BJA Advance Access published online on July 9, 2007
British Journal of Anaesthesia, doi:10.1093/bja/aem197
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Faster wash-out and recovery for desflurane vs sevoflurane in morbidly obese patients when no premedication is used
1 Department of Anesthesiology
2 Department of Plastic and Reconstructive Surgery, Vita-Salute San Raffaele University School of Medicine, IRCCS San Raffaele, Via Olgettina 60, 20132 Milan, Italy
3 Department of Anesthesiology, University of Modena and Reggio Emilia, Modena, Italy
* Corresponding author. E-mail: l.lacolla{at}studenti.hsr.it
Accepted for publication June 1, 2007.
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionAcknowledgementReferences |
|---|
Background: The aim of this study was to compare desflurane vs sevoflurane kinetics and dynamics in morbidly obese patients and their recovery profile when no premedication had been used.
Methods: Twenty-eight unpremedicated obese patients were randomly allocated to receive either sevoflurane (n=14) or desflurane (n=14) as the main anaesthetic agent. After induction of anaesthesia, either sevoflurane 2% or desflurane 6% was administered for 30 min via a non-rebreathing circuit. The kinetics of sevoflurane and desflurane were determined by measuring and recording end-tidal samples during this time. The bispectral index was used to indicate the level of hypnosis. At the end of the procedure, the end-tidal concentrations of sevoflurane and desflurane were recorded during the first 5 min after stopping their administration. Time from discontinuation of the anaesthetic drugs to eye opening on verbal command, squeezing the observer's hand on command, extubation, stating their name, giving their correct date of birth, discharge from the recovery room, and duration of the surgery and anaesthesia were also recorded.
Results: The FA/FI ratio was significantly higher in the desflurane group from the 15th to the 30th min. The wash-out phase was faster for desflurane during the total observation period. When desflurane was used, recovery was also faster.
Conclusions: Desflurane provides faster wash-in and wash-out than sevoflurane in morbidly obese patients, and recovery is much faster after desflurane administration when no premedication has been used.
Keywords: anaesthetic techniques, inhalation; anaesthetics volatile, desflurane; anaesthetics volatile, sevaflurane; pharmacokinetics, obesity
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionAcknowledgementReferences |
|---|
The kinetic behaviour of many drugs is different in obese patients compared with non-obese patients, depending on factors related both to obesity and to the drug used.1–3 Both fat and lean body mass increase in the obese individual, although there is a relative decrease in lean body mass; water content and blood flow per gram of fat tissue are reduced in obese patients compared with non-obese subjects.4–7 For these reasons, obesity is likely to increase the degree of importance of partition coefficients (
blood/gas, oil/gas) of inhaled drugs as total body weight and duration of anaesthesia increase. The new fluorinated agents have markedly improved the quality and the time required for recovery compared with the older inhaled anaesthetics. Desflurane, in particular, is a new fluorinated anaesthetic agent with a very low blood–gas partition coefficient (about 30% less than sevoflurane) and low oil–gas partition coefficient (about 64% less than sevoflurane), which allow for quick modification of the anaesthetic plan and rapid emergence at the end of surgery,8–10 even in obese patients. Nonetheless, obesity markedly affects the cardiovascular and respiratory systems, the proportion of different tissues in body composition, and perfusion, uptake, and solubility. These changes can potentially affect not only wash-in and wash-out kinetics of the aforesaid new inhalational agents, but also recovery times in obese patients. Although desflurane has shown a significantly better recovery profile compared with propofol and isoflurane10 in obese patients, there is still some grade of uncertainty between desflurane and sevoflurane. This could have been caused partially by the poor study designs used (e.g. anaesthetics were not carefully titrated) and partially by the use of premedication. These causes may have masked the theoretical differences between these two halogenated gases.
The aim of this prospective, randomized, double-blind study was to compare wash-in and wash-out curves and recovery times after sevoflurane vs desflurane anaesthesia in morbidly obese patients when no premedication had been used, and careful titration of drugs was possible thanks to a bispectral (BIS) index monitor.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionAcknowledgementReferences |
|---|
Twenty-eight patients [ASA physical status II–III, age 37.1 (SD 12.9) yr, BMI 50.6 (5.4)] scheduled for elective bilio-intestinal bypass surgery were prospectively studied. Patients with ASA physical status>III, aged <20 or >65 yr, with a history of alcohol or drug abuse, or with heart dysfunctions were excluded.
