Absence of Renal and Hepatic Toxicity After Four Hours of 1.25 Minimum Alveolar Anesthetic Concentration Sevoflurane Anesthesia in Volunteers

Comparison of Two Different Inhalation Anesthetics on Grafted Kidney Function in Patients Undergoing Renal Transplantation Surgery: Desflurane or Sevoflurane?

BACKGROUND

Anesthetic management of patients during renal transplantation is vitally important for ensuring proper functioning of kidneys that have undergone ischemia-reperfusion damage. The goal of this prospective study was to compare the effects of 2 different inhalation agents (sevoflurane and desflurane) on grafted kidney function in renal transplantation surgery.

METHODS

Sixty-five patients who were scheduled for living donor renal transplantation were enrolled in the study. General anesthesia was performed on all patients. Thirty-five pairs of recipients and donors were anesthetized with sevoflurane (group S) and 30 pairs of recipients and donors were anesthetized with desflurane (group D). Each patient's demographic characteristics, immunologic and clinical data, and hemodynamic parameters were recorded. The estimated glomerular filtration rate was calculated in the preoperative period and on postoperative days 1 and 7. The blood samples were collected before the operation and on postoperative days 1 and 7 for measurement of serum creatinine, neutrophil gelatinase-associated lipocalin, and interleukin 18.

RESULTS

There were no significant differences in demographic characteristics or immunologic data between group D and group S. Intraoperative heart rate and mean arterial blood pressure were the same between groups. Creatinine, estimated glomerular filtration rate, neutrophil gelatinase-associated lipocalin, and interleukin 18 values did not differ between groups (P > .05) in the preoperative period and postoperative days 1 and 7.

CONCLUSIONS

Sevoflurane and desflurane had no adverse effects on grafted kidney functions according to short-term graft outcomes in patients undergoing living donor renal transplantation.

The effects of desflurane and sevoflurane on hepatic and renal functions after right hepatectomy in living donors*

We compared postoperative hepatic and renal functions between the two inhalational anesthetics, desflurane and sevoflurane in living donors undergoing right hepatectomy. Seventy-four adult donors were randomly allocated into Des group (n = 37) and sevo group (n = 37). Before the induction of anesthesia, morphine sulfate 400 microg was injected intrathecally. Anesthesia was maintained with one minimum alveolar concentration (MAC) of deflurane or sevoflurane plus continuous intravenous remifentanil. Liver and renal function tests were performed and analysed at preoperative period, immediately after operation, and on 1st, 2nd, 3rd, 5th, 7th, and 30th postoperative days (PODs). Aspartate aminotransferase (AST) showed significant elevations from the day of surgery to POD 3 and alanine aminotransferase (ALT) was significantly elevated on POD 1 and POD 3 in the sevo group. Albumin level was significantly lower on POD 2 in the sevo group. Creatinine was significantly higher on POD 3 and POD 30 and estimated glomerular filtration ratio was significantly lower on POD 3 and POD 30 in the sevo group. No patient developed hepatic or renal failures. The results of our study showed better postoperative hepatic and renal function test with desflurane than sevoflurane at equivalent dose of 1 MAC in living donors undergoing right hepatectomy, but further study is required to evaluate clinical importance.

