Desflurane Allows for a Faster Emergence When Compared to Sevoflurane without Affecting the Baseline Cognitive Recovery Time

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.

Translation and concurrent validity, sensitivity and specificity of Chinese version of Short Orientation Memory Concentration Test in people with a first cerebral infarction

Purpose

This study aimed to translate the English version of the Short Orientation-Memory-Concentration (SOMC) test into a Chinese version, denoted the C-SOMC test, and to investigate the concurrent validity, sensitivity, and specificity of the C-SOMC test against a longer and widely used screening instrument in people with a first cerebral infarction.

Methods

An expert group translated the SOMC test into Chinese using a forward-backward procedure. Eighty-six participants (67 men and 19 women, mean age = 59.31 ± 11.57 years) with a first cerebral infarction were enrolled in this study. The validity of the C-SOMC test was determined using the Chinese version of Mini Mental State Examination (C-MMSE) as the comparator. Concurrent validity was determined using Spearman's rank correlation coefficients. Univariate linear regression was used to analyze items' abilities to predict the total score on the C-SOMC test and the C-MMSE score. The area under the receiver operating characteristic curve (AUC) was used to demonstrate the sensitivity and specificity of the C-SOMC test at various cut-off values distinguishing cognitive impairment from normal cognition.

Results

The total score for the C-SOMC test and the score for item 1 on this test exhibited moderate-to-good correlations with the C-MMSE score, with respective ρ-values of 0.636 and 0.565 (P < 0.001). The scores for each of items 2, 4, 5, 6, and 7 yielded fair correlations with C-MMSE score, with ρ-value from 0.272 to 0.495 (P < 0.05). The total score on the C-SOMC test and the item score were good predictors (adjusted R² = 0.049 to 0.615) of the C-MMSE score, and six items were good predictors (adjusted R² = 0.134 to 0.795) of the total score. The AUC was 0.92 for the C-SOMC test. A cut-off of 17/18 on the C-SOMC test gave optimal performance: correct classification of 75% of participants, with 75% sensitivity and 87.9% specificity.

Conclusion

The C-SOMC test demonstrated good concurrent validity, sensitivity and specificity in a sample of people with a first cerebral infarction, demonstrating that it could be used to screen for cognitive impairment in stroke patients.

Knowledge Gaps in Anesthetic Gas Utilization in a Large Academic Hospital System: A Multicenter Survey

Inhaled anesthetics account for a significant portion of the greenhouse gases generated by perioperative services within the healthcare systems. This cross-sectional study aimed to identify knowledge gaps and practice patterns related to carbon dioxide (CO₂) absorbents and intraoperative delivery of fresh gas flows (FGF) for future sustainability endeavors. Secondary aims focused on differences in these knowledge gaps based on the level of training. Surveys were distributed at five large academic medical centers. In addition to site-specific CO₂ absorbent use and practice volume and experience, respondents at each institution were queried about individual practice with FGF rates during anesthetic maintenance as well as the cost-effectiveness and environmental impact of different volatile anesthetics. Results were stratified and analyzed by the level of training. In total, 368 (44% physicians, 30% residents, and 26% nurse anesthetists) respondents completed surveys. Seventy-six percent of respondents were unaware or unsure about which type of CO₂ absorbent was in use at their hospital. Fifty-nine percent and 48% of respondents used sevoflurane and desflurane with FGF ≥1 L/min, respectively. Most participants identified desflurane as the agent with the greatest environmental impact (89.9%) and a greater proportion of anesthesiologists correctly identified isoflurane as a cost-effective anesthetic (78.3%, p=0.02). Knowledge gaps about in-use CO₂ absorbent and optimal FGF usage were identified within the anesthesia care team. Educational initiatives to increase awareness about the carbon emissions from anesthesia and newer CO₂ absorbents will impact the environmental and economic cost per case and align anesthesia providers toward healthcare decarbonization.

Greenhouse gas reduction in anaesthesia practice: a departmental environmental strategy

Sustainability interventions were implemented at the Royal Brisbane and Women’s Hospital (RBWH) following identification of inhaled anaesthetic gases as a target for reducing medical carbon emissions. This quality improvement study assessed and evaluated the impact of sustainability interventions on the environmental and financial cost of inhaled anaesthetic gas use in order to guide future initiatives and research in reducing carbon emissions from healthcare practice.

