Diffuse alveolar hemorrhage induced by inhaled Sevoflurane. Case report and literature review.

Diffuse alveolar hemorrhage secondary to sevoflurane inhalation is a rare condition. It should be considered in postoperative patients presenting symptoms of hemoptysis, hypoxemia, or radiographic alveolar infiltrates. We present the case of a 42-year-old man who experienced a diffuse alveolar hemorrhage following sedation with sevoflurane during a low-risk orthopedic procedure. Initially, the patient presented hemoptysis, hypoxemia, and dyspnea. X-ray findings suggested alveolar hemorrhage and the diagnosis was confirmed with fiberoptic bronchoscopy. The patient improved under the care of the pulmonary service and was discharged. Early identification and management of this respiratory complication were crucial for a successful recovery.

Usefulness of Inhaled Sedation in Patients With Severe ARDS Due to COVID-19.

BACKGROUND: Sedation in intensive care is fundamental for optimizing clinical outcomes. For many years the world has been facing high rates of opioid use, and to combat the increasing opioid addiction plans at both national and international level have been implemented.1 The COVID-19 pandemic posed a major challenge for health systems and also increased the use of sedatives and opioid analgesia for prolonged periods of time, and at high doses, in a significant proportion of patients. In our institutions, the shortage of many drugs for intravenous (IV) analgosedation forces us to alternatives to replace out-of-stock drugs or to seek sedation goals, which are difficult to obtain with traditional drugs at high doses.2 METHODS: This was an analytical retrospective cohort study evaluating the follow-up of subjects with inclusion criteria from ICU admission to discharge (alive or dead). Five end points were measured: need for high-dose opioids (≥ 200 µg/h), comparison of inhaled versus IV sedation of opioid analgesic doses, midazolam dose, need for muscle relaxant, and risk of delirium. RESULTS: A total of 283 subjects were included in the study, of whom 230 were administered IV sedation and 53 inhaled sedation. In the inhaled sedation group, the relative risks (RRs) were 0.5 (95% CI 0.4-0.8, P = .045) for need of high-dose fentanyl, 0.3 (95% CI 0.20-0.45, P < .001) for need of muscle relaxant, and 0.8 (95% CI 0.61-1.15, P = .25) for risk of delirium. The median difference of fentanyl dose between the inhaled sedation and IV sedation groups was 61 µg/h or 1,200 µg/d (2.2 ampules/d, P < .001), and that of midazolam dose was 5.7 mg/h. CONCLUSIONS: Inhaled sedation was associated with lower doses of opioids, benzodiazepines, and muscle relaxants compared to IV sedation. This therapy should be considered as an alternative in critically ill patients requiring prolonged ventilatory support and where IV sedation is not possible, always under adequate supervision of ICU staff.

Isoflurane and Sevoflurane Induce Cognitive Impairment in Neonatal Rats by Inhibiting Neural Stem Cell Development Through Microglial Activation, Neuroinflammation, and Suppression of VEGFR2 Signaling Pathway.

Inhaled anesthetics are known to induce neurotoxicity in the developing brains of rodents, although the mechanisms are not well understood. The aim of this study was to elucidate the molecular mechanisms underlying anesthetics-induced neurodevelopmental toxicity by VEGF receptor 2 (VEGFR2) through the interaction between microglia and neural stem cells (NSCs) in postnatal day 7 (P7) rats. Cognitive function of P7 rats exposed to isoflurane and sevoflurane were assessed using Morris Water Maze and T maze tests. We also evaluated the expression levels of NSC biomarkers (Nestin and Sox2), microglia biomarker (CD11b or or IBA1), pro-inflammatory cytokines (IL-6 and TNF-α), and VEGFR2 using western blotting and immunohistochemistry in the brains of control and anesthesia-treated rats. We found spatial learning and working memory was impaired 2 weeks after anesthetics exposure in rats. Isoflurane induced stronger and more prolonged neurotoxicity than sevoflurane. However, cognitive functions were recovered 6 weeks after anesthesia. Isoflurane and sevoflurane decreased the levels of Nestin, Sox2, and p-VEGFR2, activated microglia, decreased the number of NSCs and reduced neurogenesis and the proliferation of NSCs, and increased the levels of IL-6, TNF-α, and CD11b. Our results suggested that isoflurane and sevoflurane induced cognitive impairment in rats by inhibiting NSC development and neurogenesis via microglial activation, neuroinflammation, and suppression of VEGFR2 signaling pathway.

