Plasma-Lyte 148 is a balanced, crystalloid intravenous fluid which is both calcium-free and isotonic. It has been demonstrated to reduce the risk of hyperchloraemic metabolic acidosis and iatrogenic hyponatraemia seen with use of normal saline and hypotonic solutions respectively. Investigating the compatibility of Plasma-Lyte 148 and Plasma-Lyte 148+5% gucose with morphine, midazolam, fentanyl, ketamine, clonidine, aminophylline, salbutamol and furosemide will provide vital data to facilitate the introduction of these fluids into routine paediatric practice.Method
Chemical stability was assessed by high performance liquid chromatography (HPLC) using the ‘Hewlett Packard (Agilent) 1100’ HPLC system. A gradient method with 20 mM ammonium carbonate (A) and acetonitrile (B) mobile phases and an ‘ACE Excel 3 SuperC18’ column was used. The flow rate was set to 0.03 ml/min, temperature to 40°C and injection volume for all drug admixtures to 5 µL apart from ketamine (4 µL) and furosemide (1 µL). Physical stability was assessed by observation of precipitate formation or colour change. Six repeats of each IV fluid and drug mix were assayed at three time points: 0, 2 and 24 hours. pH changes were measured using Fisherbrand Hydrus 300. Normal saline and 5% glucose were used as controls for all experiments.Results
No precipitate formed in any of the samples. Chemical stability was defined as <5% concentration change. All examined therapeutic agents were stable at 2 and 24 hours relative to control solutions. Relative to starting concentration, all drugs except midazolam were stable to ±3%. Midazolam showed similar variation in concentration with all four fluids. All combinations remained in a safe peripheral administration pH range of 5–9. Plasma-Lyte 148 admixtures were found have a pH closest to that of the blood.Conclusion
Compared to standard diluents, the tested therapeutic agents are chemically and physically stable for 24 hours at the concentrations measured, and are all stable at commonly encountered Y site concentrations, when diluted with Plasma-Lyte 148 or Plasma-Lyte 148+5% glucose. All are pH stable and all are suitable for peripheral administration.