Patients fasted for 8 h before surgery and received no premedication. After arrival in the operating room, two 18-gauge i.v. cannulas were inserted in the forearm, and Ringer's lactate solution 7 ml kg–1 was infused. A radial artery catheter was inserted for invasive arterial pressure monitoring. Standard monitoring, including electrocardiography, heart rate (Lead II), and pulse oximetry, was used throughout the study. In each patient, the BIS index was also monitored using an EEG monitor (BIS XP electrodes for an A 2000 monitor; Aspect Medical Systems Inc., Natick, MA, USA). Neuromuscular block was assessed by the response to single twitch stimuli at 0.1 Hz during the onset time and subsequently by train-of-four (TOF) stimulation at a frequency of four stimuli at 2 Hz interposed by a 10 s interval with surface electrodes placed at the wrist for ulnar nerve stimulation. All patients were intubated using a flexible fibreoptic bronchoscopic technique facilitated by target-controlled infusion (TCI) of remifentanil set at 2.5 mg ml–1. After tracheal intubation, general anaesthesia was induced with propofol 2 mg kg–1. Ventilation was assisted with oxygen 50% in air mixture and then mechanically controlled using a non-rebreathing system. Lung ventilation was adjusted to maintain an end-tidal partial pressure of carbon dioxide ranging between 32 and 35 mm Hg and facilitated by cis-atracurium as neuromuscular blocking agent.
Remifentanil was administered using a pharmacokinetic model-driven, computer-assisted continuous infusion system allowing constant target concentrations to be achieved and maintained. The system consisted of an Acer TravelMate 518TX computer connected to a Graseby 3500 infusion pump (Sims Graseby Limited, Waterford, Herts, UK) using the Rugloop software (designed by Tom De Smet and Michel Struys, Department of Anaesthesia, University Hospital, Ghent, Belgium). The pharmacokinetic parameters used in the computer-assisted continuous infusion for the administration of remifentanil were based on the model described by Minto and colleagues.11 12
For remifentanil TCI, weight was corrected according to the formula suggested by Lemmens and colleagues:13
Ideal body weight=22xH2 (m).
Immediately after the stabilization of the ventilatory parameters, the patients were randomly assigned either to the sevoflurane group (n=14) or to the desflurane group (n=14), and a square-wave of either sevoflurane 2% or desflurane 6% was administered for 30 min via the non-rebreathing circuit. The sampling of inspired (FI) and end-tidal (FA) gases was carried out by means of an infrared gas analyser (RMG 5250, Ohmeda), previously calibrated according to the manufacturer's instructions.
The kinetics of sevoflurane and desflurane were determined by collecting end-tidal gas samples from first breaths at 1, 5, 10, 15, 20, 25, and 30 min; then the surgical procedure started. During the surgery, anaesthesia was maintained with either sevoflurane 1–2% or desflurane 3–4% in an oxygen/air mixture (FIO2) adapted to the needs of each patient in order to maintain stable BIS values ranging from 40 to 50. Target remifentanil concentration was modified after the first surgical stimulus had occurred and titrated to maintain heart rate and arterial pressure within ±10% of baseline values.
While the peritoneum was being sutured, morphine sulphate 0.05 mg kg–1 and ketorolac 30 mg were administered to control the early acute postoperative pain.
During the last 20 min of each case, the end-expiratory anaesthetic concentration was gradually titrated in order to achieve a BIS value of 60. Near the end of the surgery, residual neuromuscular block was antagonized with prostigmine 2 mg and atropine 1 mg. Remifentanil was discontinued when the surgeon started the skin suture. After the last skin stitch, fresh gas flows were increased to 10 litre min–1 and the end-tidal concentration of anaesthetic gases was recorded from five consecutive breaths immediately before discontinuing their administration; then end-tidal samples of inhalational agents were collected at 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5 min after suspension.
Mechanical ventilation was maintained until the first spontaneous breath occurred; then lung ventilation was manually assisted with oxygen 100%, and the tracheal tube was removed when a TOF ratio above 0.9 was reached.
A blinded observer recorded the time from discontinuation of the anaesthetic drug to eye opening after verbal command, squeezing the observer's hand, extubation, ability to state their name and give their correct date of birth, and discharge from the recovery room, and the duration of the surgery and anaesthesia.
