A randomized controlled trial on pharmacological preconditioning in liver surgery using a volatile anesthetic. Ann Surg. 2008;248:909-918. [PMID: 19092335 DOI: 10.1097/sla.0b013e31818f3dda]

Abdominal Organ Transplantation: Noteworthy Literature in 2024

This review highlights noteworthy literature published in 2024 pertinent to anesthesiologists and critical care physicians caring for patients undergoing abdominal organ transplantation. We feature 13 studies from over 5555 peer-reviewed publications on kidney transplantation, 4 studies from 1963 publications on pancreas transplantation, and 3 studies from 1879 publications on intestinal transplantation. The liver transplantation section includes a special focus on 22 studies from 4571 clinical trials published in 2024. We identified the new findings with our specialty interest, including cardiovascular risk assessment, machine perfusion, hemodynamic management, mode of anesthesia and regional techniques, donor management, fluid management, intraoperative monitoring, blood salvage, frailty, and rehabilitation and prehabilitation.

Comparison of total intravenous anesthesia and inhalational anesthesia in patients undergoing liver surgery: a systematic review and meta-analysis

BACKGROUND

The impact of choosing between inhalational anesthetics and propofol for maintenance anesthesia in liver transplantation or liver resections remains uncertain.

METHODS

A systematic search was conducted on PubMed, Scopus, Embase, Web of Science, and the Cochrane Library on September 5, 2023, adhering to the Cochrane Handbook and PRISMA guidelines.

RESULTS

Fifteen randomized controlled trials and five observational studies, comprising 1,602 patients, were included. The statistical analysis was categorized into three groups: liver transplantation (four studies), living donor hepatectomy (four studies), and liver mass hepatectomy (twelve studies). The liver mass hepatectomy group was further subdivided based on the performance of the Pringle maneuver and the use of pharmacological preconditioning. Statistically significant results are described below. In liver transplant recipients, propofol anesthesia was associated with lower AST levels on the first postoperative day. Hepatic donors anesthetized with propofol had higher total infusion volumes and intraoperative urine output. Patients undergoing liver mass resection with the Pringle maneuver and propofol anesthesia had higher peak AST and ALT levels compared to those who received pharmacological preconditioning. Patients undergoing liver mass resection with the Pringle maneuver and propofol anesthesia had higher AST and ALT levels on both the first and third postoperative days, increased total infusion volumes, and shorter hospital stays, when compared to pharmacological conditioning.

CONCLUSIONS

Our findings do not offer sufficient evidence to inform clinical practice. The choice between propofol-based and inhalational anesthesia should be tailored to the individual patient's condition and the nature of the procedure being performed.

REGISTRATION

PROSPERO ID: CRD42023460715.

The Effects of Volatile Anesthetics on Early Clinical Outcomes in Liver Transplantation: A Systematic Review and Meta-Analysis

BACKGROUND

The aim of this systematic review and meta-analysis was to evaluate the effects of volatile anesthesia (VA) on early clinical outcomes in liver transplantation.

METHODS

We searched electronic databases to identify relevant studies comparing VA to non-VA in liver transplant recipients. The primary outcome assessed was early allograft dysfunction (EAD), and secondary outcomes were postoperative peak liver function tests (LFT) including aspartate transaminase (AST) and alanine transaminase (ALT) levels, and hospitalization time.

RESULTS

Six relevant studies involving 919 patients were analyzed. In meta-analysis of prospective studies, VA was associated with fewer incidence of EAD than non-VA (RR: 0.45; 95% CI: 0.25, 0.84; P = .012; I2 = 0%; Ph = 0.334) but this association was not significant in meta-analysis of retrospective studies (OR: 0.83; 95% CI: 0.58, 1.19; P = .310; I2 = 0%; Ph = 0.624). No significant difference in peak AST (SMD: -0.14 U/L; 95% CI: -0.65, 0.37 U/L; P = .594; I2 = 69.9%; Ph = 0.036) and ALT (SMD: -0.16 U/L; 95% CI: -0.65, 0.33 U/L; P = .529; I2 = 67.0%; Ph = 0.048) were found between VA and non-VA. The hospitalization time also did not differ between the two groups (SMD: -0.09 days; 95% CI: -0.29, 0.10 days; P = .350; I2 = 0%; Ph = 0.864).

CONCLUSIONS

While there is potential protective effect of VA against EAD in liver transplant recipients, certainty remains low, whereas VA was not associated with postoperative LFT or hospitalization time.

Major liver resections, perioperative issues and posthepatectomy liver failure: A comprehensive update for the anesthesiologist

Significant advances in surgical techniques and relevant medium- and long-term outcomes over the past two decades have led to a substantial expansion in the indications for major liver resections. To support these outstanding results and to reduce perioperative complications, anesthesiologists must address and master key perioperative issues (preoperative assessment, proactive intraoperative anesthesia strategies, and implementation of the Enhanced Recovery After Surgery approach). Intensive care unit monitoring immediately following liver surgery remains a subject of active and often unresolved debate. Among postoperative complications, posthepatectomy liver failure (PHLF) occurs in different grades of severity (A-C) and frequency (9%-30%), and it is the main cause of 90-d postoperative mortality. PHLF, recently redefined with pragmatic clinical criteria and perioperative scores, can be predicted, prevented, or anticipated. This review highlights: (1) The systemic consequences of surgical manipulations anesthesiologists must respond to or prevent, to positively impact PHLF (a proactive approach); and (2) the maximal intensive treatment of PHLF, including artificial options, mainly based, so far, on Acute Liver Failure treatment(s), to buy time waiting for the recovery of the native liver or, when appropriate and in very selected cases, toward liver transplant. Such a clinical context requires a strong commitment to surgeons, anesthesiologists, and intensivists to work together, for a fruitful collaboration in a mandatory clinical continuum.

Early sevoflurane sedation in severe COVID-19-related lung injury patients. A pilot randomized controlled trial

BACKGROUND

This study aimed to assess a potential organ protective effect of volatile sedation in a scenario of severe inflammation with an early cytokine storm (in particular IL-6 elevation) in patients suffering from COVID-19-related lung injury with invasive mechanical ventilation and sedation.

METHODS

This is a small-scale pilot multicenter randomized controlled trial from four tertiary hospitals in Switzerland, conducted between April 2020 and May 2021. 60 patients requiring mechanical ventilation due to severe COVID-19-related lung injury were included and randomized to 48-hour sedation with sevoflurane vs. continuous intravenous sedation (= control) within 24 h after intubation. The primary composite outcome was determined as mortality or persistent organ dysfunction (POD), defined as the need for mechanical ventilation, vasopressors, or renal replacement therapy at day 28. Secondary outcomes were the length of ICU and hospital stay, adverse events, routine laboratory parameters (creatinine, urea), and plasma inflammatory mediators.

RESULTS

28 patients were randomized to sevoflurane, 32 to the control arm. The intention-to-treat analysis revealed no difference in the primary endpoint with 11 (39%) sevoflurane and 13 (41%) control patients (p = 0.916) reaching the primary outcome. Five patients died within 28 days in each group (16% vs. 18%, p = 0.817). Of the 28-day survivors, 6 (26%) and 8 (30%) presented with POD (p = 0.781). There was a significant difference regarding the need for vasopressors (1 (4%) patient in the sevoflurane arm, 7 (26%) in the control one (p = 0.028)). Length of ICU stay, hospital stay, and registered adverse events within 28 days were comparable, except for acute kidney injury (AKI), with 11 (39%) sevoflurane vs. 2 (6%) control patients (p = 0.001). The blood levels of IL-6 in the first few days after the onset of the lung injury were less distinctly elevated than expected.

CONCLUSIONS

No evident benefits were observed with short sevoflurane sedation on mortality and POD. Unexpectedly low blood levels of IL-6 might indicate a moderate injury with therefore limited improvement options of sevoflurane. Acute renal issues suggest caution in using sevoflurane for sedation in COVID-19.

TRIAL REGISTRATION

The trial was registered on ClinicalTrials.gov (NCT04355962) on 2020/04/21.

Sevoflurane preconditioning in living liver donation is associated with better initial graft function after pediatric transplantation: a retrospective study

INTRODUCTION

Initial allograft function determines the patient's immediate prognosis in pediatric liver transplantation. Ischemia-reperfusion injuries play a role in initial poor graft function (IPGF). In animal studies, preconditioning with inhaled anesthetic agents has demonstrated a protective effect on the liver. In humans, the few available studies are conflicting. This study assesses the association between the hypnotic agent used to maintain anesthesia during hepatectomy in living donors and the occurrence of IPGF after pediatric transplantation.

METHODS

We conducted a single-center retrospective analysis of children who received a living donor liver transplant (LDLT) between 2010 and 2019. We analyzed the incidence of EAD according to the hypnotic agent used to maintain general anesthesia during donor hepatectomy.

RESULTS

We included 183 pairs of patients (living donors-recipients). The anesthetics used in the donor were propofol (n = 85), sevoflurane (n = 69), or propofol with sevoflurane started 30 min before clamping (n = 29). Forty-two children (23%) developed IPGF. After multivariate logistic regression analysis, factors significantly associated with the occurrence of IPGF were the anesthesia maintenance agent used in the donor (p = 0.004), age of the donor (p = 0.03), duration of transplant surgery (p = 0.009), preoperative receiver neutrophil to lymphocyte ratio (p = 0.02), and albumin (p = 0.05).

