Slipping up on the sliding scale: fluid and electrolyte management in variable rate intravenous insulin infusions

Abstract

This study aimed to analyse variations in intravenous fluid therapy and electrolyte management with variable rate intravenous insulin infusions (VRIIIs); and to quantify serum electrolyte changes pre- versus post-VRIII and variations therein depending on supplemented fluid electrolyte compositions. A retrospective study was undertaken involving 174 VRIIIs prescribed over a 10-week period at a tertiary teaching hospital. Each VRIII had their associated fluid prescription and serum electrolytes analysed. The results showed that 5% dextrose (46%) and 0.9% NaCl (34%) were the most commonly prescribed fluids; 64% of fluids did not have the recommended potassium supplementation. Administration of a VRIII resulted in a significant drop in serum potassium levels (p < 0.0001) for those who did not receive supplementation. There was no drop in serum potassium for those patients who did receive supplemental potassium. Eleven patients (6.4%) developed new-onset hypokalaemia (K ≤3.5 mmol/L) after implementation of a VRIII. Our study supports the hypothesis that VRIIIs cause hypokalaemia and that this can be averted by supplemental potassium, thus preventing potentially avoidable hypokalaemic complications. A large variation exists in prescribing fluids with VRIIIs. Introduction of the national surgical and medical VRIII guidelines, together with improved availability to recommended fluids, and a quality improvement project, are our next steps to improve patient outcomes. Copyright © 2016 John Wiley & Sons.