Sevoflurane versus isoflurane for maintenance of anesthesia: are serum inorganic fluoride ion concentrations of concern?

Management of T cell responses by anesthetic drugs-propofol & isoflurane in perioperative breast cancer patients: A prospective hospital-based study

Background & objectives The choice of anesthetic for better perioperative conservation of immune responses has always been contentious. This study investigated the differential impact of the intravenous anesthetic, propofol, and the volatile anesthetic, isoflurane on the T cell immune responses, if any, among individuals going through perioperative breast cancer. Methods Perioperative blood samples (preoperative, intraoperative and postoperative) collected from participants with breast cancer in two arms namely isoflurane arm (n=50) and the propofol arm (n=50) were analyzed for T cell immune response using flow cytometry and ELISA. The interactions of anesthetics with CD4/CD8 were probed with molecular docking and molecular dynamic (MD) simulations. Results Linear mixed model analysis showed that isoflurane in comparison to propofol inhibited CD4+ helper (Th) [β-coefficient: -8.75; 95% CI: -13.00 to -4.51] and CD19+ B cell (β: -7.51; 95% CI: -15.46 to 0.44) frequencies during the intraoperative period in perioperative breast cancer patients. Further, interleukin (IL)-10 and IL-12 were significantly increased during the intra- and postoperative periods in the isoflurane group as compared to the propofol group. Molecular docking (MD) validated propofol's better binding energy with CD4/CD8 than isoflurane. MD simulations propagated that in contrast to isoflurane, propofol formed a more compact and stabilized structure with CD4/CD8, making the amino acid residues on the surface of CD4/CD8 inaccessible for any interaction. Interpretation & conclusions The clinical observations and the in silico findings exhibited that propofol in comparison to isoflurane better regulated T cell immuno-inflammatory response in perioperative breast cancer patients.

Acute Fulminant Hepatic Failure Caused by Sevoflurane Linked to Influenza A

Sevoflurane is a volatile anesthetic agent that does not tend to cause clinically significant hepatotoxicity, but there are some reported hepatotoxicity cases in the literature. In the case presented here, adenotonsillectomy was performed during influenza infection, and sevoflurane was administered, after which acute fulminant hepatitis developed. At hour 24 of hospitalization after fulminant hepatic failure, liver transplant was performed in a 3.5-year-old patient without any known diseases. In such cases, etiology investigations should be planned, life support therapy should be administered, and information should be given to the patient to avoid exposure to sevoflurane in the future.

Sevoflurane and isoflurane genotoxicity in kidney cells of mice

The aim of this study was to evaluate the DNA damage and repair in kidney cells of Swiss albino mice after repeated exposure to sevoflurane and isoflurane and compare their detrimental effects. We used the alkaline comet assay to establish the genetic damage and measured three parameters: tail length, tail moment, and tail intensity of comets. These parameters were measured immediately after exposure to the above mentioned inhalation anaesthetics, two hours, six hours, and 24 hours later and were compared with the control group. Mean values of all three parameters were significantly higher in experimental groups compared to the control group. DNA damage in kidney cells of mice exposed to sevoflurane increased continuously before it reached its peak 24 hours after exposure. Isoflurane induced the highest DNA damage two hours after exposure. Levels of DNA damage recorded 24 h after cessation of exposure to both tested compounds suggest that sevoflurane was slightly more genotoxic than isoflurane to kidney cells of mice. According to these results, the currently used volatile anaesthetics sevoflurane and isoflurane are able to damage DNA in kidney cells of mice. Such findings suggest a possibility for similar outcomes in humans and that fact must be taken into account in everyday clinical practice.

Pharmacokinetics of fluoride in toddlers after application of 5% sodium fluoride dental varnish