Power was calculated using previous reports. After a mean duration of anaesthetic procedure of 258 min, Strum and colleagues14 reported a time to initial response to command of 18.5 (8.7) min after sevoflurane anaesthesia in morbidly obese patients. During desflurane anaesthesia, we considered significant a 50% reduction of initial response to command so that the sample size was estimated as 14 patients for each group with an 
error of 0.05 and a power of 0.8.
Statistical analysis was performed using the program Statistica 5.0 (StatSoft Italia, Vigonza, Padova, Italy). Normality for every variable was assessed by means of Kolmogorov–Smirnov test. A two-way analysis of variance for repeated measures extended by Sheffe's post hoc test was used to analyse changes over time. Student's t-test was used when appropriate. Ordinal data were analysed using the contingency table analysis using Fisher's exact test. Continuous variables are presented as mean and SD, whereas ordinal data are presented as number (%). A value of P<0.05 was considered significant.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionAcknowledgementReferences |
|---|
No differences in age [34.3 (13.9) yr in the sevoflurane group and 40.0 (8.8) yr in the desflurane group, P=0.569], gender (eight males and six females in both groups), BMI [47.9 (1.6) in the sevoflurane group and 53.3 (5.9) in the desflurane group, P=0.180], height [169.3 (7.0) in the sevoflurane group and 160.3 (6.7) in the desflurane group, P=0.160], weight [137.5 (13.8) in the sevoflurane group and 135.8 (5.9) in the desflurane group, P=0.847], BIS index value at the time of anaesthetic suspension [59.4 (1.9) in the sevoflurane group and 59.6 (1.6) in the desflurane group, P=0.660], duration of surgery [130.4 (23.2) min in the sevoflurane group and 148.6 (30.1) min in the desflurane group, P=0.583], and anaesthesia procedure [180 (16.9) min in the sevoflurane group and 193 (12.7) min in the desflurane group, P=0.232] were reported between the two groups (Table 1).
|
Figure 1 shows the wash-in curve measured in the sevoflurane and desflurane groups. The desflurane group shows a higher FA/FI ratio during the total observation period, although it is statistically significant only from the 15th to the 30th min (Table 2).
|
|
Figure 2 shows the wash-out curve for the same groups of patients. The FA/FA0 ratio is significantly higher in the desflurane group during the total observation period (Table 3).
|
|
Patients in the desflurane group reported early recovery times compared with those of sevoflurane group (Table 4). In particular, the time from discontinuation of the anaesthetic drug to eye opening after verbal command, squeezing the observer's hand, extubation, and ability to state their name and give their correct date of birth are all significantly shorter at the 0.001 level. The time from discontinuation of the anaesthetic drug to discharge from the recovery room is also significantly shorter in the desflurane group (P<0.001).
|
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionAcknowledgementReferences |
|---|
The results of this prospective, randomized, double-blind study show faster wash-in and wash-out for desflurane compared with sevoflurane in morbidly obese patients. This is consistent with its very low blood–gas partition coefficient (
blood/gas about 30% less than sevoflurane) and its low oil–gas partition coefficient (oil/gas about 64% less than sevoflurane),8 9 which suggest a more rapid kinetic profile. For this reason, desflurane could be more suitable for morbidly obese patients. In fact, it is safe and effective in maintaining balanced general anaesthesia, and its use is followed by rapid recovery.10 Although absorption by/delivery to body tissues is mainly determined by drug solubility,15 few studies have compared the kinetic curves of sevoflurane and desflurane in obese patients. Three factors govern the uptake and distribution of potent inhaled anaesthetics. Cardiac output, alveolar-to-venous partial pressure difference, and solubility in blood, defined as the blood–gas partition coefficient, contribute to the wash-in curves observed in different ways. These wash-in curves show a higher FA/FI ratio in the desflurane group compared with the sevoflurane group from the 15th to the 30th min. As reported in non-obese patients, this result can be explained by the slower distribution of desflurane to the peripheral compartments,16 which in turn causes a more rapid saturation of the central compartment. In fact, the apparent distribution volume of desflurane is smaller than the apparent distribution volume of sevoflurane,16 therefore the uptake of desflurane is lower. As far as the anaesthetic uptake from the baseline to the 15th min is concerned, desflurane has a higher FA/FI ratio, that is not, however, statistically significant in our study. At the beginning of anaesthesia, alveolar-to-venous partial pressure is maximal because no inhalational agent is present in mixed venous blood. As a result, initially, uptake is proportional to the blood solubility multiplied by the cardiac output. Although we used equal MAC fractions of anaesthetics during the wash-in phase, the similar wash-in curves observed from the baseline to the 15th min between sevoflurane and desflurane could have been because of a lower cardiac output during this period in the sevoflurane group compared with the desflurane group. In theory, a lower cardiac output in the sevoflurane group could have offset its higher solubility, resulting in an uptake similar to that of desflurane.
