Post-conditioning by a short administration of desflurane reduced renal reperfusion injury after differing of ischaemia times in rats

Inhaled sedation in the intensive care unit

Inhaled sedation with halogenated agents, such as isoflurane or sevoflurane, is now feasible in intensive care unit (ICU) patients through dedicated vaporisers and scavenging systems. Such a sedation strategy requires specific equipment and adequate training of ICU teams. Isoflurane and sevoflurane have ideal pharmacological properties that allow efficient, well-tolerated, and titratable light-to-deep sedation. In addition to their function as sedative agents, these molecules may have clinical benefits that could be especially relevant to ICU patients. Our goal was to summarise the pharmacological basis and practical aspects of inhaled ICU sedation, review the available evidence supporting inhaled sedation as a viable alternative to intravenous sedation, and discuss the remaining areas of uncertainty and future perspectives of development.

Use of volatile agents for sedation in the intensive care unit: A national survey in France

Background

Current intensive care unit (ICU) sedation guidelines recommend strategies using non-benzodiazepine sedatives. This survey was undertaken to explore inhaled ICU sedation practice in France.

Methods

In this national survey, medical directors of French adult ICUs were contacted by phone or email between July and August 2019. ICU medical directors were questioned about the characteristics of their department, their knowledge on inhaled sedation, and practical aspects of inhaled sedation use in their department.

Results

Among the 374 ICUs contacted, 187 provided responses (50%). Most ICU directors (73%) knew about the use of inhaled ICU sedation and 21% used inhaled sedation in their unit, mostly with the Anaesthetic Conserving Device (AnaConDa, Sedana Medical). Most respondents had used volatile agents for sedation for <5 years (63%) and in <20 patients per year (75%), with their main indications being: failure of intravenous sedation, severe asthma or bronchial obstruction, and acute respiratory distress syndrome. Sevoflurane and isoflurane were mainly used (88% and 20%, respectively). The main reasons for not using inhaled ICU sedation were: “device not available” (40%), “lack of medical interest” (37%), “lack of familiarity or knowledge about the technique” (35%) and “elevated cost” (21%). Most respondents (80%) were overall satisfied with the use of inhaled sedation. Almost 75% stated that inhaled sedation was a seducing alternative to intravenous sedation.

Conclusion

This survey highlights the widespread knowledge about inhaled ICU sedation in France but shows its limited use to date. Differences in education and knowledge, as well as the recent and relatively scarce literature on the use of volatile agents in the ICU, might explain the diverse practices that were observed. The low rate of mild adverse effects, as perceived by respondents, and the users’ satisfaction, are promising for this potentially important tool for ICU sedation.

Desflurane Preconditioning Protects Against Renal Ischemia-Reperfusion Injury and Inhibits Inflammation and Oxidative Stress in Rats Through Regulating the Nrf2-Keap1-ARE Signaling Pathway

OBJECTIVE

Kidney is sensitive to ischemia-reperfusion (I/R) injury because of its special structure and function. In this study, we aimed to explore the mechanism of desflurane (DFE) preconditioning effecting on renal I/R injury in rats.

METHODS

Renal I/R injury rats model was constructed, and the expressions of serum renal function parameters (blood urea nitrogen (BUN) and serum creatinine (SCr)) and lipid peroxidation-related factors were detected using corresponding commercial kits to assess the degrees of renal functional damage and oxidative stress. Hematoxylin--eosin (HE) staining and Masson trichrome staining were applied to measure the renal histologic damage. The expressions of inflammation-related factors were determined by ELISA assay. The cell apoptosis was analyzed using TUNEL, Western blot and immunohistochemistry (IHC). IHC was also used to detect the number of myeloperoxidase (MPO)-positive cells. The expressions of proteins associated with the Nrf2-Keap1-ARE pathway were assessed by Western blot and IHC.

