[Preoperative increase in the plasma concentration of free fatty acids during minor elective interventions using a...

Plasma concentrations of free fatty acids (FFApl) can be used as a parameter to measure stress. The present study aimed to evaluate the changes in the concentration of FFA during perioperative stress caused by minor elective surgery under a standard anaesthetic technique using enflurane. The premedication administered included heptabarbital on the preoperative night and morphine with promethazine prior to the transfer of the patient to the theatre. Blood samples for the analysis of FFA were obtained from 12 patients at the following times: 1 day preoperatively (control, c), prior to induction of anaesthesia (s1), following the administration of thiopentone (s2), following tracheal intubation (s3), 10 min after the commencement of enflurane administration (s4), following surgical incision (s5), intraoperatively (s6), following extubation (s7), 1 h after extubation (s8), and on the 1st postoperative day (s9). FFA were extracted from plasma with hexane and analysed in duplicate by a specific and sensitive gas-chromatographic assay with flame ionisation detection using pentadecanoic acid as the internal standard. All FFApl from the preoperative day (c) were within normal range. FFA concentrations at s1, s2, s3 and (to a lesser extent) at s4 were statistically significantly increased compared to control values. The maximum concentration of FFA in plasma occurred at s2. A decrease from this maximum was found in samples s4, s5 and s6 (the latter was the minimum intraoperative FFApl). The FFApl levels at s7, s8 and s9 were similar to control. A different response was found for each individual free fatty acid. The maximum increase ranged from 40% (stearic acid) to 300% (oleic acid).(ABSTRACT TRUNCATED AT 250 WORDS)