Recovery and kinetic characteristics of desflurane and sevoflurane in volunteers after 8-h exposure, including kinetics of degradation products

Pharmacokinetics of desflurane uptake and disposition in piglets

Introduction

Many respiratory but few arterial blood pharmacokinetics of desflurane uptake and disposition have been investigated. We explored the pharmacokinetic parameters in piglets by comparing inspiratory, end-tidal, arterial blood, and mixed venous blood concentrations of desflurane.

Methods

Seven piglets were administered inspiratory 6% desflurane by inhalation over 2 h, followed by a 2-h disposition phase. Inspiratory and end-tidal concentrations were detected using an infrared analyzer. Femoral arterial blood and pulmonary artery mixed venous blood were sampled to determine desflurane concentrations by gas chromatography at 1, 3, 5, 10, 20, 30, 40, 50, 60, 80, 100, and 120 min during each uptake and disposition phase. Respiratory and hemodynamic parameters were measured simultaneously. Body uptake and disposition rates were calculated by multiplying the difference between the arterial and pulmonary artery blood concentrations by the cardiac output.

Results

The rates of desflurane body uptake increased considerably in the initial 5 min (79.8 ml.min-1) and then declined slowly until 120 min (27.0 ml.min-1). Similar characteristics of washout were noted during the subsequent disposition phase. Concentration-time curves of end-tidal, arterial, and pulmonary artery blood concentrations fitted well to zero-order input and first-order disposition kinetics. Arterial and pulmonary artery blood concentrations were best fitted using a two-compartment model. After 2 h, only 21.9% of the desflurane administered had been eliminated from the body.

Conclusion

Under a fixed inspiratory concentration, desflurane body uptake in piglets corresponded to constant zero-order infusion, and the 2-h disposition pattern followed first-order kinetics and best fitted to a two-compartment model.

Clinical Effects and Adverse Events Associated With Desflurane Use in Adult Patients Undergoing Supratentorial Craniotomy: A Systematic Review

Desflurane is an inhalational anesthetic agent with an appealing recovery profile. The present systematic review investigates the clinical effects and adverse events associated with desflurane use during supratentorial craniotomy for brain tumor resection in adults in comparison with other inhalational and intravenous anesthetic agents. A literature search was conducted across the MEDLINE, Library of Congress and LISTA (EBSCO) databases from January 2001 to January 2021. Twelve studies published between 2003 and 2020 were included in this systematic review. Desflurane was compared with either isoflurane, sevoflurane, or propofol for anesthesia maintenance. Brain relaxation scores showed no statistically significant difference between desflurane and the other anesthetic agents. Recovery timepoints, such as time to recovery, time to eye opening, time to extubation, time to follow commands, and time to reach a modified Aldrete score ≥9 were significantly shorter with desflurane in the majority of studies. Systemic hemodynamic variables (mean arterial pressure and heart rate) and cerebral hemodynamics (intracranial pressure and cerebrospinal fluid pressure) were comparable between desflurane and other anesthetic agents in each study. The results of this systematic review demonstrate that desflurane is associated with few adverse events when used for anesthesia maintenance in adult patients undergoing supratentorial brain tumor surgery. Large, prospective, comprehensive studies, utilizing standardized parameter evaluation could provide higher levels of evidence to support these findings.

Nephrogenic Diabetes Insipidus following an Off-Label Administration of Sevoflurane for Prolonged Sedation in a COVID-19 Patient and Possible Influence on Aquaporin-2 Renal Expression

During the recent COVID-19 pandemic, the rapidly progressive shortage of intravenous sedative drugs led numerous intensive care units to look for potential alternatives in patients requiring mechanical ventilation for severe acute respiratory distress syndrome (ARDS). Inhalational sedation using the AnaConDa® device for sevoflurane administration is a possible option. In a 54-year-old COVID-19 patient with severe ARDS requiring extracorporeal membranous oxygenation (ECMO), sevoflurane on AnaConDa® device was administered for 8 days but was complicated by the development of nephrogenic diabetes insipidus (NDI). Other causes of NDI or central diabetes insipidus were reasonably excluded, as in other previously published cases of NDI in ICU patients receiving prolonged sevoflurane-based sedation. In addition, the postmortem examination suggested a lower expression of aquaporin-2 in renal tubules. This observation should prompt further investigations to elucidate the role of aquaporin-2 in sevoflurane-related NDI. Inhaled isoflurane sedation is a possible alternative.

Arterial and Mixed Venous Kinetics of Desflurane and Sevoflurane, Administered Simultaneously, at Three Different Global Ventilation to Perfusion Ratios in Piglets with Normal Lungs

BACKGROUND

Previous studies have established the role of various tissue compartments in the kinetics of inhaled anesthetic uptake and elimination. The role of normal lungs in inhaled anesthetic kinetics is less understood. In juvenile pigs with normal lungs, the authors measured desflurane and sevoflurane washin and washout kinetics at three different ratios of alveolar minute ventilation to cardiac output value. The main hypothesis was that the ventilation/perfusion ratio (VA/Q) of normal lungs influences the kinetics of inhaled anesthetics.

METHODS

Seven healthy pigs were anesthetized with intravenous anesthetics and mechanically ventilated. Each animal was studied under three different VA/Q conditions: normal, low, and high. For each VA/Q condition, desflurane and sevoflurane were administered at a constant, subanesthetic inspired partial pressure (0.15 volume% for sevoflurane and 0.5 volume% for desflurane) for 45 min. Pulmonary arterial and systemic arterial blood samples were collected at eight time points during uptake, and then at these same times during elimination, for measurement of desflurane and sevoflurane partial pressures. The authors also assessed the effect of VA/Q on paired differences in arterial and mixed venous partial pressures.

RESULTS

For desflurane washin, the scaled arterial partial pressure differences between 5 and 0 min were 0.70 ± 0.10, 0.93 ± 0.08, and 0.82 ± 0.07 for the low, normal, and high VA/Q conditions (means, 95% CI). Equivalent measurements for sevoflurane were 0.55 ± 0.06, 0.77 ± 0.04, and 0.75 ± 0.08. For desflurane washout, the scaled arterial partial pressure differences between 0 and 5 min were 0.76 ± 0.04, 0.88 ± 0.02, and 0.92 ± 0.01 for the low, normal, and high VA/Q conditions. Equivalent measurements for sevoflurane were 0.79 ± 0.05, 0.85 ± 0.03, and 0.90 ± 0.03.

CONCLUSIONS

Kinetics of inhaled anesthetic washin and washout are substantially altered by changes in the global VA/Q ratio for normal lungs.

EDITOR’S PERSPECTIVE

Is Prevention of Postoperative Vomiting Surgery Dependent? A Retrospective Cohort Study of Total Knee Arthroplasty

The study of postoperative nausea and vomiting (PONV) has been ongoing since the early days of general anesthesia. The search for risk factors of PONV and the development of new agents to treat PONV are the two main strategies to combat the adverse side effects of general anesthesia. Female sex, non-smoking status, a history of PONV/motion sickness, and postoperative opioid use are the four independent risk factors for PONV derived after a series of prospective studies, evidence-based systematic reviews, and meta-analyses. The two frequently asked questions that arise ask whether risk factors apply to different clinical settings and whether prevention measures of PONV can be surgery dependent. We conducted a comprehensive review of 665 patients who underwent primary total knee arthroplasty (TKA) between January and December 2019. As nausea is subjective and its measurement is not standardized, postoperative vomiting (POV) was used as a study endpoint. The exclusion criteria were desflurane anesthesia, spinal anesthesia, anesthesia without bispectral index monitoring, and day surgery. Three well-recognized risk factors, consisting of body weight, sevoflurane consumption, and postoperative opioid consumption, were not considered as independent risk factors of POV, while female sex, preoperative adductor canal block (ACB), and dexamethasone were identified as being so in this study. The risk of POV in the female sex was 2.49 times that in the male sex; however, when dexamethasone was used, this risk was reduced by >40% compared with no antiemetic use, and by >50% when patients received preoperative ACB compared with those without the block. The clinical characteristics of our TKA patients—female dominance, old age, and their fairly constant body weights that were distinct from those of other surgical patients—suggested that age may play a crucial role in determining the relative contributions of the different risk factors of POV. We concluded that risk factors of POV are dependent on clinical settings. Based on these results, it is reasonable to speculate that a surgery-dependent plan for the prevention of POV is feasible for patients in similar clinical settings.

