Inhaled sedation in the intensive care unit

Effects of Sevoflurane and Propofol During Mechanical Ventilation: A Meta-analysis of Randomized Controlled Trials

PURPOSE

To compare the inflammatory response, hemodynamic stability, and postoperative recovery of sevoflurane versus propofol after mechanical ventilation during surgery, to provide references for rational anesthesia utility in clinical practice by meta-analysis.

DESIGN

Systematic review and meta-analysis.

METHODS

Pubmed, Web of Science, Cochrane Library, Wanfang Data, China National Knowledge Infrastructure, and Chinese BioMedical Literature Database were searched by computer for trials on the anesthetic effects of sevoflurane and propofol after mechanical ventilation during surgery. A random- or fixed-effects model was applied to analyze the clinical indicators and adverse impact based on heterogeneity.

FINDINGS

As of April 21, 2023, 912 articles were retrieved, and 36 eligible articles were finally identified after screening, covering 2,691 surgical patients for meta-analysis. The combined results exhibited that the level of tumor necrosis factor (TNF)-α in alveolar lavage was significantly different between the 2 groups (-0.94, 95% confidence interval [CI]: -1.82 to -0.05, P = .038). Compared with sevoflurane, propofol significantly increased TNF-α levels in alveolar lavage. In plasma or serum, propofol significantly increased the levels of interleukin-10 (-0.73, 95% CI: -1.36 to -0.10, P = .023) and TNF-α (-0.65, 95% CI: -1.21 to -0.09, P = .022).

CONCLUSIONS

At alveolar lavage and serum or plasma levels of inflammatory factors, the proinflammatory factor TNF-α was significantly lower in the sevoflurane group than in the propofol group. This indicates that sevoflurane has a certain role in alleviating local and systemic lung inflammation. However, more randomized controlled studies are warranted in the future to confirm whether there is a difference in hemodynamic stability and postoperative recovery of patients.

Anesthetic Gas Scavenging System for Gas Evacuation in the ICU

Background: Inhaled sedation is increasing in ICUs, with active carbon filters (ACFs) commonly used for evacuating halogenated gases. However, the potential benefits of a waste anesthetic gas system (WAGS) similar to the ones used in operating rooms should be explored. To limit the suction over the flow sensor where the WAGS is connected on ICU ventilators, an anesthetic gas receiving system (AGRS) is required, constituting with the WAGS an active gas receiving and scavenging system (AGRSS). Ensuring that this whole device does not compromise the flow sensor reliability is crucial. The aim of this study was to compare various gas evacuation devices and assess the reliability of AGRSS on ICU ventilators. Methods: In this experimental study, pressures and flows were recorded during the ventilation of a test lung using various ventilator settings and gas evacuation methods: no device (reference condition), ACF, the WAGS alone, AGRSS (WAGS and AGRS together), and the expiratory valve connected to the medical vacuum system with the AGRS in between. Visual comparisons of the pressure and flow curves followed by a statistical analysis comparing median pressures and flows of each device to the reference were performed. Results: The test lung model demonstrated consistent comparability in pressures and flows among all devices, except for the WAGS alone, which exhibited discordance through significant overestimation or underestimation. Conclusions: These findings indicate that using a WAGS with the AGRS system appeared to be reliable for managing gas evacuation in ICUs without compromising pressure or flow delivery. The data from this experimental trial should be confirmed with clinical studies involving human subjects. Given the increasing use of inhaled sedation in ICUs, these results support the daily application of the WAGS with the AGRS for gas evacuation, similar to its established use in anesthesiology.

Isoflurane vs. Propofol Sedation in Patients with Severe Stroke: A Clinical Proof-of-Concept-Study

