Summary Background Plasma‐Lyte 148® is a balanced, crystalloid intravenous (IV) fluid which is both calcium‐free and isotonic. It prevents the hyperchloremic metabolic acidosis and iatrogenic hyponatremia seen with use of 0.9% sodium chloride and hypotonic solutions, respectively. However, data on compatibility with commonly used drugs are lacking. Aims To investigate the stability of Plasma‐Lyte 148® and Plasma‐Lyte 148® + 5% Glucose with eight commonly used therapeutic agents when compared with 5% glucose and 0.9% sodium chloride as diluents. We aimed to provide vital data which may facilitate the introduction of what appears to be a safer and more economic fluid. Methods Plasma‐Lyte 148® and Plasma‐Lyte 148® + 5% Glucose were mixed with morphine, midazolam, fentanyl, ketamine, clonidine, aminophylline, salbutamol, and furosemide at set concentrations. Comparisons were made to 0.9% sodium chloride and 5% glucose fluid controls. Six repeats of each IV fluid and drug admixture were analyzed through high‐performance liquid chromatography at three time points: 0, 2, and 24 hours. A concentration change of <5% was defined as chemically stable. Physical stability was assessed by observation of precipitate formation or color change. pH changes were measured using a Fisherbrand Hydrus 300 pH meter. Results Relative to starting concentration, all drugs except midazolam were stable to ±3%. All examined therapeutic agents were chemically stable at 2 and 24 hours relative to control solutions. No precipitate formed in any of the samples. All Plasma‐Lyte 148® and Plasma‐Lyte 148® + 5% Glucose drug admixtures remained in a safe, peripheral administration pH range of 5‐9 and were closer to the pH of blood than standard fluid‐drug admixtures. Conclusion Morphine, fentanyl, ketamine, salbutamol, aminophylline, and clonidine are stable for 24 hours when mixed with Plasma‐Lyte 148® and Plasma‐Lyte 148®+5% Glucose for administration at concentrations equivalent to those found at a typical Y‐site with maintenance fluid. Furosemide is stable at lower concentrations than those seen at a Y‐site, but midazolam displayed instability.

This paper compares the finite element predictions of elasto-plastic and creep behaviour with experimental data for axially loaded, shouldered tube models. Four shouldered tube models were made of a lead alloy and tested at 61°C, using strain gauges to measure the elasto-plastic and creep strains in the plain tube and fillet regions of the models. Instantaneous stress-strain and creep data were obtained from strain-gauged, uniaxial tensile specimens. The finite element solutions are based on the incremental Prandtl-Reuss equations. The elasto-plastic iterative solutions use a ‘negative gradient’ from the calculated point to the equivalent stress-equivalent strain curve to get the next estimate of the plastic strain increment. A time incremental method is used to obtain the creep solutions. Tests with the mean tube stress below, at and above the yield stress showed very good agreement between prediction and measurement of initial strains in the fillets. Differences between predictions and measurements of creep strains are attributable to cast-to-cast variations.

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