Preoperative Sedative-hypnotic Medication Use and Adverse Postoperative Outcomes

OBJECTIVE

To determine the association between preoperative benzodiazepine and nonbenzodiazepine receptor agonist ("Z-drugs") use and adverse outcomes after surgery.

BACKGROUND

Prescriptions for benzodiazepines and Z-drugs have increased over the past decade. Despite this, the association of preoperative benzodiazepines and Z-drug receipt with adverse outcomes after surgery is unknown.

METHODS

Using the Optum Clinformatics Datamart, we performed a retrospective cohort study of adults 18 years or older who underwent any of 10 common surgical procedures between 2010 and 2015. The principal exposure was one or more filled prescriptions for a benzodiazepine or Z-drug in the 90 days before surgery. The primary outcome was any emergency department visit or hospital admission for either (1) a drug related adverse medical event or overdose or (2) a traumatic injury in the 30 days after surgery.

RESULTS

Of 785,346 patients meeting inclusion criteria, 94,887 (12.1%) filled a preoperative prescription for a benzodiazepine or Z-drug. From multivariable logistic regression, benzodiazepine or Z-drug use was associated with an increased odds of an adverse postoperative event [odds ratio 1.13; 95% confidence interval: 1.08-1.18). In a separate regression, coprescription of benzodiazepines or Z-drugs with opioids was associated with a 1.45 odds of an adverse postoperative event (95% confidence interval: 1.37-1.53).

CONCLUSIONS

Preoperative benzodiazepines and Z-drug use is common and associated with increased odds of adverse outcomes after surgery, particularly when coprescribed with opioids. Counseling on appropriate benzodiazepine and Z-drug use in advance of elective surgery may potentially increase the safety of surgical care.

Risk Factors of Postoperative Vomiting in the Eye of "Real-World Evidence"-Modifiable and Clinical Setting-Dependent Risk Factors in Surgical Trauma Patients

Numerous studies on postoperative nausea and vomiting (PONV) have been carried out since the early days of contemporary surgery. The incidence of PONV has been greatly reduced in recent years and new drugs for PONV keep evolving in the market; however, a substantial number of patients are still under the threat of PONV. Female gender, non-smokers, a history of PONV/motion sickness, and postoperative opioid use are four well-recognized risk factors of PONV. Many potential risk factors reported in previous studies were not consistently presented as predictors for PONV. Two questions then arise; are risk factors clinical setting dependent and are risk factors modifiable? We attempted to answer the questions through a comprehensive review of perioperative records of surgical patients from the Trauma Department of our hospital. As nausea is subjective and no standard is applicable for its measurement, postoperative vomiting (POV) was used as an endpoint in this study. To the best of our knowledge, this is the first study to address the POV issue in surgical trauma patients. A total of 855 patients were enrolled in this study after excluding age below 20 years old, total intravenous anesthesia, desflurane anesthesia, or records with missing data. Our results showed that female gender (OR 4.89) is the strongest predicting factor, followed by a less potent predicting factor—more intraoperative opioid consumption (OR 1.07)—which favor more POV. More intraoperative crystalloid supply (OR 0.71) and a higher body weight (OR 0.9) favor less POV. Other potential risk factors did not reach statistical significance in this study as independent risk factors. Our results also showed that when the intraoperative crystalloid infusion rate is greater than 4 mL/kg/h (OR 0.20), it favors a lower rate of POV; when intraoperative opioid consumption is greater than 12 mg morphine equivalents, MME (OR 1.87), it favors a higher rate of POV. We concluded that dominance of any independent risk factor over other risk factors depends on how individual factors interact with the clinical setting. Some risk factors could be modified, and a cut-off value could be derived to facilitate a better plan for POV prevention.

Titration of sevoflurane anesthesia to optimize the time to regain airway reflexes in patients undergoing elective surgery: A randomized clinical trial comparing desflurane and sevoflurane anesthesia

BACKGROUND

Desflurane has adverse environmental effects, but has clinical advantages to speed emergence and return of protective airway reflexes compared with sevoflurane. We hypothesized that weaning of the inspired sevoflurane during the final 15 minutes of surgery would eliminate differences in airway reflex recovery between these agents.

METHODS

After obtaining IRB approval and informed consent, 40 patients undergoing elective surgery (≥1-hour) randomly received desflurane or sevoflurane. Patients swallowed 20 mL of water without drooling or coughing, and then received sedation and PONV pre-medication. Anesthesia was induced using propofol and fentanyl and maintained with desflurane or sevoflurane through a laryngeal mask airway maintaining a bispectral index of 45-50 and 50-60 during the final 15 minutes before surgery end. Cardiorespiratory variables and age-adjusted minimal alveolar concentration were recorded. The duration between anesthetic discontinuation and first appropriate response to command was measured; the laryngeal mask airway was removed. Two minutes after responding to command, patients were positioned semi-upright and attempted to swallow water. If successful swallowing was not achieved, the test was repeated every 4 minutes after each failure until successful swallowing was achieved.

RESULTS

Average anesthetic concentration and bispectral index was similar in patients receiving desflurane vs sevoflurane. Response times after discontinuation of anesthetics were similar. There were no differences in the recovery of swallowing ability between desflurane and sevoflurane groups.

CONCLUSION

Weaning of sevoflurane during the final 15 minutes of surgery eliminates clinical advantages of the more rapid return of airway reflexes with desflurane.

Comparison of the Level of Free Hexafluoro-isopropanol in Adults' Blood and the Incidence of Emergence Agitation After Anesthesia With Different Concentrations of Sevoflurane in Laparoscopic Gastrointestinal Surgery: A Randomized Controlled Clinical Trial

PURPOSE

The aim of the study is to compare the free hexafluoro-isopropanol (HFIP) concentration in adults' blood and the incidence of emergence agitation (EA) after inhaled different concentrations of sevoflurane.

METHODS

Sixty adult patients planning to undergo laparoscopic gastrointestinal surgery were randomly assigned to 3 groups. Each group received sevoflurane as the volatile anesthetic at different concentrations: 0.5 minimum alveolar concentration (MAC), 1.0 MAC, and 1.5 MAC. The use of sevoflurane was continued until the end of surgery. Venous blood samples were obtained at 30, 60, 120, and 180 minutes after starting the use of sevoflurane and subsequently at 60, 180, and 300 minutes after discontinuation of volatile anesthetic administration. Blood concentrations of sevoflurane and free HFIP were determined using gas chromatography. The recovery time and the incidence of EA at different time points were evaluated among the 3 groups.

FINDINGS

Changes in the blood concentrations of sevoflurane and free HFIP during and after the use of sevoflurane were similar in all 3 groups. The peak blood concentration of free HFIP occurred 60 minutes after onset of sevoflurane anesthesia in all 3 groups (P < 0.05). The lowest level of free HFIP and the longest recovery time were found in the 1.5-MAC group (P < 0.05). No significant difference was found in the incidence of EA or moderate pain among the 3 groups during recovery.

IMPLICATIONS

The generation of HFIP would be inhibited when the inhaled sevoflurane concentration increased to 1.5 MAC. However, the incidence of EA during recovery had nothing to do with the inhaled different sevoflurane concentrations (within 1.5 MAC) in adults. ChicCTR.org identifier: ChiCTR-IPD-17011558.

