Toxicity following methoxyflurane anaesthesia. IV. The role of obesity and the effect of low dose anaesthesia on fluoride metabolism and renal function

Seven obese and five normal weight patients were studied before, during and after one hour of methoxyflurane-nitrous oxide anaesthesia during peripheral surgical operations and compared with eight patients of normal weight anaesthetized with nitrous oxide-meperidine and d-tubocurare. Estimates were made of renal function, including serum and urinary electrolytes, osmolarity, uric acid, urea and creatinine. Renal clearances for the latter three substances were also calculated. Serum and urinary inorganic and organic fluoride concentrations were measured, as were renal clearances. This low dose methoxyflurane anaesthesia resulted only in a decrease in uric acid clearance among all the measures, when compared to the meperidine-nitrous oxide controls. The clearance of uric acid remained depressed for longer in the obese patients, but otherwise they did not differ from the normal weight patients. It is possible but not proven that depressed uric acid clearance may be related to the organic fluoride metabolite and an early indicator of methoxyflurane renal toxicity. The previously documented biotransformation of methoxyflurane was seen in this study. A double peak in serum inorganic fluoride was shown in all patients but one. Rather large differences in peak levels of serum inorganic fluoride occurred. The only significant difference between the obese and normal weight patients as far as fluoride metabolism was concerned was a greater variability in the serum inorganic fluoride levels in the obese patients. It would appear that the obese patient metabolizes methoxyflurane in a quantitatively if not qualitatively different fashion than the normal weight patient, perhaps because of fatty infiltration of the liver. Caution is advised in the use of methoxyflurane for more than 90 minutes of low concentration administration in view of the unpredictability of the biotransformation.     

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.     

Influence of sevoflurane and isoflurane anesthesia on renal function in elderly patients

We examined the influence of sevoflurane and isoflurane anesthesia on renal function in elderly patient who underwent gastrectomy. Plasma inorganic fluoride level was significantly higher in sevoflurane group compared with isoflurane group from 3 hours after the beginning of anesthesia to the 3rd operative day. In contrast, parameters such as urinary beta 2 microglobulin, urinary N-acetyl-beta-D-glucosaminidase, and urinary gamma-GTP activities increased in both groups, but the increase was not significant. Serum BUN and creatinine levels were within normal limits. These results suggest that elderly patients without renal dysfunction appear unlikely to have any significant problem after prolonged sevoflurane anesthesia.     

Accuracy of estimated creatinine clearance in obese patients with stable renal function in the intensive care unit

We compared agreement between creatinine clearance values in obese, critically ill patients calculated using three common empirically derived formulas and modifications thereof, with creatinine clearance obtained by conventional 24-hour urine collection. We selected the charts of 22 patients in intensive care units (86% medical, 14% surgical) according to the following criteria: actual body weight greater than 150% of ideal body weight; serum creatinine variation of less than 15% from the day of starting 24-hour urine collection to the day before or after the collection; presence of a urinary bladder catheter; no history of renal dialysis; and clinical indication for renal function assessment. Mean measured 24-hour urinary creatinine clearance for all patients was 72 +/- 64 ml/minute (range 8-248 ml/min). The method of estimating creatinine clearance that showed the least mean bias was the equation of Salazar and Corcoran using a corrected serum creatinine concentration (mean bias -2 ml/min); however, the corresponding 95% confidence intervals were wide (-133-129 ml/min). The narrowest range of 95% confidence intervals were seen with Jelliffe's equation (mean bias 25 ml/min, 95% confidence intervals -41-90 ml/min). In this sample, estimated creatinine clearances did not agree acceptably with measured values. Despite low mean bias values, none of the empirically derived equations that we studied had clinically acceptable 95% confidence intervals. We recommend using the 24-hour urine collection method when assessing creatinine clearance in obese, critically ill patients.     