CONCLUSION

Significantly fewer children who received a graft from a donor in whom only sevoflurane was used to maintain anesthesia developed IPGF. Although additional research is needed, this preconditioning strategy may provide an option to prevent IPGF after living liver donation.

PREVENTION OF PATHOLOGICAL EFFECT OF ISCHEMIA-REPERFUSION IN LIVER RESECTION BY SEVOFLURANE PRECONDITIONING

BACKGROUND

The intermittent Pringle maneuver remains the major technique for controlling hemorrhage during liver surgery. Nevertheless, this procedure involves a risk of triggering a cascade of pathological changes resulting in the ischemia-reperfusion injury (I/R) effect. The pharmacological prevention of this I/R injury represents a promising approach. The aim of the study was to compare the effects of pharmacological preconditioning with sevoflurane and propofol-based intravenous anesthesia on the postoperative function of the liver as the primary end-point.

MATERIALS AND METHODS

A prospective cohort study includes the analysis of the data of 73 patients who underwent liver surgery. In the study group (n = 41), preconditioning with sevoflurane inhalation was provided 30 minutes prior to liver resection. In the control group (n = 32), sevoflurane preconditioning was not provided. The primary endpoints were blood lactate concentration shortly after the surgery and one day later; alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities on postoperative Days 1, 3, and 5 as markers of hepatocyte damage.

RESULTS

On postoperative Day 1, in patients of the study group, lactate decreased to preoperative levels, while in the control group, lactate content increased as compared to both preoperative levels and the levels immediately after liver resection. A significant difference in AST activity levels between the groups was registered on Day 5, although this difference was not clinically relevant. The decrease in the prothrombin index in the study group on Day 3 was superior to that in the control group. The multiple regression analysis demonstrated a moderate positive association between the number of resected liver segments and the markers of the functional state of the liver in the study group while in the control group, such association was not significant.

CONCLUSION

The protective effect of sevoflurane on the postoperative function of the liver is manifested by the lower level of blood lactate and the stable level of transaminase activity.

Anesthesia in patients with chronic liver disease: An updated review

Anesthesia in chronic liver disease patients can be challenging because of the medications given or interventions performed and their effects on liver physiology. Also, the effects of liver disease on coagulation and metabolism should be considered carefully. This review focuses on anesthesia in patients with different chronic liver disease stages. A literature search was performed for Scopus and PubMed databases for articles discussing different types of anesthesia in patients with chronic liver disease, their safety, usage, and risks. The choice of anesthesia is of crucial importance. Regional anesthesia, especially neuroaxial anesthesia, may benefit some patients with liver disease, but coagulopathy should be considered. Regional anesthesia provides optimum intraoperative relaxation and analgesia that extends to the postoperative period while avoiding the side effects of intravenous anesthetics and opioids. Pharmacodynamics and pharmacokinetics of anesthetic medications must guard against complications related to overdose or decreased metabolism. The choice of anesthesia in chronic liver disease patients is crucial and could be tailored according to the degree of liver compensation and the magnitude of the surgical procedure.

Protective effect of propofol compared with sevoflurane on liver function after hepatectomy with Pringle maneuver: A randomized clinical trial

While the Pringle maneuver reduces intraoperative blood loss in hepatectomies, this technique can also be hepatotoxic. Hepatectomies require general anesthesia with propofol or volatile anesthetics like sevoflurane, agents known to offer multi-organ protection. However, their clinical effect after liver resection is unclear. We aimed to assess the effect of the two anesthetics on post-hepatectomy liver damage via measuring liver function tests. Fifty-six patients who underwent elective hepatectomies with the Pringle maneuver due to metastatic hepatic masses were preoperatively randomized to be anesthetized by sevoflurane or propofol. The primary and secondary outcomes were the postoperative peak levels of aspartate transaminase (AST) and alanine transaminase (ALT), respectively. Patients anesthetized by propofol exhibited significantly lower transaminases than those given sevoflurane (AST, p = 0.005; ALT, p = 0.006). The former agent significantly affected postoperative transaminases (AST hazard ratio -192.2, 95% confidence interval [-332.1 to -52.4], p = 0.00; ALT hazard ratio -140.2, 95% confidence interval [-240.0 to -40.7], p = 0.007). In conclusion, propofol had a greater hepatoprotective effect than sevoflurane as assessed by postoperative transaminases after hepatectomy with Pringle maneuver for metastatic liver tumors.

Volatile anesthetic and outcome in acute trauma care: planned secondary analysis of the PROPPR study

Background

This retrospective analysis of prospectively collected data from the PROPPR study describes volatile anesthetic use in severely injured trauma patients undergoing anesthesia.

Methods

After exclusions, 402 subjects were reviewed of the original 680, and 292 had complete data available for analysis. Anesthesia was not protocolized, so analysis was of contemporary practice.

Results

The small group who received no volatile anesthetic (n = 25) had greater injury burden (Glasgow Coma Scale P = 0.05, Injury Severity Score P = 0.001, Revised Trauma Score P = 0.03), higher 6- and 24-hour mortality (P < 0.001), and higher incidence of systemic inflammatory response syndrome (P = 0.003) and ventilator-associated pneumonia (P = 0.02) than those receiving any volatile (n = 267). There were no differences in mortality between volatile agents at 6 hours (P = 0.51) or 24 hours (P = 0.35). The desflurane group was less severely injured than the isoflurane group. Mean minimum alveolar concentration was < 0.6 and lowest in the isoflurane group compared to the sevoflurane and desflurane groups (both P < 0.01). The incidence of systemic inflammatory response syndrome was lower in the desflurane group than in the isoflurane group (P = 0.007).

Conclusion

In this acutely injured trauma population, choice of volatile anesthetic did not appear to influence short-term mortality and morbidity. Subjects who received no volatile were more severely injured with greater mortality, representing hemodynamic compromise where volatile agent was limited until stable. As anesthetic was not protocolized, these findings that choice of specific volatile was not associated with short-term survival require prospective, randomized evaluation.

Effects of sevoflurane and its metabolite hexafluoroisopropanol on hypoxia/reoxygenation-induced injury and mitochondrial bioenergetics in murine cardiomyocytes

Background

The volatile anaesthetic sevoflurane protects cardiac tissue from reoxygenation/reperfusion. Mitochondria play an essential role in conditioning. We aimed to investigate how sevoflurane and its primary metabolite hexafluoroisopropanol (HFIP) affect necrosis, apoptosis, and reactive oxygen species formation in cardiomyocytes upon hypoxia/reoxygenation injury. Moreover, we aimed to describe the similarities in the mode of action in a mitochondrial bioenergetics analysis.

Methods

Murine cardiomyocytes were exposed to hypoxia (0.2% O2 for 6 h), followed by reoxygenation (air with 5% CO2 for 2 h) in the presence or absence sevoflurane 2.2% or HFIP 4 mM. Lactate dehydrogenase (LDH) release (necrosis), caspase activation (apoptosis), reactive oxygen species, mitochondrial membrane potential, and mitochondrial function (Seahorse XF analyser) were measured.

Results

Hypoxia/reoxygenation increased cell death by 44% (+31 to +55%, P<0.001). Reoxygenation in the presence of sevoflurane 2.2% or HFIP 4 mM increased LDH release only by +18% (+6 to +30%) and 20% (+7 to +32%), respectively. Apoptosis and reactive oxygen species formation were attenuated by sevoflurane and HFIP. Mitochondrial bioenergetics analysis of the two substances was profoundly different. Sevoflurane did not influence oxygen consumption rate (OCR) or extracellular acidification rate (ECAR), whereas HFIP reduced OCR and increased ECAR, an effect similar to oligomycin, an adenosine triphosphate (ATP) synthase inhibitor. When blocking the metabolism of sevoflurane into HFIP, protective effects of sevoflurane - but not of HFIP - on LDH release and caspase were mitigated.

Conclusion

Together, our data suggest that sevoflurane metabolism into HFIP plays an essential role in cardiomyocyte postconditioning after hypoxia/reoxygenation injury.

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.

Experimental and Clinical Aspects of Sevoflurane Preconditioning and Postconditioning to Alleviate Hepatic Ischemia-Reperfusion Injury: A Scoping Review

Ischemia-reperfusion injury (IRI) is an inflammatory process inherent in organ transplantation procedures. It is associated with tissue damage and, depending on its intensity, can impact early graft function. In liver transplantation (LT), strategies to alleviate IRI are essential in order to increase the use of extended criteria donor (ECD) grafts, which are more susceptible to IRI, as well as to improve postoperative graft and patient outcomes. Sevoflurane, a commonly used volatile anesthetic, has been shown to reduce IRI. This scoping review aims to give a comprehensive overview of the existing experimental and clinical data regarding the potential benefits of sevoflurane for hepatic IRI (HIRI) and to identify any gaps in knowledge to guide further research. We searched Medline and Embase for relevant articles. A total of 380 articles were identified, 45 of which were included in this review. In most experimental studies, the use of sevoflurane was associated with a significant decrease in biomarkers of acute liver damage and oxidative stress. Administration of sevoflurane before hepatic ischemia (preconditioning) or after reperfusion (postconditioning) appears to be protective. However, in the clinical setting, results are conflicting. While some studies showed a reduction of postoperative markers of liver injury, the benefit of sevoflurane on clinical outcomes and graft survival remains unclear. Further prospective clinical trials remain necessary to assess the clinical relevance of the use of sevoflurane as a protective factor against HIRI.