Background: Severe strokes often require deep sedation, yet the optimal sedation regimen remains unclear. This comparative study compared the efficacy of achieving target sedation depth using inhaled (isoflurane) versus intravenous (propofol) sedation. Methods: This prospective, observational, proof-of-concept study was conducted between July 2022 and June 2023 at two University Hospitals with dedicated neurological intensive care units. We included conservatively treated patients with severe space-occupying strokes (ischemic or haemorrhagic) requiring deep sedation. Patients received either inhaled or intravenous sedation. Sedation targets were defined in the morning rounds using the Richmond-Agitation-Sedation-Scale and were assessed at two subsequent time points (7 p.m. and 7 a.m.) during hospital stay. The primary outcome was the number of days where the predefined sedation target was achieved at both time points, comparing between the two sedation regimens. Secondary and safety outcomes included the incidence of delirium, pneumonia, functional outcomes, mortality, and vasopressor doses. Results: Seventy-nine patients (age 71 [63-81] years, 31 female) were included. Patients sedated with isoflurane achieved the sedation target significantly more often, with 182/444 (41%) compared to 80/497 (16%) assessments in patients sedated with propofol (RR 1.4; 95%-CI: 1.3-1.6). This effect was consistent across all sedation stages, specifically in the deep sedation targets (RR 1.5; 95%-CI: 1.2-1.9) and no-sedation target (RR 5.1; 95%-CI: 2.8-9.4). Secondary and safety outcomes revealed no significant differences. Conclusions: Isoflurane sedation offers a benefit for invasively ventilated stroke patients with respect to sedation targets. Specifically, isoflurane facilitates faster awakening when transitioning from deep sedation to awakening. These data encourage further confirmatory studies for specific stroke-patient groups.

Inhaled Anesthetics: Beyond the Operating Room

The development of inhaled anesthetics (IAs) has a rich history dating back many centuries. In modern times they have played a pivotal role in anesthesia and critical care by allowing deep sedation during periods of critical illness and surgery. In addition to their sedating effects, they have many systemic effects allowing for therapy beyond surgical anesthesia. In this narrative review we chronicle the evolution of IAs, from early volatile agents such as ether to the contemporary use of halogenated hydrocarbons. This is followed by a discussion of the mechanisms of action of these agents which primarily involve the modulation of lipid membrane properties and ion channel activity. IAs' systemic effects are also examined, including their effects on the cardiovascular, respiratory, hepatic, renal and nervous systems. We discuss of the role of IAs in treating systemic disease processes including ischemic stroke, delayed cerebral ischemia, status epilepticus, status asthmaticus, myocardial ischemia, and intensive care sedation. We conclude with a review of the practical and logistical challenges of utilizing IAs outside the operating room as well as directions for future research. This review highlights the expanding clinical utility of IAs and their evolving role in the management of a diverse range of disease processes, offering new avenues for therapeutic exploration beyond anesthesia.

Early deep-to-light sedation versus continuous light sedation for ICU patients with mechanical ventilation: A cohort study

BACKGROUND

Sedation strategies have not been well established for patients being treated with invasive mechanical ventilation (MV). This study aimed to compare the potential effects of alternative sedation strategies - including early deep-to-light sedation (DTLS), continuous deep sedation (CDS) and continuous light sedation (CLS, the currently recommended strategy) - on ventilator, intensive care unit (ICU) or hospital mortality.

METHODS

A cohort study was conducted using two large validated ICU databases, including the Registry of Healthcare-associated Infections in ICUs in China (ICU-HAI) and the Medical Information Mart for Intensive Care (MIMIC). Patients who received MV for more than 3 days with one of three sedation strategies were included. Multivariable survival analyses with inverse probability-weighted competing risk models were conducted separately for ICU-HAI and MIMIC cohorts. Adjusted estimates were pooled using fixed-effects models.

RESULTS

In total, 6700 patients (2627 ICU-HAI, 4073 MIMIC) were included in the cohort study, of whom 2689 received CLS, 2079 CDS and 1932 DTLS. Compared to CLS, DTLS was associated with lower ICU mortality (9.3% vs. 11.0%; pooled adjusted HR 0.78, 95% CI 0.66-0.94) and hospital mortality (16.0% vs. 14.1%; 0.86, CI 0.74-1.00); and CDS was associated with higher ventilator mortality (32.8% vs. 7.0%; 4.65, 3.91-5.53), ICU mortality (40.6% vs. 11.0%; 3.39, 2.95-3.90) and hospital mortality (46.8% vs. 14.1%; 3.27, 2.89-3.71) than CLS. All HRs were qualitatively consistent in both cohorts.