Clinical pharmacokinetics of sisomicin: dosage schedules in renal-impaired patients

The pharmacokinetics of intravenously administered sisomicin were studied in 33 patients with normal renal function and different degrees of renal impairment. In all patients, the serum disappearance of sisomicin, once distribution equilibrium had been achieved, followed first-order kinetics and percentage of hourly loss from serum decreased proportionally with decreasing renal function. Half-lives averaged 2.06 h in normal subjects (endogenous creatinine clearance greater than 80 ml/min per 1.73 m(2)) and reached 35.3 h in a virtually anephric subject. Linear relationships were defined between sisomicin serum half-life and the reciprocal of the endogenous creatinine clearance and serum creatinine concentration. The latter relationship indicates that the half-life of sisomicin may be approximated as twice the serum creatinine concentration and may be used for dosage adjustment in renal-impaired patients. Prediction of the extent of sisomicin removal by hemodialysis may be made from the relationship between the dialyzate of sisomicin and that of creatinine and blood urea nitrogen. Dosage schedules and methods of administration compatible with the pharmacokinetic properties of the antibiotic are finally proposed.     

Pharmacokinetics of carboplatin in a patient with cervical cancer with ureteric obstruction before, during, and after hemodialysis

The pharmacokinetics of total and free (ultrafilterable) platinum were investigated in a patient with cervical cancer with ureteric obstruction who, at the time of carboplatin administration, appeared to have a mild renal impairment (i.e., creatinine clearance 1 mL/s), but developed an acute renal failure shortly thereafter, which required hemodialysis. The decline in the concentration of total or free Pt in plasma as function of time correlated well (P < 0.0098) with that of serum creatinine concentration. The elimination half-lives (t1/2) of total and free Pt in this patient were eight- and nine-fold longer than those observed earlier for patients with normal renal function, and the total body clearance was 12.4% and 18.4%, respectively. Although t1/2 of Pt during dialysis was two to three times (total Pt) and eight times (free Pt) shorter than those observed before and after dialysis, three sessions of hemodialysis removed only 5.6% of total Pt and 9.3% of free Pt. Because the pre- and post-dialysis t1/2 values were similar, hemodialysis apparently had no impact on the intrinsic elimination of Pt in this patient.     

Application of alpha-keto acid decarboxylases in biotransformations

BACKGROUND: Low-flow sevoflurane anesthesia is associated with increasing circuit concentrations of compound A, which is nephrotoxic in rats, but the effect of compound A and low-flow sevoflurane anesthesia on renal function in humans is unclear. The authors compared the effects of high- and low-flow sevoflurane and isoflurane anesthesia on renal function and on several possible markers of nephrotoxicity in humans. METHODS: Forty-two patients without preexisting renal disease underwent either low-flow isoflurane (1 l/min, n = 14), low-flow sevoflurane (1 l/min, n 14), or high-flow sevoflurane (6 l/min, n = 14) anesthesia for body-surface-area surgery scheduled to last at least 4 h. Twenty-four-hour urinary excretion of N-acetyl-beta-glucosaminidase (NAG), beta2-microglobulin, protein, glucose, blood urea nitrogen (BUN), and serum creatinine concentrations were measured before and after anesthesia. RESULTS: There were no differences in blood urea nitrogen, creatinine, and creatinine clearance among the three groups after anesthesia. Increased urinary N-acetyl-beta-glucosaminidase excretions were seen in the low-flow and high-flow sevoflurane groups, but not in the low-flow isoflurane group (P < 0.01). Ten patients in the low-flow sevoflurane group had 24-h urinary excretion of protein that exceeded the normal ranges after anesthesia, but only one patient in the isoflurane and none in the high-flow sevoflurane groups had this. CONCLUSIONS: Low-flow sevoflurane anesthesia was associated with mild and transient proteinuria. However, the observed proteinuria was not associated with any changes in blood urea nitrogen, creatinine, and creatinine clearance in these patients with no preexisting renal disease.     