Sevoflurane Impairs Insulin Secretion and Tissue-Specific Glucose Uptake In Vivo

The use of anaesthetics severely influences substrate metabolism. This poses challenges for patients in clinical settings and for the use of animals in diabetes research. Sevoflurane can affect regulation of glucose homoeostasis at several steps, but the tissue-specific response remains to be determined. The aim of the study was to investigate the pharmacological effect of sevoflurane anaesthesia on glucose homoeostasis during hyperinsulinaemic clamp conditions, the gold standard method for assessment of whole-body insulin sensitivity. Conscious mice (n = 6) and mice under sevoflurane anaesthesia (n = 8) underwent a hyperinsulinaemic clamp where constant infusion of insulin and donor blood was administered during variable glucose infusion to maintain isoglycaemia. 2-[1-¹⁴ C]-deoxy-D-glucose was infused to determine tissue-specific uptake of glucose in adipose tissue, heart, brain and skeletal muscle. Sevoflurane anaesthesia severely impaired insulin-stimulated whole-body glucose uptake demonstrated by a 50% lower glucose infusion rate (GIR). This was associated with decreased glucose uptake in brain, soleus, triceps and gastrocnemius muscles in sevoflurane-anaesthetized mice compared to conscious mice. Plasma-free fatty acids (FFA), a potent inducer of insulin resistance, increased by 42% in mice during sevoflurane anaesthesia. In addition, insulin secretion from pancreatic β-cell was lower in fasted, anaesthetized mice. Sevoflurane anaesthesia impairs insulin secretion, induces insulin resistance in mice and reduces glucose uptake in non-insulin-sensitive tissue like the brain. The underlying mechanisms may involve sevoflurane-induced mobilization of FFA.

Protocol for the Reconstructing Consciousness and Cognition (ReCCognition) Study

Important scientific and clinical questions persist about general anesthesia despite the ubiquitous clinical use of anesthetic drugs in humans since their discovery. For example, it is not known how the brain reconstitutes consciousness and cognition after the profound functional perturbation of the anesthetized state, nor has a specific pattern of functional recovery been characterized. To date, there has been a lack of detailed investigation into rates of recovery and the potential orderly return of attention, sensorimotor function, memory, reasoning and logic, abstract thinking, and processing speed. Moreover, whether such neurobehavioral functions display an invariant sequence of return across individuals is similarly unknown. To address these questions, we designed a study of healthy volunteers undergoing general anesthesia with electroencephalography and serial testing of cognitive functions (NCT01911195). The aims of this study are to characterize the temporal patterns of neurobehavioral recovery over the first several hours following termination of a deep inhaled isoflurane general anesthetic and to identify common patterns of cognitive function recovery. Additionally, we will conduct spectral analysis and reconstruct functional networks from electroencephalographic data to identify any neural correlates (e.g., connectivity patterns, graph-theoretical variables) of cognitive recovery after the perturbation of general anesthesia. To accomplish these objectives, we will enroll a total of 60 consenting adults aged 20-40 across the three participating sites. Half of the study subjects will receive general anesthesia slowly titrated to loss of consciousness (LOC) with an intravenous infusion of propofol and thereafter be maintained for 3 h with 1.3 age adjusted minimum alveolar concentration of isoflurane, while the other half of subjects serves as awake controls to gauge effects of repeated neurobehavioral testing, spontaneous fatigue and endogenous rest-activity patterns.

Anaesthesia with sevoflurane in pigeons: minimal anaesthetic concentration (MAC) determination and investigation of cardiorespiratory variables at 1 MAC

The objective of the study was to determine the minimal anaesthetic concentration (MAC) of sevoflurane (SEVO) in pigeons and investigate the effects of 1 MAC SEVO anaesthesia on cardiovascular and respiratory variables compared with the awake state. This is a prospective, experimental study. Animals were seven healthy adult pigeons. After acclimatisation to handling, heart rate (HR), heart rhythm, respiratory rate (fR), end-expired carbon dioxide tension (PE'CO2), inspired CO2 tension, indirect systolic arterial blood pressure (SAP) and cloacal temperature were measured to determine baseline, 'awake' values. Pigeons were then anaesthetised with SEVO and MAC was determined by the 'bracketing' method. The same variables were monitored during a 40 minute period at 1.0 MAC SEVO for each bird. Mean MAC was 3.0±0.6 per cent for SEVO. During maintenance of anaesthesia at 1.0 MAC, SAP decreased significantly (P<0.001) without any significant change in HR. Although PE'CO2 increased significantly (P=0.001) despite an increase in fR, awake PE'CO2 values were unexpectedly low. Sinus arrhythmias were detected in two birds under SEVO anaesthesia. The times to tracheal intubation and to recovery were 2.5±0.7 and 6.4±1.7 minutes, respectively. Recovery was rapid and uneventful in all birds. In conclusion, SEVO is suitable for anaesthesia in pigeons.

The Effect of Anesthetic Choice (Sevoflurane Versus Desflurane) and Neuromuscular Management on Speed of Airway Reflex Recovery

BACKGROUND

Nonintubated patients receiving sevoflurane have slower protective airway reflex recovery after anesthesia compared with patients receiving desflurane. We asked whether this difference would remain significant among intubated patients receiving rocuronium or whether the impact of variable neuromuscular recovery would predominate and thus minimize differences between anesthetics.

METHODS

After obtaining written informed consent, patients were randomly assigned to receive sevoflurane (n = 41) or desflurane (n = 40), with neuromuscular monitoring by quantitative train-of-four (TOF) method using accelerometry. Intubation was facilitated by administration of 1 mg/kg rocuronium. Neuromuscular block was produced, with the goal of maintaining 10% to 15% of baseline function. After surgery, neostigmine 70 µg/kg + glycopyrrolate 14 µg/kg was administered. When TOF ratio reached ≥ 0.7, anesthetic was discontinued and fresh gas flow was raised to 15 L/m. The time of first response to command was noted, after which patients were given a 20-mL water swallowing test at 2, 6, 14, 22, 30, and 60 minutes. The following average time intervals were compared between the 2 intervention groups: anesthetic discontinuation to first response to command (T1); first response to command to first successful passing of swallow test (T2); and anesthetic discontinuation to first successful passing of swallow test (T3). We also compared the rates of successful swallow tests at 2 minutes after first response to command in the 2 groups, first categorizing as failures all those who were unable to take the test at 2 minutes, and then excluding 10 patients unable to take the test at this time for reasons other than somnolence (n = 10).

RESULTS

Patients receiving desflurane passed the swallowing test at shorter time intervals after first response to command than did patients receiving sevoflurane (Wilcoxon-Mann-Whitney odds = 1.60; 95% confidence interval [CI], 1.01-2.69; P = 0.054). Two minutes after the first response to command, among all 81 patients, the chance of passing the swallowing test was higher after desflurane compared with sevoflurane anesthesia (relative risk = 1.6; 95% CI, 1.0-2.5; P = 0.04). Of the 71 patients (as above), we observed a significantly higher chance of passing at 2 minutes after first response to command (relative risk = 1.8; 95% CI, 1.2-2.7; P = 0.006) in patients receiving desflurane (25/33) compared with those receiving sevoflurane (16/38). In 18 of 81 and 16 of 71 patients, the neuromuscular monitoring and reversal protocols were not followed (neostigmine underdosed, extubation at TOF <0.7, or reliance on tactile as opposed to quantitative TOF measurement). In both the total cohort and the subset of 71, neuromuscular protocol adherence increased the chance of passing the swallow test, independent of anesthetic assignment in multivariable logistic regression (P = 0.02 and P = 0.006, respectively), demonstrating significant effect on airway reflex recovery independent of chosen anesthetic.

CONCLUSIONS

Compared with sevoflurane, desflurane allowed faster recovery of airway reflexes after anesthesia in intubated patients. Clinical management of neuromuscular block, including full reversal and the use of quantitative TOF, affects airway reflex recovery-an effect that may be at least as profound as the choice of potent inhaled anesthetic.

Standard Anesthetic Technique for Middle Ear Surgical Procedures: A Comparison of Desflurane and Sevoflurane

Objective:

This study was designed to compare desflurane and sevoflurane anesthesia for middle ear microsurgery.

Study Design:

One hundred healthy adults undergoing middle ear surgery were assigned to receive either desflurane or sevoflurane as their anesthetic. Intraoperative hemodynamics and BIS numbers were recorded. Hemodynamics, pain, nausea/vomiting, discharge readiness, and other parameters were compared postoperatively and 24 hours later.

Results:

No intraoperative differences were noted except in BIS scores which trended lower with desflurane. PACU blood pressures were higher after desflurane but pain scores, nausea/vomiting, rescue anti-emetics, recovery scores, and discharge times were similar. A significant difference was noted in anesthetic costs (desflurane > sevoflurane), and in patients with the lowest BIS scores associated with more nausea/vomiting.

