The effect of halothane, isoflurane, sevoflurane and propofol infusion on renal function after coronary artery bypass surgery.

Renal insufficiency after cardiac surgery is associated with increased mortality, morbidity, and length of stay in the intensive care unit. We investigated the effect of isoflurane, halothane, sevoflurane and propofol anesthesia on perioperative renal function following elective coronary artery surgery. The medical records of 224 patients, in the Hacettepe University Medical Faculty Hospital who had undergone cardiac surgery in one year, were retrospectively reviewed. 65 (29%) patients received isoflurane, 68 (30%) patients received halothane, 64 (29%) patients received sevoflurane, and 27 (12%) patients received propofol infusion as part of maintenance anesthesia for coronary artery bypass surgery. Patient characteristics (age, sex, preoperative ejection fraction), operative data (duration of CPB, duration of operation, number of distal anastomoses, usage of diuretic, intraoperative crystalloid and blood transfusion), intraoperative urinary output, preoperative and postoperative (6th hours and 24th hours) BUN and plasma creatinine levels, were not statistically significant between and within groups. Intraoperative inotropic agent (dopamine) was used in 8 (12.3%) patients in the isoflurane group, in 10 (14.7%) patients in the halothane group, in 11 (17.2%) patients in sevoflurane group and in 9 (33.3%) patients in the propofol group. Postoperatively fluid and blood transfusion, postoperative drainage, urinary output, diuretic usage were smiliar between the four groups (p>0,05). Inotropic agent was used in 8 (12.3%) patients in the isoflurane group, in 9 (13.2%) patients in the halothane group, in 16 (25%) patients in the sevoflurane group and in 7 (25.9%) patients in the propofol group. It is concluded that, halothane, isoflurane, sevoflurane and propofol infusion anesthesia as part of anesthesia maintenance for elective coronary artery bypass surgery does not affect early postoperative renal functions.

A rapid and simple method for determination of halothane, isoflurane and sevoflurane in blood using gas chromatography.

We have developed a technique to determine the concentration of volatile anesthetics (halothane, isoflurane and sevoflurane) in blood that is a modification of a method used for volatile anesthetics in Krebs solution. Methylene chloride was the internal standard and chloroform was used to extract the volatile anesthetic from blood. The congealed blood proteins were separated from the chloroform solvent (containing anesthetic) using a two-compartment vial that filtered out the proteinaceous material during centrifuging. Recovery averaged 102%. Linearity was excellent (r = 0.992-0.999) in the 50-600, 50-300 and 50-300 microg/mL range for halothane, isoflurane and sevoflurane, respectively. Intra-day and inter-day precisions were likewise excellent, with relative standard deviations <5.3 and <7.1%, respectively. Accuracy ranged from 0.8 to 9.5% of the estimated theoretical value. Extracted anesthetic in chloroform solvent was stable over 4-5 days, with <3% variability. The time from obtaining the blood sample to determination of the concentration from the chromatographic peak was 15 min or less.

Blood/gas partition coefficients of halothane, isoflurane and sevoflurane in horse blood.

BACKGROUND: Blood/gas partition coefficients (lambda(b/g)) for volatile agents in horse blood are reported for halothane but not for isoflurane and sevoflurane. We measured the lambda(b/g) of halothane, isoflurane and sevoflurane in the blood of fasted horses. The correlation with age, weight and some haematological and biochemical variables was studied. The temperature correction factor for isoflurane solubility was calculated. METHODS: Twenty-four horses were randomly allocated to halothane (n=8), isoflurane (n=8) or sevoflurane (n=8). Blood samples were taken after 10 h' fasting. Calculation of lambda(b/g) was based on the measurement of anaesthetic partial pressures in blood at 37 degrees C, which was achieved with tonometer equilibration and headspace gas chromatography. RESULTS: Mean lambda(b/g) was 1.66 (SD 0.06) for halothane, 0.92 (0.04) for isoflurane, and 0.47 (0.03) for sevoflurane. The lambda(b/g) values were all significantly lower than in humans (P<0.001). No correlation was found between lambda(b/g) and weight, age, haematocrit, plasma triglycerides, cholesterol or total bilirubin. The change in isoflurane solubility per 1 degrees C temperature increase was -2.63 (0.13)%. CONCLUSION: The lambda(b/g) values of halothane, isoflurane and sevoflurane in fasted horses are significantly lower than those reported in humans. The lambda(b/g) for halothane in this study agrees with values reported in the literature but a positive correlation with plasma triglycerides could not be confirmed. Knowledge of lambda(b/g) can refine models of anaesthetic uptake.

