Clinical Effects of Halothane Concentration on Trifluoroacetic Acid Excretion in Urine

Excreted amount of urinary trifluoroacetic acid (TFA) during and after halothane anesthesia in twelve surgical patients was determined isotachophoretically. The levels of urinary TFA which amount was zero or a trace during the anesthesia increased after discontinuation of halothane inhalation. The values of daily excreted TFA were the highest on the 2.1±0.3 postoperative day (M±SEM). The urinary TFA values of patients inhaling a low concentration (0.8%) of halothane reverted to zero or a trace level on the 11.2±1.0 postoperative day (M±SEM) and the total amount of averaged 21.53 ± 3.23 mmol (M ± SEM). In patients to levels seen on the 7 .0 ± 0.6 postoperative day (M±SEM) and the total amount of TFA excreted was 20.20±4.77 mmol (M±SEM). These clinical findings indicate that the aerobic biotransformation of halothane after anesthesia is enhanced by high concentration of halothane.