RESULTS

DFE preconditioning inhibited I/R injury-induced BUN and SCr increase and renal histologic injury in rats. Also, DFE suppressed the inflammation, apoptosis and oxidative stress caused by renal I/R injury in vivo. In addition, DFE preconditioning repressed peroxide-related factors (MDA, MPO and NO) expressions and promoted antioxidant-related factors (GSH, SOD, GPx and CAT) expressions. In addition, DFE promoted Nrf2-Keap1-ARE-related proteins including Nrf2, NQO1, HO-1, γ-GCS, GSR and GCLc expressions.

CONCLUSION

DFE preconditioning protected the kidney as well as inhibited the inflammation, cell apoptosis and oxidative stress in renal I/R injury rats by activating the Nrf2-Keap1-ARE signaling pathway.

Volatile anesthetics and AKI: risks, mechanisms, and a potential therapeutic window

AKI is a major clinical problem with extremely high mortality and morbidity. Kidney hypoxia or ischemia-reperfusion injury inevitably occurs during surgery involving renal or aortic vascular occlusion and is one of the leading causes of perioperative AKI. Despite the growing incidence and tremendous clinical and financial burden of AKI, there is currently no effective therapy for this condition. The pathophysiology of AKI is orchestrated by renal tubular and endothelial cell necrosis and apoptosis, leukocyte infiltration, and the production and release of proinflammatory cytokines and reactive oxygen species. Effective management strategies require multimodal inhibition of these injury processes. Despite the past theoretical concerns about the nephrotoxic effects of several clinically utilized volatile anesthetics, recent studies suggest that modern halogenated volatile anesthetics induce potent anti-inflammatory, antinecrotic, and antiapoptotic effects that protect against ischemic AKI. Therefore, the renal protective properties of volatile anesthetics may provide clinically useful therapeutic intervention to treat and/or prevent perioperative AKI. In this review, we outline the history of volatile anesthetics and their effect on kidney function, briefly review the studies on volatile anesthetic-induced renal protection, and summarize the basic cellular mechanisms of volatile anesthetic-mediated protection against ischemic AKI.

Reduced sevoflurane loss during cardiopulmonary bypass when using a polymethylpentane versus a polypropylene oxygenator

PURPOSE

The goal of this investigation was to examine the influence of two oxygenators with different membranes, made of either polypropylene (PPL) or polymethylpentane (PMP), on the plasma concentration of sevoflurane during cardiopulmonary bypass.

METHODS

The concentrations of sevoflurane during cardiopulmonary bypass were examined in patient plasma, endotracheal tubes, cardiotomy reservoirs and the outlets of the heart-lung oxygenators in twenty patients who underwent elective heart surgery.

RESULTS

The sevoflurane losses are smaller in cardiopulmonary bypass when using a polymethylpentane versus a polypropylene oxygenator. Ten minutes after beginning cardiopulmonary bypass, the sevoflurane plasma concentration in the PPL oxygenator group compared to the PMP oxygenator group fell significantly (PPL 0.48-1.79 (0.93) vs. PMP 0.80-2.15 (1.56) µL × 100 mL-1, p = 0.02). This difference persisted until ten minutes after the termination of cardiopulmonary bypass.

CONCLUSION

The results of this study show that using a polymethylpentane membrane oxygenator rather than a polypropylene oxygenator significantly reduces the losses of sevoflurane, resulting in higher plasma concentrations and greater depth of anesthesia.

Effect of sevoflurane on grafted kidney function in renal transplantation

BACKGROUND

The objective of this retrospective study was to determine if there are any differences in grafted kidney function in recipients of kidney transplantation (KT) when donors and recipients were anesthetized with sevoflurane compared to desflurane.

