COMPARISON OF ISOFLURANE AND SEVOFLURANE FOR SHORT-TERM ANESTHESIA IN MEERKATS (SURICATA SURICATTA)-ARE THERE BENEFITS THAT OUTWEIGH COSTS?

Meerkats ( Suricata suricatta ) are routinely anesthetized with isoflurane in zoo and field settings. Twenty healthy adult meerkats of mixed age and sex held in the Zoological Society of London's collection were anesthetized with 4% isoflurane by face mask for routine health examinations. The procedure was repeated 5 mo later in the same group of animals utilizing sevoflurane at 5% for induction, and again 3 mo later with sevoflurane at 6.5% for induction to approximate equipotency with isoflurane. The speed and quality of induction and recovery were compared between the two volatile anesthetic agents. There was no statistically significant difference in the speed of induction across any of the anesthetic regimes. There was a significant difference in recovery times between isoflurane and 6.5% sevoflurane (427 ± 218 and 253 ± 65 sec, respectively [mean ± SD]). Under the conditions of this study, sevoflurane at 6.5% induction dose resulted in better quality induction and recovery than sevoflurane at 5% induction or isoflurane. The mean heart and respiratory rates during anesthesia were higher using 5% sevoflurane for induction but there was no significant difference in either rate between isoflurane and sevoflurane used at a 6.5% induction dose. This study suggests that sevoflurane at a dose of 6.5% for induction and 4% for maintenance is a safe and effective anesthetic agent in healthy adult meerkats. Rapid return to normal behavior after anesthesia is important in all zoo species but particularly so in animals with a complex social and hierarchical structure such as meerkats. For this species, the advantage afforded by the speed of recovery with sevoflurane may offset the cost in certain circumstances.

Limiting the accessibility of cost-prohibitive drugs reduces overall anesthetic drug costs: a retrospective before and after analysis.

PURPOSE: Cost effectiveness is becoming increasingly important in today's healthcare environment. Remifentanil, dexmedetomidine, and desflurane are costly agents that often have suitable alternatives to their use. We sought to identify changes in cost and outcomes following interventions that limited the availability of these drugs. METHODS: We calculated anesthetic drug costs for all operating room procedures performed before and after the accessibility interventions. We retrospectively compared drug costs per case and the frequency of agent use before and after the interventions. In addition, we analyzed the incidence of adverse outcomes, including delayed out-of-room times, postoperative nausea and vomiting (PONV), unplanned intubations, use of naloxone, and reintubations. Wilcoxon-Mann-Whitney and Chi square analyses were used to quantify differences in cost, use, and outcomes between cohorts. RESULTS: Of the 27,233 cases we identified, 24,201 cases were analyzed. The mean anesthetic drug costs per case were significantly lower after the interventions vs before at ($21.44 vs $32.39, respectively), a cost savings of $10.95 (95% confidence interval, $9.86 to $12.04; P < 0.001). Additionally, a comparison of data after vs before the interventions revealed the following results: remifentanil use was significantly lower (3.5% vs 9.2% of cases; P < 0.001). Dexmedetomidine use did not differ significantly (0.4% vs 0.5% of cases; P = 0.07), and desflurane use was significantly lower (0.6% vs 20.2% of cases; P < 0.001). There was no significant relationship between the interventions and the frequency of delayed out-of-room times (15.5% vs 15.9%; P = 0.41), unplanned intubations (0.02% vs 0.03%; P = 0.60), and reintubations (0.01% vs 0.03%; P = 0.28). Postoperative nausea and vomiting decreased significantly after the interventions (22.8% vs 24.4%; P = 0.003), and naloxone use showed a significant increase (0.22% vs 0.11% of cases; P = 0.04). CONCLUSIONS: Reducing the accessibility of these cost-prohibitive agents resulted in significant anesthetic drug cost savings and decreased utilization of remifentanil and desflurane. The interventions had no significant effect on patient recovery time, incidence of unplanned intubations, or incidence of reintubation, but they were associated with a decrease in PONV and an increase in naloxone use.

Effect of transversus abdominis plane block on cost of laparoscopic cholecystectomy anesthesia.