Conclusions:

Both anesthetics may be used for ototic surgery but propofol anesthesia should still be considered in patients with a history of emetic sequelae.

Significance:

Short-acting inhalational anesthetics produce excellent operating conditions and reduce costs for otologic surgery.

Postoperative recovery after anesthesia in morbidly obese patients: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Obese patients present a challenge to safe general anesthesia because of impaired cardiopulmonary physiology and increased risks of aspiration and acute upper airway obstruction. Since studies are lacking regarding the postoperative effects on recovery from general anesthesia in morbidly obese patients, we conducted a systematic review and meta-analysis of recovery outcomes in morbidly obese patients who had undergone general anesthesia.

SOURCE

We systematically searched the PubMed, EMBASE™, Cochrane, and Scopus™ databases for randomized controlled trials that evaluated the outcome of anesthesia with desflurane, sevoflurane, isoflurane, or propofol in morbidly obese patients. Using a random effects model, we conducted meta-analyses to assess recovery times (eye opening, hand squeezing, tracheal extubation, and stating name or birth date), time to discharge from the postanesthesia care unit (PACU), and the incidence and severity of postoperative nausea and vomiting (PONV).

PRINCIPAL FINDINGS

We reviewed results for 11 trials and found that patients given desflurane took less time: to respond to commands to open their eyes (weighted mean difference [WMD] -3.10 min; 95% confidence interval (CI): -5.13 to -1.08), to squeeze the investigator's hand (WMD -7.83 min; 95% CI: -8.81 to -6.84), to be prepared for tracheal extubation (WMD -3.88 min; 95% CI: -7.42 to -0.34), and to state their name (WMD -7.15 min; 95% CI: -11.00 to -3.30). We did not find significant differences in PACU discharge times, PONV, or the PACU analgesic requirement.

CONCLUSION

Postoperative recovery was significantly faster after desflurane than after sevoflurane, isoflurane, or propofol anesthesia in obese patients. No clinically relevant differences were observed regarding PACU discharge time, incidence of PONV, or postoperative pain scores. The systematic review was registered with PROSPERO (CRD42014009480).

Comparison of intraoperative brain condition, hemodynamics and postoperative recovery between desflurane and sevoflurane in patients undergoing supratentorial craniotomy

Background:

Post operative recovery has been reported to be faster with desflurane than sevoflurane anesthesia in previous studies. The use of desflurane is often criticized in neurosurgery due to the concerns of cerebral vasodilation and increase in ICP and studies comparing desflurane and sevoflurane in neurosurgey are scarce. So we compared the intraoperative brain condition, hemodynamics and postoperative recovery in patients undergoing elective supratentorial craniotomy receiving either desflurane or sevoflurane.

Materials and Methods:

Fifty three patients between 18-60yr undergoing elective supratentorial craniotomy receiving N₂O and oxygen (60%:40%) and 0.8-1.2 MAC of either desflurane or sevoflurane were randomized to group S (Sevoflurane) or group D (Desflurane). Subdural intra cranial pressure (ICP) was measured and brain condition was assessed.. Emergence time, tracheal extubation time and recovery time were recorded. Cognitive behavior was evaluated with Short Orientation Memory Concentration Test (SOMCT) and neurological outcome (at the time of discharge) was assessed using Glasgow Outcome Score (GOS) between the two groups.

Results:

The emergence time [Group D 7.4 ± 2.7 minutes vs. Group S 7.8 ± 3.7 minutes; P = 0.65], extubation time [Group D 11.8 ± 2.8 minutes vs. Group S 12.9 ± 4.9 minutes; P = 0.28] and recovery time [Group D 16.4 ± 2.6 minutes vs. Group S 17.1 ± 4.8 minutes; P = 0.50] were comparable between the two groups. There was no difference in ICP [Group D; 9.1 ± 4.3 mmHg vs. Group S; 10.9 ± 4.2 mmHg; P = 0.14] and brain condition between the two groups. Both groups had similar post-operative complications, hospital and ICU stay and GOS.

Conclusion:

In patients undergoing elective supratentorial craniotomy both sevoflurane and desflurane had similar intra-operative brain condition, hemodynamics and post operative recovery profile.

Hemodynamics and early recovery characteristics of desflurane versus sevoflurane in bariatric surgery

Context:

Morbidly obese patients are prone for intraoperative hemodynamic disturbances and postoperative airway complications.

Aim:

Comparison of intraoperative hemodynamics and postoperative recovery characteristics of desflurane versus sevoflurane in morbidly obese patients undergoing laparoscopic bariatric surgery.

Settings and Design:

Randomized controlled trial

Materials and Methods:

After institutional ethics committee approval and written informed consent, 40 morbidly obese patients (BMI > 35 kg/m²) were randomized to receive desflurane or sevoflurane as part of a standardized general anesthesia technique. Volatile anesthetic concentration was titrated to maintain electroencephalographic bispectral index score (BIS) in the range of 40-60. Mean arterial pressure (MAP) and heart rate (HR) were recorded preoperatively, at induction and intubation, then at regular intervals. After extubation, early recovery was recorded by time to emergence and orientation to time and place. In post anesthesia care unit, intermediate recovery was assessed by modified Aldrete Score and Digit Symbol Substitution Test (DSST).

Results:

Intraoperative MAP and HR did not differ between the two groups (P > 0.05). The time to response to painful stimuli, obeying verbal commands and spontaneous eye opening was shorter (P = 0.001) and modified Aldrete Score was higher after desflurane anesthesia than after sevoflurane anesthesia (P = 0.049). DSST also returned towards normal faster after desflurane (28.50 ± 6.30 min vs. 35.0 ± 5.62 min, P = 0.03).

Conclusions:

Both desflurane and sevoflurane produce similar hemodynamic changes but the immediate and intermediate recovery was significantly faster after desflurane thus contributing to fast tracking and early discharge of patients.

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.

[Incidence of cough after desflurane and sevoflurane administration through a laryngeal mask: a controlled clinical trial]

OBJECTIVE

To determine the incidence of cough with the administration of desflurane and sevoflurane through a laryngeal mask.

METHODS

A double-blind controlled clinical trial in 90 patients who received general anesthesia for ear, nose and throat surgery outpatient. The experimental group (n = 45) inhaled desflurane and the control group (n = 45) inhaled sevoflurane. Rugloop simulation software was used to assure that each patient was under the effect of the induction agent (propofol). The Gasman program was used to ascertain that a minimum alveolar concentration of 1 had been achieved before the hypnotic effect of propofol was lost. Cough was evaluated on the Shahbaz scale during the 10 minutes following induction and at the end of the procedure.

RESULTS

Cough in the first 10 minutes was recorded in 53.6% of patients in the desflurane group and in 2.4% in the sevoflurane group (P < .05). Between-group differences were also evident at the end of surgery (desflurane group, 24%; sevoflurane group, 9.7%; P< .05).

CONCLUSION

The patients who inhaled desflurane through a laryngeal mask had a higher incidence of cough than those who inhaled sevoflurane. The mechanism by which cough is being triggered by desflurane should be studied to determine whether the effect is chemical or mechanical and whether it is acting in the larynx or in the distal portion of the lung.

Effect of increased body mass index and anaesthetic duration on recovery of protective airway reflexes after sevoflurane vs desflurane

BACKGROUND

Increased BMI may increase the body's capacity to store potent inhaled anaesthetics, more so with more soluble agents. Accordingly, we asked whether increased BMI and longer anaesthesia prolonged airway reflex recovery.

METHODS

We measured time from anaesthetic discontinuation until first response to command (T1); from response to command until ability to swallow (T2); and from anaesthetic discontinuation to recovery of ability to swallow (T3) in 120 patients within three BMI ranges (18-24, 25-29, and >or=30 kg m(-2)). All received sevoflurane or desflurane, delivered via an LMA.