METHODS

Seventy-three pairs of donors-recipients were anesthetized with sevoflurane (Sevo group) and 71 pairs were anesthetized with desflurane (Des group). We retrospectively investigated the blood urea nitrogen (BUN) levels, creatinine (Cr) levels, and estimated glomerular filtration rates (eGFR) of the recipients in both groups for 1 year postoperatively. We tested non-inferiority for serum creatinine at discharge and 1 year after KT. Short-term (1 year) outcomes of KT were assessed by the incidence of delayed graft function (DGF), acute rejection episodes (ARE), and graft failure.

RESULTS

There were no differences in BUN, Cr, eGFR, or outcomes of KT at 1 year postoperatively. Specifically, the 95% confidence interval for the difference in creatinine levels between the Sevo and Des groups was less than the margin of equivalence at the time of discharge and 1 year after surgery. The occurrences of DGF, ARE, and graft failure were comparable between the groups.

CONCLUSIONS

Compared to desflurane, sevoflurane had no adverse effects on grafted renal function or on the short-term outcome of renal transplantation.

Desflurane: a clinical update of a third-generation inhaled anaesthetic

Available volatile anaesthetics are safe and efficacious; however, their varying pharmacology provides small but potentially clinically important differences. Desflurane is one of the third-generation inhaled anaesthetics. It is the halogenated inhaled anaesthetic with the lowest blood and tissue solubilities, which promotes its rapid equilibration and its rapid elimination following cessation of administration at the end of anaesthesia. The low fat solubility of desflurane provides pharmacological benefits, especially in overweight patients and in longer procedures by reducing slow compartment accumulation. A decade of clinical use has provided evidence for desflurane's safe and efficacious use as a general anaesthetic. Its benefits include rapid and predictable emergence, and early recovery. In addition, the use of desflurane promotes early and predictable extubation, and the ability to rapidly transfer patients from the operating theatre to the recovery area, which has a positive impact on patient turnover. Desflurane also increases the likelihood of patients, including obese patients, recovering their protective airway reflexes and awakening to a degree sufficient to minimise the stay in the high dependency recovery area. The potential impact of the rapid early recovery from desflurane anaesthesia on intermediate and late recovery and resumption of activities of daily living requires further study.

Modulation of 11β-hydroxysteroid dehydrogenase 1 by β2-adrenoceptor in the ischaemia-reperfused rat kidney

BACKGROUND

11β-Hydroxysteroid dehydrogenase Type 1 (11βHSD-1) amplifies intracellular levels of active glucocorticoids which possess protective effects against organ ischaemia and reperfusion (I/R). However, the mechanisms by which 11βHSD-1 is modified after a renal I/R challenge remain unclear. This study investigated the effect of β(2)-adrenoceptor (β(2)-AR) activation and the subsequent signalling pathways on renal 11βHSD-1 gene expression following renal I/R.

METHODS

Renal I/R was induced using 25 min of bilateral renal artery occlusion in 4-week-old Wistar rats followed by an intraperitoneal injection of various doses of adeno-β(2)-AR gene. Following renal I/R, kidneys, plasma and urine were collected to assay 11βHSD messenger RNA (mRNA) levels, β(2)-AR signalling cascades and renal function.

RESULTS

On the second day after the renal I/R challenge, there was a reduction in renal 11βHSD-1 mRNA levels associated with a decrease in stimulatory G protein α (Gsα) and adenylate cyclase-1 (ACY-1) in the kidney. The addition of the adeno-β(2)-AR gene resulted in greater increases in 11βHSD-1 mRNA and β(2)-AR-Gsα-ACY-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) activity in the kidney but had no effect on 11βHSD-2 mRNA or protein kinase C levels in the kidney.

CONCLUSIONS

Over-expression of β(2)-AR resulting from the gene delivery improved renal function and 11βHSD-1 production following renal I/R, which were actions exerted through the cAMP-PKA pathway. The stimulatory effect of functional β(2)-AR activation on renal 11βHSD-1 expression may offer a means of protection from renal I/R injury.