Hexafluoroisopropanol decreases liver ischemia-reperfusion injury by downregulation of high mobility group box-1 protein

Liver ischemia-reperfusion (IR) injury is associated with poor outcome after liver transplantation and liver resections. Hexafluoroisopropanol (HFIP) is a tri-fluorinated metabolites of volatile anesthetics and has modulatory effects on inflammation that have been observed mainly in cell culture experiments. In this survey, we investigated the effects of HFIP in a rat model of normothermic hepatic ischemia-reperfusion injury. Twenty-four male Wistar rats were randomized into three groups: (1) control in which animals were submitted to 30 min of partial liver ischemia with resection of non-ischemic liver lobes immediate after reperfusion, (2) pre-ischemia (PI) group in which animals received intravenous HFIP (67 mg/kg) 5 min before liver ischemia, and (3) pre-reperfusion (PR) group in which animals received intravenous HFIP (67 mg/kg) 5 min before reperfusion. Four hours after reperfusion, all animals were euthanized for sample collection. Aspartate and alanine transaminases, glucose, and high mobility group box-1 (HMGB-1) protein concentrations showed a significant decreased, and malondialdehyde was increased in the PR group compared with control and PI groups. Interleukin 6 (IL-6) was increased in the PI group compared with control and PR groups. IL-10 and -12 were increased in the PR and PI groups, respectively, when compared with the control group. Glucose decreased in the PR when compared with the control group. Post-conditioning with HFIP led to a decrease in hepatocellular injury and was associated with a downregulation of HMGB-1. The HFIP resulted in a better control of inflammatory response to ischemia-reperfusion even without causing a reduction in oxidative stress.

Mitochondria and Cancer Recurrence after Liver Transplantation-What Is the Benefit of Machine Perfusion?

Tumor recurrence after liver transplantation has been linked to multiple factors, including the recipient's tumor burden, donor factors, and ischemia-reperfusion injury (IRI). The increasing number of livers accepted from extended criteria donors has forced the transplant community to push the development of dynamic perfusion strategies. The reason behind this progress is the urgent need to reduce the clinical consequences of IRI. Two concepts appear most beneficial and include either the avoidance of ischemia, e.g., the replacement of cold storage by machine perfusion, or secondly, an endischemic organ improvement through perfusion in the recipient center prior to implantation. While several concepts, including normothermic perfusion, were found to reduce recipient transaminase levels and early allograft dysfunction, hypothermic oxygenated perfusion also reduced IRI-associated post-transplant complications and costs. With the impact on mitochondrial injury and subsequent less IRI-inflammation, this endischemic perfusion was also found to reduce the recurrence of hepatocellular carcinoma after liver transplantation. Firstly, this article highlights the contributing factors to tumor recurrence, including the surgical and medical tissue trauma and underlying mechanisms of IRI-associated inflammation. Secondly, it focuses on the role of mitochondria and associated interventions to reduce cancer recurrence. Finally, the role of machine perfusion technology as a delivery tool and as an individual treatment is discussed together with the currently available clinical studies.

Inhaled Anesthetics for Sedation in ICU: Widening Horizons!

How to cite this article: Krishna B. Inhaled Anesthetics for Sedation in ICU: Widening Horizons! Indian J Crit Care Med 2022;26(8):889-891.

Sevoflurane Preconditioning Increases Stress Resistance via IMB-2/DAF-16 in Caenorhabditis Elegans

Sevoflurane preconditioning has been proved to possess therapeutic effects on stress. However, the mechanism by which sevoflurane preconditioning protects against stress remains unclear. In this study, an acute model of heat stress in C.eleans was established. We investigated the dose-response of sevoflurane exposure on coordinated movement in C.elegans and time course for protection against heat stress of sevoflurane preconditioning to determine the optimal concentration and time point in the following experiments. EC99 of sevoflurane is 1.7% (1.3EC50) and sevoflurane preconditioning exerts the maximal protection at 6 hours after incubation, and these 2 parameters were used in our following experiments. We found that sevoflurane preconditioning increased DAF-16 nuclear translocation and enhanced the expression of DAF-16 during heat stress in N2 strain of C.elegans. DAF-16 mutation abolished the sevoflurane preconditioning-induced protection for heat stress. Furthermore, suppression of IMB-2 by RNAi prevented the upregulation of DAF-16 and enhancement of stress resistance caused by sevoflurane preconditioning. Overall, this work reveals that sevoflurane preconditioning increases the expression of DAF-16 via IMB-2 to enhance the stress resistance of C.elegans.

Quo Vadis Anesthesiologist? The Value Proposition of Future Anesthesiologists Lies in Preserving or Restoring Presurgical Health after Surgical Insult

This Special Issue of the Journal of Clinical Medicine is devoted to anesthesia and perioperative care [...].

Anesthetic Management of Brain-dead Adult and Pediatric Organ Donors: The Harborview Medical Center Experience

INTRODUCTION

The exposure of anesthesiologists to organ recovery procedures and the anesthetic technique used during organ recovery has not been systematically studied in the United States.

METHODS

A retrospective cohort study was conducted on all adult and pediatric patients who were declared brain dead between January 1, 2008, and June 30, 2019, and who progressed to organ donation at Harborview Medical Center. We describe the frequency of directing anesthetic care by attending anesthesiologists, anesthetic technique, and donor management targets during organ recovery.

RESULTS

In a cohort of 327 patients (286 adults and 41 children), the most common cause of brain death was traumatic brain injury (51.1%). Kidneys (94.4%) and liver (87.4%) were the most common organs recovered. On average, each year, an attending anesthesiologist cared for 1 (range: 1 to 7) brain-dead donor during organ retrieval. The average anesthetic time was 127±53.5 (mean±SD) minutes. Overall, 90% of patients received a neuromuscular blocker, 63.3% an inhaled anesthetic, and 33.9% an opioid. Donor management targets were achieved as follows: mean arterial pressure ≥70 mm Hg (93%), normothermia (96%), normoglycemia (84%), urine output >1 to 3 mL/kg/h (61%), and lung-protective ventilation (58%).

CONCLUSIONS

During organ recovery from brain-dead organ donors, anesthesiologists commonly administer neuromuscular blockers, inhaled anesthetics, and opioids, and strive to achieve donor management targets. While infrequently being exposed to these cases, it is expected that all anesthesiologists be cognizant of the physiological perturbations in brain-dead donors and achieve physiological targets to preserve end-organ function. These findings warrant further examination in a larger multi-institutional cohort.

Methods of Attenuating Ischemia-Reperfusion Injury in Liver Transplantation for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most frequent indications for liver transplantation. However, the transplantation is ultimately associated with the occurrence of ischemia-reperfusion injury (IRI). It affects not only the function of the graft but also significantly worsens the oncological results. Various methods have been used so far to manage IRI. These include the non-invasive approach (pharmacotherapy) and more advanced options encompassing various types of liver conditioning and machine perfusion. Strategies aimed at shortening ischemic times and better organ allocation pathways are still under development as well. This article presents the mechanisms responsible for IRI, its impact on treatment outcomes, and strategies to mitigate it. An extensive review of the relevant literature using MEDLINE (PubMed) and Scopus databases until September 2020 was conducted. Only full-text articles written in English were included. The following search terms were used: "ischemia reperfusion injury", "liver transplantation", "hepatocellular carcinoma", "preconditioning", "machine perfusion".

Interleukin-6 Is an Early Plasma Marker of Severe Postoperative Complications in Thoracic Surgery: Exploratory Results From a Substudy of a Randomized Controlled Multicenter Trial

BACKGROUND

Postoperative complications in surgery are a significant burden, not only for the patients but also economically. While several predicting factors have already been identified, it is still not well known if increased levels of inflammatory markers in the immediate perioperative phase correlate with a higher incidence of postoperative complications. This study aimed to evaluate which patient characteristics and intraoperative parameters correlate with increased plasma values of monocyte chemoattractant protein 1 (MCP-1) and interleukin 6 (IL-6) of thoracic surgery patients. A second goal was to explore whether MCP-1 and IL-6 are associated with the incidence of postoperative complications. We hypothesized that there is a positive association between inflammatory markers and the occurrence of complications within 6 months after surgery.

METHODS

This is a substudy of a recent randomized controlled trial, which defined the effect of desflurane versus propofol anesthesia on morbidity and mortality in patients undergoing thoracic surgery. MCP-1 and IL-6 were determined in plasma obtained before and 30 minutes after 1-lung ventilation, 6 hours after surgery, and on postoperative days 1 and 2. Complications were recorded for 6 months. Mixed linear models were used to examine factors associated with MCP-1 and IL-6 levels. Logistic regression models and receiver operating characteristic curves were used to determine the association between MCP-1 and IL-6 and postoperative complications.

RESULTS

In the original study, 460 patients were included, MCP-1 and IL-6 levels were determined in 428 patients. MCP-1 was positively associated with the duration of surgery (P = .016), whereas IL-6 levels increased with both the length (P < .001) and invasiveness of lung surgery (thoracoscopic wedge resection or lobectomy versus open lobectomy, P = .005; thoracoscopic wedge resection or lobectomy versus pneumonectomy, P = .021). In an exploratory approach, elevated IL-6 plasma peaks were associated with the occurrence of severe complications defined as Clavien-Dindo score grade ≥IVa during the postoperative phase up to 6 months after thoracic surgery (P = .006).