Dynamic changes in blood solubility of desflurane, isoflurane, and halothane during cardiac surgery.

OBJECTIVE: To determine an estimate of blood/gas partition coefficients of volatile anesthetics during cardiac surgery. DESIGN: Descriptive SETTING: University hospital PARTICIPANTS: Six adult patients undergoing valvular replacement with hypothermic cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS: Blood samples were obtained from patients at 6 time points: before induction, at skin incision, at aortic cannulation, at rewarming during bypass, at weaning off bypass, and at skin suture. Measured blood/gas partition coefficients were plotted against corresponding solubilities estimated according to the combined effects of hypothermia and hemodilution. Significant differences were found in blood/gas partition coefficients of the 3 anesthetics at different times during surgery (p < 0.05). Blood/gas partition coefficients at weaning off bypass were the lowest, about 75% of that before anesthetic induction. A direct linear relationship for estimated solubility against measured solubility was found (r2 = 0.94; p < 0.05). CONCLUSION: Dynamic changes in blood/gas partition coefficients of volatile anesthetics were found during cardiac surgery. They could be estimated by using multiple linear regression equations reflecting the combined effects of hypothermia and hemodilution.

Sensitive determination of four general anaesthetics in human whole blood by capillary gas chromatography with cryogenic oven trapping.

Four general anaesthetics, sevoflurane, isoflurane, enflurane and halothane, in human whole blood, have been found measurable with very high sensitivity by capillary gas chromatography-flame ionization detection (GC-FID) with cryogenic oven trapping upon injection of headspace (HS) vapor sample. To a 7-ml vial, containing 0.48 ml of distilled water and 20 microl of internal standard solution (5 microg), a 0.5-ml of whole blood sample spiked with or without anaesthetics, was added, and the mixture was heated at 55 degrees C for 15 min. A measure of 10 ml HS vapor was injected into the GC in the splitless mode at -40 degrees C oven temperature, which was programmed up to 250 degrees C. All four peaks were clearly separated; no impurity peaks were found among their peaks. Their extraction efficiencies were about 10%. The calibration curves showed good linearity in the range of 0.5-20 microg/ml; their detection limits were 10-100 ng/ml, which are almost comparable to those by previous reports. The coefficients of intra-day and day-to-day variations were 6.5-9.8 and 7.3-17.2%, respectively. Isoflurane or enflurane was also measured from whole blood samples in which three volunteers inhaled each compound.

Changes in the defense against free radicals in the liver and plasma of the dog during hypoxia and/or halothane anaesthesia.

Defenses against free radicals were evaluated in the dog under different conditions of ventilation. Changes in the levels of reduced glutathione (GSH), alpha-tocopherol (vitamin E), ascorbic acid (vitamin C) and the lipid peroxidation end-products, estimated as malondialdehyde (MDA) and the activity of superoxide dismutase (SOD), were studied in serial liver biopsies from dogs ventilated with either oxygen, halothane and oxygen, hypoxic gas mixture of 8% oxygen and 92% nitrogen or halothane under hypoxic conditions. Simultaneous determination of GSH, vitamin E and MDA were carried out in the plasma. The results showed time-dependent depletion of GSH and vitamin E in liver and plasma and vitamin C in the liver. This was accompanied by a simultaneous increase in the levels of MDA. The magnitude of the change was in the following order: halothane and hypoxia > hypoxia > halothane and oxygen > oxygen. The greatest depletion was observed for vitamin E and the least for vitamin C. The rise in the level of MDA in plasma was much higher than in the liver tissue. Hypoxia resulted in inhibition of liver SOD activity. It seems that increased production of free radicals under hypoxic conditions may have overwhelmed the anti-oxidant defenses in the liver. In addition, the much higher level of MDA in plasma, as compared to liver tissue, may indicate that MDA could have originated in tissues or organs other than the liver and leaked into the blood, indicating possible damage in other locations in the body.