CONCLUSIONS

Compared to the continuous light sedation, early deep-to-light sedation strategy was associated with improved patient outcomes, and continuous deep sedation was confirmed with poorer patient outcomes.

Effects of inhalation versus total intravenous anaesthesia on long-term mortality in older patients after noncardiac surgery: a retrospective observational study

BACKGROUND

Whether the anaesthetic agent used influences postoperative mortality in older patients remains unclear. We evaluated the effect of total intravenous anaesthesia (TIVA) vs inhalation anaesthesia on long-term mortality in older patients after noncardiac surgery.

METHODS

We retrospectively analysed 45,879 patients aged ≥60 yr who underwent noncardiac surgery under general anaesthesia (for ≥2 h) between January 2011 and June 2019. They were divided into two groups according to the type of maintenance anaesthetic. The primary outcome was all-cause mortality within 1 yr after surgery. Secondary outcomes included postoperative complications (postoperative pulmonary complications, perioperative adverse cardiovascular events, and acute kidney injury), and 3-yr and 5-yr mortality after surgery. The stabilised inverse probability of treatment weighting method was used to adjust for potential confounders.

RESULTS

Among 45,879 patients, 7273 (15.9%) patients received TIVA and 38,606 (84.1%) patients received inhalation anaesthesia. After adjustment with inverse probability of treatment weighting, there was no association between the type of anaesthetic agent and 1-yr mortality (hazard ratio=0.95; 95% confidence interval [CI] 0.84-1.08). Results for 3-yr and 5-yr mortality were similar. However, inhalation anaesthesia was associated with increased risk of postoperative complications (odds ratio [OR]=1.30; 95% CI 1.22-1.37 for postoperative pulmonary complications, OR=1.34; 95% CI 1.22-1.48 for perioperative adverse cardiovascular events, and OR=2.19; 95% CI 1.88-2.57 for acute kidney injury). In the subgroup analysis, the choice of anaesthetic agent showed differential effects on 1-yr mortality for female patients and emergency surgery.

CONCLUSION

The choice of anaesthetic agent during the intraoperative period was not associated with 1-yr mortality in older patients undergoing noncardiac surgery.

CLINICAL TRIAL REGISTRATION

Clinical Research Information Service of the Republic of Korea (KCT 0006363).

Volatile anesthetics for lung- and diaphragm-protective sedation

This review explores the complex interactions between sedation and invasive ventilation and examines the potential of volatile anesthetics for lung- and diaphragm-protective sedation. In the early stages of invasive ventilation, many critically ill patients experience insufficient respiratory drive and effort, leading to compromised diaphragm function. Compared with common intravenous agents, inhaled sedation with volatile anesthetics better preserves respiratory drive, potentially helping to maintain diaphragm function during prolonged periods of invasive ventilation. In turn, higher concentrations of volatile anesthetics reduce the size of spontaneously generated tidal volumes, potentially reducing lung stress and strain and with that the risk of self-inflicted lung injury. Taken together, inhaled sedation may allow titration of respiratory drive to maintain inspiratory efforts within lung- and diaphragm-protective ranges. Particularly in patients who are expected to require prolonged invasive ventilation, in whom the restoration of adequate but safe inspiratory effort is crucial for successful weaning, inhaled sedation represents an attractive option for lung- and diaphragm-protective sedation. A technical limitation is ventilatory dead space introduced by volatile anesthetic reflectors, although this impact is minimal and comparable to ventilation with heat and moisture exchangers. Further studies are imperative for a comprehensive understanding of the specific effects of inhaled sedation on respiratory drive and effort and, ultimately, how this translates into patient-centered outcomes in critically ill patients.

Effect of different sedatives on the prognosis of patients with mechanical ventilation: a retrospective cohort study based on MIMIC-IV database

Aim

To compare the effects of midazolam, propofol, and dexmedetomidine monotherapy and combination therapy on the prognosis of intensive care unit (ICU) patients receiving continuous mechanical ventilation (MV).