Preconditioning, postconditioning, and remote conditioning in solid organ transplantation: basic mechanisms and translational applications

Ischemia and reperfusion (I/Rp) injury is inherent to solid organ transplantation and can result in primary nonfunction or delayed function of grafts, which is associated with a significant morbidity and mortality posttransplantation. It is also a major obstacle for the use of marginal grafts to increase the donor pool, as these grafts are prone to a higher degree of I/Rp injury. Pre-, post-, and remote conditioning are protective strategies against I/Rp injury, which can be applied in the transplant setting. These strategies hold the potential to reduce graft injury and to safely expand the donor pool. However, despite convincing experimental data, the protective effects of the "conditioning" protocols remain unclear, and only few have translated to clinical practice. This review summarizes pre-, post-, and remote conditioning strategies in clinical use in solid organ transplantation and discusses an overview of the mechanistic pathways involved in each strategy.

[Ischaemic and pharmacologic preconditioning: desflurane reduces renal reperfusion injury in rabbits]

BACKGROUND

Anaesthetic preconditioning, i.e. administration of volatile agents before ischemia, is known to have protective effects on several organs, but remains uncertain on the kidney. We developed a rabbit model for acute ischaemia-reperfusion injury, and examined a possible protective effect of desflurane preconditioning on the kidney.

METHODS

Forty New Zealand male rabbits, 3 months old, weighing 2-3 kg, were anaesthetized by titrated intramuscular injections of xylazine-ketamine, mechanically ventilated and monitored. They were randomly assigned into four groups: group ischaemia (I), group ischaemic preconditioning (IPC), group desflurane preconditioning (DPC), and group SHAM (S). Groups I, IPC and DPC were subjected to 45 minutes of bilateral renal ischaemia followed by 3 hours reperfusion. Group IPC was subjected to 3 x 3 minutes ischaemia, 5 minutes before the 45-minute clamping period. Group DPC was administered one MAC desflurane for 30 minutes, before a 30-minute wash-out period. Histological analysis of the cortical zone of both kidneys were blindly performed. Tubular cell damage was graded from 1 (no lesion) to 4 (>50 % cell necrosis). Pycnotic nuclei and intratubular hyaline casts were counted on each section.

RESULTS

DPC (1[1-2]) and S (1[1-1]) groups displayed lower histological grades than group 1(4[3-4]) (p<0.01); IPC had a grade of 3 (2-3), I and IPC groups had higher scores of pycnotic nuclei and hyaline casts than DPC and S.

CONCLUSION

Desflurane preconditioning was associated with a diminution of tubular cell damage. Ischaemic preconditioning did not show a significant renal protective effect.

The effect of iloprost on renal dysfunction after renal I/R using cystatin C and beta2-microglobulin monitoring

The purpose of this study was to investigate the effect of iloprost, a cytoprotective prostacyclin analog, on renal injury during unilateral renal I/R in rats and to determine whether the levels of serum cystatin C (CyC) and beta2-microglobulin (B2M), as markers of glomerular function, might denote this injury. Thirty-two Wistar rats were randomized into four groups (n = 8) as follows: control (sham laparotomy), renal I/R (60-min left renal ischemia and 120-min reperfusion), renal I/R + iloprost (20 ng kg(-1) min(-1) infusion during renal I/R period, i.v.), and control + iloprost. Blood and kidney tissue samples were obtained for biochemical and histological analysis from all rats. Serum urea, creatinine, CyC, and B2M levels were evaluated for biochemical analysis. Histopathological changes in renal structure were examined for histological analysis. Serum urea, creatinine, and CyC levels were significantly increased in the renal I/R group. Iloprost treatment decreased these three markers in the renal I/R + iloprost group. beta2-Microglobulin levels were not significantly changed in any group. Histological analyses showed that renal I/R elicited significant renal injury, whereas iloprost significantly decreased I/R-induced renal injury. Serum CyC level is one of the good indicators of acute renal damage due to I/R produced by renal artery occlusion. In contrast, we have shown that there are no significant changes in the levels of serum B2M levels that would make it an accurate diagnostic tool for detecting acute changes in renal injury subject to renal I/R in rats.