CONCLUSIONS

In summary, this substudy reveals factors, which correlate with high MCP-1 and IL-6 values. Moreover, higher IL-6 seems to be associated with postoperative severe complications. Perioperative IL-6 monitoring might be helpful for risk estimation in the perioperative setting of patients after lung surgery.

Sevoflurane Postconditioning Attenuates Hepatic Ischemia-Reperfusion Injury by Limiting HMGB1/TLR4/NF-κB Pathway via Modulating microRNA-142 in vivo and in vitro

Preconditioning of sevoflurane (Sevo) has been demonstrated to protect the liver from ischemia/reperfusion (I/R) injury. However, it is unknown whether it has hepatoprotective when given at the onset of reperfusion (postconditioning), a protocol with more clinical impact. The present study aimed to explore the hepatoprotective effects of Sevo postconditioning against hepatic IR injury in vivo and in vitro and the possible mechanisms. Using a mouse model of hepatic I/R, Sevo postconditioning significantly improved hepatic injury after reperfusion, as demonstrated by reduced AST, ALT, and LDH serum levels and reduced histologic damage in liver tissues. Furthermore, Sevo postconditioning could suppress the apoptosis, inhibit oxidative stress and inflammatory response in liver tissue of HIRI mice, as well as improve the survival rate of HIRI mice. Through analyzing GSE72314 from the gene expression omnibus (GEO) database, it was demonstrated that microRNA (miR)-142 is downregulated by HIRI, which was reversed by Sevo treatment. Further investigation showed that agomiR-142 injection could enhance the hepatoprotective effects of Sevo postconditioning on I/R injury, while antagomiR-142 reversed these effects in mice. Notably, high mobility group box 1 (HMGB1), an important inflammatory factor, was directly targeted by miR-142 in hepatic cells, and we further found that Sevo could inhibit the expression of HMGB1 through up-regulating miR-142 expression in HIRI mice model. In addition, we found that I/R injury induced the activation of TLR4/NF-κB inflammatory pathway was partially suppressed by Sevo postconditioning, and miR-142 mediated the regulatory role of Sevo postconditioning. In line with the in vivo results, Sevo treatment improved the cell viability, inhibited cell apoptosis, oxidative stress and inflammatory response in vitro HIRI model, while these effects were reversed by antagomiR-142 transfection. Collectively, our findings demonstrated that Sevo postconditioning counteracts the downregulation of miR-142 provoked by I/R, in turn decreased the expression of HMGB1, blocking TLR4/NF-κB pathway activation, thus improving hepatic I/R injury. Our data suggest that Sevo may be a valuable alternative anaesthetic agent in liver transplantation and major liver surgeries.

Volatile and Intravenous Anesthetics for Brain Protection in Cardiac Surgery: Does the Choice of Anesthesia Matter?

Postoperative neurologic complications have a significant effect on morbidity, mortality, and long-term disability in patients undergoing cardiac surgery. The etiology of brain injury in patients undergoing cardiac surgery is multifactorial and remains unclear. There are several perioperative causative factors for neurologic complications, including microembolization, hypoperfusion, and systemic inflammatory response syndrome. Despite technologic advances and the development of new anesthetic drugs, there remains a high rate of postoperative neurologic complications. Moreover, despite the strong evidence that volatile anesthesia exerts cardioprotective effects in patients undergoing cardiac surgery, the neuroprotective effects of volatile agents remain unclear. Several studies have reported an association of using volatile anesthetics with improvement of biochemical markers of brain injury and postoperative neurocognitive function. However, there is a need for additional studies to define the optimal anesthetic drug for protecting the brain in patients undergoing cardiac surgery.

Effect of volatile anesthetics on early and delayed outcomes in pancreas transplantation

BACKGROUND

Ischemia-reperfusion injury (IRI) is a common cause of allograft dysfunction and patient morbidity in solid organ transplantation. This study compares the effect of different inhaled anesthetics on early IRI and clinical outcomes in pancreas allograft recipients.

METHODS

Data were extracted retrospectively for pancreas transplants at a single center over a 15-year period. Early postoperative pancreatic amylase and lipase levels were used as a marker for graft injury. Clinical outcomes measured included length of hospital stay, readmission, and graft survival.

RESULTS

There were 625 pancreas transplants included in the analysis with 3 primary inhaled anesthetics: sevoflurane (53%), desflurane (35%), and isoflurane (12%). In the first 30 days post-transplant, peak amylase was lowest for sevoflurane (147) followed by desflurane (159) and isoflurane (229) (p = .03). Peak lipase levels followed the same trend (peak values 118, 131, and 135, respectively; p = .02). Early graft loss, length of hospital stay, and readmission within 3 months were similar among all three anesthetic groups. There was no difference in 10-year graft survival by Cox regression.

CONCLUSIONS

Sevoflurane and desflurane are associated with lower peak amylase and lipase levels postoperatively in pancreas transplantation. Short- and long-term clinical outcomes were equivalent for the three agents.

Desflurane protects against liver ischemia/reperfusion injury via regulating miR-135b-5p

BACKGROUND

A number of anesthetics have protective effect against ischemia-reperfusion (I/R) injury, including desflurane. But the function and molecular mechanism of desflurane in liver I/R injury have not been fully understood. The aim of this study was to investigate the effect of desflurane on liver I/R injury and further investigated the molecular mechanisms involving in miR-135b-5p.

METHODS

The models of liver I/R injury in rats were established, and received desflurane treatment throughout the injury. Serum alanine transaminase (ALT) and aspartate transaminase (AST) were measured and compared between groups. H/R-induced cell model in L02 was established, and were treated with desflurane before hypoxia. Quantitative real-time polymerase chain reaction was performed to determine the expression of miR-135b-5p in different groups. The cell apoptosis was detected using flow cytometry assay. Western blot was used for the measurement of protein levels.

RESULTS

I/R significantly increased serum levels of ALT and AST in rats, which were reversed by desflurane treatment. Desflurane also significantly attenuated the increase of cell apoptosis induced by I/R in both vivo and vitro. MiR-135b-5p significantly reversed the protective effect of desflurane against liver I/R injury. Additionally, Janus protein tyrosine kinase (JAK)2 was shown to be a target gene of miR-135b-5p, and miR-135b-5p overexpression significantly decreased the protein levels of p-JAK2, JAK2, p-STAT3.

CONCLUSION

Desflurane attenuated liver I/R injury through regulating miR-135b-5p, and JAK2 was the target gene of mIR-135b-5p. These findings provide references for further development of therapeutic strategies in liver injury.

Anaesthesia and ICU sedation with sevoflurane do not reduce myocardial injury in patients undergoing cardiac surgery: A randomized prospective study

BACKGROUND

To evaluate the effect of anaesthesia and ICU sedation with sevoflurane to protect the myocardium against ischemia-reperfusion injury associated to cardiac surgery assessed by troponin release.

METHODS

We performed a prospective, open-label, randomized study in cardiac surgery with cardiopulmonary bypass. Patients were randomized to an algorithm-based intervention group and a control group. The main outcome was the perioperative kinetic of cardiac troponin I (cTnI). The secondary outcomes included composite endpoint, GDF-15 (macrophage inhibitory cytokine-1) value, arterial lactate levels, and the length of stay (LOS) in the ICU.

RESULTS

Of 82 included patients, 81 were analyzed on an intention-to-treat basis (intervention group: n = 42; control group: n = 39). On inclusion, the intervention and control groups did not differ significantly in terms of demographic and surgical data. The postoperative kinetics of cTnI did not differ significantly between groups: the mean difference was 0.44 ± 1.09 μg/ml, P = .69. Incidence of composite endpoint and GDF-15 values were higher in the sevoflurane group than in propofol group. The intervention and control groups did not differ significantly in terms of ICU stay and hospital stay.

CONCLUSION

The use of an anaesthesia and ICU sedation with sevoflurane was not associated with a lower incidence of myocardial injury assessed by cTnI. Sevoflurane administration was associated with higher prevalence of acute renal failure and higher GDF-15 values.

Metalloproteinase expression after desflurane preconditioning in hepatectomies: A randomized clinical trial

BACKGROUND

Hepatectomy with inflow occlusion results in ischemia-reperfusion injury; however, pharmacological preconditioning can prevent such injury and optimize the postoperative recovery of hepatectomized patients. The normal inflammatory response after a hepatectomy involves increased expression of metalloproteinases, which may signal pathologic hepatic tissue reformation.

AIM

To investigate the effect of desflurane preconditioning on these inflammatory indices in patients with inflow occlusion undergoing hepatectomy.

METHODS

This is a single-center, prospective, randomized controlled trial conducted at the 4^th Department of Surgery of the Medical School of Aristotle University of Thessaloniki, between August 2016 and December 2017. Forty-six patients were randomized to either the desflurane treatment group for pharmacological preconditioning (by replacement of propofol with desflurane, administered 30 min before induction of ischemia) or the control group for standard intravenous propofol. The primary endpoint of expression levels of matrix metalloproteinases and their inhibitors was determined preoperatively and at 30 min posthepatic reperfusion. The secondary endpoints of neutrophil infiltration, coagulation profile, activity of antithrombin III (AT III), protein C (PC), protein S and biochemical markers of liver function were determined for 5 d postoperatively and compared between the groups.