Methods

11,491 participants from the Medical Information Mart for Intensive Care (MIMIC)-IV database 2008-2019 was included in this retrospective cohort study. The primary outcome was defined as incidence of ventilator-associated pneumonia (VAP), in-hospital mortality, and duration of MV. Univariate and multivariate logistic regression analyses were utilized to evaluate the association between sedation and the incidence of VAP. Univariate and multivariate Cox analyses were performed to investigate the correlation between sedative therapy and in-hospital mortality. Additionally, univariate and multivariate linear analyses were conducted to explore the relationship between sedation and duration of MV.

Results

Compared to patients not receiving these medications, propofol alone, dexmedetomidine alone, combination of midazolam and dexmedetomidine, combination of propofol and dexmedetomidine, combination of midazolam, propofol and dexmedetomidine were all association with an increased risk of VAP; dexmedetomidine alone, combination of midazolam and dexmedetomidine, combination of propofol and dexmedetomidine, combination of midazolam, propofol and dexmedetomidine may be protective factor for in-hospital mortality, while propofol alone was risk factor. There was a positive correlation between all types of tranquilizers and the duration of MV. Taking dexmedetomidine alone as the reference, all other drug groups were found to be associated with an increased risk of in-hospital mortality. The administration of propofol alone, in combination with midazolam and dexmedetomidine, in combination with propofol and dexmedetomidine, in combination with midazolam, propofol and dexmedetomidine were associated with an increased risk of VAP compared to the use of dexmedetomidine alone.

Conclusion

Dexmedetomidine alone may present as a favorable prognostic option for ICU patients with mechanical ventilation MV.

Volatile Anesthetic Sedation for Critically Ill Patients

Volatile anesthetics have multiple properties that make them useful for sedation in the intensive care unit. The team-based approach to volatile anesthetic sedation leverages these properties to provide a safe and effective alternative to intravenous sedatives.

The influence of anaesthesia on cancer growth

BACKGROUND

Oncological patients make up a large proportion of all surgical patients. Through its influence on the patient's inflammatory and immune system, the choice of anaesthetic technique has an indirect impact on the health of the individual patient and on public health. Both the specific and the non-specific immune system have a major influence on the recurrence of carcinomas. The pathophysiological basis for growth and metastasis after surgery is the physiological response to stress. Inflammation is the organism's universal response to stress. Anaesthetics and adjuvants influence perioperative inflammation in different ways and have an indirect effect on tumour growth and metastasis. In vitro studies have shown how individual anaesthetics influence the growth and spread of cancer, but clinical studies have not confirmed these results. Nevertheless, it is advisable to use an anaesthetic that has shown lesser effect on the growth of cancer cells in vitro.

CONCLUSIONS

In this review, we focus on the area of the effects of anaesthesia on tumour growth. The field is still relatively unexplored, there are only few clinical prospective studies and their results are controversial. Based on the review of new research findings we report on recommendations about anaesthetics and anaesthetic techniques that might be preferable for oncological surgical procedures.

Effects on mechanical power of different devices used for inhaled sedation in a bench model of protective ventilation in ICU

BACKGROUND

Inhaled sedation during invasive mechanical ventilation in patients with acute respiratory distress syndrome (ARDS) has received increasing attention. However, inhaled sedation devices increase dead-space ventilation and an undesirable effect is the increase in minute ventilation needed to maintain CO2 removal. A consequence of raising minute ventilation is an increase in mechanical power (MP) that can promote lung injury. However, the effect of inhaled sedation devices on MP remains unknown.

METHODS

We conducted a bench study to assess and compare the effects of three devices delivering inhaled sevoflurane currently available in ICU (AnaConDa-50 mL (ANA-50), AnaConDa-100 mL (ANA-100), and MIRUS) on MP by using a test lung model set with three compliances (20, 40, and 60 mL/cmH2O). We simulated lung-protective ventilation using a low tidal volume and two levels of positive end-expiratory pressure (5 and 15 cmH2O) under ambient temperature and dry conditions. Following the insertion of the devices, either the respiratory rate or tidal volume was increased in 15%-steps until end-tidal CO2 (EtCO2) returned to the baseline value. MP was calculated at baseline and after EtCO2 correction using a simplified equation.