Pharmacokinetics of cefamandole in patients undergoing hemodialysis and peritoneal dialysis

The pharmacokinetics of cefamandole nafate, a new parenteral cephalosporin derivative, were evaluated in 11 patients with chronic renal failure (creatinine clearance less than 5 ml/min), including five patients during hemodialysis, four patients during routine peritoneal dialysis, and two patients during the interdialytic period. Peak serum levels of cefamandole were comparable to those observed in patients with normal renal function. Clearance of the drug during the interdialytic period and during hemodialysis and peritoneal dialysis was minimal, with a resultant significant prolongation of serum half-life. The nondialyzability of cefamandole is in contrast with reported studies of cephalothin, where significant reduction of the serum half-life was achieved during hemodialysis but not peritoneal dialysis. The concentration of cefamandole in the peritoneal dialysate after parenteral administration was observed to be bactericidal for many gram-negative pathogens and, with the exception of Streptococcus faecalis, most gram-positive organisms found in bacterial peritonitis in patients with severe renal failure. The present data suggest that if stable bactericidal serum levels of cefamandole are to be maintained during hemodialysis and peritoneal dialysis, a parenteral loading dose must be administered followed by one-half the loading dose every half-life.     

Pharmacokinetics and clinical effects of cefuroxime in patients with severe renal insufficiency

The pharmacokinetics and clinical effects of cefuroxime were investigated in 5 patients with severe impairment of renal function (creatinine clearance less than or equal to 23 ml/min), suffering from an urinary tract infection. Bolus i.v. injections of cefuroxime 750 mg b.i.d. or 750 mg once daily were given to the patients depending on the degree of renal impairment. The concentration of drug in serum and urine was measured during treatment, and pharmacokinetic parameters were evaluated on the second and last days; the parameters obtained on the 2 days did not differ significantly. Drug elimination half-life increased from 4.2 h (creatinine clearance 23.0 ml/min) to 22.3 h (creatinine clearance 5.0 ml/min) with decreasing renal function. The apparent volume of distribution ranged from 11.6 to 17.9 l, and showed a substantial increase to 29.6 l in the patient with the poorest renal function. A linear correlation was found between the total and renal clearance of cefuroxime and the creatinine clearance; the extrarenal clearance was 8.24 ml/min. Concomitant treatment with furosemide did not impair renal function and no evidence of nephrotoxicity was found. The clinical efficacy of the drug was good. Symptoms of infection subsided after 3-4 days and the isolated pathogens were eradicated. No relapse or episodes of reinfection were observed in a following-up period of 3 months. The drug was well tolerated and no side effects or changes in haematological or biochemical values were seen.     

The motor organization of the sense of rhythm

Serum inorganic fluoride levels in obese versus control patients were compared during and after sevoflurane anesthesia. Mean serum inorganic fluoride levels in the obese group increased more rapidly and were significantly higher than in the control group at each sampling time (P < 0.01). The area under the curve of fluoride concentration, versus time up to 24 h and 48 h in the obese patients, was significantly greater than that in the nonobese patients (P < 0.001). Peak serum fluoride level in the obese patients was 51.7 +/- 2.5 mumol/L and exceeded 50 mumol/L for nearly 2 h. Our study showed that serum fluoride concentrations between mildly obese and nonobese patients differed during and after sevoflurane anesthesia.     

Founder effect at PGL1 in hereditary head and neck paraganglioma families from the Netherlands

After repeated exposure to inhaled anesthetics, the hepatic function and metabolism of anesthetics may change. The purpose of this study was to investigate inorganic fluoride (F-) kinetics and renal and hepatic function after repeated exposure to sevoflurane. Ten patients (aged 40-70 yr) who had received sevoflurane anesthesia with a gas flow of 6 L/min for neurosurgery twice in 30-90 days were studied. Serum and urine F- concentrations were measured up to 24 h after anesthesia. Blood urea nitrogen, serum creatinine, serum and urine beta2-microglobulin, urine N-acetyl-beta-D-glucosaminidase, serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin concentrations were measured up to 7 days after anesthesia. The area under the curve (AUC) of serum and urine F- concentration and half-life of serum F concentration were calculated. Urine beta2-microglobulin, AST, and ALT increased to abnormal levels after both anesthesias, with no difference between anesthesias. No measured variables, AUC of serum and urine F- concentration, or half-life of serum F- concentration showed any differences between the first and second anesthesias. In conclusion, the second exposure to sevoflurane with a high gas flow of 6 L/min in 30-90 days did not change the hepatic and renal function or affect the metabolism of sevoflurane. Implications: We studied the changes of metabolism of sevoflurane and hepatic and renal function after repeated sevoflurane anesthesia in 30-90 days. There were changes indicative of mild liver and kidney injury after sevoflurane anesthesia, but repeated exposure to sevoflurane did not enhance these changes.     

