Renal function and fluoride formation and excretion during enflurane anaesthesia

Area of Science:

• Anesthesiology
• Nephrology
• Pharmacology

Background:

• Enflurane is an inhalational anesthetic agent.
• Renal function can be affected by anesthesia and surgery.
• Fluoride is a metabolite of enflurane, and its excretion is primarily renal.

Purpose of the Study:

• To investigate the effects of enflurane anesthesia and surgery on central circulation, renal function, and fluoride metabolism.
• To assess changes in cardiac output, systemic arterial pressure, and renal parameters.
• To evaluate fluoride formation, plasma levels, and clearance during and after enflurane anesthesia.

Main Methods:

• Studied nine patients undergoing enflurane anesthesia and surgery.
• Monitored central circulation (cardiac output, mean systemic arterial pressure).
• Assessed renal function (urine flow rate, inulin clearance, PAH clearance, fractional sodium excretion) and fluoride clearance (CF).

Main Results:

• Cardiac output and mean systemic arterial pressure remained stable.
• Urine flow, inulin clearance, PAH clearance, and fractional sodium excretion decreased significantly during anesthesia.
• Fluoride clearance (CF) markedly decreased during anesthesia but recovered postoperatively. Peak fluoride levels were observed 4 hours after anesthesia, with no correlation to renal function impairment.

Conclusions:

• Enflurane anesthesia and surgery transiently impair renal function and reduce fluoride clearance.
• Renal function recovers after the cessation of anesthesia.
• No direct correlation was found between plasma fluoride levels and the observed depression of renal function.