Prospective validation of gas man simulations of sevoflurane in O2/air over a wide fresh gas flow range.

The use of inhaled anesthetics has come under increased scrutiny because of their environmental effects. This has led to a shift where sevoflurane in O2/air has become the predominant gas mixture to maintain anesthesia. To further reduce environmental impact, lower fresh gas flows (FGF) should be used. An accurate model of sevoflurane consumption allows us to assess and quantify the impact of the effects of lowering FGFs. This study therefore tested the accuracy of the Gas Man® model by determining its ability to predict end-expired sevoflurane concentrations (FETsevo) in patients using a protocol spanning a wide range of FGF and vaporizer settings. After IRB approval, 28 ASA I-II patients undergoing a gynecologic or urologic procedure under general endotracheal anesthesia were enrolled. Anesthesia was maintained with sevoflurane in O2/air, delivered via a Zeus or FLOW-i workstation (14 patients each). Every fifteen min, FGF was changed to randomly selected values ranging from 0.2 to 6 L/min while the sevoflurane vaporizer setting was left at the discretion of the anesthesiologist. The FETsevo was collected every min for 1 h. For each patient, a Gas Man® simulation was run using patient weight and the same FGF, vaporizer and minute ventilation settings used during the procedure. For cardiac output, the Gas Man default setting was used (= Brody formula). Gas Man®'s performance was assessed by comparing measured with Gas Man® predicted FETsevo using linear regression and Varvel's criteria [median performance error (MDPE), median absolute performance error (MDAPE), and divergence]. Additional analysis included separating performance for the wash-in (0-15 min) and maintenance phase (15-60 min). For the FLOW-i, MDPE, MDAPE and divergence were 1% [- 6, 8], 7% [3, 15] and - 0.96%/h [- 1.14, - 0.88], respectively. During the first 15 min, MDPE and MDAPE were 18% [1, 51] and 21% [8, 51], respectively, and during the last 45 min 0% [- 7, 5] and 6% [2, 10], respectively. For the Zeus, MDPE, MDAPE and divergence were 0% [- 5, 8], 6% [3, 12] and - 0.57%/h [- 0.85, - 0.16], respectively. During the first 15 min, MDPE and MDAPE were 7% [- 6, 28] and 13% [6, 32], respectively, and during the last 45 min - 1% [- 5, 5] and 5% [2, 9], respectively. In conclusion, Gas Man® predicts FETsevo in O2/air in adults over a wide range of FGF and vaporizer settings using different workstations with both MDPE and MDAPE < 10% during the first hour of anesthesia, with better relative performance for simulating maintenance than wash-in. In the authors' opinion, this degree of performance suffices for Gas Man® to be used to quantify the environmental impact of FGF reduction in real life practice of the wash-in and maintenance period combined.

Memsorb™, a novel CO2 removal device part II: in vivo performance with the Zeus IE®.