BACKGROUND: Use of transversus abdominis plane (TAP) block for postoperative analgesia is continuously increasing. However, few studies have investigated intraoperative effects of TAP block. We aimed to study the effects of TAP block in terms of cost-effectiveness and consumption of inhalation agents. MATERIAL AND METHODS: Forty patients undergoing laparoscopic cholecystectomy were enrolled in this study. Patients were randomly divided into 2 groups: Group 1 (n=20) patients received TAP block and Group 2 (n=20) patients did not receive TAP block. Standard anesthesia induction was used in all patients. For the maintenance of anesthesia, fractional inspired oxygen (FIO2) of 50% in air with desflurane was used with a fresh gas flow of 4 L/min. All patients were monitored with electrocardiography and for peripheral oxygen saturation (SpO2), end-tidal carbon dioxide (ET), heart rate (HR), noninvasive mean blood pressure (MBP), and bispectral index (BIS). Bilateral TAP blocks were performed under ultrasound guidance to Group 1 patients. The BIS value was maintained at between 40 and 50 during the surgery. The Dion formula was used to calculate consumption of desflurane for each patient. RESULTS: There was no difference between the groups with respect to demographic characteristics of the patients. Duration of anesthesia, surgery time, and dosage of fentanyl were similar in the 2 groups. However, the cost and consumption of desflurane was significantly lower in Group 1. CONCLUSIONS: Total anesthesia consumption was lower and the cost-effectiveness of anesthesia was better in TAP block patients with general anesthesia than in non-TAP block patients undergoing laparoscopic cholecystectomy.

Calculation of volatile anaesthetics consumption from agent concentration and fresh gas flow.

BACKGROUND: The assessment of volatile agents' consumption can be performed by weighing vapourisers before and after use. This method is technically demanding and unavailable for retrospective analysis of anaesthesia records. Therefore, a method based on calculations from fresh gas flow and agent concentration is presented here. METHODS: The presented calculation method herein enables a precise estimation of volatile agent consumption when average fresh gas flows and volatile agent concentrations are known. A pre-condition for these calculations is the knowledge of the vapour amount deriving from 1 ml fluid volatile agent. The necessary formulas for these calculations and an example for a sevoflurane anaesthesia are presented. RESULTS: The amount of volatile agent vapour deriving from 1 ml of fluid agent are for halothane 229 ml, isoflurane 195 ml, sevoflurane 184 m, and desflurane 210 ml. The constant for sevoflurane is used in a fictitious clinical case to exemplify the calculation of its consumption in daily routine resulting in a total expenditure of 23.6 ml liquid agent. CONCLUSIONS: By application of the presented specific volatile agent constants and equations, it becomes easy to calculate volatile agent consumption if the fresh gas flows and the resulting inhaled concentration of the volatile agent are known. By this method, it is possible to extract data about volatile agent consumption both ways: (1) retrospectively from sufficiently detailed and accurate anaesthesia recordings, as well as (2) by application of this method in a prospective setting. Therefore, this method is a valuable contribution to perform pharmacoeconomical surveys.

[Impact of the decrease of nitrous oxide use on the consumption of halogenated agents]. / Impact de la diminution d'utilisation du protoxyde d'azote sur la consommation d'agents halogénés.

OBJECTIVE: Nitrous oxide (N2O) toxicity and its impact on pollution lead to restrict its use. A decrease of N2O consumption should increase the hypnotic inhaled consumption. This monocentric study estimated consumptions and costs of halogenated agents (HA) and N2O over 5 years when the N2O consumption was reduced. STUDY DESIGN: Retrospective from a computerized database. PATIENTS: Between 2006 and 2010, 34,097 procedures were studied after two meetings exposing the risks of the N2O. METHODS: At the end of anesthesia, consumptions of hypnotic agents (millilitres transmitted by the injectors and the blender) were archived in the database. The annual consumption of agents was obtained by adding the individual consumptions, then divided by the annual number of cases. The costs were given by the hospital pharmacy from invoices. RESULTS: N2O consumption per anesthesia constantly decreased during the study, from 75.1L by act to 22.7L. The sum of the annual consumptions of N2O and air did not change suggesting that total fresh gas flow remained stable. Between 2006 and 2010, the sevoflurane consumption by act increased by 25%, from 16.5 to 20.6mL, and desflurane consumption by 37%, from 46.1 to 63.1mL by patient. The costs of the administration of hypnotic agents remained stable. CONCLUSION: N2O consumption decrease had an impact on the consumption of HA. The cost reduction of the N2O was counterbalanced by the increase of halogenated vapor cost. The profit of the ecological impact of the reduction in N2O use could be quantified.

Financial and environmental costs of manual versus automated control of end-tidal gas concentrations.