Ethical exemption was granted from the RBWH Research Ethics Committee (EX/2021/QRBW/76078). Usage (bottles) and expenditure for desflurane and sevoflurane from January 2016 to December 2021 were obtained. Global warming potential and carbon dioxide equivalent (CO₂e) were used to report environmental impact of volatile agents. Methods to estimate this were performed in Excel based on Campbell and Pierce methodology. An Environmental Protection Agency greenhouse gas equivalency calculator was used to convert CO₂e to equivalent petrol carbon emissions and kilometres travelled by a typical passenger vehicle.

The total number of bottles of sevoflurane and desflurane purchased between January 2016 and December 2021 decreased by 34.76% from 1991 to 1299. The number of desflurane bottles purchased decreased by 95.63% from 800 to 35 bottles. The number of sevoflurane bottles purchased increased by 6.13% from 1191 bottles to 1264 bottles. This was achieved by implementing quality improvement interventions such as staff education of desflurane-sparing practices, distribution of posters and progressive removal of desflurane from operating theatres. Total carbon emission from volatile anaesthetics equalled 2326 tonnes CO₂e. Combined desflurane and sevoflurane emissions decreased by 87.88%. In 2016, desflurane made up 92.39% of the annual CO₂e, which steadily decreased to 33.36% in 2021. Combined sevoflurane and desflurane usage costs decreased by 58.33%.

Substantial reductions in carbon emissions from volatile anaesthetics demonstrate the significant degree to which environmentally sustainable practices have been implemented. Applying desflurane-sparing practice can heavily limit anaesthetic drug expenditure and contribution to environmental waste. This is important given the global health sector’s challenge to optimise patient outcomes in the face of global climate change crisis.

A comparison of postoperative respiratory complications associated with the use of desflurane and sevoflurane: a single-centre cohort study

Sevoflurane and desflurane are the most commonly used volatile anaesthetics for maintenance of anaesthesia. In this study, we aimed to evaluate the relationship between choice of volatile anaesthetic and early postoperative respiratory complications, and to address a critical knowledge gap in safety outcomes between these two commonly used agents. We performed a retrospective analysis of adult (non-cardiac surgery) patients who received sevoflurane or desflurane for the maintenance of general anaesthesia at our institution between 2005 and 2018. We evaluated the association between desflurane exposure (when compared with sevoflurane) and the primary outcome of postoperative respiratory complications, defined by early post-extubation desaturation (S_p O₂  < 90%) or re-intubation within 7 days postoperatively. Multivariable regression analyses were performed and adjusted for confounding factors, including patient, anaesthetic and surgical factors. Propensity matched, interaction and sub-group analyses were performed to assess outcomes in high-risk groups: morbidly obese (BMI > 35 kg.m^-2 ); elderly (age > 65 years); and high risk of respiratory complications as well as the primary outcome at 24 h. Desflurane was used for 23,830 patients and sevoflurane for 84,608 patients. Patients exposed to desflurane did not demonstrate a reduced risk of postoperative respiratory complications when compared with sevoflurane (adjusted odds ratio 0.99, 95%CI 0.94-1.04, p = 0.598). These findings were consistent across all sub-groups of high-risk patients and in the propensity score matched cohort. In summary, desflurane use was not associated with reduced postoperative respiratory complications when compared with sevoflurane. In the context of environmental and cost concerns with volatile anaesthetic agents, our study provides important data to support organisational decisions regarding the use of desflurane.

A randomised prospective comparison of equilibration point and changing gas composition during low-flow anaesthesia with sevoflurane vs desflurane

Background and Aims:

Safety and economy are the main concerns while using low- flow anaesthesia with newer inhalational agents. The main objective of this study was to use and compare 'equilibration time' of sevoflurane and desflurane after change-over from high-to-low flow anaesthesia.

Methods:

This prospective study included consenting adult patients between 18–70 years undergoing elective surgery under general anaesthesia. Patients were randomised initially to receive high-flow anaesthesia with 1.3 MAC of either desflurane or sevoflurane with nitrous oxide. After equilibration point, low-flow anaesthesia was initiated. Heart rate, non-invasive blood pressure, pulse oximeter, 5 electrode ECG and gas monitoring was done. Statistical analysis was done with the help of Med CalC version 12.5.0.0 (student version) and IBM SPSS Version 20.0.

Results:

Mean equilibration time in sevoflurane group was higher (4.59 ± 0.77 minutes) than desflurane group (3.78 ± 0.56 minutes, P < 0.001). Inspired concentrations of both inhalational agents varied from their vaporiser settings over 2 hours, more so with sevoflurane than desflurane. Inspired oxygen concentration (FiO2) remained above 30% during anaesthesia in both groups with stable haemodynamics.