Memsorb™ (DMF Medical, Halifax, Canada) is a novel device based upon membrane oxygenator technology designed to eliminate CO2 from exhaled gas when using a circle anesthesia circuit. Exhaled gases pass through semipermeable hollow fibers and sweep gas flowing through these fibers creates a diffusion gradient for CO2 removal. In vivo Memsorb™ performance was tested during target-controlled closed-circuit anesthesia (TCCCA) with desflurane in O2/air using a Zeus IE® anesthesia workstation (Dräger, Lübeck, Germany). Clinical care protocols for using this novel device were guided by in vitro performance results from a prior study (submitted simultaneously). After IRB approval, written informed consent was obtained from 10 ASA PS I-III patients undergoing robot-assisted radical prostatectomy. TCCCA targets were 39% inspired O2 concentration (FIO2) and 5.0% end-expired desflurane concentration (FETdes). Minute ventilation (MV) was adjusted to maintain 4.5-6.0% FETCO2. The O2/air (40% O2) sweep flow into the Memsorb™ was manually adjusted in an attempt to keep inspired CO2 concentration (FICO2) ≤ 0.8%. The following data were collected: FIO2, FETdes, FICO2, FETCO2, MV, fresh gas flow (FGF, O2 and air), sweep flow, and cumulative desflurane usage (Vdes). Vdes of the Zeus IE®-Memsorb™ combination was compared with historical Vdes observed in a previous study when soda lime (DrägerSorb 800 +) was used. Results are reported as median and inter-quartiles. A combination of manually adjusting sweep flow (26 [21,27] L/min) and MV sufficed to maintain FICO2 ≤ 0.8% and FETCO2 ≤ 6.0%, except in one patient in whom the target Zeus IE® FGF had to be increased to 0.7 L/min for 6 min. FIO2 and FETdes were maintained close to their targets. Zeus IE® FGF after 5 min was 0 [0,0] mL/min. Average Vdes after 50 min was higher with Memsorb™ (20.3 mL) compared to historical soda lime canister data (12.3 mL). During target-controlled closed-circuit anesthesia in patients undergoing robot-assisted radical prostatectomy, the Memsorb™ maintained FICO2 ≤ 0.8% and FETCO2 ≤ 6.0%, and FIO2 remained close to target. Modest amounts of desflurane were lost with the use of the Memsorb™. The need for adjustments of sweep flow, minute ventilation, and occasionally Zeus IE® FGF indicates that the Memsorb™ system should preferentially be integrated into an automated closed-loop system.

Memsorb™, a novel CO2 removal device part I: in vitro performance with the Zeus IE®.

Soda lime-based CO2 absorbents are safe, but not ideal for reasons of ecology, economy, and dust formation. The Memsorb™ is a novel CO2 removal device that uses cardiopulmonary bypass oxygenator technology instead: a sweep gas passes through semipermeable hollow fibers, adding or removing gas from the circle breathing system. We studied the in vitro performance of a prototype Memsorb™ used with a Zeus IE® anesthesia machine when administering sevoflurane and desflurane in O2/air mixtures. The Zeus IE® equipped with Memsorb™ ventilated a 2L breathing bag with a CO2 inflow port in its tip. CO2 kinetics were studied by using different combinations of CO2 inflow (VCO2), Memsorb™ sweep gas flow, and Zeus IE® fresh gas flow (FGF) and ventilator settings. More specifically, it was determined under what circumstances the inspired CO2 concentration (FICO2) could be kept < 0.5%. O2 kinetics were studied by measuring the inspired O2 concentration (FIO2) resulting from different combinations of Memsorb™ sweep gas flow and O2 concentrations, and Zeus IE® FGFs and O2 concentrations. Memsorb™'s sevoflurane and desflurane waste was determined by measuring their injection rates during target-controlled closed-circuit anesthesia (TCCCA), and were compared to historical controls when using a soda lime absorbent (Draegersorb 800+) under identical conditions. With 160 mL/min VCO2 and 5 L/min minute ventilation (MV), lowering the sweep gas flow at any fixed Zeus IE® FGF increased FICO2 in a non-linear manner. Sweep gas flow adjustments kept FICO2 < 0.5% over the entire Zeus IE® FGF range tested with VCO2 up to 280 mL/min; tidal volume and respiratory rate affected the required sweep gas flow. At 10 L/min MV and low FGF (< 1.5 L/min), even a maximum sweep flow of 43 L/min was unable to keep FICO2 ≤ 0.5%. When the O2 concentration in the Zeus IE® FGF and the Memsorb™ sweep gas flow differed, FIO2 drifted towards the sweep gas O2 concentration, and more so as FGF was lowered; this effect was absent once FGF > minute ventilation. During sevoflurane and desflurane TCCCA, the Zeus IE® FGF remained zero while agent usage per % end-expired agent increased with increasing end-expired target agent concentrations and with a higher target FIO2. Agent waste during target-controlled delivery was higher with Memsorb™ than with the soda lime product, with the difference remaining almost constant over the FGF range studied. With a 5 L/min MV, Memsorb™ successfully removes CO2 with inflow rates up to 240 mL/min if an FICO2 of 0.5% is accepted, but at 10 L/min MV and low FGF (< 1.5 L/min), even a maximum sweep flow of 43 L/min was unable to keep FICO2 ≤ 0.5%. To avoid FIO2 deviating substantially from the O2 concentration in the fresh gas, the O2 concentration in the fresh gas and sweep gas should match. Compared to the use of Ca(OH)2 based CO2 absorbent, inhaled agent waste is increased. The device is most likely to find its use integrated in closed loop systems.