Emerging technologies that reduce the economic and environmental costs of anaesthesia have had limited assessment. We hypothesised that automated control of end-tidal gases, a new feature in anaesthesia machines, will consistently reduce volatile agent consumption cost and greenhouse gas emissions. As part of the planned replacement of anaesthesia machines in a tertiary hospital, we performed a prospective before and after study comparing the cost and greenhouse gas emissions of isoflurane, sevoflurane and desflurane when using manual versus automated control of end-tidal gases. We analysed 3675 general anaesthesia cases with inhalational agents: 1865 using manual control and 1810 using automated control. Volatile agent cost was $18.87/hour using manual control and $13.82/hour using automated control: mean decrease $5.05/hour (95% confidence interval: $0.88-9.22/hour, P=0.0243). The 100-year global warming potential decreased from 23.2 kg/hour of carbon dioxide equivalents to 13.0 kg/hour: mean decrease 10.2 kg/hour (95% confidence interval: 2.7-17.7 kg/hour, P=0.0179). Automated control reduced costs by 27%. Greenhouse gas emissions decreased by 44%, a greater than expected decrease facilitated by a proportional reduction in desflurane use. Automated control of end-tidal gases increases participation in low flow anaesthesia with economic and environmental benefits.

Halothane: how should it be used in a developing country?

The anaesthetic agent halothane is still widely used in developing countries including the Islamic Republic of Iran because of its low price. Because of halothane-induced hepatitis, a rare complication, it has been replaced by other inhalation anaesthetics in Western countries; it has been suggested by some Iranian professionals that the Islamic Republic of Iran should do the same. We evaluated various dimensions of this replacement through a literature review to assess the incidence of halothane-induced hepatitis and costs of anaesthetics in the country. We also conducted a questionnaire survey of 30 anaesthesiology/gastroenterology experts about their views on the subject. The results indicate that the incidence of halothane hepatitis in the Islamic Republic of Iran is very low and could mostly be avoided by strict adherence to guidelines. Complete withdrawal of halothane in the Islamic Republic of Iran might not be appropriate at present. Comprehensive cost-effectiveness studies are needed before a decision is made on complete replacement of halothane with other anaesthetics.

Effects of lidocaine infiltration on cost of rhinoplasty made under general anesthesia.

This study aimed to compare the effects of combined and noncombined lidocaine with adrenaline infiltration in general anesthesia (GA) procedures, in which the standard anesthesia depth is monitored by Bispectral Index monitoring, on minimum alveolar concentration (MAC) levels and the costs. Following approval by the local ethics committee, an American Society of Anesthesiologists physical status I­II group of 40 adult patients for whom elective rhinoplasties under GA were planned was divided into 2 double-blind randomized groups. In group 1, GA and lidocaine + adrenaline were administered, whereas in group 2, only GA and adrenaline were administered. All the patients who had been taken to the operation room underwent electrocardiography and measurements of the peripheral oxygen saturation, end-tidal carbon dioxide, heart rate, mean blood pressure, and Bispectral Index monitoring. Using the operation time and the MAC% values, the total consumed inhalation agent amounts were calculated, and the cost difference was determined. The mean blood pressure values were lower in group 1 (P < 0.05). In group 1, the MAC% was 20.83% lower than that of group 2; the consumed desflurane amount was 20.29%, and the cost was 20.29% lower than that of group 2 (P < 0.05). In rhinoplasties under GA, the lidocaine + adrenaline combination infiltration not only decreased inhaled anesthetic requirement and cost but also supported the hemodynamic stability. In addition, surgical satisfaction increased in the lidocaine + adrenaline group because of small number of agitated patients during the recovery period.

Pharmacoeconomics of volatile inhalational anaesthetic agents: an 11-year retrospective analysis.

With continuously increasing expenditure on health care resources, various cost containment strategies have been suggested in regard to controlling the cost of inhalational anaesthetic agents. We performed a cost identification analysis assessing inhalational anaesthetic agent expenditure at a tertiary level hospital, along with an evaluation of strategies to contain the cost of these agents. The number of bottles of isoflurane, sevoflurane and desflurane used during the financial years 1997 to 2007 was retrospectively determined and the acquisition costs and cumulative drug expenditure calculated. Pharmacoeconomic modelling using low fresh gas flow anaesthesia was performed to evaluate practical methods of cost reduction. The use of isoflurane decreased from 384 bottles during 1997 to 204 in 2007. In contrast, use of sevoflurane increased from 226 bottles during 1998 to 875 during 2007. Desflurane use increased from 34 bottles per year during 2002 (its year of introduction) to 163 bottles per year in 2007. While the inflation-adjusted cumulative expenditure for these inhalational agents (Australian dollars) increased from $132,000 in 1997 to over $326,000 in 2007, an increase of 168%, patient workload over the same period increased by only 11%. Pharmacoeconomic modelling demonstrated that sevoflurane at 2 l/minute costs 19 times more than isoflurane at 0.5 l/minute. For the financial years 1997 to 2007, we found a progressive shift from the cheaper isoflurane to the more expensive agents, sevoflurane and desflurane, a shift associated with marked increases in costs. Low flow anaesthesia with isoflurane is one strategy to reduce costs.

