Volume kinetics of glucose 2.5% solution during laparoscopic cholecystectomy

Background. Analyses of the distribution and elimination ofglucose 2.5% solutions can be used to suggest combinations ofinfusion rates and infusion times which yield a predeterminedplasma glucose level and degree of plasma dilution during surgery. Methods. Twelve patients aged between 27 and 51 (mean 40) underwentlaparoscopic cholecystectomy. An i.v. infusion of 1.4 litresof glucose 2.5% over 60 min was started when surgery began.A volume kinetic model was fitted to measurements of the plasmaglucose concentration and the degree of haemodilution. Nomogramswere constructed based on the kinetic results. Results. The volume of distribution for the glucose and infusedfluid and the plasma insulin levels were similar to the onesrecorded in previous volunteer studies, but 50–70% lowervalues were obtained for the clearance of glucose (mean 0.21litres min^–1), endogenous glucose production (1.1 mmolmin^–1) and the elimination rate constant for the infusedfluid (median 37 ml min^–1). Urinary excretion was markedlydepressed and amounted to 9% of the infused fluid volume 4 hafter starting surgery. To prevent hyperglycaemia, nomogramssuggested that the infusion should be directed towards a ‘target’glucose concentration and then slowed down in a controlled way.At steady state, the infused fluid maintains a 3.5% plasma dilutionfor each mmol that plasma glucose remains above baseline. Conclusion. Metabolic changes warrant careful balancing of infusionrates of glucose 2.5% during laparoscopic cholecystectomy, whichis facilitated by a nomogram. Volume expansion from the infusedfluid volume should be recognized. Br J Anaesth 2004; 92: 485–92