The prevalence of dental caries (tooth decay) among preschool children is increasing, driven partially by an earlier age of onset of carious lesions. The American Academy of Pediatrics recommends application of 5% sodium fluoride varnish at intervals increasing with caries risk status, as soon as teeth are present. However, the varnishes are marketed for treatment of tooth sensitivity and are regulated as medical devices rather than approved by the US Food and Drug Administration for prevention of dental caries (tooth decay). The objective of this research is to examine the safety of use in toddlers by characterizing the absorption and distribution profile of a currently marketed fluoride varnish. We measured urinary fluoride for 5 hours after application of fluoride varnish to teeth in 6 toddlers aged 12 to 15 months. Baseline levels were measured on a separate day. The urine was extracted from disposable diapers, measured by rapid diffusion, and extrapolated to plasma levels. The mean estimated plasma fluoride concentration was 13 μg/L (SD, 9 μg/L) during the baseline visit and 21 μg/L (SD, 8 μg/L) during the 5 hours after treatment. Mean estimated peak plasma fluoride after treatment was 57 μg/L (SD, 22 μg/L), and 20 μg/kg (SD, 4 μg/L) was retained on average. Retained fluoride was 253 times lower than the acute toxic dose of 5 mg/kg. Mean plasma fluoride after placement of varnish was within an SD of control levels. Occasional application of fluoride varnish following American Academy of Pediatrics guidance is safe for toddlers.

Kidney function in living donors undergoing nephrectomy by sevoflurane or desflurane anesthesia

PURPOSE

Although there is no clinical evidence of nephrotoxicity with the volatile anesthetics currently used in general anesthesia, a better agent should be needed in terms of preserving postoperative renal function in living kidney donors who have only single remaining kidney. The purpose of the current retrospective, single-center study was to evaluate and compare renal function of living kidney donors after nephrectomy under either sevoflurane or desflurane anesthesia.

MATERIALS AND METHODS

From January 2006 through December 2011, a total of 228 donors undergoing video assisted minilaparotomy surgery nephrectomy for kidney donation were retrospectively enrolled in the current study. The donors were categorized into a sevoflurane group or desflurane group based on the type of volatile anesthetic used. We collected laboratory data from the patients preoperatively, immediately after the operation, on the first postoperative day and on the third postoperative day. We also compared renal function of the kidney donors after donor nephrectomy by comparing creatinine level and estimated glomerular filtration rate (eGFR).

RESULTS

The decrease in renal function after surgery in both groups was the most prominent on the first postoperative day. There were no significant differences between the two groups in postoperative changes of creatinine or eGFR.

CONCLUSION

Sevoflurane and desflurane can be used safely as volatile anesthetics in donors undergoing nephrectomy.

Renal toxicity with sevoflurane: a storm in a teacup?

The inhaled anaesthetic sevoflurane is metabolised into two products that have the potential to produce renal injury. Fluoride ions are produced by oxidative defluorination of sevoflurane by the cytochrome P450 system in the liver. Until recently, inorganic fluoride has been thought to be the aetiological agent responsible for fluorinated anaesthetic nephrotoxicity, with a toxic concentration threshold of 50 micromol/L in serum. However, studies of sevoflurane administration in animals and humans have not shown evidence of fluoride-induced nephrotoxicity, despite serum fluoride concentrations in this range. Compound A (fluoromethyl-2,2-difluoro-1-[trifluoromethyl] vinyl ether) is a breakdown product of sevoflurane produced by its interaction with carbon dioxide absorbents in the anaesthesia machine. The patient then inhales compound A. Compound A produces evidence of transient renal injury in rats. The mechanism of compound A renal toxicity is controversial, with the debate focused on the role of the renal cysteine conjugate beta-lyase pathway in the biotransformation of compound A. The significance of this debate centres on the fact that the beta-lyase pathway is 10- to 30-fold less active in humans than in rats. Therefore, if biotransformation by this pathway is responsible for the production of nephrotoxic metabolites of compound A, humans may be less susceptible to compound A renal toxicity than are rats. In three studies in human volunteers and one in surgical patients, prolonged (8-hour) sevoflurane exposures and low fresh gas flow rates resulted in significant exposures to compound A. Transient abnormalities were found in biochemical markers of renal injury measured in urine. These studies suggested that sevoflurane can result in renal toxicity, mediated by compound A, under specific circumstances. However, other studies using prolonged sevoflurane administration at low flow rates did not find evidence of renal injury. Finally, there are substantial data to document the safety of sevoflurane administered for shorter durations or at higher fresh gas flow rates. Therefore, the United States Food and Drug Administration recommends the use of sevoflurane with fresh gas flow rates at least 1 L/min for exposures up to 1 hour and at least 2 L/min for exposures greater than 1 hour. We believe this is a rational, cautious approach based on available data. However, it is important to note that other countries have not recommended such limitations on the clinical use of sevoflurane and problems have not been noted.