Inorganic Fluoride Kinetics and Renal Tubular Function After Sevoflurane Anesthesia in Chronic Renal Failure Patients Receiving Hemodialysis

Perioperative Pharmacologic Management of Patients with End Stage Renal Disease

The pharmacokinetics of numerous medications used in the perioperative period are altered in patients with end-stage renal disease. Clearance of drugs, or their metabolites, that are normally excreted by the kidney is markedly reduced in ESRD. In addition, patients with ESRD may also have alterations in gastrointestinal absorption, volume of distribution, protein binding, and metabolic clearance of pharmacologic agents. Finally, drug removal may be augmented during dialysis. All of these factors contribute to the need for dose adjustment of medications, including analgesics, anesthetics, neuromuscular blockers, and antimicrobial agents, which may be used in the perioperative management of the ESRD patient.

The effects of low-flow sevoflurane and isoflurane anesthesia on renal function in patients with stable moderate renal insufficiency

Sevoflurane degrades to Compound A, which is nephrotoxic in rats. Therefore, the renal effects of Compound A is an area of intense debate. We investigated the effects of low-flow sevoflurane and isoflurane anesthesia on renal function in patients with stable renal insufficiency. Seventeen patients with a serum creatinine level of more than 1.5 mg/dL were anesthetized with sevoflurane or isoflurane at a total flow of 1 L/min. Serum creatinine and blood urea nitrogen were measured before anesthesia and again 1, 2, 3, 5, 7, and 14 days after anesthesia. The 24-h creatinine clearance was measured before anesthesia and 7 days after anesthesia. There were no significant differences in the blood urea nitrogen levels, serum creatinine concentrations, or creatinine clearance before and after anesthesia within each group. These results suggest that sevoflurane and isoflurane have similar effects on renal function in patients with moderately impaired renal function. Further study of the effects of low-flow sevoflurane anesthesia on impaired renal function with a larger sample size than ours is required to resolve the issue of sevoflurane safety in patients with renal insufficiency.

IMPLICATIONS

The serum creatinine and blood urea nitrogen data indicate that, for exposures of <130 ppm/h in Compound A inspired area under the curve, renal effects of low-flow sevoflurane are similar to those of isoflurane in patients with stable renal insufficiency.

Anesthetic considerations for the patient with renal failure

Patients in end-stage renal disease and chronic liver failure present a number of challenges to the anesthesiologist. They may be chronically ill and debilitated and have the potential for multisystem organ dysfunction. To safely manage these patients we need to understand the benefits and limitations of dialysis and the altered pharmacology of commonly used anesthetic agents and perioperative medications in chronic renal failure.

Investigation of fluoride elimination during a dialysis session

We have conducted a study of the elimination kinetics of fluoride ions by a log linear regression analysis of plasma levels obtained during a bicarbonate hemodialysis session, with a dialyzer in polymercaprin for six patients with chronic renal failure. Using plasma fluoride levels of 35 patients studied for 20 months, we have validated these kinetics for hemodialysis with sodium bicarbonate, acetate-free biofiltration, hemodiafiltration with low flow rate and other dialyzers. Our results show that the decrease in plasma fluoride levels is statistically significant only after the first hour, and the fall reaches approximately 30% after a 4 h dialysis session. We propose that post-dialysis measurements of plasma fluoride are now not necessary if levels before dialysis are known.