Abstract
In humans the biliary excretion of trifluoroacetic acid, the major halothane metabolite, has not been studied. We investigated the biliary excretion of trifluoroacetic acid in two infants aged five months and two months following halothane anaesthesia for the operation of choledocholithotomy. Bile, urine and faeces were collected continuously for five days after operation and trifluoroacetic acid excretion measured. Estimates of halothane uptake, daily bile flow and the proportion of daily bile flow collected via the T-tube drainage catheter were subject to percentage errors possibly as large as 50%. Of the total trifluoroacetic acid produced from halothane metabolism, it was estimated that 17% in the five-month-old infant and 20% in the two-month infant was excreted in bile. In the five-month-old infant where approximately 80% of the bile produced entered the duodenum in the normal way, no faecal trifluoroacetic acid was detected suggesting an enterohepatic circulation for this metabolite.