Low flow and economics of inhalational anaesthesia

Even when anaesthesia does not represent a major part of the expense of a given surgical operation, reducing costs is not negligible because the large number of patients passing through a department of anaesthesia accounts for a huge annual budget. Volatile anaesthetics contribute 20% of the drug expenses in anaesthesia, coming just behind the myorelaxants; however, the cost of halogenated agents has potential for savings because a significant part of the delivered amount is wasted when a non- or partial-rebreathing system is used. The cost of inhaled agents is related to more than the amount taken up; it also depends on their market prices, their relative potencies, the amount of vapour released per millilitre of liquid, and last but not least the fresh-gas flow rate (FGF) delivered to the vaporizer--the most important factor determining the cost of anaesthesia. Poorly soluble agents like desflurane and sevoflurane facilitate the control of low-flow anaesthesia and reduce the duration of temporary high-flow phases to rapidly wash in or adjust the circuit gas concentrations. Modelling low-flow or minimal-flow anaesthesia will help anaesthetists to understand the kinetics of inhaled agents in those circumstances and to design their own clinical protocols. The monitoring facilities present on modern anaesthesia machines should convince clinicians that low- or even minimal-flow anaesthesia would not jeopardize the safety of their patients. Cost containment requires primarily a decrease in FGFs, but it may also be influenced by a rational use of the available halogenated agents. Isoflurane, the cheapest generic agent, might be advantageous for maintenance of anaesthesia of less than 3 hours. Sevoflurane is the agent of choice for inhalational induction and might also be used for maintenance. Desflurane might be preferred for long anaesthetics where rapid recovery will generate savings in the PACU.

Kidney transplantation: recent developments and recommendations for anesthetic management

Kidney transplantation is the treatment of choice for patients with end-stage renal disease. After receiving a transplant, survival rates are higher and comorbidities may resolve. As a consequence, more patients with significant comorbidities such as advanced cardiovascular disease will present for transplantation. This review highlights commonly encountered issues in patients undergoing kidney transplantation and recommendations are made for their anesthetic management.

Sevoflurane: an ideal agent for adult day-case anesthesia?

Sevoflurane has several properties which make it potentially useful as a day case anaesthetic. Following induction of anaesthesia with propofol, awakening from sevoflurane is faster compared to isoflurane, faster or similar compared to propofol and comparable (in the majority of studies) to desflurane. Subsequent recovery and discharge is generally similar following all agents. Sevoflurane may also be used to induce anaesthesia, which is generally well-received and causes less hypotension and apnoea compared to propofol. When used as a maintenance anaesthetic, the incidence of postoperative nausea and vomiting after sevoflurane is comparable to other inhaled anaesthetics, but this complication appears more common after inhaled inductions. The tolerability and low solubility of sevoflurane facilitate titration of anaesthesia and may reduce the need for opioid analgesia, which in turn may limit the occurrence of nausea and vomiting.

Halogenated inhalational anaesthetics

The halogenated inhalational anaesthetics halothane, enflurane, isoflurane and desflurane can produce metabolic hepatocellular injury in humans to a variable extent. During metabolism of these anaesthetics, tissue acetylation occurs due to the formation of reactive intermediates. Proteins modified by acetylation may constitute neo-antigens with a potential for triggering an antibody-mediated immune response. The likelihood of suffering post-operative immune hepatitis depends on the amount of the anaesthetic metabolized and is thereby considerably less with enflurane, isoflurane or desflurane compared with halothane. Plasma inorganic fluoride concentrations are regularly increased after sevoflurane. Elevated inorganic fluoride concentrations have been associated with nephrotoxicity following methoxyflurane anaesthesia but not after sevoflurane. Another source of concern is the products of degradation from reactions with carbon dioxide absorbents. Most important is compound A, which has been shown to exhibit nephrotoxicity in rodents. However, no significant changes in renal function parameters have been reported in surgical patients.

The choice of inhalation anaesthetic for major abdominal surgery in children with liver disease

Many children with liver disease undergo major abdominal surgery. Maintenance of anaesthesia is thus an important consideration in this surgical population. Despite a comprehensive and painstaking review of the literature, a sound evidence base, on which a choice of inhalation anaesthetic may be made, is lacking due to limited research in these patients. Differences between the more recent agents such as isoflurane, sevoflurane and desflurane are minor. Sevoflurane is favoured in paediatric practice for gaseous induction, but desflurane or isoflurane are marginally the preferred agents for maintenance of anaesthesia in children with liver disease undergoing major abdominal surgery. However, on the evidence that exists, much of it admittedly in animals and in adults, all three are preferable to halothane in this group of patients. More work is needed in this area before sound conclusions can be drawn and one agent proved to be definitely superior to the others.