RESULTS

T1 and T3 after sevoflurane exceeded T1 and T3 after desflurane: 6.6 (sd 4.2) vs 4.0 (1.9) min (P<0.001), and 14.1 (sd 8.3) vs 6.1 (2.0) min (P<0.0001). T3 correlated more strongly with BMI after sevoflurane (28 s per kg m(-2), P=0.02) than desflurane (7 s per kg m(-2), P=0.03). Regarding T2, patients receiving sevoflurane with BMI >or=30 kg m(-2) were less often able to swallow 2 min after response to command than were those with BMI 18-24 or 25-29 kg m(-2) (3/20 vs 10/20 or 9/20, P<0.05). Each sevoflurane MAC-hour delayed T3 by 4.5 min (268 s) (R=0.46, P<0.001) whereas each desflurane MAC-hour delayed T3 by 0.2 min (16 s) (R=0.10, P=0.44).

CONCLUSIONS

Prolonged sevoflurane administration and greater BMI delay airway reflex recovery. The contribution of BMI to this delay is more pronounced after sevoflurane than desflurane.

Effect of administration of propofol and xylazine hydrochloride on recovery of horses after four hours of anesthesia with desflurane

OBJECTIVE

To compare characteristics of horses recovering from 4 hours of desflurane anesthesia with and without immediate postanesthetic IV administration of propofol and xylazine. Animals-8 healthy horses (mean +/- SEM age, 6.6 +/- 1.0 years; mean body weight, 551 +/- 50 kg).

PROCEDURES

Horses were anesthetized twice. Both times, anesthesia was induced with a combination of xylazine hydrochloride, diazepam, and ketamine hydrochloride and then maintained for 4 hours with desflurane in oxygen. Choice of postanesthetic treatment was randomly assigned via a crossover design such that each horse received an IV injection of propofol and xylazine or saline (0.9% NaCl) solution after the anesthetic episode. Recovery events were quantitatively and qualitatively assessed. Venous blood samples were obtained before and after anesthesia for determination of serum creatine kinase activity and plasma propofol concentration.

RESULTS

Anesthetic induction and maintenance were unremarkable in all horses. Compared with administration of saline solution, postanesthetic administration of propofol and xylazine resulted in an increased interval to emergence from anesthesia but improved quality of recovery-related transition to standing. Compared with administration of saline solution, administration of propofol also delayed the rate of decrease of end-tidal concentrations of desflurane and carbon dioxide and added to conditions promoting hypoxemia and hypoventilation.

CONCLUSIONS AND CLINICAL RELEVANCE

Propofol and xylazine administered IV to horses after 4 hours of desflurane anesthesia improved the quality of transition from lateral recumbency to standing but added potential for harmful respiratory depression during the postanesthetic period.

Comparative pharmacodynamic modeling of desflurane, sevoflurane and isoflurane

BACKGROUND

We compared dose-response curves of the hypnotic effects of desflurane, sevoflurane and isoflurane. In addition, we analyzed the k(e0) values of the different anesthetics. The EEG parameters Bispectral index (BIS, Aspect Medical Systems, Natick, MA, version XP) and Narcotrend index (MonitorTechnik, Bad Bramstedt, Germany, version 4.0) were used as measures of the pharmacodynamic effect.

METHODS

With IRB approval and informed consent we analyzed the data of three studies including 61 adult patients scheduled for radical prostatectomies. At least 45 min after induction of general anesthesia, end-tidal concentrations of desflurane, sevoflurane or isoflurane were varied between 0.5 and 2 MAC. We transferred the end-tidal concentrations into age-related MAC values. The relationship between MAC effect compartment concentrations and EEG was modeled with a variation of the classical fractional sigmoid E(max) model with two linked sigmoidal curves. All parameters were calculated as a population fit by NONMEM V (GloboMax, Hanover, USA) by minimizing log likelihood.

RESULTS

The k(e0) values of the population fit derived from BIS data were 0.54 min(-1) for desflurane, 0.24 min(-1) for sevoflurane and 0.16 min(-1) for isoflurane, from the Narcotrend index 0.43 min(-1) for desflurane, 0.26 min(-1) for sevoflurane and 0.18 min(-1) for isoflurane. The change between the first and the second sigmoidal curve was positioned at nearly the same Narcotrend- and BIS index values between 41 and 44.

CONCLUSIONS

The first order rate constant (k(e0) value) determining the equilibration between age-related MAC values and MAC effect site concentration is substantially higher for desflurane than for sevoflurane or isoflurane.

A comparison between sevoflurane and desflurane anesthesia in patients undergoing craniotomy for supratentorial intracranial surgery

BACKGROUND

Desflurane in neurosurgery may be beneficial because it facilitates postoperative early neurologic evaluation. However, its use has been debated because of its capacity to promote cerebral vasodilatation. Sevoflurane has been extensively used in neurosurgical patients. In this prospective clinical trial, we compared early postoperative recovery and cognitive function in patients undergoing craniotomy for supratentorial expanding lesions and receiving sevoflurane or desflurane anesthesia.

METHODS

One hundred twenty patients, ASA physical status I-III (66 men), Glascow Coma Scale 15, undergoing craniotomy for supratentorial expanding lesions were enrolled in the study. Patients were randomly allocated to two anesthetic regimens. In Group S (60 patients, 52 +/- 16 yr), anesthesia was maintained using sevoflurane with end-tidal of 1.5%-2% and was age adjusted to obtain approximately 1.2 minimum alveolar anesthetic concentration. In Group D (60 patients, 60 +/- 14 yr), anesthesia was maintained using desflurane with end-tidal of 6%-7% and was age adjusted to obtain approximately 1.2 minimum alveolar concentration. Emergence time was measured as the time from drug discontinuation to the time at which patients opened their eyes; tracheal extubation time was measured as the time from anesthetic discontinuation and tracheal extubation. Recovery time was measured as the time elapsing from discontinuation of anesthetic and the time when patients were able to recall their name and date of birth. Cognitive behavior was evaluated with the Short Orientation Memory Concentration Test. In the postanesthesia care unit, a blinded observer monitored the patients for 3 h; the incidence of hemodynamic events, pain, nausea, and shivering requiring rescue medication was recorded.

RESULTS

The mean emergence time (12.2 +/- 4.9 min in Group S vs 10.8 +/- 7.2 min in Group D; P = ns) was similar in the two groups, whereas the mean extubation time and recovery time were longer in Group S (15.2 +/- 3.0 min in Group S vs 11.3 +/- 3.9 min in Group D and 18.2 +/- 2.3 min in Group S vs 12.4 +/- 7.7 min in Group D, respectively; P < 0.001). The Short Orientation Memory Concentration Test score differed between the two groups only at the earliest assessment (15 min after extubation). No difference between the two groups was found in pain, shivering, nausea, vomiting, and incidence of postoperative hemodynamic events.

CONCLUSION

Patients who received desflurane had a shorter extubation and recovery time but similar intraoperative and postoperative incidence of complications compared with those who received sevoflurane.

Pharmakokinetische/pharmakodynamische Modelle für Inhalationsanästhetika

Pharmacokinetic models can be differentiated into two groups: physiological-based models and empirical models. Traditionally the pharmacokinetics of volatile anaesthetics are described using physiological-based models together with the respective tissue-blood distribution coefficients. The compartments of the empirical model have no anatomical equivalents and are merely the product of the mathematical procedure for parameter estimation. The end expiratory concentration of volatile anaesthetics is approximately equal to the arterial concentration and, therefore, the description of the transition between plasma and effect site for volatile anaesthetics plays a central role. The most important parameter here is the k(e0) value which is a time constant and describes the time delay for the transition from the central compartment to the calculated effect compartment. The k(e0) values for sevoflurane and isoflurane are the same but the concentration balance between the end-tidal concentration and the effect compartment occurs twice as quickly with desflurane. In clinical practice volatile anaesthetics are normally combined with N(2)O and/or opioids. This results in an additive interaction between volatile anaesthetics and N(2)O but a synergistic interaction of volatile anaesthetics with opioids. However, there are relatively few investigations on the interactions between the clinically widely used combination of volatile anaesthetics, N(2)O and opioids.

Recovery of older patients undergoing ambulatory anaesthesia with isoflurane or sevoflurane

BACKGROUND

Delayed recovery of cognitive function is a well-recognized phenomenon in older patients. The potential for the volatile anaesthetic used to contribute to alterations in postoperative cognitive function in older patients following minor surgical procedures has not been determined. We compared emergence from isoflurane and sevoflurane anaesthesia in older surgical patients undergoing urological procedures of short duration.