In contrast, the wash-out phase of desflurane was significantly shorter than that of sevoflurane during the total observation period, suggesting faster clearance of desflurane compared with sevoflurane. This result can be explained both by a larger amount of tissue deposits and by the higher blood–gas partition coefficient of sevoflurane, causing a slower rate of decrease both in the arterial circulation and from the lungs. This, in turn, allows the anaesthetic to recirculate and delays the wash-out. Despite the numerically similar difference between sevoflurane and desflurane values during the wash-in and wash-out phases and despite the fact that both are statistically significant, the difference during the emergence from anaesthesia is particularly important because of its clinical significance. In fact, the first can be easily compensated for by an increase in the delivered agent, whereas the second cannot. As we show in this paper, this results in important clinical differences as far as recovery times are concerned.
The wash-in and wash-out curves of desflurane and sevoflurane were determined in an oxygen–air mixture, excluding a second gas effect.17 However, the kinetic curves of inhalational agents can also be influenced both by the surgical procedure and by changes in the cardiovascular function. In our study, surgeons performed open bariatric surgery, excluding those cardiovascular modifications related to laparoscopic procedures.18 Moreover, the inhalational agent (Fi) was adapted to the needs of each patient to maintain stable BIS values ranging between 40 and 50, whereas the effect-site concentration of remifentanil was titrated to maintain heart rate and arterial pressure within ±10% of baseline values. Furthermore, near the end of surgery, the BIS index value was gradually titrated to 60 in both groups. This anaesthetic technique minimized not only the cardiovascular effects, which could have potentially affected the kinetic profile of the inhalational agents, and the sympathetic responses to abdominal surgery,19 but also a possible delay in wash-out or recovery because of a significantly different level of hypnosis.
The use of an infrared analyser for the quantification of the concentration of volatile anaesthetic agents instead of gas chromatography could be considered a possible shortcoming of this study. The determination of the kinetic profiles of inhalational agents using respiratory gas analysis is an established method.20 21 Traditionally, gas chromatography assays have been used. In this study, we used the data that are routinely available from anaesthetic workstations. As described by Rietbrock and colleagues,22 the data gathered during routine monitoring are sufficient to provide reliable estimates of the pharmacokinetic parameters, especially when a non-rebreathing circuit is used.
As regards recovery, we decided to evaluate recovery profiles when anaesthetic gas delivery was carefully titrated using the BIS index and no premedication had been used. Our results are in contrast with those of another study which tried to evaluate recovery profiles of desflurane vs sevoflurane in morbidly obese patients when anaesthetic delivery had been titrated according to the BIS index, especially near the end of surgery.23–25 This difference can be explained by our use of only the ultra-short-acting opioid remifentanil and the inhalational agent, avoiding other drugs, such as midazolam, and a long-acting opioid such as fentanyl, which could smooth out or even abolish recovery differences.