Pre-medication and renal pre-conditioning: a role for alprazolam, atropine, morphine and promethazine

Four pre-medication drugs are used to relieve pain, allay anxiety, reduce secretion and enhance hypnosis, were evaluated for their effects on ischemia reperfusion (I/R) injury which is one of the major complications of vascular and transplantation surgery. Right kidney was removed from female rats (210-250 g) 3 weeks before surgical procedure. Different doses of morphine (0.5, 2 and 5 mg/kg), promethazine (1, 2 and 5 mg/kg), atropine (0.1, 0.3 and 0.5 mg/kg) and alprazolam (0.08, 0.32 and 0.64 mg/kg) were administered subcutaneously 30 min before left renal artery occlusion and 6 h reperfusion. Left kidneys were processed for histological evaluations. Creatinine and BUN were measured in serum samples. Morphine, promethazine, atropine and alprazolam at all evaluated doses significantly decreased serum creatinine and BUN levels and histopathological scores. The effects of promethazine (1 mg/kg) and all doses of alprazolam were more potent than other pre-medication drugs and doses. This study suggested a protective effect of these pre-medication drugs on I/R injury. Although obvious studies are required, these findings may lead to effective therapies against I/R injury.

Preconditioning, but not postconditioning, with Sevoflurane reduces pulmonary neutrophil accumulation after lower body ischaemia/reperfusion injury in rats

BACKGROUND AND OBJECTIVES

Aortic ischaemia and reperfusion may induce pulmonary sequestration of neutrophil granulocytes. Preconditioning and postconditioning with volatile anaesthetics confer protection against reperfusion injury in various organs, such as heart, kidneys or brain. We tested the hypothesis that pre- or postconditioning with Sevoflurane attenuates pulmonary neutrophil accumulation after ischaemia/reperfusion injury of the aorta.

METHODS

Anaesthetized and mechanically ventilated Wistar rats underwent laparotomy and were randomly assigned to one of the following groups: Sham (n = 10), ischaemia/reperfusion (n = 8, lower body ischaemia by clamping of the infrarenal aorta for 2 h followed by 3 h of reperfusion), preconditioning (n = 10, 2.0% Sevoflurane administered over 30 min prior to ischaemia) and postconditioning (n = 9, 2.0% Sevoflurane during reperfusion). Following reperfusion, the lungs were removed for microscopic determination of neutrophil accumulation.

RESULTS

Ischaemia/reperfusion induced a significant increase in pulmonary neutrophil accumulation (mean +/- SD, 29.9 +/- 7.4 vs. 15.8 +/- 6.6 neutrophils per microscopic field in ischaemia/reperfusion vs. Sham, respectively, P < 0.001). Sevoflurane preconditioning resulted in a lower neutrophil count (20.3 +/- 7.1 neutrophils, P < 0.001 vs. ischaemia/reperfusion), while postconditioning showed no effects (25.8 +/- 9.8 neutrophils vs. ischaemia/reperfusion, not significant).

CONCLUSIONS

Preconditioning, but not postconditioning, with Sevoflurane reduces pulmonary neutrophil accumulation after ischaemia/reperfusion injury of the lower body. Since neutrophil accumulation plays a major role in the pathophysiology of acute lung injury, our data suggest a protective effect of Sevoflurane preconditioning on remote pulmonary ischaemia/reperfusion injury.

Anaesthesia for renal transplant surgery

Renal transplantation is the preferred therapeutic option for patients with end-stage renal disease. Survival rates are much higher in patients who receive a transplant. Patients with renal failure have significant concomitant medical conditions, such as cardiovascular disease. This article provides an overview of the important issues to be considered in patients undergoing renal transplant, and discusses the anaesthetic management of these patients.