Anesthetics, analgesics and cognitive function / 中国临床药理学与治疗学

Cognitive dysfunction has become a pivotal factor affecting the quality of life of elderly patients. The existing literatures can not explain the factors causing cognitive decline. Many researchers believe that anesthetics and analgesics may play important roles in cognitive dysfunction. This review will discuss the effects of different anesthetics and analgesics on cognitive function and briefly describe their mechanisms, so as to provide reference for the rational choice of medications in clinical practice.

General anesthetic techniques for enhanced recovery after surgery: Current controversies.

General anesthesia technique can influence not only immediate postoperative outcomes, but also long-term outcomes beyond hospital stay (e.g., readmission after discharge from hospital). There is lack of evidence regarding superiority of total intravenous anesthesia over inhalation anesthesia with regards to postoperative outcomes even in high-risk population including cancer patients. Optimal balanced general anesthetic technique for enhance recovery after elective surgery in adults includes avoidance of routine use preoperative midazolam, avoidance of deep anesthesia, use of opioid-sparing approach, and minimization of neuromuscular blocking agents and appropriate reversal of residual paralysis. Given that the residual effects of drugs used during anesthesia can increase postoperative morbidity and delay recovery, it is prudent to use a minimal number of drug combinations, and the drugs used are shorter-acting and administered at the lowest possible dose. It is imperative that the discerning anesthesiologist consider whether each drug used is really necessary for accomplishing perioperative goals.

Malignant Hyperthermia Syndrome: A Clinical Case Report.

Malignant hyperthermia is a pharmacogenetic disorder. It manifests as a hypercatabolic skeletal muscle syndrome linked to inhaled volatile anesthetics or depolarizing muscle relaxants. Its clinical signs and symptoms are tachycardia, hyperthermia, hypercapnia, acidosis, muscle rigidity, rhabdomyolysis, hyperkalemia, arrhythmia and renal failure. Mortality without specific treatment is 80% and decreases to 5% with the use of dantrolene sodium. This article presents the case of a 39-year-old patient admitted to the Intensive Care Unit for malignant hyperthermia after surgery for septoplasty plus turbinoplasty.

Inhaled Anesthetics: Environmental Role, Occupational Risk, and Clinical Use.

Inhaled anesthetics have been in clinical use for over 150 years and are still commonly used in daily practice. The initial view of inhaled anesthetics as indispensable for general anesthesia has evolved during the years and, currently, its general use has even been questioned. Beyond the traditional risks inherent to any drug in use, inhaled anesthetics are exceptionally strong greenhouse gases (GHG) and may pose considerable occupational risks. This emphasizes the importance of evaluating and considering its use in clinical practices. Despite the overwhelming scientific evidence of worsening climate changes, control measures are very slowly implemented. Therefore, it is the responsibility of all society sectors, including the health sector to maximally decrease GHG emissions where possible. Within the field of anesthesia, the potential to reduce GHG emissions can be briefly summarized as follows: Stop or avoid the use of nitrous oxide (N2O) and desflurane, consider the use of total intravenous or local-regional anesthesia, invest in the development of new technologies to minimize volatile anesthetics consumption, scavenging systems, and destruction of waste gas. The improved and sustained awareness of the medical community regarding the climate impact of inhaled anesthetics is mandatory to bring change in the current practice.

Measurement of anesthetic pollution in veterinary operating rooms for small animals: Isoflurane pollution in a university veterinary hospital.