RESULTS

The desflurane treatment group showed significantly increased levels of tissue inhibitor of metalloproteinases 1 and 2, significantly decreased levels of matrix metalloproteinases 2 and 9, decreased neutrophil infiltration, and less profound changes in the coagulation profile.  During the 5-d postoperative period, all patients showed significantly decreased activity of AT III, PC and protein S (vs baseline values, P < 0.05). The activity of AT III and PC differed significantly between the two groups from postoperative day 1 to postoperative day 5 (P < 0.05), showing a moderate drop in activity of AT III and PC in the desflurane treatment group and a dramatic drop in the control group. Compared to the control group, the desflurane treatment group also had significantly lower international normalized ratio values on all postoperative days (P < 0.005) and lower serum glutamic oxaloacetic transaminase and serum glutamic pyruvic transaminase values on postoperative days 2 and 3 (P < 0.05).   Total length of stay was significantly less in the desflurane group (P = 0.009).

CONCLUSION

Desflurane preconditioning can lessen the inflammatory response related to ischemia-reperfusion injury and may shorten length of hospitalization.

A Comparison of Volatile Anesthesia and Total Intravenous Anesthesia (TIVA) Effects on Outcome From Cardiac Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

The primary objective of this study was to compare one-year mortality in patients undergoing cardiac surgery with volatile anesthesia or total intravenous anesthesia (TIVA). Secondary objectives were to compare in-hospital and 30-day mortality, postoperative levels of creatine kinase (CK-MB) and cardiac troponin, and durations of tracheal intubation, intensive care unit (ICU) and hospital stays.

DESIGN

Systematic review and meta-analysis of randomized controlled trials (RCTs).

SETTING

International, multi-institution centers.

PARTICIPANTS

Adults patients undergoing heart surgery.

INTERVENTIONS

Volatile anesthesia and TIVA.

MEASUREMENTS AND MAIN RESULTS

Meta-analysis found no statistically significant difference between patients receiving TIVA and volatile anesthesia in one-year mortality (n = 6440, OR = 1.22, 95% CI 0.97 to 1.54, p = 0.09, Z = 1.67, I² = 0%), troponin (n = 3127, SMD = 0.26, 95% CI -0.01 to 0.52, p = 0.05, Z = 1.92, I² = 90%) and CK-MB concentration 24h postoperatively (n = 1214, SMD = 0.10, 95% CI -0.17 to 0.36, unadjusted p = 0.48, Z = 0.71, I² = 79%), or time to tracheal extubation (n = 1059, SMD = 0.10, 95% CI -0.28 to 0.49, p = 0.60, Z = 0.53, I2 = 88%). The durations of ICU stay (n = 2003, SMD = 0.29, 95% CI 0.01 to 0.57, p = 0.04, Z = 2.05, I² = 88%) and hospital stay (n = 1214, SMD = 0.42, 95% CI 0.10 to 0.75, p = 0.01, Z = 2.53, I² = 91%) were shorter in the volatile anesthetic compared to TIVA group.

CONCLUSIONS

No significant differences in mortality (in-hospital, 30-day, 1-year), troponin and CK-MB concentrations 24 h postoperatively, or time to tracheal extubation were found between patients who had volatile anesthesia or TIVA. Compared to TIVA, volatile anesthesia was associated with shorter durations of hospital and ICU stays.

Preconditioning Effect of Remifentanil Versus Fentanyl in Prevalence of Early Graft Dysfunction in Patients After Liver Transplant: A Randomized Clinical Trial

OBJECTIVES

One of the most prevalent complications of orthotopic liver transplant is primary graft dysfunction. Recent studies have shown the preconditioning effect of remifentanil on animal livers but not human livers. Here, we compared the preconditioning effects of remifentanil and fentanyl in orthotopic liver transplant in human patients.

MATERIALS AND METHODS

In this double-blind clinical trial, 100 patients who underwent liver transplant from deceased donors were randomly allocated into 2 groups. Patients in the remifentanil group received remifentanil infusion, and those in the fentanyl group received fentanyl infusion during maintenance of anesthesia. Serum aminotransferase levels, prothrombin time (international normalized ratio), partial thrombin time, arterial blood gas levels, and renal function tests were evaluated over 7 days posttransplant. Intensive care unit stay and hospitalization were also recorded.

RESULTS

The median peak alanine aminotransferase level during 7 days after transplant was 2100 U/L (interquartile range, 1230-3220) in the remifentanil group and 3815 U/L (interquartile range, 2385-5675) in the fentanyl group (P = .048). Metabolic acidosis, renal state, prothrombin time (international normalized ratio), and partial thrombin time were similar in both groups (P > .05). Durations of stay in the intensive care unit and hospital were not significantly different between the 2 groups (P = .75 and P = .23, respectively). Overall, the clinical outcomes were similar in the remifentanil and fentanyl groups (P > .05).

CONCLUSIONS

We found that remifentanil and fentanyl were not different with regard to their preconditioning effects and graft protection in orthotopic liver transplant recipients.

Study design of the DAS-OLT trial: a randomized controlled trial to evaluate the impact of dexmedetomidine on early allograft dysfunction following liver transplantation

Background

Perioperative ischemia/reperfusion (I/R) injury during liver transplantation is strongly associated with early allograft dysfunction (EAD), graft loss, and mortality. Hepatic I/R injury also causes remote damage to other organs including the renal and pulmonary systems. Dexmedetomidine (DEX), a selective α2-adrenoceptor agonist which is used as an adjuvant to general anesthesia, has been shown in preclinical studies to provide organ protection by ameliorating the effects of I/R injury in a range of tissues (including the liver). However, prospective clinical evidence of any potential benefits in improving outcomes in liver transplantation is lacking. This study aimed to verify the hypothesis that the application of dexmedetomidine during the perioperative period of liver transplantation can reduce the incidence of EAD and primary graft non-function (PNF). At the same time, the effects of dexmedetomidine application on perioperative renal function and lung function were studied.

Methods

This is a prospective, single-center, randomized, parallel-group study. Two hundred participants (18–65 years) scheduled to undergo liver transplantation under general anesthesia will be included in this study. For participants in the treatment group, a loading dose of DEX will be given after induction of anesthesia (1 μg/kg over 10 min) followed by a continuous infusion (0.5 μg/kg /h) until the end of surgery. For participants in the placebo group, an equal volume loading dose of 0.9% saline will be given after the induction of anesthesia followed by an equal volume continuous infusion until the end of surgery. All other supplements, e.g., opioids, sedatives, and muscle relaxant, will be identical in both arms and administered according to routine clinical practice.

Discussion

The present trial will examine whether DEX confers organoprotective effects in the liver, in terms of reducing the incidence of EAD and PNF in orthotopic liver transplantation recipients.

Trial registration

ClinicalTrials.gov NCT03770130. Registered on 10 December 2018. https://clinicaltrials.gov/ct2/show/NCT03770130

Sevoflurane sedation attenuates early cerebral oedema formation through stabilisation of the adherens junction protein beta catenin in a model of subarachnoid haemorrhage: A randomised animal study

BACKGROUND

Severe neurological impairment is a problem after subarachnoid haemorrhage (SAH). Although volatile anaesthetics, such as sevoflurane, have demonstrated protective properties in many organs, their use in cerebral injury is controversial. Cerebral vasodilation may lead to increased intracranial pressure (ICP), but at the same time volatile anaesthetics are known to stabilise the SAH-injured endothelial barrier.

OBJECTIVE

To test the effect of sevoflurane on ICP and blood-brain barrier function.

DESIGN

Randomised study.

PARTICIPANTS

One hundred male Wistar rats included, 96 analysed.

INTERVENTIONS

SAH was induced by the endoluminal filament method under ketamine/xylazine anaesthesia. Fifteen minutes after sham surgery or induction of SAH, adult male Wistar rats were randomised to 4 h sedation with either propofol or sevoflurane.

MAIN OUTCOME MEASURES

Mean arterial pressure (MAP), ICP, extravasation of water (small), Evan's blue (intermediate) and IgG (large molecule) were measured. Zonula occludens-1 (ZO-1) and beta-catenin (β-catenin), as important representatives of tight and adherens junction proteins, were determined by western blot.

RESULTS

Propofol and sevoflurane sedation did not affect MAP or ICP in SAH animals. Extravasation of small molecules was higher in SAH-propofol compared with SAH-sevoflurane animals (79.1 ± 0.9 vs. 78.0 ± 0.7%, P = 0.04). For intermediate and large molecules, no difference was detected (P = 0.6 and P = 0.2). Both membrane and cytosolic fractions of ZO-1 as well as membrane β-catenin remained unaffected by the injury and type of sedation. Decreased cytosolic fraction of β-catenin in propofol-SAH animals (59 ± 15%) was found to reach values of sham animals (100%) in the presence of sevoflurane in SAH animals (89 ± 21%; P = 0.04).

CONCLUSION

This experiment demonstrates that low-dose short-term sevoflurane sedation after SAH in vivo did not affect ICP and MAP and at the same time may attenuate early brain oedema formation, potentially by preserving adherens junctions.

TRIAL REGISTRATION

No 115/2014 Veterinäramt Zürich.