Augmenting solute clearance in peritoneal dialysis

BACKGROUND: The removal of low molecular weight solutes by peritoneal dialysis is less than by hemodialysis. The targets for Kt/Vurea and creatinine clearance formulated in the Dialysis Outcome Quality Initiative are unlikely to be achieved in a substantial portion of peritoneal dialysis patients. Possibilities to increase small solute clearances have therefore been subject to many investigations. METHODS: A review of the literature and of recent new data on determinants of solute removal, such as residual renal function, the role of drained dialysate volume and manipulation of the diffusive capacity of the peritoneum are presented. RESULTS: The contribution of residual GFR is more important for the clearance of creatinine than for Kt/Vurea. It is even more important for the removal of organic acids that are removed from the body by tubular secretion. High dosages of furosemide increase the urinary volume and the fractional Na+ excretion, but have no effect on the magnitude of residual GFR, renal creatinine clearance, renal urea clearance, and peritoneal transport characteristics. The drained dialysate volume per day is the main determinant of the peritoneal removal of urea. Its effect decreases the higher the molecular weight of a solute. It can be augmented by using large instillation volumes, by the application of more exchanges, and by increasing peritoneal ultrafiltration. A large exchange volume is especially effective in patients with an average transport state, but in those with high solute transport rates, Kt/Vurea is especially influenced by the number of exchanges. Possibilities to increase ultrafiltration are discussed. The diffusive capacity of the peritoneum can be augmented by using low dosages of intraperitoneally administered nitroprusside. This increases solute transport most markedly when it is applied in combination with icodextrin as osmotic agent. CONCLUSIONS: Small solutes clearances cannot be increased by furosemide. Increasing the instilled volume of dialysis fluid and the number of exchanges both affect solute clearance. Studies are necessary on long-term effects of manipulation of the peritoneal membrane with nitroprusside.     

Lactogenic hormone signal transduction

Dialyzers are reused in approximately three quarters of the dialysis units in the United States, but the effect of reprocessing on dialyzer performance has not been extensively evaluated. In a crossover study of six chronic hemodialysis patients, we determined urea, creatinine, phosphate, and beta2-microglobulin clearances and dialysate protein loss for two types of low-flux and two types of high-flux dialyzers during use numbers 1, 2, 5, and 15. Dialyzers were reprocessed by an automated machine using Renalin (Renal Systems, Plymouth, MN) as the germicide. Dialyzer arterial and venous blood and dialysate outflow samples were obtained at 5 and 180 minutes of each dialysis session to evaluate solute clearances. Urea, creatinine, and phosphate clearances were calculated using dialysate concentrations, whereas beta2-microglobulin clearance was calculated using plasma concentrations to include its removal by adsorption to the dialysis membrane. There was a trend for urea, creatinine, and phosphate clearances to decrease with reuse for both low-flux and high-flux dialyzers, but these differences were not statistically significant. The clearance of beta2-microglobulin and dialysate total protein concentration was small for low-flux dialyzers; these values were not dependent on reuse. There was a trend for beta2-microglobulin clearance and dialysate total protein concentration to decrease during a dialysis treatment using high-flux dialyzers. More significantly, beta2-microglobulin clearance and dialysate total protein concentration decreased substantially with the reuse of high-flux dialyzers. These observations show that the maintenance of small solute clearances during reuse of high-flux dialyzers does not ensure the maintenance of large solute clearances.     