INTRODUCTION: Inhaled anesthetics are used worldwide for anesthesia maintenance both in human and veterinary operating rooms. High concentrations of waste anesthetic gases can lead to health risks for the professionals exposed. Considering that anesthetic pollution in a veterinary surgical center in developing countries is unknown, this study aimed, for the first time, to measure the residual concentration of isoflurane in the air of operating rooms for small animals in a Brazilian university hospital. METHOD: Residual isoflurane concentrations were measured by an infrared analyzer at the following sites: corner opposite to anesthesia machine; breathing zones of the surgeon, anesthesiologist, and patient (animal); and in front of the anesthesia machine at three time points, that is, 5, 30 and 120 minutes after anesthesia induction. RESULTS: Mean residual isoflurane concentrations gradually increased in the corner opposite to anesthesia machine and in the breathing zones of the surgeon and the anesthesiologist (p <  0.05). There was an increase at 30 minutes and 120 minutes when compared to the initial time points in the animal's breathing zone, and in the front of the anesthesia machine (p <  0.05). There was no significant difference at measurement sites regardless of the moment of assessment. CONCLUSION: This study reported high residual isoflurane concentrations in veterinary operating rooms without an exhaust system, which exceeds the limit recommended by an international agency. Based on our findings, there is urgent need to implement exhaust systems to reduce anesthetic pollution and decrease occupational exposure.

Effect of inhaled anesthetic gases on immune status alterations in health care workers.

The objective of this research was to evaluate consequences to the immune system of long-term exposure to waste anesthetic gases (WAG) by medical theater personnel. Two groups were recruited: (i) 60 healthy male controls; (ii) 120 medical professionals exposed to WAG, subdivided according to theater role, i.e. surgeons, surgical assistants (SA), anesthetists, anesthetic assistants (AA), nurses, and workers. Serum levels of fluoride, hexafluoroisopropanol (HFIP), total lymphocyte counts, as well as of CD3, CD4, and CD8 cells, CD4/CD8 ratios, and immunoglobulins IgA, IgG, IgM, and IgE were assayed. The results showed that fluoride and HFIP titers were significantly increased in anesthetists and AA compared with the other exposed groups. All exposed groups demonstrated significant elevation in lymphocyte count, CD4+ cell levels, CD4/CD8 ratios, as well as levels of IgE, IgM and IgG compared with the controls. With regard to the latter outcomes, a significant increase in IgE was seen in the surgeon, nurse, and worker groups compared with the other professions. Surgeons, anesthetists and AA exhibited higher IgM titers compared with their colleagues. Significantly higher IgG levels were identified in the SA, anesthetists, AA, and workers than in their nurses and surgeon coworkers. Of the six sub-groups, only the anesthetists and their assistants (AA) displayed a significant increase in CD4+ cells and CD4/CD8 ratios and a decrease of CD8+ cells compared with the controls. This spectrum of results suggests that variation exists in immunomodulatory responses to WAG exposure amongst hospital personnel.

Inhalation of low-dose desflurane prevents the hemodynamic instability caused by target-controlled infusion of remifentanil and propofol during laparoscopic gynecological surgery: A randomized controlled trial.

The objective of the present study was to determine whether the addition of inhaled desflurane is superior to remifentanil-propofol total intravenous anesthesia (TIVA) alone in patients undergoing laparoscopic gynecological surgery. A total of 60 patients who were scheduled to undergo laparoscopic gynecological surgery were prospectively enrolled and randomly allocated to receive either propofol-remifentanil (PR group; n=30) or combined propofol-remifentanil and low-dose desflurane (PRD group; n=30) for the maintenance of anesthesia. Hemodynamics [mean arterial pressure (MAP); heart rate (HR)], recovery parameters and complications were recorded. The results of the present study indicated that the addition of desflurane significantly reduced the amount of propofol and remifentanil that was administered in the PRD group, compared with that in the PR group. MAP and HR were significantly higher at T3 (5 min post-pneumoperitoneum), but significantly lower at T4 (removal of pneumoperitoneum needle) and T5 (post-operation immediately) in the PR group, compared with the PRD group. Moreover, MAP and HR were significantly altered at multiple time points within the PR group; however, they were relatively stable in the PRD group. There were no significant differences in the recovery parameters and complications between the two groups. In conclusion, combining low-dose desflurane with PR may represent an efficient anesthesia regimen to prevent the hemodynamic instability of TIVA in patients undergoing laparoscopic gynecological surgery.