Serum fluoride concentrations, biochemical and histopathological changes associated with prolonged sevoflurane anaesthesia in horses

The volatile anaesthetic sevoflurane is degraded to fluoride (F-) and a vinyl ether (Compound A), which have the potential to harm kidney and liver. Whether renal and hepatic injuries can occur in horses is unknown. Cardiopulmonary, biochemical and histopathological changes were studied in six healthy thoroughbred horses undergoing 18 h of low-flow sevoflurane anaesthesia. Serum F- concentrations were measured and clinical laboratory tests performed to assess hepatic and renal function before and during anaesthesia. Necropsy specimens of kidney and liver were harvested for microscopic examination and compared to pre-experimental needle biopsies. Cardiopulmonary parameters were maintained at clinically acceptable levels throughout anaesthesia. Immediately after initiation of sevoflurane inhalation, serum F- levels began to rise, reaching an ongoing 38-45 micromol 1(-1) plateau at 8 h of anaesthesia. Serum biochemical analysis revealed only mild increases in glucose and creatinine kinase and a decrease in total calcium. Beyond 10 h of anaesthesia mild, time-related changes in urine included increased volume, glucosuria and enzymuria. Histological examination revealed mild microscopic changes in the kidney involving mainly the distal tubule, but no remarkable alterations in liver tissue. These results indicate that horses can be maintained in a systemically healthy state during unusually prolonged sevoflurane anaesthesia with minimal risk of hepatocellular damage from this anaesthetic. Furthermore, changes in renal function and morphology observed after sevoflurane inhalation are judged minimal and appear to be clinically irrelevant; they may be the result of anaesthetic duration, physiological stressors, sevoflurane (or its degradation products) or other unkown factors associated with these animals and study conditions.

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.

Effects of sevoflurane general anesthesia: immunological studies in mice

Based on the immunomodulatory effects of anesthesia and surgery, a study was undertaken to assess the effect of sevoflurane anesthesia on the immune system in a murine model without surgery. Adult male mice were anesthetized with 3% sevoflurane (1.2 minimal alveolar concentration, MAC) in oxygen for 40 min, whereas nontreated animals served as controls. After sevoflurane anesthesia, peripheral blood leukocyte counts, the splenic composition and in vitro macrophage phagocytic activity and lymphoproliferative response were assessed. The in vivo specific immune response to sheep red blood cells (SRBC), a conventional T-dependent antigen was determined. In addition, liver, spleen, thymus and kidney histopathology and also hepatic and renal functions after anesthesia were studied. Sevoflurane diminished the number of peripheral blood lymphocytes and splenic B-cell counts, enhancing CD4+ lymphocytes in spleen. The in vitro functionality of macrophages and the mitogen-induced lymphoproliferative response were preserved, while the in vivo immune response to SRBC was enhanced in treated animals. Microscopic studies revealed conserved architecture of the spleen, thymus, lymph node, liver and kidney, and there were no differences in serum parameters of hepatic and renal functions between treated and control groups. Our results suggest that 3 days after the anesthetic exposure, animals treated with sevoflurane modulated their peripheral blood leukocyte counts, splenic lymphoid composition and the characteristics of the specific response to SRBC, while there was no evidence of hepatic or renal toxicity.

Toxicity of a sevoflurane degradation product incubated with rat liver and renal cortical slices

Compound A (2-fluoromethoxy-1,1,3,3,3-pentafluoro-1-propene) is a degradation product of the anesthetic sevoflurane which is created in closed-circuit anesthetic machines. Past in vivo and in vitro studies have implied that Compound A is nephrotoxic via bioactivation through the cysteine conjugate beta-lyase pathway. Although glutathione (GSH) conjugates of Compound A have been reported, it is not clear if they are formed enzymatically or via direct reaction with GSH. To determine if these metabolites are produced and toxic, a tissue slice system that first exposes male Fischer 344 rat liver slices to volatilized Compound A followed by exposure of rat kidney slices to the liver incubate was employed. Liver slices exposed to volatilized Compound A (6-12 microM medium conc.; approximately 23 ppm) exhibited a loss of K+ by 6 h, which was not seen in kidney slices exposed to Compound A. Aminobenzotriazole, a cytochrome P 450 suicide inhibitor, initially inhibits the cytotoxicity of Compound A to liver slices (at these times and concentrations). The sequential liver/kidney slice experiments using Compound A have not demonstrated nephrotoxic results. GSH conjugates were synthesized and was found to be nephrotoxic at concentrations above 91 microM (18 h), with higher concentrations showing toxicity at earlier times. Additionally, non-enzymatic reactions of Compound A with GSH or sulfhydryl-containing medium produces nephrotoxic products. These studies show that Compound A is directly toxic to the liver, possibly via P 450 activation, and Compound A can react with sulfhydryls directly to produce a nephrotoxic.