METHODS

Seventy-one patients, 60 yr of age or older, undergoing anaesthesia expected to last less than 60 min for ambulatory surgery, were randomly assigned to receive isoflurane or sevoflurane. A standardized anaesthetic protocol was used, with intravenous fentanyl 1 microg kg(-1) and propofol 1.5-2.0 mg kg(-1) administered to induce anaesthesia. Anaesthesia was maintained with either sevoflurane or isoflurane in 65% nitrous oxide and oxygen. Early and intermediate recovery times were recorded. The Mini Mental State Examination and digit repetition forwards and backwards were administered at baseline, and at 1, 3 and 6 h postoperatively, to assess cognitive function.

RESULTS

There were no between-group differences in (sevoflurane vs. isoflurane, mean +/- standard error of the mean) times to removal of the laryngeal mask airway (7.7 +/- 0.6 vs. 7.1 +/- 0.4 min), verbal response time (10.1 +/- 0.7 vs. 9.9 +/- 0.7 min) and orientation (12.1 +/- 0.7 vs. 12.1 +/- 0.7 min). Intermediate recovery, as measured by time to readiness for discharge from the post anaesthesia care unit (44.9 +/- 1.5 vs. 44.3 +/- 1.5 min), was similar in the two groups. Postoperative indices of cognitive function and attention were comparably reduced at 1 h, but returned to baseline in both groups at 6 h.

CONCLUSIONS

Isoflurane and sevoflurane anaesthesia resulted in similar clinical and neurocognitive recovery profiles in older patients undergoing ambulatory surgical procedures of short duration.

Anesthetic Properties of Some Fluorinated Oxolanes and Oxetanes

BACKGROUND

The search for new potent inhaled anesthetics has slowed, in large part because of the excellence of the two most recent additions, desflurane and sevoflurane. Nonetheless, neither desflurane nor sevoflurane are ideal anesthetics, desflurane causing cardiorespiratory stimulation, and sevoflurane having a slower (albeit rapid) recovery from anesthesia. Sevoflurane also can produce convulsions and postoperative agitation.

METHODS AND RESULTS

In the present report, we describe the physical and anesthetic properties of 31 cyclic ethers halogenated solely with fluorine. Although several produced anesthesia, none had solubilities that would make them better than sevoflurane. The remaining ethers were unstable or produced obvious central nervous system irritation, including convulsions.

CONCLUSIONS

We find that none of these cyclic ethers appear to provide advantages over desflurane or sevoflurane.

Remifentanil-propofol in vertebral disk operations: hemodynamics and recovery versus desflurane-n(2)o inhalation anesthesia

The purpose of this study was to ascertain whether total intravenous anesthesia (TIVA) with propofol and remifentanil differs from inhalational anesthesia with desflurane and nitrous oxide in terms of hemodynamics, recovery profile, and postoperative analgesic demand in patients undergoing elective microsurgical vertebral disk resection. A total of 60 patients were randomly assigned to receive TIVA with propofol and remifentanil or inhalational anesthesia with desflurane and nitrous oxide. The TIVA group (n=30) then received 50%/50% N(2)O/O(2). A constant infusion of remifentanil was provided at 0.125 microg/kg/min accompanied by propofol at 10 mg/kg/h in the first 10 min, 6 mg/kg/h in the second 10 min, then 4 mg/kg/h. The desflurane group (n=30) received 50%/50% N(2)O/O(2), with 5% desflurane after intubation and 6% before incision; desflurane was administered in a minimum alveolar concentration 1 fashion during the operation. Hemodynamic, O(2) saturation, and end-tidal CO(2) data were recorded before induction, after intubation, after prone positioning, 5, 10, 15, 20, and 30 min into the operation, and at 15-min intervals thereafter until the end of the operation. Details on perioperative bradycardia, hypotension or hypertension, spontaneous breathing, extubation, eye opening, recovery time of ability to give name and date of birth, postoperative nausea and vomiting, shivering, agitation, and hypoxia were recorded. Patients anesthetized with desflurane responded to skin incision with increasing blood pressure and tachycardia; however, no other hemodynamic differences were noted between the 2 groups. In the TIVA group, recovery times were shorter for spontaneous ventilation (2.33-3.53 min), extubation (3.13-3.88 min), eye opening (4.06-6.23 min), and being able to give name and date of birth (5.4-7.9 min) compared with times in the desflurane group (P<.05). In the TIVA group, more postoperative shivering (16.7% of patients) and greater analgesic demand were seen than in the desflurane group. Although nausea and vomiting were more common in the desflurane group, no difference in bronchospasm was reported. In the TIVA group, a shorter recovery period and a greater demand for postoperative analgesia were seen. Because of the lack of residual analgesic effects, postoperative analgesic treatment should be initiated immediately in patients undergoing TIVA.

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.

Hypotensive Anesthesia and Recovery of Cognitive Function in Long-term Craniofacial Surgery

The aim of our study was to compare three different anesthesiological techniques with regard to hemodynamics, recovery, and postoperative morbidity, for craniofacial surgery. One hundred twenty patients with American Society of Anesthesiologists (ASA) classification of I or II patients, 18 to 32 years old, and undergoing maxillary and mandibular osteotomies were randomly assigned to receive anesthesia with propofol-remifentanil (group P), desflurane-remifentanil (group D), or sevoflurane-remifentanil (group S). All patients were given premedication: midazolam 0.03 mg/kg, atropine 0.007 mg/kg, desametasone 0.1 mg/kg, NaCl 0.9% 100 mL + 2 mg/kg ketoprofene + 1.5 mg/kg ranitidine + 1 microg/kg clonidine. Anesthesia was induced by O2/air (FiO2 0.5), remifentanil 0.5 microg/kg/min, propofol 2 mg/kg, rocuronium 0.6 mg/kg. Maintenance group P received O2/air (FiO2 0.5), remifentanil 0.25 to 1.5 microg/kg/min, propofol 6 to 10 mg/kg/h; groups D and S received O2/air (FiO2 0.5), remifentanil 0.25 to 1.5 microg/kg/min, and respectively, sevoflurane or desflurane 0.5 minimum alveolar anesthetic concentration. The dosage of propofol, desflurane, and sevoflurane, obtained with a value of bispectral index (BIS) 40, was kept unchanged throughout the course, and remifentanil was titrated to maintain controlled hypotension: systolic arterial blood pressure 70 to 90 mmHg and mean arterial blood pressure 50 to 65 mmHg. A 24-hour elastomeric infusion system (ketoprofene 320 mg) was started 60 minutes before induction and cloridrat ondansetron 0.1 mg/kg was administered 30 minutes before the end of surgery. Hypotension was successfully obtained in all three groups with a bloodless surgical field, and there was no need for additional use of a potent hypotensive agent. Early and late recovery were faster and more complete in the D group; P < 0.05. Postoperative morbidity (nausea, vomiting, shivering, pain, and edema) was slight and did not significantly differ among the groups.

Solubility of volatile anesthetics in bovine white matter, cortical gray matter, thalamus, hippocampus, and hypothalamic area

Although known for whole brain, values are lacking for solubilities of modern volatile anesthetics in specific brain regions. Some regions should differ from others (e.g., gray matter versus white matter) because they differ in lipid content and because potent inhaled anesthetics are lipophilic. In the present report, we examined this issue in bovine brain, finding that white matter/gas partition coefficients are 1.6 (desflurane) to 2.4 (halothane) times larger than gray matter/gas partition coefficients, with values for isoflurane and sevoflurane lying between these at 1.9. Values for thalamus/gas, hypothalamic area/gas, and hippocampal/gas partition coefficients lie between those for gray and white matter. These data may be useful in defining the parts of the brain involved with return to consciousness during recovery from anesthesia.