Repeated low-flow sevoflurane anesthesia: effects on hepatic and renal function in beagles

We studied the effects of repeated low-flow sevoflurane anesthesia for 6 hours. Five beagle dogs received 1.3 MAC (3%) sevoflurane anesthesia. Anesthesia of 6 hours was repeated on at the 7th day after the first anesthesia. Compound A gas samples were collected from the inspiratory limb during anesthesia. Concentrations of serum and renal fluoride, hepatic and renal function parameters were measured during and up to 7 days after the first and second anesthesia. The peak concentration of compound A was 23.7 +/- 3.6 ppm at 2 hours and the same level remained during the anesthesia. Plasma fluoride level exceeded 50 mmol.l-1 during anesthesia and rapidly decreased to the preanesthesia level thereafter. Serum GOT increased slightly only on the first postanesthesia day. No significant changes in other blood chemistry studies were observed. The excretion of renal tubular enzymes did not increase during and after anesthesia. Repeated low flow sevoflurane anesthesia in beagles did not affect hepatic and renal function significantly.     

Recurrent urinary tract infections. Biological suppositions and clinical treatment with thymopentin]

We estimated the glomerular filtration rate in 33 patients from our diabetic clinic using three methods: the creatinine clearance measured from a timed urine sample and a serum creatinine; the creatinine clearance calculated from the serum creatinine according to the formula of Cockcroft and Gault; and, the plasma clearance of ethylenediaminetetra-acetic acid (EDTA) labeled with 51Cr ([51Cr]EDTA). We repeated the measurements in seven subjects. The measured creatinine clearance was not reproducible. The other two methods were correlated, but not according to the formula y = x. The calculated creatinine clearance significantly underestimated the [51Cr]EDTA clearance particularly at higher [51Cr]EDTA clearance rates. [51Cr]EDTA clearance has been shown by others to parallel, but underestimate, inulin clearance, the optimal method of estimating glomerular filtration rate but difficult to perform in routine practice. Accurately measuring renal function in routine clinical practice is difficult, and this must be borne in mind when making clinical decisions based on current measurements.     

Serotonin inhibits nitric oxide synthesis in rat vascular smooth muscle cells stimulated with interleukin-1

The elimination half-life of fluoride is significantly increased in patients with chronic renal failure. This led us to conduct a study of variations of its plasma levels in 35 patients receiving dialysis treatment. In this population, there is a gaussian distribution of the values before and after the hemodialysis session, with a significant decrease in the averages. Furthermore, there is a highly significant correlation between fluoride levels before and after the dialysis session (P < 0.00001), and also between the amount of time in hemodialysis (in months) and the average fluoride level before dialysis (r = 0.624; P = 0.008). The presence of a group of patients consuming fluoride waters such as Vichy St-Yorre Water was easily identified by their excessive fluoride levels (above 100 micrograms/l), which could have a tendency to increase the risks of this group.     

Influence of sevoflurane on renal medullary blood flow in humans

Proper anesthetic management is necessary to preserve renal function during anesthesia and surgery. Using ultra-sound color Doppler, we examined the influence of sevoflurane on renal medullary blood flow in 20 adult patients without renal dysfunction. After identifying an interlobar artery in the outer medulla, we measured the velocity of the arterial blood flow before induction of anesthesia, and during sevoflurane anesthesia (1 MAC, 1.5 MAC). The minimum velocity of the interlobar arterial blood flow (Vmin) during wakefulness correlated significantly with creatinine clearance measured preoperatively. We did not find any significant change in Vmin after induction of sevoflurane anesthesia, despite significant decreases in mean arterial blood pressure.     