Sevoflurance: approaching the ideal inhalational anesthetic. a pharmacologic, pharmacoeconomic, and clinical review

Sevoflurane is a safe and versatile inhalational anesthetic compared with currently available agents. Sevoflurane is useful in adults and children for both induction and maintenance of anesthesia in inpatient and outpatient surgery. Of all currently used anesthetics, the physical, pharmacodynamic, and pharmacokinetic properties of sevoflurane come closest to that of the ideal anesthetic (200). These characteristics include inherent stability, low flammability, non-pungent odor, lack of irritation to airway passages, low blood:gas solubility allowing rapid induction of and emergence from anesthesia, minimal cardiovascular and respiratory side effects, minimal end-organ effects, minimal effect on cerebral blood flow, low reactivity with other drugs, and a vapor pressure and boiling point that enables delivery using standard vaporization techniques. As a result, sevoflurane has become one of the most widely used agents in its class.

The effects of prolonged low-flow sevoflurane anesthesia on renal and hepatic function

We assessed the effects of prolonged low-flow sevoflurane anesthesia on renal and hepatic functions by comparing high-flow sevoflurane with low-flow isoflurane anesthesia. Thirty patients scheduled for surgery of > or =10 h in duration randomly received either low-flow (1 L/min) sevoflurane anesthesia (n = 10), high-flow (6-10 L/min) sevoflurane anesthesia (n = 10), or low-flow (1 L/min) isoflurane anesthesia (n = 10). We measured the circuit concentrations of Compound A and serum fluoride. Renal function was assessed by blood urea nitrogen, serum creatinine, creatinine clearance, and urinary excretion of glucose, albumin, protein, and N:-acetyl-beta-D-glucosaminidase. The hepatic function was assessed by serum aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, alkaline phosphatase, and total bilirubin. Compound A exposure was 277 +/- 120 (135-478) ppm-h (mean +/- SD [range]) in the low-flow sevoflurane anesthesia. The maximum concentration of serum fluoride was 53.6 +/- 5.3 (43.4-59.3) micromol/L for the low-flow sevoflurane anesthesia, 47.1 +/- 21.2 (21.4-82.3) micromol/L for the high-flow sevoflurane anesthesia, and 7.4 +/- 3.2 (3.2-14.0) micromol/L for the low-flow isoflurane anesthesia. Blood urea nitrogen and serum creatinine were within the normal range, and creatinine clearance did not decrease throughout the study period in any group. Urinary excretion of glucose, albumin, protein, and N:-acetyl-beta-D-glucosaminidase increased after anesthesia in all groups, but no significant differences were seen among the three groups at any time point after anesthesia. Lactate dehydrogenase and alkaline phosphatase on postanesthesia Day 1 were higher in the high-flow sevoflurane group than in the low-flow sevoflurane group. However, there were no significant differences in any other hepatic function tests among the groups. We conclude that prolonged low-flow sevoflurane anesthesia has the same effect on renal and hepatic functions as high-flow sevoflurane and low-flow isoflurane anesthesia.

IMPLICATIONS

During low-flow sevoflurane anesthesia, intake of Compound A reached 277 +/- 120 ppm-h, but the effect on the kidney and the liver was the same in high-flow sevoflurane and low-flow isoflurane anesthesia.