RESULTS

Following device insertion, the EtCO2 increase was significantly greater with MIRUS (+ 78 ± 13%) and ANA-100 (+ 100 ± 11%) than with ANA-50 (+ 49 ± 7%). After normalizing EtCO2 by adjusting minute ventilation, MP significantly increased by more than 50% with all inhaled sedation devices compared to controls. The lowest increase in MP was observed with ANA-50 (p < 0.05 versus ANA-100 and MIRUS). The Costa index, another parameter assessing the mechanical energy delivered to the lungs, calculated as driving pressure × 4 + respiratory rate, significantly increased by more than 20% in all experimental conditions. Additional experiments performed under body temperature, ambient pressure, and gas saturated with water vapor conditions, confirmed the main results with an increase in MP > 50% with all devices after normalizing EtCO2 by adjusting minute ventilation.

CONCLUSION

Inhaled sedation devices substantially increased MP in this bench model of protective ventilation, which might limit their benefits in ARDS.

Appraisal of Postoperative Outcomes of Volatile and Intravenous Anesthetics: A Network Meta-Analysis of Patients Undergoing Cardiac Surgery

OBJECTIVES

To determine the relative efficacy of specific regimens used as primary anesthetics, as well as the potential combination of volatile and intravenous anesthetics among patients undergoing cardiac, thoracic, and vascular surgery.

DESIGN

This frequentist, random-effects network meta-analysis was registered prospectively (CRD42022316328) and conducted according to the PRISMA-NMA framework. Literature searches were conducted up to April 1, 2022 across relevant databases. Risk of bias (RoB) and confidence of evidence were assessed by RoB-2 and CINeMA, respectively. Pooled treatment effects were compared with propofol monotherapy.

SETTING

Fifty-three randomized controlled trials (N = 8,085) were included, of which 46 trials (N = 6,604) enrolled patients undergoing cardiac surgery.

PARTICIPANTS

Trials enrolling adults (≥18) undergoing cardiac, thoracic, and vascular surgery, using the same induction regimens, and comparing volatile and/or total intravenous anesthesia for the maintenance of anesthesia. Given that the majority of trials focused on those undergoing cardiac surgery and the heterogeneity, analyses were restricted to this population.

MEASUREMENT AND MAIN RESULTS

Outcomes of interest included intensive care unit (ICU) length of stay (LOS), myocardial infarction, in-hospital and 30-day mortality, stroke, and delirium. Across 19 trials (N = 1,821; 9 arms; I2 = 64.5%), sevoflurane combined with propofol decreased ICU LOS (mean difference [MD] -18.26 hours; 95% CI -34.78 to -1.73 hours), whereas midazolam with propofol (MD 17.51 hours; 95% CI 2.78-32.25 hours) was associated with a significant increase in ICU LOS, when compared with propofol monotherapy. Among 27 trials (N = 4,080; 10 arms; I2 = 0%), midazolam was associated with significantly greater risk of myocardial infarction versus propofol (risk ratio 1.94; 95% CI 1.01-3.71). There were no significant differences across other outcomes.

CONCLUSION

In patients undergoing cardiac surgery, sevoflurane with propofol was associated with decreased ICU LOS compared with propofol monotherapy. Midazolam with propofol increased ICU LOS compared with propofol alone. The combined use of intravenous and volatile anesthetics should be explored further. Future trials in thoracic and vascular surgery are warranted.

Comparison between sevoflurane and propofol on immunomodulation in an in vitro model of sepsis

Introduction

Patients with sepsis often require sedation and/or anesthesia. Although the immunomodulatory effects of anesthetics have been increasingly recognized, the molecular mechanisms require better elucidation. We compared the effects of sevoflurane with propofol on the expression of pro- and anti-inflammatory biomarkers released by monocytes/macrophages and blood/bronchoalveolar lavage fluid (BALF) neutrophils, the phagocytic capacity of monocytes/ macrophages, and neutrophil migration, as well as mediators associated with alveolar epithelial and endothelial cells obtained from rats with sepsis.

Methods

Polymicrobial sepsis was induced by cecal ligation and puncture in nine male Wistar rats. After 48 h, animals were euthanized and their monocytes/alveolar macrophages, blood and BALF neutrophils, as well as alveolar epithelial and endothelial cells were extracted, and then exposed to (1) sevoflurane (1 minimal alveolar concentration), (2) propofol (50 μM), or (3) saline, control (CTRL) for 1 h.