Our results show a statistically (and also clinically) significant difference between the recovery profiles of patients who received desflurane vs sevoflurane. These data are consistent with the faster kinetic profile of desflurane and its faster wash-out from the body. For desflurane, time from discontinuation of the anaesthetic gas to eye opening on verbal command, squeezing the observer's hand on command, extubation, stating their name, giving their correct date of birth, and discharge from the recovery room were all significantly shorter at a 0.001 level (Table 4). Our results conform with those of Strum and colleagues,14 even though they administered midazolam as premedication. De Baerdemaeker and colleagues26 also demonstrated faster wash-out and recovery times using an inhalation bolus technique to optimize anaesthetic administration to morbidly obese patients. Desflurane has demonstrated its rapidity and consistency in recovery times even compared with propofol and isoflurane.10
Although few studies have been carried out in obese patients, the effects of desflurane and sevoflurane on the non-obese population are well known. Behne and colleagues27 reported no significant differences between desflurane, sevoflurane, or isoflurane, but patients in their study were premedicated and no EEG monitor was used. Others28 reported that sevoflurane was associated with a slower emergence from anaesthesia than desflurane after minor gynaecological laparoscopic surgery, but recovery of cognitive function and discharge times were similar in the two anaesthetic groups. Indeed, they used a long-acting opioid such as fentanyl, and no EEG monitor and no premedication drug was used. According to Tarazi and Philip,29 sevoflurane provided a faster recovery, even though not in a statistically significant manner. Larsen and colleagues30 reported that propofol was associated with a better emergence compared with sevoflurane and desflurane, with no significant difference between them. After 30 min, desflurane resulted in a superior quality of recovery compared with sevoflurane. Finally, Eger and colleagues31 showed that recovery was faster with desflurane, whatever the duration of anaesthesia.
In conclusion, our study confirms the more rapid kinetic profile of desflurane, which results in faster recovery when its administration is carefully titrated according to the BIS index value and when no premedication drugs are used.
|
Acknowledgement |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionAcknowledgementReferences |
|---|
The authors wish to thank Michael John for the English revision of the manuscript.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionAcknowledgementReferences |
|---|
1 World Health Organization. Report of a WHO Consultation on obesity: preventing and managing the global epidemic. (1998) Geneva: WHO. 3–5. June.
2 Abernethy DR, Greenblatt DJ. Drug disposition in obese humans. An update. Clin Pharmacokinet (1986) 11:199–213.[Web of Science][Medline]
3 Blouin RA, Kolpek JH, Mann HJ. Influence of obesity on drug disposition. Clin Pharm (1987) 6:706–14.[Web of Science][Medline]
4 Cheymol G. Clinical pharmacokinetics of drugs in obesity. An update. Clin Pharmacokinet (193) 25:103–14.
5 Cheymol G. Effects of obesity on pharmacokinetic implications for drug therapy. Clin Pharmacokinet (2000) 39:215–31.[CrossRef][Web of Science][Medline]
6 Bolinder J, Kerckhoffs DA, Moberg E, Hagstrom-Toft E, Arner P. Rates of skeletal muscle and adipose tissue glycerol release in nonobese and obese subjects. Diabetes (2000) 49:797–802.[Abstract]
7 Virtanen KA, Lonnroth P, Parkkola R. Glucose uptake and perfusion in subcutaneous and visceral adipose tissue during insulin stimulation in nonobese and obese humans. J Clin Endocrinol Metab (2002) 87:3902–10.
8 Strum DP, Eger EI II. Partition coefficients for sevoflurane in human blood, saline, and olive oil. Anesth Analg (1987) 66:654–6.
9 Eger EI II. Partition coefficients of I-653 in human blood, saline, and olive oil. Anesth Analg (1987) 66:971–3.
10 Juvin P, Vadam C, Malek, Dupont H, Marmuse JP, Desmonts JM. Postoperative recovery after desflurane, propofol, or isoflurane anaesthesia among morbidly obese patients: a prospective randomized study. Anesth Analg (2000) 91:714–9.
11 Minto CF, Schnider TW, Egan TD, et al. Influence of age and gender on the pharmacokinetics and pharmacodynamics of remifentanil. I. Model development. Anesthesiology (1997) 86:10–23.[CrossRef][Web of Science][Medline]
12 Minto CF, Schnider TW, Shafer SL. Pharmacokinetics and pharmacodynamics of remifentanil. II. Model application. Anesthesiology (1997) 86:24–33.[CrossRef][Web of Science][Medline]
13 Lemmens HJ, Brodsky JB, Bernstein DP. Estimating ideal body weight—a new formula. Obes Surg (2005) 15:1082–3.[CrossRef][Web of Science][Medline]
14 Strum EM, Szenohradszki J, Kaufman WA, Anthone GJ, Manz IL, Lumb PD. Emergence and recovery characteristics of desflurane versus sevoflurane in morbidly obese adult surgical patients: a prospective, randomized study. Anesth Analg (2004) 99:1848–53.