Emergence and recovery characteristics of desflurane versus sevoflurane in morbidly obese adult surgical patients: a prospective, randomized study

We compared postoperative recovery after desflurane (n = 25) versus sevoflurane (n = 25) anesthesia in morbidly obese adults (body mass index >/=35) who underwent gastrointestinal bypass surgery via an open laparotomy. After premedication with midazolam and metoclopramide 1 h before surgery, epidural catheter placement, induction of anesthesia with fentanyl and propofol, and tracheal intubation facilitated with succinylcholine, anesthesia was maintained with age-adjusted 1 minimum alveolar concentration (MAC) desflurane or sevoflurane. Fentanyl IV, morphine or local anesthetics epidurally, and vasoactive drugs as needed were used to maintain arterial blood pressure at +/-20% of baseline value and to keep bispectral index of the electroencephalogram values between 40 to 60 U. Although patients were anesthetized with desflurane for a longer time (261 +/- 50 min versus 234 +/- 37 min, mean +/- sd; P < 0.05, desflurane versus sevoflurane, respectively) and for more MAC-hours (4.2 +/- 0.9 h versus 3.7 +/- 0.8 h; P < 0.05), significantly earlier recovery of response to command and tracheal extubation occurred in patients given desflurane than in patients given sevoflurane. The modified Aldrete score was greater in desflurane-anesthetized patients on admission to the postanesthesia care unit (PACU) (P = 0.01) but not at discharge (P = 0.47). On admission to PACU, patients given desflurane had higher oxygen saturations (97.0% +/- 2.4%) than patients given sevoflurane (94.8% +/- 4.4%, P = 0.035). Overall, the incidence of postoperative nausea and vomiting and the use of antiemetics did not differ between the two anesthetic groups. We conclude that morbidly obese adult patients who underwent major abdominal surgery in a prospective, randomized study awoke significantly faster after desflurane than after sevoflurane anesthesia and the patients anesthetized with desflurane had higher oxygen saturation on entry to the PACU.

Recovery of elderly patients from two or more hours of desflurane or sevoflurane anaesthesia †

BACKGROUND

The solubility of desflurane compared with sevoflurane suggests more rapid recovery from desflurane anaesthesia. This could be important after prolonged anaesthesia and fast recovery may be advantageous in the elderly where slow recovery of mental function is a concern. We compared emergence from desflurane vs sevoflurane in elderly patients undergoing two or more hours of anaesthesia.

METHODS

Fifty ASA physical status I, II, or III patients, 65 yr of age or older, undergoing anaesthesia expected to last two or more hours were randomly assigned to receive desflurane/nitrous oxide or sevoflurane/nitrous oxide anaesthesia. Patients were given 1-2 microg x kg(-1) fentanyl i.v. and anaesthesia was induced with propofol 1.5-2.5 mg x kg(-1) i.v. and maintained with either desflurane 2-6% or sevoflurane 0.6-1.75% with nitrous oxide 65% in oxygen. Inspired anaesthetic concentrations were adjusted to obtain adequate surgical anaesthesia and to maintain mean arterial pressure within 20% of baseline values. Early and intermediate recovery times were recorded. Digit-Symbol Substitution Test (DSST) scores and Visual Analog Scale (VAS) scores for pain and nausea were recorded before pre-medication and every 15 min in the Post Anaesthesia Care Unit (PACU) until patients were discharged.

RESULTS

Early recovery times are given as median, quartiles. The times to extubation (5 (4-9); 9 (5-13) min), eye opening (5 (3-5); 11 (8-16) min), squeezing fingers on command (7 (4-9); 12 (8-17) min); and orientation (7 (5-9); 16 (10-21) min) were significantly less (P<0.05) for desflurane than for sevoflurane. Intermediate recovery, as measured by the DSST and time to ready for discharge from the PACU (56 (35-81); 71 (61-81) min) was similar in the two groups.

CONCLUSIONS

Early but not intermediate recovery times of elderly patients undergoing a wide range of surgical procedures requiring two or more hours of anaesthesia is significantly (P<or=0.05) faster after desflurane.

Comparison of recovery after intermediate duration of anaesthesia with sevoflurane and isoflurane

BACKGROUND

The purpose of this study was to compare recovery from anaesthesia after sevoflurane and isoflurane were administered to children for more than 90 min.

METHODS

After parental informed consent and ethical committee approval, children aged between 2 months and 6 years, ASA I or II, were randomly allocated to sevoflurane (n=20) or isoflurane (n=20) groups. Halogenated agents were discontinued following skin closure and patients were ventilated mechanically with 100% oxygen until minimum alveolar concentration (MAC) values awake were obtained (endtidal concentrations 0.6 MAC for sevoflurane and 0.4 MAC for isoflurane). Effective perioperative analgesia was provided by a caudal block.

RESULTS

The mean (+/- SD) duration of anaesthesia was 132 +/- 38 min and 139 +/- 49 min for sevoflurane and isoflurane, respectively. Early recovery occurred sooner in the isoflurane group (time to extubation was 16 +/- 7 min and 11 +/- 5 min, P<0.01; Aldrete's score at 0 min was 5.5 +/- 1.5 and 7.4 +/- 1.8, P<0.001, respectively). But the time to be fit for discharge from recovery room was similar at 136 +/- 18 min and 140 +/- 20 min, respectively.

CONCLUSIONS

After intermediate duration of anaesthesia administered to children for up to 90 min, isoflurane and sevoflurane allow recovery after approximatively the same lapse of time.

Isoflurane, desflurane and sevoflurane for carotid endarterectomy

After carotid endarterectomy under general anaesthesia, the rapid elimination of desflurane and sevoflurane may allow earlier postoperative neurological assessment than after the use of isoflurane. However, desflurane may be associated with tachycardia and hypertension and may therefore increase cardiovascular risk. We investigated haemodynamic and recovery characteristics in patients scheduled for carotid endarterectomy who were anaesthetised with isoflurane, sevoflurane or desflurane. No significant peri-operative differences were noted in cardiac index or ST segment analysis. The times to extubation, movement on command and consciousness were shorter after desflurane and sevoflurane than after isoflurane anaesthesia. Postoperative pain, nausea, vomiting and shivering were similar in the three study groups.

Recovery after anesthesia with remifentanil combined with propofol, desflurane, or sevoflurane for otorhinolaryngeal surgery

Because no previous investigation has directly compared the combination of remifentanil (REM) and a hypnotic with that of REM and the newer volatile anesthetics, we studied recovery characteristics and patient satisfaction after the combination of REM with propofol (PRO), desflurane (DES), or sevoflurane (SEVO). One hundred twenty patients were randomly assigned to receive anesthesia with either REM/PRO, REM/DES, REM/SEVO, or thiopental/alfentanil/isoflurane/N(2)O (control group) for ear, nose, and throat surgery (n = 30 each). In the REM groups, the dosage of PRO (75 microg. kg(-1). min(-1)), and of DES or SEVO (0.5 minimum alveolar anesthetic concentration) was kept unchanged, and REM was titrated to hemodynamic response. The control group was managed according to standard practice. Early recovery (times to eye opening, extubation, and statement of name and date of birth) was predictably faster and more complete in the REM groups compared with the control group. However, late recovery (times to discharge from postanesthesia care unit and hospital) and overall patient satisfaction were not different among groups. No clinically relevant differences existed among the three REM groups. In conclusion, the combination of REM infusion with small-dose DES, SEVO, or PRO is characterized by predictably rapid, early recovery. However, late recovery and patient satisfaction are comparable to a conventional anesthetic technique.

IMPLICATIONS

Remifentanil anesthesia, combined with small-dose propofol, desflurane, or sevoflurane, enables predictably fast and smooth early recovery after ear, nose, and throat surgery. Despite such faster, early recovery and less need for postoperative analgesic and antiemetic medication, late recovery was comparable among the remifentanil combination groups and the control group.

Sevoflurane and anesthesia for neurosurgery: a review

This review assesses the extent to which sevoflurane fulfills the requirements of the ideal inhalational agent for use in neuroanesthetic practice. Sevoflurane's pharmacokinetic profile is outlined. Data from animal and human studies are used to discuss its effects on cerebral hemodynamics, central nervous system monitoring, and cardiovascular parameters. Where possible, sevoflurane is compared with isoflurane, currently considered the inhalational agent of choice in neuroanesthesia. Sevoflurane's potential for toxicity is reviewed.