Meta-analysis of average and variability of time to extubation comparing isoflurane with desflurane or isoflurane with sevoflurane.

BACKGROUND: We recently determined how to use anesthesia information management system data to model the time from end of surgery to extubation. We applied that knowledge for meta-analyses of trials comparing extubation times after maintenance with desflurane and sevoflurane. In this study, we repeated the meta-analyses to compare isoflurane with desflurane and sevoflurane. METHODS: A Medline search through December 2009 was used to identify studies with (1) humans randomly assigned to isoflurane or desflurane groups without other differences (e.g., induction drugs) between groups, and (2) mean and SD reported for extubation time and/or time to follow commands. The search was repeated for random assignment to isoflurane or sevoflurane groups. We considered extubation times >15 minutes (representing 15% of cases in the anesthesia information management system data) to be prolonged. RESULTS: Desflurane reduced the mean extubation time by 34% and reduced the variability in extubation time by 36% relative to isoflurane. These reductions would reduce the incidence of prolonged extubation times by 95% and 97%, respectively. Sevoflurane reduced the mean extubation time by 13% and reduced the SD by 8.7% relative to isoflurane. These reductions would reduce the incidence of prolonged extubation times by 51% and 35%, respectively. CONCLUSIONS: The pharmacoeconomics of volatile anesthetics are highly sensitive to measurement of relatively small time differences. Therefore, surgical facilities should use these values combined with their local data (e.g., mean baseline extubation times) when making evidence-based management decisions regarding pharmaceutical purchases and usage guidelines.

Managing inhaled anesthesia: challenges from a health-system pharmacist's perspective.

PURPOSE: To discuss the challenges that health-system pharmacists face in managing the use and costs of inhaled anesthesia in the operating room (OR), the characteristics of inhaled anesthesia agents, systems for delivering inhaled anesthesia, and the role of inhaled anesthetics in fast-track recovery after surgery. SUMMARY: Inhaled anesthetic agents are the most common drugs used in general anesthesia and are a substantial part of the anesthetic drug budget in health systems. Challenges for health-system pharmacists in managing costs associated with these agents include the lack of a dedicated OR pharmacy, limited access to the OR, unfamiliarity with some of the medications used in the OR, and difficulty quantifying inhaled anesthetic drug use. The three inhaled anesthesia agents currently used in the United States have proven to be safe and effective. These agents have differences in solubility in blood and tissues, which affect onset, absorption, and excretion. Isoflurane has the highest solubility in blood and tissues, which may result in slower recovery. Lower solubility allows for a faster recovery. The two newest agents on the market, sevoflurane and desflurane, both have low solubility, with desflurane having lower solubility than sevoflurane. Sevoflurane has the advantage of low pungency and is not associated with respiratory irritation. As a cost-savings initiative, the inhalation agents may be used with low flow rates, which minimizes the amount of inhaled anesthetic used. In addition, using the less soluble inhaled anesthetic agents as part of a fast-track approach will accelerate recovery by reducing time to emergence and recovery. This approach can potentially reduce costs to the institution. CONCLUSION: Understanding the differences in characteristics and delivery of the inhaled anesthesia agents will enable health-system pharmacists to collaborate with anesthesia care providers to better manage the use and costs of these agents.

Economic considerations in the use of inhaled anesthetic agents.

