95% confidence interval 0.16–0.33) versus 0.27 mmol/L (0.15–0.39) respectively (p = 0.73). Multivariable linear regression did not alter results. The success of achieving a minimum potassium concentration defined by the specific protocol was similar for intravenous (61%) and enteral (59%) administration. Overall, 77% of potassium chloride doses were administered at a time when patients were eligible to receive an enteral dosage form. Conclusion The enteral route was as effective as the intravenous route in increasing the plasma potassium concentration. The enteral route was widely available for potassium replenishment. Despite enteral route availability and the well-known reliability of potassium chloride absorption, the majority of doses were administered intravenously.