Clinical and economic factors important to anaesthetic choice for day-case surgery

Clinical and economic factors that are important to consider when selecting anaesthesia for day-case surgery can differ from those for inpatient anaesthesia. Patients undergoing day-case surgery tend to be healthier and have shorter durations of surgery. They expect less anxiety before surgery, amnesia for the surgical experience, a rapid return to normal (normal mentation with minimal pain and nausea) after surgery, and lower expenses. However, the latter 2 expectations can conflict; older generic drugs have lower acquisition costs but often impose longer recovery times. Longer recovery periods can increase costs by prolonging the time to discharge from labour-intensive areas such as the operating suite or the post-anaesthesia recovery unit. The challenge for today's anaesthetist is to use newer drugs judiciously to minimise their expense without compromising the rate or quality of recovery. Several approaches can secure these aims. Most apply the least anaesthetic needed. 'Least anaesthetic' may mean the particular form of anaesthetic (e.g. local infiltration with monitored anaesthesia care versus a general anaesthetic), or may mean the delivery of the smallest effective dose, perhaps guided by anaesthetic monitors such as end-tidal analysers or the bispectral index. For patients requiring general anaesthesia, a combination of several drugs usually secures the closest approach to the ideal. Drug combinations used usually include a short-acting properative anxiolytic (e.g. midazolam), intravenous propofol (a short-acting potent anxiolytic and amnestic agent) for induction of anaesthesia (and sometimes for maintenance) and primary maintenance of anaesthesia with inhaled nitrous oxide combined with a poorly soluble (low solubility produces rapid recovery; the least soluble is desflurane) potent inhaled anaesthetic delivered at a low inflow rate (to minimise cost). Although old, nitrous oxide is inexpensive and has favourable pharmacokinetic and cardiovascular advantages; however, it is limited in its anaesthetic/amnestic potency, and has the capacity to increase nausea. In children, induction of anaesthesia is often accomplished with sevoflurane rather than desflurane; although sevoflurane is modestly more soluble than desflurane, it is non-pungent whereas desflurane is pungent. Moderate- or short-acting opioids (fentanyl is popular) or nonsteroidal anti-inflammatory agents (especially ketorolac), or local anaesthetics are added to secure analgesia during and after surgery. Similarly, when needed, moderate- or short-acting muscle relaxants are selected. Before the end of anaesthesia, an intravenous antiemetic may be given. With this drug combination, patients usually awaken within minutes after anaesthesia and can often move themselves to the vehicle for transport to the recovery unit. These combinations of anaesthetics and techniques minimise use of expensive drugs while expediting recovery (again minimising cost) with minimal or no compromise in the quality of recovery.

Recovery of cognitive function after remifentanil-propofol anesthesia: a comparison with desflurane and sevoflurane anesthesia

We compared the recovery characteristics of remifentanil, desflurane, and sevoflurane when used for anesthesia in elective operative procedures. Sixty ASA physical status I and II patients, aged 18-65 yr, were randomly assigned to receive remifentanil-propofol, desflurane-N2O, or sevoflurane-N2O anesthesia. Before the induction of anesthesia, the patients of the desflurane and sevoflurane groups received fentanyl 2 microg/kg. In all groups, anesthesia was induced with propofol and maintained either with remifentanil 0.25 microg x kg(-1) x min(-1), desflurane, or sevoflurane 0.85 MAC with 65% nitrous oxide in oxygen. Anesthetics were titrated to achieve an adequate level of surgical anesthesia and to maintain mean arterial pressure within 20% of baseline values. Early recovery times and a modified Aldrete Recovery Score > 9 were recorded. Trieger Dot Test and Digit Substitution Test (DSST) were performed the day before surgery and in the postanesthesia care unit to evaluate intermediate recovery. The remifentanil-propofol group had a significantly faster emergence than desflurane or sevoflurane, with no difference between both inhaled anesthetics. Thirty min after anesthesia administration, patients in the remifentanil-propofol and in the desflurane groups gave significantly more correct responses in the DSST compared with sevoflurane (remifentanil 87%, desflurane 83%, sevoflurane 56%), the impairment in the sevoflurane patients corresponding to the effects of a blood alcohol level of approximately 0.1% and, thus, being of clinical importance. Ninety minutes after anesthesia administration, no significant difference could be demonstrated among the groups in the DSST scores. Emergence and return of cognitive function was significantly faster after remifentanil-propofol compared with desflurane and sevoflurane up to 60 min after anesthesia administration.

IMPLICATIONS

We compared awakening and intermediate recovery times after remifentanil-propofol anesthesia to desflurane-N2O and sevoflurane-N2O anesthesia. Emergence and return of cognitive function was significantly faster after remifentanil-propofol compared with desflurane and sevoflurane up to 60 min after anesthesia administration.

Peripheral neuropathy in healthy men volunteers anesthetized with 1.25 MAC sevoflurane for 8 hours

Two men volunteers developed peripheral neuropathy after prolonged anesthesia with 1.25 minimum alveolar concentration sevoflurane at an inflow rate of 2 L/minute of fresh gas that caused concurrent administration of relatively large doses (ppm-hrs) of the degradation product of sevoflurane, compound A. Other similarly treated volunteers had lesser degrees of transient neuropathy. This result does not prove but raises the question of whether compound A or other factors associated with sevoflurane anesthesia can predispose patients to peripheral neuropathy.

Recovery and pharmacokinetic parameters of desflurane, sevoflurane, and isoflurane in patients undergoing urologic procedures

STUDY OBJECTIVE

To compare the pharmacokinetics and the speed of recovery after inhalation anesthesia with desflurane, sevoflurane, and isoflurane in elective surgery.

DESIGN

Prospective, randomized study.

SETTING

University medical center.

PATIENTS

30 ASA physical status I and II adults presenting for elective surgery.

INTERVENTIONS

Anesthesia was induced with etomidate and maintained with desflurane (n = 10), sevoflurane (n = 10), or isoflurane (n = 10) and nitrous oxide. The inhalation drugs were titrated until an adequate clinical depth of anesthesia was reached. At the end of anesthesia, the patients breathed oxygen via the endotracheal tube and after extubation via a face mask.

MEASUREMENTS AND MAIN RESULTS

The groups were similar with respect to age, weight, duration of anesthesia, and mean arterial pressure. Mean end-tidal concentration (FA = FA0) at the end of anesthesia was 6.34 +/- 1.15% after desflurane, 1.85 +/- 0.42% after sevoflurane, and 1.10 +/- 0.24% after isoflurane. FA/FA0 decreased significantly faster with desflurane than with isoflurane, while there was little difference between desflurane and sevoflurane. As for the terminal half-life (t1/2), there were no differences among the groups (8.16 +/- 3.15 min after desflurane, 9.47 +/- 4.46 min after sevoflurane, and 10.0 +/- 5.57 min after isoflurane). The time until a command was followed for the first time was the same in all three groups (13.0 +/- 4.7 min after desflurane, 13.4 +/- 4.4 min after sevoflurane, and 13.6 +/- 3.4 min after isoflurane). There was no significant correlation between duration of anesthesia and the time until recovery.

CONCLUSIONS

There are only minor differences with regard to the recovery phase in premedicated patients who receive clinically titrated inhalation anesthesia with desflurane, sevoflurane, or isoflurane.

Carbon dioxide absorption: toxicity from sevoflurane and desflurane

The degradation of volatile anaesthetics by desiccated carbon dioxide absorbents can result in adverse outcomes. Desiccated carbon dioxide absorbent reacting with desflurane can cause potentially life-threatening intraoperative carbon monoxide exposure; the reaction with sevoflurane can cause the formation of several toxic breakdown products, e.g. compound A. Compound A-related renal toxicity in humans is still a matter of controversy.

Desflurane and sevoflurane. New volatile anesthetic agents

Desflurane and sevoflurane, recently licensed for use in humans, have kinetics that result in rapid induction and easy maintenance of a stable level of anesthesia. Recovery is also rapid. Cardiopulmonary effects are similar to those of isoflurane. In humans, desflurane can cause airway irritation and sympathetic stimulation, but these side effects have not caused problems in animal trials. Metabolites of sevoflurane and breakdown products from its reaction with carbon dioxide absorbents theoretically could result in hepatic and renal damage, but such toxicity has not occurred despite extensive medical use. Clinical trials in animals are now in progress.