Quantitative study of Lowe's square-root-of-time method of closed-system anaesthesia.

Intermittent injection of liquid anaesthetic into a closed breathing system is particularly suitable in countries with limited resources. A method of calculating appropriate times and magnitudes of the injected doses was described by Lowe but the method has never been assessed rigorously. Such an assessment was the purpose of this study. The technique was used in a double-blind, randomized comparison of halothane, enflurane and isoflurane in oxygen-air, with 20 ASA I or II patients in each group, undergoing superficial or abdominal surgery. The prescribed times of injection were adhered to, but the doses, after the first two, were adjusted to maintain systolic arterial pressure within 20% of the reference preoperative value. Partial pressures of the anaesthetics were monitored but concealed from the investigator-anaesthetist. The mean doses found necessary for each anaesthetic were within 33% of those calculated to produce 1.3 MAC. However, end-tidal partial pressure (just before each dose) stabilized at a steady level of only 0.97, 0.42 and 0.77 MAC for halothane, enflurane and isoflurane, respectively. Recovery from enflurane was much more rapid than that from the other agents but no patient admitted to any dreams. We conclude that the rate of uptake of anaesthetic declines more slowly than predicted and that the patients receiving enflurane were less deeply anaesthetized because the greater hypotensive effect of enflurane led to the use of smaller doses.

Contaminación por halotano en el quirófano, con el uso de dos circuitos anestésicos: Circuito semicerrado y circuito semiabierto / Halothane pollution in operating room. a comparison using semiclosed and semiopen anesthetic circuits

Por cromatografía de gases, fue identificada y cuantificada la existencia de halotano en el área respiratoria del anestesiólogo y en la sangre del anestesiólogo, cirujano e instrumentista, durante el transcurso de un acto quirúrgico bajo anestesia general inhalatoria con halotano y el comportamiento de estos niveles durante una jornada de trabajo de 6 hrs, con el empleo de dos circuitos anestésicos: circuito semicerrado y circuito semiabierto. Los resultados muestran que los niveles de contaminación por halotano en el área respiratoria del anestesiólogo al final de una cirugía bajo anestesia general inhalatoria son similares con el uso de circuito semicerrado y semiabierto, siendo estos cuando menos 10 veces más altos que los valores permisibles por la NIOSH. Las concentraciones sanguíneas de halotano en el personal que integra el equipo quirúrgico son más altos cuando se utiliza el circuito semiabierto, y superan los niveles permisibles incluso para medio ambiente

Comparisons of sevoflurane, isoflurane, and halothane anesthesia in spontaneously breathing cats.

The clinical effects of sevoflurane, isoflurane, and halothane anesthesia with or without nitrous oxide, were compared in healthy, premedicated cats breathing spontaneously during 90 minutes of anesthesia. The effect of nitrous oxide in accelerating the induction of and recovery from anesthesia was more evident for halothane than for sevoflurane or isoflurane. The cats recovered more rapidly from sevoflurane-oxygen than from either halothane- or isoflurane-oxygen. Heart rates did not significantly change during anesthesia with any of the anesthetics. Arterial blood pressures during sevoflurane-oxygen anesthesia were somewhat higher than those with either isoflurane- or halothane-oxygen. There were no significant differences in arterial blood pressures among sevoflurane, isoflurane, and halothane anesthesia when combined with nitrous oxide. The respiration rate during sevoflurane-oxygen was similar to that during halothane-oxygen. There were no significant differences in respiration rate among sevoflurane, isoflurane, and halothane anesthesia when combined with nitrous oxide. The degree of hypercapnia and acidosis during sevoflurane anesthesia was similar to that observed during isoflurane anesthesia and less than during halothane anesthesia. The three anesthetic regimens, with or without nitrous oxide, induced a similar degree of hyperglycemia and hemodilution during anesthesia. Serum biochemical examination did not reveal any hepatic or renal injuries after each anesthesia.

Suffocation from use of modified gas mask.

We report a case of suffocation caused by use of a gas mask modified by the attachment of a plastic bag with evidence of halothane inhalation. Gas masks and plastic bags are sometimes used to aid in the inhalation of volatile substances. Improper use or modification of gas masks or other respiratory protection devices may result in asphyxial death.