May sevoflurane prevent the development of neurogenic pulmonary edema and improve the outcome? Or as a new sedation method for severe brain injury patients

Neurogenic pulmonary edema (NPE) is a life-threatening complication that develops rapidly and dramatically after injury to the central nervous system (CNS). Severe primary brain injury and subsequent secondary brain injury cascade events are thought to be involved in the development of NPE. Activation of the sympathetic nervous system and release of vasoactive substances are also essential prerequisites for NPE. We hypothesize that sevoflurane may be an effective treatment for preventing the development of NPE. Sevoflurane may play a role in protecting brain and lung tissue after acute brain injury through its sympatholytic, antioxidative, ion channel stabilizing, anti-inflammatory, anti-apoptotic, and pulmonary protection effects. It has the potential to be used as a sedative in the neurosurgical intensive care unit (NICU), which can help maintain nervous system and cardiopulmonary function in patients with acute brain injury to improve prognosis. Sevoflurane also has the advantages of fast induction of anesthesia, rapid drug metabolism, little interference to the cardiovascular system, and controllable depth of anesthesia. If our hypothesis is supported by further experiments, use of sevoflurane may open a new door for the treatment of acute brain injury and NPE.

Carbon monoxide in intensive care medicine-time to start the therapeutic application?!

Carbon monoxide (CO) is not only known as a toxic gas due to its characteristics as an odorless molecule and its rapid binding to haem-containing molecules, thus inhibiting the respiratory chain in cells resulting in hypoxia. For decades, scientists established evidence about its endogenously production in the breakdown of haem via haem-oxygenase (HO-1) and its physiological effects. Among these, the modulation of various systems inside the body are well described (e.g., anti-inflammatory, anti-oxidative, anti-apoptotic, and anti-proliferative). Carbon monoxide is able to modulate several extra- and intra-cellular signaling molecules leading to differentiated response according to the specific stimulus. With our growing understanding in the way CO exerts its effects, especially in the mitochondria and its intracellular pathways, it is tempting to speculate about a clinical application of this substance. Since HO-1 is not easy to induce, research focused on the application of the gaseous molecule CO by itself or the implementation of carbon monoxide releasing molecules (CO-RM) to deliver the molecule at a time- and dose dependently safe way to any target organ. After years of research in cellular systems and animal models, summing up data about safety issues as well as possible target to treat in various diseases, the first feasibility trials in humans were established. Up-to-date, safety issues have been cleared for low-dose carbon monoxide inhalation (up to 500 ppm), while there is no clinical data regarding the injection or intake of any kind of CO-RM so far. Current models of human research include sepsis, acute lung injury, and acute respiratory distress syndrome as well as acute kidney injury. Carbon monoxide is a most promising candidate in terms of a therapeutic agent to improve outbalanced organ conditions. In this paper, we summarized the current understanding of carbon monoxide’s biology and its possible organ targets to treating the critically ill patients in tomorrow’s ICU.

Effect of Remote Ischemic Preconditioning in Patients Undergoing Hepatectomy With Portal Triad Clamping: A Randomized Controlled Trial

BACKGROUND

Remote ischemic preconditioning (RIPC) is reported to reduce liver injury in patients undergoing hepatectomy for colorectal liver metastasis, but its role is unclear in hepatocellular carcinoma patients with portal triad clamping during hepatectomy.

METHODS

In this prospective, randomized trial, 140 patients with hepatocellular carcinoma undergoing liver resection requiring portal triad clamping were randomized to a RIPC group or a control group. Patients in the RIPC group received RIPC (3 cycles of 5-minute ischemia and 5-minute reperfusion in right upper limb with cuff pressure at 30 kPa [225 mm Hg]) approximately 10 minutes after induction of anesthesia. In the control group, patients received sham RIPC (the cuff was not inflated). The primary outcome was the postoperative peak level of total bilirubin (TBIL) and was analyzed with the independent t test. Secondary outcomes were liver function test at postoperative days 1, 3, and 5; postoperative morbidity and mortality during the first month; and the length of postoperative hospital stay.

RESULTS

Data from 136 patients (69 in the RIPC group and 67 in the control group) were analyzed. The RIPC group had on average a 5.9 μmol lower peak level of TBIL than the control group; the mean difference is -5.9, and the 95% confidence interval (CI) reverses to -17.9 to 6.1. There were no significant differences between the 2 groups in liver function test at postoperative days 1, 3, and 5; postoperative morbidity and mortality during the first month; and the length of postoperative hospital stay.

CONCLUSIONS

We found no evidence that RIPC can reduce postoperative liver injury after hepatectomy.

Sevoflurane Promotes Bactericidal Properties of Macrophages through Enhanced Inducible Nitric Oxide Synthase Expression in Male Mice

BACKGROUND

Sevoflurane with its antiinflammatory properties has shown to decrease mortality in animal models of sepsis. However, the underlying mechanism of its beneficial effect in this inflammatory scenario remains poorly understood. Macrophages play an important role in the early stage of sepsis as they are tasked with eliminating invading microbes and also attracting other immune cells by the release of proinflammatory cytokines such as interleukin-1β, interleukin-6, and tumor necrosis factor-α. Thus, the authors hypothesized that sevoflurane mitigates the proinflammatory response of macrophages, while maintaining their bactericidal properties.

METHODS

Murine bone marrow-derived macrophages were stimulated in vitro with lipopolysaccharide in the presence and absence of 2% sevoflurane. Expression of cytokines and inducible NO synthase as well as uptake of fluorescently labeled Escherichia coli (E. coli) were measured. The in vivo endotoxemia model consisted of an intraperitoneal lipopolysaccharide injection after anesthesia with either ketamine and xylazine or 4% sevoflurane. Male mice (n = 6 per group) were observed for a total of 20 h. During the last 30 min fluorescently labeled E. coli were intraperitoneally injected. Peritoneal cells were extracted by peritoneal lavage and inducible NO synthase expression as well as E. coli uptake by peritoneal macrophages was determined using flow cytometry.

RESULTS

In vitro, sevoflurane enhanced lipopolysaccharide-induced inducible NO synthase expression after 8 h by 466% and increased macrophage uptake of fluorescently labeled E. coli by 70% compared with vehicle-treated controls. Inhibiting inducible NO synthase expression pharmacologically abolished this increase in bacteria uptake. In vivo, inducible NO synthase expression was increased by 669% and phagocytosis of E. coli by 49% compared with the control group.

CONCLUSIONS

Sevoflurane enhances phagocytosis of bacteria by lipopolysaccharide-challenged macrophages in vitro and in vivo via an inducible NO synthase-dependent mechanism. Thus, sevoflurane potentiates bactericidal and antiinflammatory host-defense mechanisms in endotoxemia.

Propofol-based total intravenous anesthesia did not improve survival compared to desflurane anesthesia in breast cancer surgery

BACKGROUND

Breast cancer is the most common cancer in women and several perioperative factors may account for tumor recurrence and metastasis. The anesthetic agents employed during cancer surgery might play a crucial role in cancer cell survival and patient outcomes. We conducted a retrospective cohort study to investigate the relationship between the type of anesthesia and overall survival in patients who underwent breast cancer surgery performed by one experienced surgeon.

METHODS

All patients who underwent breast cancer surgery by an experienced surgeon between January 2006 and December 2010 were included in this study. Patients were separated into two groups according to the use of desflurane or propofol anesthesia during surgery. Locoregional recurrence and overall survival rates were assessed for the two groups (desflurane or propofol anesthesia). Univariable and multivariable Cox regression models and propensity score matching analyses were used to compare the hazard ratios for death and adjust for potential confounders (age, body mass index, American Society of Anesthesiologists physical status classification, TNM stage, neoadjuvant chemotherapy, Charlson Comorbidity Index, anesthesiologists, and functional status).

RESULTS

Of the 976 breast cancer patients, 632 patients underwent breast cancer surgery with desflurane anesthesia, while 344 received propofol anesthesia. After propensity scoring, 592 patients remained in the desflurane group and 296 patients in the propofol group. The mortality rate was similar in the desflurane (38 deaths, 4%) and propofol (22 deaths, 4%; p = 0.812) groups in 5-year follow-up. The crude hazard ratio (HR) for all patients was 1.13 (95% confidence interval [CI] 0.67-1.92, p = 0.646). No significant difference in the locoregional recurrence or overall 5-year survival rates were found after breast surgery using desflurane or propofol anesthesia (p = 0.454). Propensity score-matched analyses demonstrated similar outcomes in both groups. Patients who received propofol anesthesia had a higher mortality rate than those who received desflurane anesthesia in the matched groups (7% vs 6%, respectively) without significant difference (p = 0.561). In the propensity score-matched analyses, univariable analysis showed an insignificant finding (HR = 1.23, 95% CI 0.72-2.11, p = 0.449). After adjustment for the time since the earliest included patient, the HR remained insignificant (HR = 1.23, 95% CI 0.70-2.16, p = 0.475).

CONCLUSION

In our non-randomized retrospective analysis, neither propofol nor desflurane anesthesia for breast cancer surgery by an experienced surgeon can affect patient prognosis and survival. The influence of propofol anesthesia on breast cancer outcome requires further investigation.

Effect of pharmacological preconditioning with sevoflurane during hepatectomy with intermittent portal triad clamping

BACKGROUND

During hepatectomy, intermittent portal triad clamping (IPC) reduces ischemia-reperfusion injuries. Pharmacological preconditioning with sevoflurane revealed similar properties. The aim of the study was to evaluate the combination of a sevoflurane preconditioning regimen with IPC on ischemia-reperfusion injuries.

METHODS

Three regimens of anesthesia were applied: group SEV with continuous application of sevoflurane, group PRO with continuous propofol infusion and group PC where continuous propofol was substituted by sevoflurane (adjusted to reach MAC∗1.5) for 15 min before IPC. Endpoints were the values of AST and ALT, factor V, prothrombin time, bilirubinemia over the 5-postoperative days (POD), morbidity and mortality at POD30 and POD90.

