The elimination of inorganic fluoride after enflurane anesthesia--transitory action on parathyroid tissue

Enflurane has been introduced as a potentially useful clinical anesthetic compound. Its administration is followed by elevations of blood and urine concentrations of inorganic fluoride, whose nephrotoxicity has been previously described. Although the action of this element on the skeleton is well documented when ingested orally, its influence has not yet been investigated when it results from the metabolism of fluorinated anesthetic drugs. The present study examines renal function and calcium-phosphorus balance after administration of low concentration of enflurane. Twenty-one patients of both sexes undergoing minor surgery were selected. A statistical analysis of biologic items determined before and after anesthesia showed no significant variations of parameters involved in renal function. On the contrary, it was shown that biodegradation of enflurane was responsible for a significant change in blood and urine phosphorus concentrations. Moreover variations in phosphorus clearance suggested a transitory hypersecretion of parathyroid hormones, probably related to inorganic fluoride metabolism. Such a result is interesting because of the low blood concentration of inorganic fluoride and its transitory character.