Anaesthesia for urological surgery

Blood ammonia levels after intravenous infusion of glycine solution with and without ethanol

OBJECTIVE

Absorption of glycine 1.5% during transurethral resection of the prostate may increase blood ammonia levels, but hyperammonaemia has not been described when the fluid also contained ethanol 1%. The aim of this experimental study was to evaluate whether ethanol 1% reduces glycine-induced hyperammonaemia.

MATERIAL AND METHODS

Two intravenous infusions of glycine solution with and without ethanol 1% added were given on different occasions to 20 male volunteers (mean age 30 years). Half of them received 22 g of glycine over 50 min and the others approximately 18 g over 30 min. Blood ammonia was measured before and 30 min after the infusion. The serum levels of free amino acids were measured on 7 occasions during 10 of the experiments.

RESULTS

The glycine infusions increased blood ammonia levels from 37 micromol/l (median, 10th and 90th percentile limits 34-53) to 57 micromol/l (27-110; p < 0.001). The change was greater after the larger glycine dose, regardless of whether the fluid contained ethanol (p < 0.05). The only amino acid concentration correlating with blood ammonia was glycine, which showed higher levels in those who had a rise in blood ammonia of 50% or more.

CONCLUSIONS

Ethanol 1% did not reduce the increase in blood ammonia concentration after the administration of glycine solution.