Dose of compound A, not sevoflurane, determines changes in the biochemical markers of renal injury in healthy volunteers

Administration of sevoflurane in a circle absorption system generates Compound A, a nephrotoxin in rats. Reports examining the potential of Compound A to produce renal injury in humans have provided conflicting results. We tested the possibility that there is a threshold to Compound A-induced renal injury in humans and that, above this threshold, renal injury increases with increasing doses of Compound A. Eleven volunteers received 3% sevoflurane for 8 h at 2 L/min, and three volunteers received 3% sevoflurane for 8 h at 4-6 L/min. We measured inspired and expired concentrations of Compound A and urinary excretion of albumin, alpha-glutathione-S-transferase (GST), and glucose. The median urinary excretion of albumin, glucose, and alpha-GST for the first 3 days after anesthesia increased significantly from preanesthetic values in the 2-L/min group. Compound A doses < 240 ppm-h resulted in normal urinary excretion of albumin, glucose, and alpha-GST. Five of seven subjects who received doses > 240 ppm-h had abnormal excretion of albumin, and six of seven had abnormal alpha-GST urinary excretion (P < 0.05). Urinary excretion of albumin, alpha-GST, and glucose was normal by 14 days after exposure. We conclude that sevoflurane administration for 8 h at 2 L/min results in albuminuria and enzymuria when the dose of Compound A exceeds 240 ppm-h. That is, a Compound A concentration of 30 ppm breathed for > or = 8 h may produce transient renal injury.

IMPLICATIONS

We examined the dose-response relationship of sevoflurane/Compound A and urinary excretion of albumin, glucose, and alpha-GST. Sevoflurane exposure for 8 h at a 2-L/min inflow rate produces transient albuminuria and enzymuria in healthy volunteers when the dose of Compound A exceeds 240 ppm-h (30 ppm for 8 h).

Renal function in patients during and after hypotensive anesthesia with sevoflurane

STUDY OBJECTIVES

To evaluate renal function during and after hypotensive anesthesia with sevoflurane compared with isoflurane in the clinical setting.

DESIGN

Randomized, prospective study.

SETTING

Inpatient surgery at Rosai Hospital.

PATIENTS

26 ASA physical status I and II patients scheduled for orthopedic surgery.

INTERVENTIONS

Patients received isoflurane, nitrous oxide (N2O), and fentanyl (Group I = isoflurane group; n = 13) or sevoflurane, N2O, and fentanyl (Group S = sevoflurane group; n = 13). Controlled hypotension was induced with either isoflurane or sevoflurane to maintain mean arterial pressure at 60 mmHg for 120 minutes.

MEASUREMENTS AND MAIN RESULTS

Measurements included serum inorganic fluoride (previously speculated to influence renal function), creatinine clearance (CCr; to assess renal glomerular function), urinary N-acetyl-beta-D-glucosaminidase (NAG; to assess renal tubular function), blood urea nitrogen (BUN), and serum creatinine (as clinical renal function indices). Serum fluoride, CCr, and NAG were measured before hypotension, 60 minutes, and 120 minutes after the start of hypotension, 30 minutes after recovery of normotension, and on the first postoperative day. BUN and serum creatinine were measured preoperatively and on the third and seventh postoperative days. Minimum alveolar concentration times hour was 3.6 +/- 1.8 in Group I and 4.0 +/- 0.7 in Group S. In both groups, BUN and serum creatinine did not change, and CCr significantly decreased after the start of hypotension. In Group I, serum fluoride and NAG did not change. In Group S, serum fluoride significantly increased after the start of hypotension compared with prehypotension values and compared with Group I values. In addition, NAG significantly increased at 120 minutes after the start of hypotension and at 30 minutes after recovery of normotension, but returned to prehypotension values on the first postoperative day.

CONCLUSIONS

Two hours of hypotensive anesthesia with sevoflurane under 5 L/min total gas flow in patients having no preoperative renal dysfunction transiently increased NAG, which is consistent with a temporary, reversible disturbance of renal tubular function.