15 Eger EI II. Uptake and distribution. In: Miller's Anesthesia—Miller RD, ed. (2005) 4th Edn. Philadelphia: Elsevier Churchill Livingstone. 131–53.
16 Wissing H, Kuhn I, Rietbrock S, Fuhr U. Pharmacokinetic of inhaled anaesthetic in a clinical setting: comparison of desflurane, isoflurane and sevoflurane. Br J Anaesth (2000) 84:443–9.
17 Stoelting RK, Eger EI II. An additional explanation for the second gas effect: a concentrating effect. Anesthesiology (1969) 30:273–7.[Web of Science][Medline]
18 Torri G, Casati A, Albertin A, et al. Randomized comparison of isoflurane and sevoflurane for laparoscopic gastric banding in morbidly obese patients. J Clin Anesth (2001) 17:300–5.[CrossRef]
19 Schrincker T, Galeone M, Wykes L, Carli F. Effect of desflurane/remifentanil anaesthesia on glucose metabolism during surgery: a comparison with desflurane/epidural anaesthesia. Acta Anaesthesiol Scand (2004) 48:169–73.[CrossRef][Web of Science][Medline]
20 Carpenter L, Eger EI II, Johnson BH, Unadkat JD, Sheiner LB. Pharmacokinetic of inhaled anaesthetics in humans. Anesth Analg (1984) 65:575–82.
21 Carpenter L, Eger EI II, Johnson BH, Unadkat JD. A new concept in inhaled anaesthetics pharmacokinetic. Anesth Analg (1984) 64:197.[Web of Science]
22 Rietbrock S, Wissing H, Kuhn I, Fuhr U. Pharmacokinetics of inhaled anaesthetics in a clinical setting: evaluation of a method based on routine monitoring data. Br J Anaesth (2000) 84:437–42.
23 Arain SR, Barth CD, Shankar H, Eberth TJ. Choice of volatile anaesthetic for the morbidly obese patients: sevoflurane or desflurane. J Clin Anesth (2005) 17:413–9.[CrossRef][Web of Science][Medline]
24 Vallejo MC, Sah N, Phelps AL, O'Donnell J, Romeo RC. Desflurane versus sevoflurane for laparoscopic gastroplasty in morbidly obese patients. J Clin Anesth (2007) 19:3–8.[CrossRef][Web of Science][Medline]
25 De Baerdemaeker LE, Jacobs S, Den Blauwen NM, et al. Postoperative results after desflurane or sevoflurane combined with remifentanil in morbidly obese patients. Obes Surg (2006) 16:728–33.[CrossRef][Web of Science][Medline]
26 De Baerdemaeker LE, Struys MM, Jacobs S, et al. Optimization of desflurane administration in morbidly obese patients: a comparison with sevoflurane using an ‘inhalation bolus’ technique. Br J Anaesth (2003) 91:638–50.
27 Behne M, Wilke HJ, Lischke V. Recovery and pharmacokinetic parameters of desflurane, sevoflurane, and isoflurane in patients undergoing urologic procedures. J Clin Anesth (1999) 11:460–5.[CrossRef][Web of Science][Medline]
28 Nathanson MH, Fredman B, Smith I, White PF. Sevoflurane versus desflurane for outpatient anaesthesia: a comparison of maintenance and recovery profiles. Anesth Analg (1995) 81:1186–90.[Abstract]
29 Tarazi EM, Philip BK. A comparison of recovery after sevoflurane or desflurane in ambulatory anaesthesia. J Clin Anesth (1998) 10:272–7.[CrossRef][Web of Science][Medline]
30 Larsen B, Seitz A, Larsen R. Recovery of cognitive function after remifentanil–propofol anaesthesia: a comparison with desflurane and sevoflurane anaesthesia. Anesth Analg (2000) 90:168–74.
31 Eger EI II, Gong D, Koblin DD, et al. The effect of anaesthetic duration on kinetic and recovery characteristics of desflurane versus sevoflurane, and on the kinetic characteristics of Compound A, in volunteers. Anesth Analg (1998) 86:414–21.[Abstract]
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  H. J. M. Lemmens, L. J. Saidman, E. I. Eger II, and M. J. Laster Obesity Modestly Affects Inhaled Anesthetic Kinetics in Humans Anesth. Analg., December 1, 2008; 107(6): 1864 - 1870. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||