PURPOSE: To describe the components of and factors contributing to the costs of inhaled anesthesia, basis for quantifying and comparing these costs, and practical strategies for performing pharmacoeconomic analyses and reducing the costs of inhaled anesthetic agents. SUMMARY: Inhaled anesthesia can be costly, and some of the variable costs, including fresh gas flow rates and vaporizer settings, are potential targets for cost savings. The use of a low fresh gas flow rate maximizes rebreathing of exhaled anesthetic gas and is less costly than a high flow rate, but it provides less control of the level of anesthesia. The minimum alveolar concentration (MAC) hour is a measure that can be used to compare the cost of inhaled anesthetic agents at various fresh gas flow rates. Anesthesia records provide a sense of patterns of inhaled anesthetic agent use, but the amount of detail can be limited. Cost savings have resulted from efforts to reduce the direct costs of inhaled anesthetic agents, but reductions in indirect costs through shortened times to patient recovery and discharge following the judicious use of these agents are more difficult to demonstrate. The patient case mix, fresh gas flow rates typically used during inhaled anesthesia, availability and location of vaporizers, and anesthesia care provider preferences and practices should be taken into consideration in pharmacoeconomic evaluations and recommendations for controlling the costs of inhaled anesthesia. CONCLUSION: Understanding factors that contribute to the costs of inhaled anesthesia and considering those factors in pharmacoeconomic analyses and recommendations for use of these agents can result in cost savings.

Cost minimisation and cost effectiveness in anaesthesia for total hip replacement surgery, in Belgium? A study comparing three general anaesthesia techniques.

The aim of the prospective randomised study is to compare the cost effectiveness of three general anaesthesia techniques for total hip replacement surgery and the cost minimisation by use of anaesthetics. For induction propofol was used in the three techniques. For maintenance, we used desflurane, or sevoflurane, or propofol. There was no significant difference in consumption of drugs for pain treatment, treatment of nausea and vomiting or cost of hospital stay or total cost for pharmacy. In terms of cost-effectiveness we can consider that the three techniques are similar. The cost of an i.v. technique was always higher than inhaled anaesthetics. The major cost in anaesthesia is the fee for the anaesthesiologist. But all in, the cost of anaesthesia was only 15.1% of the total cost of the procedure. Cost of inhaled or i.v. anaesthetics was 0.55% to 1.0% of the total cost. There was a discrepancy between the measured consumption of inhaled anaesthetics and the consumption (and cost) on the invoice. Cost minimisation based on anaesthetic medication is ridiculously by small considering the total cost of the procedure.

[Desflurane and isoflurane in minimal-flow anesthesia. Consumption and costs with forced fresh gas reduction]. / Desfluran und Isofluran bei Niedrigflussnarkosen. Verbrauch und Kosten bei forcierter Frischgasreduktion.

BACKGROUND: In the present investigation we compared the consumption of desflurane (DES) and isoflurane (ISO) using a standardized minimal-flow protocol with a forced reduction of the fresh gas flow (FGF). METHODS: 54 adult women were examined. After induction of anaesthesia a forced reduction of the FGF was started: 5 min 0.5 l/min O(2) + 1 l/min N(2)O, 10 min 0.5 l/min O(2) + 0.5 l/min N(2)O; finally 0.3 l/min O(2) + 0.2 l/min N(2)O up to the end of surgery. The consumption of DES/ISO was determined with a precision balance. RESULTS: In the DES group the uptake was around 0.3 vol-%, i.e. less than 8% of the target 2/3 MAC value was taken up. For ISO the uptake was around 0.25 vol-%, i.e. the uptake was approximately 30% of the target 2/3-MAC value. The DES consumption was after 60 min 17.0+/-1.1 g, 120 min--27.3+/-1.8 g and 180 min--36.5+/-1.7 g. ISO consumption was significantly lower: 7.6+/-0.8 g, 12.4+/-1.7 g and 15.5+/-1.6 g. The use of DES yielded higher costs, i.e. 2.28 EUR for 60 min, 3.63 EUR for 120 min and 4.97 EUR for 180 min. The consumption of the inhaled anaesthetics can be calculated as: DES (g)=4.84+0.184 x duration (min) (R(2)=0.981), ISO (g)=2.049+0.0826 x duration (R(2)=0.979). The costs are: DES (EUR)=0.85+0.0323 x duration (min); ISO (EUR)=0.19+0.0077 x duration (min). CONCLUSION: With a forced reduction of the FGF the DES consumption is still higher.

Efficacy and costs of 3 anesthetic regimens in the prevention of postoperative nausea and vomiting.