Inhaled sedation with sevoflurane in critically ill children during extracorporeal membrane oxygenation.

Sedation can be challenging in critically ill children. Inhaled anesthetics such as sevoflurane have proved to be useful in difficult or long-term sedation. However, its use in children out of the operating room is still limited and little is yet known about its use in patients undergoing ECMO with no previous reports in children. The objective is to assess the effectiveness and safety of sevoflurane during ECMO in two pediatric patients. Sedation was successfully achieved in both patients, and patients' contribution to breathing was possible even with deep sedation. There were not any side effects during sevoflurane treatment or after withdrawal.

The implementation of low-flow anesthesia at a tertiary pediatric center: A quality improvement initiative.

INTRODUCTION: Anesthesia machines have evolved over the years to excel in delivering low-flow anesthesia (<1 L fresh gas flow) in a closed-circuit system, with the obvious benefits being decreased costs and reduced emissions of greenhouse gases. At a pediatric hospital that provides over 25 000 anesthetics a year, a quality improvement project was initiated with the aim of decreasing the amount of sevoflurane used per anesthetic by 20% over the course of a year. METHODS: Three Plan-Do-Study-Act cycles involving gathering comparative data, departmental education, improvement updates on our huddle board, and intraoperative confirmation rounds were completed. The bottles of sevoflurane used and the total number of anesthetics performed were collected each month. To account for the fluctuation of anesthetic cases per month, a metric of "Anesthetics Performed per Bottle of Sevoflurane Used" was created. RESULTS: Compared to a prior twelve-month period, the Anesthetics Performed per Bottle of Sevoflurane Used were higher with a mean increase of 25%. The bottles of sevoflurane used per month was lower with a mean decrease of 20%. The carbon footprint of our sevoflurane use was also decreased and extrapolated over a year, and the decrease was equivalent to 70 000 miles driven, over 3,200 gallons of gasoline consumed, or over 31000 pounds of coal burned. CONCLUSION: A QI initiative aimed at changing the practice of delivering at least 2L fresh gas flow to delivering a low-flow anesthetic has been a successful value-added enhancement to our pediatric anesthesia practice.

Successful management of hypothermic cardiopulmonary bypass in a malignant hyperthermia susceptible patient.

Malignant hyperthermia (MH) is a potentially lethal reaction in those that are genetically predisposed, frequently triggered by inhaled anesthetics. MH is often difficult to diagnose because it is accompanied by signs and symptoms that are shared with other disorders. The diagnosis is further obscured in cardiac surgical patients, as the signs of MH can be masked by the cardiopulmonary bypass circuit (CPB) and the use of induced hypothermia. In this case-report, we describe the successful anesthetic management of a 65-year-old MH-susceptible female, confirmed via caffeine halothane contracture test, with aortic regurgitation and ascending aortic dilatation who underwent a Bentall procedure. We have also identified certain key measures for the safe anesthetic management of these patients.

The Role of Inhaled Anesthetics in Tumorigenesis and Tumor Immunity.

Inhaled anesthetics are widely used for induction and maintenance of anesthesia during surgery, including isoflurane, sevoflurane, desflurane, haloflurane, nitrous oxide (N2O), enflurane and xenon. Nowadays, it is controversial whether inhaled anesthetics may influence the tumor progression, which urges us to describe the roles of different inhaled anesthetics in human cancers. In the review, the relationships among the diverse inhaled anesthetics and patient outcomes, immune response and cancer cell biology were discussed. Moreover, the mechanisms of various inhaled anesthetics in the promotion or inhibition of carcinogenesis were also reviewed. In summary, we concluded that several inhaled anesthetics have different immune functions, clinical outcomes and cancer cell biology, which could contribute to opening new avenues for selecting suitable inhaled anesthetics in cancer surgery.

Pediatric Drug Induced Sleep Endoscopy: A Simple Sedation Recipe.