Results

Sevoflurane reduced interleukin (IL)-6 mRNA expression in monocytes and alveolar macrophages (p = 0.007, p = 0.029), whereas propofol decreased IL-6 mRNA only in alveolar macrophages (p = 0.027) compared with CTRL. Sevoflurane increased IL-10 expression (p = 0.0002) in monocytes compared with propofol and increased IL-10 mRNA and transforming growth factor (TGF)-β mRNA (p = 0.037, p = 0.045) compared with CTRL. Both sevoflurane and propofol did not affect mRNA expression of IL-10 and TGF-β in alveolar macrophages. The phagocytic capacity of monocytes (p = 0.0006) and alveolar macrophages (p = 0.0004) was higher with sevoflurane compared with propofol. Sevoflurane, compared with CTRL, reduced IL-1β mRNA (p = 0.003, p = 0.009) and C-X-C chemokine receptor 2 mRNA (CXCR2, p = 0.032 and p = 0.042) in blood and BALF neutrophils, and increased CXCR4 mRNA only in BALF neutrophils (p = 0.004). Sevoflurane increased blood neutrophil migration (p = 0.015) compared with propofol. Both sevoflurane and propofol increased zonula occludens-1 mRNA (p = 0.046, p = 0.003) in alveolar epithelial cells and reduced Toll-like receptor 4 mRNA (p = 0.043, p = 0.006) in alveolar endothelial cells compared with CTRL. Only propofol reduced surfactant protein B mRNA (p = 0.028) in alveolar epithelial cells.

Discussion

Sevoflurane, compared with propofol, increased anti-inflammatory biomarkers in monocytes, but not in alveolar macrophages, enhanced monocyte/alveolar macrophage phagocytic capacity and increased neutrophil migration in in vitro experimental sepsis. Both propofol and sevoflurane protected lung epithelial and endothelial cells.

Effects of sevoflurane on lung epithelial permeability in experimental models of acute respiratory distress syndrome

BACKGROUND

Preclinical studies in acute respiratory distress syndrome (ARDS) have suggested that inhaled sevoflurane may have lung-protective effects and clinical trials are ongoing to assess its impact on major clinical outcomes in patients with ARDS. However, the underlying mechanisms of these potential benefits are largely unknown. This investigation focused on the effects of sevoflurane on lung permeability changes after sterile injury and the possible associated mechanisms.

METHODS

To investigate whether sevoflurane could decrease lung alveolar epithelial permeability through the Ras homolog family member A (RhoA)/phospho-Myosin Light Chain 2 (Ser19) (pMLC)/filamentous (F)-actin pathway and whether the receptor for advanced glycation end-products (RAGE) may mediate these effects. Lung permeability was assessed in RAGE^-/- and littermate wild-type C57BL/6JRj mice on days 0, 1, 2, and 4 after acid injury, alone or followed by exposure at 1% sevoflurane. Cell permeability of mouse lung epithelial cells was assessed after treatment with cytomix (a mixture of TNFɑ, IL-1β, and IFNγ) and/or RAGE antagonist peptide (RAP), alone or followed by exposure at 1% sevoflurane. Levels of zonula occludens-1, E-cadherin, and pMLC were quantified, along with F-actin immunostaining, in both models. RhoA activity was assessed in vitro.

RESULTS

In mice after acid injury, sevoflurane was associated with better arterial oxygenation, decreased alveolar inflammation and histological damage, and non-significantly attenuated the increase in lung permeability. Preserved protein expression of zonula occludens-1 and less increase of pMLC and actin cytoskeletal rearrangement were observed in injured mice treated with sevoflurane. In vitro, sevoflurane markedly decreased electrical resistance and cytokine release of MLE-12 cells, which was associated with higher protein expression of zonula occludens-1. Improved oxygenation levels and attenuated increase in lung permeability and inflammatory response were observed in RAGE^-/- mice compared to wild-type mice, but RAGE deletion did not influence the effects of sevoflurane on permeability indices after injury. However, the beneficial effect of sevoflurane previously observed in wild-type mice on day 1 after injury in terms of higher PaO₂/FiO₂ and decreased alveolar levels of cytokines was not found in RAGE^-/- mice. In vitro, RAP alleviated some of the beneficial effects of sevoflurane on electrical resistance and cytoskeletal rearrangement, which was associated with decreased cytomix-induced RhoA activity.