STUDY OBJECTIVE: The aim of the study was to compare the antiemetic efficacy and costs associated with 3 different anesthesia regimens used in gynecologic laparoscopy. DESIGN: This was a randomized, controlled study. SETTING: The study was conducted at a university hospital. PATIENTS: We studied 150 ASA physical status I or II patients, undergoing elective gynecologic laparoscopy with general anesthesia. INTERVENTION: Patients were allocated into the following 3 groups: group P-preoperative placebo tablet, propofol induction, propofol-air/O2 maintenance; group I + O-preoperative 8-mg ondansetron tablet, thiopental induction, isoflurane-N2O maintenance; group I (control)-preoperative placebo tablet, thiopental induction, isoflurane-N2O maintenance. MEASUREMENTS: The frequency of postoperative nausea and vomiting (PONV), number needed to treat to prevent PONV, and the costs of the anesthetic drugs to prevent PONV in one additional patient were evaluated. MAIN RESULTS: The frequency of PONV within the 24-hour study period was lowest in group I + O (P, 38%; I + O, 33%; and I, 59%; P < 0.05 I + O vs I). The number needed to treat was 5 in group P and 4 in group I + O, compared with group I. The median costs of anesthetic drugs to prevent PONV in one additional patient were $65 in group P and dollar 68 in group I + O, compared with group I. CONCLUSIONS: We conclude that in gynecologic laparoscopy, propofol-air/O2 anesthesia alone, and isoflurane-N2O anesthesia combined with an oral 8-mg dose of ondansetron had similar efficacy and costs to prevent PONV. Isoflurane-N2O anesthesia without ondansetron was less expensive, but was also less efficacious.

Early recovery, cognitive function and costs of a desflurane inhalational vs. a total intravenous anaesthesia regimen in long-term surgery.

BACKGROUND: The purpose of the study was to compare time of recovery, return of cognitive function, post-anaesthetic care unit (PACU) stay and costs of a propofol/remifentanil (TIVA) with a desflurane/fentanyl-based anaesthesia (desflurane group) in surgical procedures lasting more than 150 min. METHODS: Forty-nine patients undergoing elective abdominal prostatectomy were allocated randomly to receive bispectal index (BIS)-controlled desflurane/fentanyl (n=24) or propofol/remifentanil (n=25). Awakening, clinical recovery, direct drug acquisition and post-operative pain treatment were documented. Cognitive skills were tested using the Mini-Mental Status (MMST) test. RESULTS: Extubation was significantly faster with desflurane (6.9+/-3.5 min) than with TIVA (11.2+/-4.0 min) as well as times for stating name and date of birth (desflurane: 6.1+/-3.9 and 6.6+/-4.0 min; TIVA: 12.4+/-11.5 min and 13.4+/-11.3 min). There were no significant differences in PACU discharge times or MMS scores between the groups. Significantly more patients suffered post-operative nausea and vomiting (PONV) in the desflurane (33% vs. 0%) than the TIVA group. Overall costs were significantly higher in the TIVA (58.8+/-11.6 euro) than in the desflurane group (35.0+/-5.7 euro). CONCLUSION: Patients undergoing prolonged surgical procedures showed a faster early recovery after desflurane/fentanyl than using TIVA, whereas stay in the PACU and recovery of cognitive function were similar in both groups. Costs of a TIVA regimen were significantly higher than using a desflurane-based anaesthesia technique.

Inhalation anesthesiology and volatile liquid anesthetics: focus on isoflurane, desflurane, and sevoflurane.

Clinical pharmacists rarely are involved in the selection and dosing of anesthetic agents. However, when practicing evidence-based medicine in a cost-conscious health care system, optimizing drug therapy is imperative in all areas. Thus, we provide general information on anesthesiology, including the different types of breathing systems and the components of anesthesia machines. Modern inhalation anesthetics that are predominantly used in clinical practice include one gas--nitrous oxide--and new volatile liquid agents--isoflurane, desflurane, and sevoflurane. Desflurane and sevoflurane are the low-soluble inhalation anesthetics, and they offer some clinical advantages over isoflurane, such as fast induction and faster recovery with long procedures. However, efficient use of isoflurane can match the speed of induction and recovery of the other agents in certain cases. In addition, the patient characteristics, duration and type of procedure, type of breathing system, and efficiency in monitoring must be considered when selecting the most optimal therapy for each patient. Maximizing the clinical advantages of these agents while minimizing the waste of an institution's operating room and pharmacy budget requires an understanding of the characteristics, pharmacokinetics, and pharmacodynamics of these anesthetic agents and the collaborated effort from both the anesthesia and pharmacy departments. An anesthetic agent algorithm is provided as a sample decision-process tree for selecting among isoflurane, desflurane, and sevoflurane.