OBJECTIVE: To describe a minimalist approach to sedating children for DISE procedures. METHODS: We searched existing literature and derived and tested our algorithm on patients using evidence-based studies. RESULTS: We were able to successfully sedate, without airway intervention, 15 highly complex children with a variety of comorbidities for DISE procedures. CONCLUSION: We describe a minimalistic sedation approach for DISE procedures in highly complex children. Further studies are required to compare this regimen to natural sleep states.

Sevoflurane Protects against Intestinal Ischemia-Reperfusion Injury by Activating Peroxisome Proliferator-Activated Receptor Gamma/Nuclear Factor-κB Pathway in Rats.

BACKGROUND: Intestinal ischemia/reperfusion (I/R) injury is a clinical challenge with high morbidity and mortality, whereas the effective therapeutic strategy is limited. Inflammatory reaction plays important roles in I/R-induced intestinal damage and multi-organ dysfunction syndrome. Peroxisome proliferator-activated receptor gamma (PPARγ) has been identified as an endogenous anti-inflammatory regulator by inhibiting nuclear factor-κB (NF-κB) activation. Our previous research has shown that the pretreatment with inhaled anesthetic sevoflurane protects intestinal I/R injury. However, whether the protection induced by sevoflurane is mediated by inhibiting intestinal inflammatory reaction via activation of PPARγ/NF-κB pathway is underdetermined. In this study, we investigated the effects of sevoflurane on intestinal inflammatory reaction during intestinal I/R and the role of PPARγ/NF-κB pathway. METHODS: Rat model of intestinal I/R was used in this study. The superior mesenteric artery was clamped for 60 min followed by 120-min reperfusion. Sevoflurane at 0.5 minimum alveolar concentration was inhaled for 30 min before ischemic insult. GW9662, a specific PPARγ antagonist, was injected intraperitoneally before sevoflurane inhalation. RESULTS: Intestinal I/R caused severe intestinal mucosa histopathological injury evaluated by Chiu's scoring, induced epithelial cell apoptosis evaluated by terminal deoxyribonucleotide transferase-mediated dUTP nick end labeling and activation of caspase-3, upregulated serum MOD levels, reduced protein expression of Bcl-2 and PPARγ, increased protein expression of NF-κB P65 and proinflammatory cytokine tumor necrosis factor-α and interleukin-6 in the intestine. Sevoflurane preconditioning significantly ameliorated these changes induced by intestinal I/R. However, GW9662 partly blocked the protective effects induced by sevoflurane. CONCLUSIONS: Our results suggest sevoflurane-induced protection against intestinal I/R injury is partly mediated by inhibiting intestinal inflammatory reaction via activation of PPARγ/NF-κB pathway.

Minimal flow anesthesia can be initiated early with the use of higher fresh gas flow to facilitate desflurane "Wash-in".

BACKGROUND AND AIMS: More than 80% of delivered anesthetic gases get wasted at high fresh gas flows as they are vented out unused. Use of minimal flow anesthesia is associated with less waste anesthetic gas emission and environmental pollution. There is no approved or validated technique to initiate minimal flow anesthesia and simultaneously achieve denitrogenation of the breathing circuit. We studied the wash-in characteristics of desflurane, when delivered with 50% nitrous oxide, to reach a target end-tidal concentration at two different gas flow rates. MATERIAL AND METHODS: Patients were allocated randomly to two groups of 25 adults each. In Group A, with the vaporizer dial fixed at 4 vol %, after an initial fresh gas flow of 4 L/min was administered to wash-in of desflurane using the closed-circuit, with 50% N2O in O2, and in group B, 6 L/min was used. Minimal flow anesthesia, with 0.5 L/min, was initiated in both groups on attaining a target end-tidal desflurane concentration of 3.5 vol %. After initiation of desflurane delivery, the inspired/expired gas concentrations were noted every minute for 15 min. RESULTS: In Group A, the target desflurane end-tidal concentration was reached in 499.2 ± 68.6 s±, and in the Group B (P < 0.001), it was reached significantly faster in 314.4 ± 69.89 s. Denitrogenation of the circuit was adequate in both groups. CONCLUSION: Minimal flow anesthesia can be initiated, without any gas-volume deficit, in about 5 min with an initial fresh gas flow rate of 6 L/min and the vaporizer set at 4 vol%.