CONCLUSIONS

Sevoflurane decreased injury and restored epithelial barrier function in two in vivo and in vitro models of sterile lung injury, which was associated with increased expression of junction proteins and decreased actin cytoskeletal rearrangement. In vitro findings suggest that sevoflurane may decrease lung epithelial permeability through the RhoA/pMLC/F-actin pathway.

Inhaled Sedation with Volatile Anesthetics for Mechanically Ventilated Patients in Intensive Care Units: A Narrative Review

Inhaled sedation was recently approved in Europe as an alternative to intravenous sedative drugs for intensive care unit (ICU) sedation. The aim of this narrative review was to summarize the available data from the literature published between 2005 and 2023 in terms of the efficacy, safety, and potential clinical benefits of inhaled sedation for ICU mechanically ventilated patients. The results indicated that inhaled sedation reduces the time to extubation and weaning from mechanical ventilation and reduces opioid and muscle relaxant consumption, thereby possibly enhancing recovery. Several researchers have reported its potential cardio-protective, anti-inflammatory or bronchodilator properties, alongside its minimal metabolism by the liver and kidney. The reflection devices used with inhaled sedation may increase the instrumental dead space volume and could lead to hypercapnia if the ventilator settings are not optimal and the end tidal carbon dioxide is not monitored. The risk of air pollution can be prevented by the adequate scavenging of the expired gases. Minimizing atmospheric pollution can be achieved through the judicious use of the inhalation sedation for selected groups of ICU patients, where the benefits are maximized compared to intravenous sedation. Very rarely, inhaled sedation can induce malignant hyperthermia, which prompts urgent diagnosis and treatment by the ICU staff. Overall, there is growing evidence to support the benefits of inhaled sedation as an alternative for intravenous sedation in ICU mechanically ventilated patients. The indication and management of any side effects should be clearly set and protocolized by each ICU. More randomized controlled trials (RCTs) are still required to investigate whether inhaled sedation should be prioritized over the current practice of intravenous sedation.

Use of volatile anesthetics for sedation in the ICU during the COVID-19 pandemic: A national survey in France (VOL'ICU 2 study)

BACKGROUND

The COVID-19 pandemic has increased the number of patients in ICUs leading to a worldwide shortage of the intravenous sedative agents obligating physicians to find alternatives including inhaled sedation. Inhaled sedation in French ICU has been previously explored in 2019 (VOL'ICU study). This survey was designed to explore the use of inhaled sedation two years after our first survey and to evaluate how the COVID-19 pandemic has impacted the use of inhaled sedation.

METHODS

We designed a national survey, contacting medical directors of French ICUs between June and October 2021. Over a 50-item questionnaire, the survey covered the characteristics of the ICU, data on inhaled sedation, and practical aspects of inhaled ICU sedation for both COVID-19 and non-COVID-19 patients. Answers were compared with the previous survey, VOL'ICU.

RESULTS

Among the 405 ICUs contacted, 25% of the questionnaires were recorded. Most ICU directors (87%) knew about the use of inhaled ICU sedation and 63% of them have an inhaled sedation's device in their unit. The COVID-19 pandemic increased the use of inhaled sedation in French ICUs. The main reasons said by the respondent were "need for additional sedative" (62%), "shortage of intravenous sedatives" (38%) and "involved in a clinical trial" (30%). The main reasons for not using inhaled ICU sedation were "device not available" (76%), "lack of familiarity" (60%) and "no training for the teams" (58%). More than 70% of respondents were overall satisfied with the use of inhaled sedation. Almost 80% of respondents stated that inhaled sedation was a seducing alternative to intravenous sedation for management of COVID-19 patients.

CONCLUSION

The use of inhaled sedation in ICU has increased fastly in the last 2 years, and is frequently associated with a good satisfaction among the users. Even if the COVID-19 pandemic could have impacted the widespread use of inhaled sedation, it represents an alternative to intravenous sedation for more and more physicians.