RESULTS

The ALT values at POD5 were lower in the PC group (n = 27) 74 (48 -98) IU/L compared to PRO (n = 26) and SEV (n = 67) respectively 110 (75 -152) and 100 (64 -168) IU/L (p = 0.038). The variation of factor V compared to preoperative values was less important in the PC and SEV groups respectively -14% and -16% vs -30% (PRO) (p = 0.047).

CONCLUSION

Our study suggests that sevoflurane attenuates ischemia-reperfusion injuries on liver function, compared to propofol, without benefit for a specific regimen of pharmacological preconditioning when IPC is applied.

Sevoflurane Protects Hepatocytes From Ischemic Injury by Reducing Reactive Oxygen Species Signaling of Hepatic Stellate Cells: Translational Findings Based on a Clinical Trial

BACKGROUND

Randomized controlled trials (RCTs) data demonstrate that sevoflurane postconditioning improves clinical outcomes of liver resection with inflow occlusion, presumably due to hepatocyte protection from ischemic injury. However, mechanisms remain unclear. This study examines liver biopsy samples obtained in an RCT of sevoflurane postconditioning to test the hypothesis that sevoflurane attenuates hepatocyte apoptosis.

METHODS

Messenger ribonucleic acid (mRNA) of pro- and antiapoptotic regulators Bax and B-cell lymphoma 2 (Bcl2) was examined in hepatic biopsies obtained during the RCT. Hepatic stellate cells (HSCs) and hepatocytes were exposed to hypoxia/reoxygenation (H/R) in vitro to evaluate the effect of sevoflurane postconditioning on apoptosis. The role of HSC as a potential apoptosis trigger in hepatocytes through the production of reactive oxygen species induced by H/R was explored by transferring supernatants from H/R-exposed HSC to hepatocytes as target cells.

RESULTS

In patients of the RCT, the Bax/Bcl2 mRNA ratio in liver tissue was markedly decreased in the sevoflurane arm (25% ± 21% reduction; P = .001). In vitro, H/R increased reactive oxygen species production in HSC by 33% ± 16% (P = .025), while it was abolished in the presence of sevoflurane (P < .001). In hepatocytes, caspase was minimally activated by H/R. However, incubation of hepatocytes with supernatants of HSC, previously exposed to H/R, increased caspase activity by 28% ± 13% (P < .001). When exposed to supernatants from HSC undergoing sevoflurane postconditioning, caspase activation in hepatocytes was reduced by 20% ± 9% (P < .001), similarly to the sevoflurane effect on the BAX/Bcl2 mRNA ratio in the liver samples.

CONCLUSIONS

The study shows that sevoflurane postconditioning affects apoptosis of hepatocytes after ischemia-reperfusion injury in patients. It also demonstrates that HSC may be the effector cells of sevoflurane protection.

Sevoflurane has postconditioning as well as preconditioning properties against hepatic warm ischemia-reperfusion injury in rats

PURPOSE

Ischemia-reperfusion (IR) injury is inevitable after liver transplantation and liver resection with inflow occlusion. Sevoflurane has been widely used during hepatobiliary surgery and was reported to exhibit preconditioning (PreC) properties against hepatic IR injury; however, its postconditioning (PostC) properties remain unknown. This study examined whether a clinically applicable dose of sevoflurane has PostC and PreC properties against hepatic IR injury and roles of heme oxygenase-1 (HO-1).

METHODS

Warm ischemia was induced in male Wistar rats, excluding the sham group, for 1 h, followed by 3 h of reperfusion. Group C received propofol from 60 min before ischemia until the end of the experimental procedure. In the SPreC and SPostC groups, propofol was replaced by 2.5% sevoflurane for 30 min from 35 min before ischemia in the SPreC group and for 30 min from 5 min before reperfusion in the SPostC group. The SPreC+Z and SPostC+Z groups received a HO-1 inhibitor, zinc protoporphyrin (Znpp), 60 min before ischemia, and sevoflurane PreC and PostC were induced.

RESULTS

Serum aspartate aminotransferase, alanine aminotransferase, and lactic dehydrogenase levels, and histological damage scores in the SPreC and SPostC groups were significantly lower than those in group C. Inhibiting HO-1 with Znpp partially blocked these protective effects of sevoflurane. Sevoflurane PreC and PostC significantly increased the number of HO-1-positive Kupffer cells in comparison with group C, and Znpp prevented sevoflurane-induced HO-1 expression.

CONCLUSION

PostC and PreC by sevoflurane at a clinically applicable dose have equally protective effects against hepatic IR injury by increasing HO-1 expression.

Sevoflurane Preconditioning plus Postconditioning Decreases Inflammatory Response with Hemodynamic Recovery in Experimental Liver Ischemia Reperfusion

Objective

The inhalation anesthetic sevoflurane has presented numerous biological activities, including anti-inflammatory properties and protective effects against tissue ischemic injury. This study investigated the metabolic, hemodynamic, and inflammatory effects of sevoflurane pre- and postconditioning for short periods in the rescue of liver ischemia-reperfusion (IR) injury using a rat model.

Materials and Methods

Twenty Wistar rats were divided into four groups: sham group, control ischemia group (partial warm liver ischemia for 45 min followed by 4 h of reperfusion), SPC group (administration of sevoflurane 2.5% for 15 min with 5 min of washout before liver IR), and SPPoC group (administration of sevoflurane 2.5% for 15 min before ischemia and 20 min during reperfusion).

Results

All animals showed a decrease in the mean arterial pressure (MAP) and portal vein blood flow during ischemia. After 4 h of reperfusion, only the SPPoC group had MAP recovery. In both the SPC and SPPoC groups, there was a decrease in the ALT level and an increase in the bicarbonate and potassium serum levels. Only the SPPoC group showed an increase in the arterial blood ionized calcium level and a decrease in the IL-6 level after liver reperfusion. Therefore, this study demonstrated that sevoflurane preconditioning reduces hepatocellular injury and acid-base imbalance in liver ischemia. Furthermore, sevoflurane postconditioning promoted systemic hemodynamic recovery with a decrease in inflammatory response.

Sufentanil Preconditioning Protects Against Hepatic Ischemia-Reperfusion Injury by Suppressing Inflammation

BACKGROUND Inflammation is one of the most significant mechanisms of hepatic ischemia-reperfusion injury (IRI). Sufentanil has a protective effect against liver injury by reducing inflammatory response. In this study, we used a cellular hepatic ischemic/reoxygenated (IR) model to determine whether sufentanil preconditioning protects against hepatic IRI. MATERIAL AND METHODS The human normal liver cells line L-O2 was studied. The levels of glutamic oxaloacetic transaminase (AST), lactate dehydrogenase (LDH), malonaldehyde (MDA), and superoxide dismutase (SOD) were measured using corresponding assay kits. The protein levels of total and phosphorylated ERK1/2, JNK, and p38, and the expression of p65 and COX2 genes, were measured by Western blotting. The levels of inflammatory factors were examined by ELISA. The Cell Counting Kit-8 (CCK-8) was used to determine if the viability of L-O2 cells was affected by sufentanil. The effects of sufentanil on IR-induced cell apoptosis were examined by flow cytometry. RESULTS IR-induced caused L-O2 cells to become rounded and to have a lower adhesive rate than normal cells. The levels of AST, LDH, and MDA were higher but the level of SOD was lower in the IR group than in the control group. The phosphorylated protein levels of ERK1/2, JNK, and p38, along with the expression of p65 and COX2, were upregulated in the IR group compared to the normal group. In addition, a variety of inflammatory factors were secreted in L-O2 cells after IR. The viability of L-O2 cells decreased and cell apoptosis increased significantly after IR treatment. All indexes of cell injury were reversed by sufentanil in a concentration-dependent manner. CONCLUSIONS Sufentanil stimulation triggers downregulation of inflammatory factors such as HIF-1alpha, TNF-alpha, IL-1ß, and IL-6, possibly through suppressing the p38/ERK/JNK/NF-kappaB-p65/COX2 pathways, and thereby reduces the damage to IR hepatic cells.

Interaction between anesthetic conditioning and ischemic preconditioning on metabolic function after hepatic ischemia-reperfusion in rabbits

BACKGROUND

Both anesthetic-induced and ischemic preconditioning are protective against hepatic ischemia-reperfusion injury. However, the effects of these preventive methods on the metabolic function remain to be elucidated. We investigated the anesthetic conditioning and ischemic preconditioning on the metabolic function of the rabbit model of hepatic ischemia-reperfusion.

METHODS

After approval by the institutional animal care and use committee, 36 Japanese White rabbits underwent partial hepatic ischemia for 90 min either under sevoflurane or propofol anesthesia. All the rabbits underwent 90 min of hepatic ischemia, and half of the rabbits in each group underwent additional 10-min ischemia and 10-min reperfusion before index ischemia. Hepatic microvascular blood flow was intermittently measured during reperfusion period, and galactose clearance, serum aminotransferase activities, and lactate concentrations were determined 180 min after reperfusion.