Conclusion:

Change-over from high-to-low flow anaesthesia is faster in desflurane. With fresh gas flow (FGF) of 1 L with 50% oxygen and dial concentration of 1–1.5% of sevoflurane and 3.8–4.4% of desflurane, the risk of hypoxia is minimal. The disparity between the set and delivered concentrations is more (20%) in sevoflurane than desflurane (12%).

Emergence times and airway reactions during general anaesthesia with remifentanil and a laryngeal mask airway: A multicentre randomised controlled trial

BACKGROUND

Avoidance of airway complications and rapid emergence from anaesthesia are indispensable for the use of a laryngeal mask airway (LMA). Evidence from adequately powered randomised studies with a low risk of bias for the optimal anaesthetic in this context is limited.

OBJECTIVE

We tested the hypothesis that when using remifentanil-based intra-operative analgesia, desflurane would be the most suitable anaesthetic: with noninferiority in the occurrence of upper airway complications and superiority in emergence times compared with sevoflurane or propofol.

DESIGN

A randomised, multicentre, partially double-blinded, three-arm, parallel-group study.

SETTING

Two university and two regional German hospitals, from February to October 2015.

PATIENTS

A total of 352 patients (age 18 to 75 years, ASA physical status I to III, BMI less than 35 kg m⁻² and fluent in German) were enrolled in this study. All surgery was elective with a duration of 0.5 to 2 h, and general anaesthesia with a LMA was feasible.

INTERVENTION

The patients were randomised to receive desflurane, sevoflurane or propofol anaesthesia.

MAIN OUTCOME MEASURES

This study was powered for the primary outcome ‘time to state date of birth’ and the secondary outcome ‘intra-operative cough’. Time to emergence from anaesthesia and the incidence of upper airway complications were assessed on the day of surgery.

RESULTS

The primary outcome was analysed for 343 patients: desflurane (n=114), sevoflurane (n=111) and propofol (n=118). The desflurane group had the fastest emergence. The mean (± SD) times to state the date of birth following desflurane, sevoflurane and propofol were 8.1 ± 3.6, 10.1 ± 4.0 and 9.8 ± 5.1 min, respectively (P < 0.01). There was no difference in upper airway complications (cough and laryngospasm) across the groups, but these complications were less frequent than in previous studies.

CONCLUSION

When using a remifentanil infusion for intra-operative analgesia in association with a LMA, desflurane was associated with a significantly faster emergence and noninferiority in the incidence of intra-operative cough than either sevoflurane or Propofol.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02322502; EudraCT identifier: 2014-003810-96.

Environmental safety: Air pollution while using MIRUS™ for short-term sedation in the ICU

BACKGROUND

MIRUS™ is a device for target-controlled inhalational sedation in the ICU in combination with use of isoflurane, or sevoflurane, or desflurane. The feasibility of this device has recently been proven; however, ICU staff exposure may restrict its application. We investigated ICU ambient room pollution during daily work to estimate ICU personnel exposure while using MIRUS™.

METHODS

This observational study assessed pollution levels around 15 adult surgical patients who received volatile anaesthetics-based sedation for a median of 11 hours. Measurements were performed by photoacoustic gas monitoring in real-time at different positions near the patient and in the personnel's breathing zone. Additionally, the impact of the Clean Air™ open reservoir scavenging system on volatile agent pollution was evaluated.

RESULTS

Baseline concentrations [ppm] during intervention and rest periods were isoflurane c ¯ mean = 0.58 ± 0.49, c ¯ max = 5.72; sevoflurane c ¯ mean = 0.22 ± 0.20, c ¯ max = 7.93; and desflurane c ¯ mean = 0.65 ± 0.57, c ¯ max = 6.65. Refilling MIRUS™ with liquid anaesthetic yielded gas concentrations of c ¯ mean = 2.18 ± 1.48 ppm and c ¯ max = 13.03 ± 9.37 ppm in the personnel's breathing zone. Air pollution in the patient's room was approximately five times higher without a scavenging system.

CONCLUSION

Ambient room pollution was minimal in most cases, and the measured values were within or below the recommended exposure limits. Caution should be taken during refilling of the MIRUS™ system, as this was accompanied by higher pollution levels. The combined use of air-conditioning and gas scavenging systems is strongly recommended.