Absence of renal and hepatic toxicity after four hours of 1.25 minimum alveolar anesthetic concentration sevoflurane anesthesia in volunteers

Sevoflurane is degraded by CO2 absorbents to Compound A. The delivery of sevoflurane with a low fresh gas flow increases the generation of Compound A. The administration of Compound A to rats can produce injury to renal tubules that is dependent on both the dose and duration of exposure to Compound A. The present study evaluated renal and hepatic function in eight volunteers after a 1-L/min delivery of 3% (1.25 minimum alveolar anesthetic concentration) sevoflurane for 4 h. Volunteers gave their informed consent and provided 24-h urine collections before and for 3 days after sevoflurane anesthesia. Urine samples were analyzed for glucose, protein, albumin, and alpha- and pi-glutathione-S-transferase. Daily blood samples were analyzed for markers of renal and liver injury or dysfunction. Circuit Compound A and plasma fluoride concentrations were determined. During anesthesia, the average maximal inspired Compound A concentration was 39 +/- 6 (mean +/- SD). The median mean arterial pressure, esophageal temperature, and end-tidal CO2 were 62 +/- 6 mmHg, 36.5 +/- 0.3 degrees C, and 30.5 +/- 0.5 mm Hg, respectively. Two hours after anesthesia, the plasma fluoride concentration was 50 +/- 9 micromol/L. All markers of hepatic and renal function were unchanged after anesthesia (repeated-measures analysis of variance P > 0.05). Low-flow sevoflurane was not associated with renal or hepatic injury in humans based on unchanged biochemical markers of renal and liver function. IMPLICATIONS: Sevoflurane delivered in a 3% concentration with a fresh gas flow of 1 L/min for 4 h generated an average maximal Compound A concentration of 39 ppm but did not result in any significant increase in sensitive markers of renal function or injury, including urinary protein, albumin, glucose, and alpha- and pi-glutathione-S-transferase.     

A phase III, multicenter, open-label, randomized, comparative study evaluating the effect of sevoflurane versus isoflurane on the maintenance of anesthesia in adult ASA class I, II, and III inpatients

STUDY OBJECTIVE: To compare the clinical efficacy and safety of sevoflurane and isoflurane when used for the maintenance of anesthesia in adult ASA I, II, and III inpatients undergoing surgical procedures of at least 1 hour's duration. DESIGN: Phase III, randomized, open-label clinical trial. SETTING: 12 international surgical units. PATIENTS: 555 consenting inpatients undergoing surgeries of intermediate duration. INTERVENTIONS: Subjects received either sevoflurane (n = 272) or isoflurane (n = 283) as their primary anesthetic drug, each administered in nitrous oxide (N2O) (up to 70%) and oxygen (O2) after an intravenous induction using thiopental and low-dose fentanyl. The concentration of volatile drug was kept relatively constant but some titration in response to clinical variable was permitted. Comparison of efficacy was based on observations made of the rapidly and ease of recovery from anesthesia and the frequency of untoward effects for the duration of anesthesia in the return of orientation. Safety was evaluated by monitoring adverse experiences, hematologic and non-laboratory testing, and physical assessments. In 25% of patients (all patients 171 both treatment groups at selected investigational sites), plasma inorganic fluoride concentrations were determined preoperatively, every 2 hours during maintenance, at the end of anesthesia, and at 1, 2, 4, 8, 12, 24, 48, and 72 hours postoperatively. MEASUREMENTS AND MAIN RESULTS: Emergence, response to commands, orientation, and the first request for postoperative analgesia were all more rapid following discontinuation of sevoflurane than following discontinuation of isoflurane (sevoflurane, 11.0 +/- 0.6, 12.8 +/- 0.7, 17.2 +/- 0.9, 46.1 +/- 3.0 minutes, respectively, versus isoflurane, 16.4 +/- 0.6, 18.4 +/- 0.7, 24.7 +/- 0.9, 55.4 +/- 3.2 minutes). The incidence of adverse experiences was similar for sevoflurane and isoflurane patients. Forty-eight percent of patients on the sevoflurane group had no untoward effect versus 39% in the isoflurane group. Three patients who received sevoflurane had serum inorganic fluoride levels 50 microM/I. or greater though standard tests indicated no evidence of associated renal dysfunction. CONCLUSION: Sevoflurane anesthesia, as compared with isoflurane, may be advantageous in providing a smoother clinical course with a more rapid recover.