RESULTS

Neither anesthetic conditioning with sevoflurane nor ischemic preconditioning altered hepatic microvascular blood flow during reperfusion and serum transaminase activities after reperfusion. However, galactose clearance of reperfused liver was significantly higher under sevoflurane anesthesia than propofol (0.016 ± 0.005/min vs. 0.011 ± 0.004/min). Statistically significant interaction between anesthetic choice and application of ischemic preconditioning suggests that the ischemic preconditioning is selectively protective under propofol anesthesia. Increase of blood lactate concentration was significantly suppressed under sevoflurane anesthesia compared to propofol (1.5 ± 0.8 vs. 3.9 ± 1.4 mmol/l) without any statistically significant interaction with the application of ischemic preconditioning.

CONCLUSION

Sevoflurane attenuated the decrease of galactose clearance and increase of the blood lactate after reperfusion compared to propofol. Application of ischemic preconditioning was significantly protective under propofol anesthesia.

Ischemic Preconditioning Produces Comparable Protection Against Hepatic Ischemia/Reperfusion Injury Under Isoflurane and Sevoflurane Anesthesia in Rats

BACKGROUND

Various volatile anesthetics and ischemic preconditioning (IP) have been demonstrated to exert protective effect against ischemia/reperfusion (I/R) injury in liver. We aimed to determine whether application of IP under isoflurane and sevoflurane anesthesia would confer protection against hepatic I/R injury in rats.

METHODS

Thirty-eight rats weighing 270 to 300 grams were randomly divided into 2 groups: isoflurane (1.5%) and sevoflurane (2.5%) anesthesia groups. Each group was subdivided into sham (n = 3), non-IP (n = 8; 45 minutes of hepatic ischemia), and IP (n = 8, IP consisting of 10-minute ischemia plus 15-minute reperfusion before prolonged ischemia) groups. The degree of hepatic injury and expressions of B-cell lymphoma 2 (Bcl-2) and caspase 3 were compared at 2 hours after reperfusion.

RESULTS

Hepatic ischemia induced significant degree of I/R injuries in both isoflurane and sevoflurane non-IP groups. In both anesthetic groups, introduction of IP dramatically attenuated I/R injuries as marked by significantly lower aspartate aminotransferase and aminotransferase levels and better histologic grades compared with corresponding non-IP groups. There were 2.3- and 1.7-fold increases in Bcl-2 mRNA levels in isoflurane and sevoflurane IP groups, respectively, compared with corresponding non-IP groups (both P < .05). Caspase 3 level was significantly high in the isoflurane non-IP group compared with the sham group; however, there were no differences among the sevoflurane groups.

CONCLUSIONS

The degree of hepatic I/R injury was significantly high in both isoflurane and sevoflurane groups in rats. However, application of IP significantly protected against I/R injury in both volatile anesthetic groups to similar degrees, and upregulation of Bcl-2 might be an important mechanism.

Sevoflurane preconditioning ameliorates lipopolysaccharide-induced cognitive impairment in mice

Systemic inflammation induces brain neuronal inflammation, in turn causing acute cognitive disorders. Furthermore, neuronal inflammation is one cause of postoperative cognitive disorder (POCD) and delirium. However, no sufficiently established pharmacological treatment is available for neurocognitive inflammation. This study evaluated the possible neuroprotective effects of preconditioning with sevoflurane anesthesia on cognition and neuroinflammatory changes in an animal model of lipopolysaccharide (LPS)-induced systemic inflammation. Adult mice were randomly divided into (1) control, (2) 2% sevoflurane preconditioning for 1 h, (3) intraperitoneal 5 mg/kg LPS injection, and (4) 2% sevoflurane preconditioning for 1 h + LPS injection groups. At 24 h after 5 mg/kg LPS injection, microglial activation based on ionized calcium-binding adapter molecule 1 (Iba-1) expression in the hippocampus was determined using immunostaining and immunoblotting. IL-1β and IL-6 immunoblotting were used as inflammation markers, and β-site of amyloid precursor protein cleaving enzyme 1 (BACE1) immunoblotting was performed to evaluate amyloid β-protein (Aβ) accumulation. Long-term cognitive impairment was evaluated using fear conditioning tests. Intraperitoneal LPS increased levels of Iba-1 (150%), inflammation markers (160%), and Aβ accumulation (350%), and sevoflurane preconditioning suppressed these increases. Systemic LPS caused learning deficits. Sevoflurane also maintained long-term memory in mice receiving LPS injection. Sevoflurane preconditioning prevented long-term memory impairment in the mouse model administered systemic LPS by decreasing excessive microglial activation, inflammation, and Aβ accumulation. This study supports the hypothesis that sevoflurane preconditioning might also be beneficial for neuronal inflammation. Sevoflurane might be beneficial for reducing delirium and POCD.

Sevoflurane protects rat brain endothelial barrier structure and function after hypoxia-reoxygenation injury

Background

After cerebral injury blood-brain barrier disruption significantly impairs brain homeostasis. Volatile anesthetics have been shown to be protective in ischemia-reperfusion injury scenarios. Their impact on brain endothelial cells after hypoxia-reoxygenation (H/R) has not yet been studied in detail.

Methods

Rat brain endothelial cells (RBE4) were exposed to severe hypoxia and reoxygenated in air in the presence or absence of sevoflurane. Changes in dextran permeability and architecture of the cellular junctional proteins ZO-1 and β-catenin were measured. To determine necrosis and apoptosis rate DNA content, LDH release and caspase activity were quantified. The role of vascular endothelial growth factor (VEGF) as an inflammatory mediator increasing vascular permeability was assessed. At the same time, it was evaluated if sevoflurane effects are mediated through VEGF. Results were analyzed by unpaired t-tests or one way-analysis of variance followed by Bonferroni’s correction.

Results

H/R led to a 172% increase in permeability (p<0.001), cell swelling and qualitatively but not quantitatively modified expression of ZO-1, β-catenin and F-actin. In the presence of sevoflurane during reoxygenation, barrier function improved by 96% (p = 0.042) in parallel to a decrease of the cell size and less re-arranged junction proteins and F-actin. Sevoflurane-induced improvement of the barrier function could not be explained on the level of necrosis or apoptosis as they remained unchanged independent of the presence or absence of the volatile anesthetic. Increased expression of VEGF after H/R was attenuated by sevoflurane by 34% (p = 0.004). Barrier protection provided by sevoflurane was similar to the application of a blocking VEGF-antibody. Furthermore, the protective effect of sevoflurane was abolished in the presence of recombinant VEGF.

Conclusions

In H/R-induced rat brain endothelial cell injury sevoflurane maintains endothelial barrier function through downregulation of VEGF, which is a key player not only in mediating injury, but also with regard to the protective effect of sevoflurane.

Comparison of the cerebroprotective effect of inhalation anaesthesia and total intravenous anaesthesia in patients undergoing cardiac surgery with cardiopulmonary bypass: a systematic review and meta-analysis

OBJECTIVE

Neurological dysfunction remains a devastating postoperative complication in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB), and previous studies have shown that inhalation anaesthesia and total intravenous anaesthesia (TIVA) may produce different degrees of cerebral protection in these patients. Therefore, we conducted a systematic literature review and meta-analysis to compare the neuroprotective effects of inhalation anaesthesia and TIVA.

DESIGN

Searching in PubMed, EMBASE, Science Direct/Elsevier, China National Knowledge Infrastructure and Cochrane Library up to August 2016, we selected related randomised controlled trials for this meta-analysis.

RESULTS

A total of 1485 studies were identified. After eliminating duplicate articles and screening titles and abstracts, 445 studies were potentially eligible. After applying exclusion criteria (full texts reported as abstracts, review article, no control case, lack of outcome data and so on), 13 studies were selected for review. Our results demonstrated that the primary outcome related to S100B level in the inhalation anaesthesia group was significantly lower than in the TIVA group after CPB and 24 hours postoperatively (weighted mean difference (WMD); 95% CI (CI): -0.41(-0.81 to -0.01), -0.32 (-0.59 to -0.05), respectively). Among secondary outcome variables, mini-mental state examination scores of the inhalation anaesthesia group were significantly higher than those of the TIVA group 24 hours after operation (WMD (95% CI): 1.87 (0.82 to 2.92)), but no significant difference was found in arteriovenous oxygen content difference, cerebral oxygen extraction ratio and jugular bulb venous oxygen saturation, which were assessed at cooling and rewarming during CPB.

CONCLUSION

This study demonstrates that anaesthesia with volatile agents appears to provide better cerebral protection than TIVA for patients undergoing cardiac surgery with CPB, suggesting that inhalation anaesthesia may be more suitable for patients undergoing cardiac surgery.

Inhaled anesthetic agent sedation in the ICU and trace gas concentrations: a review

There is a growing interest in the use of volatile anesthetics for inhalational sedation of adult critically ill patients in the ICU. Its safety and efficacy has been demonstrated in various studies and technical equipment such as the anaesthetic conserving device (AnaConDa™; Sedana Medical, Uppsala, Sweden) or the MIRUS™ system (Pall Medical, Dreieich, Germany) have significantly simplified the application of volatile anesthetics in the ICU. However, the personnel's exposure to waste anesthetic gas during daily work is possibly disadvantageous, because there is still uncertainty about potential health risks. The fact that average threshold limit concentrations for isoflurane, sevoflurane and desflurane either differ significantly between countries or are not even defined at all, leads to raising concerns among ICU staff. In this review, benefits, risks, and technical aspects of inhalational sedation in the ICU are discussed. Further, the potential health effects of occupational long-term low-concentration agent exposure, the staffs' exposure levels in clinical practice, and strategies to minimize the individual gas exposure are reviewed.