Protective effect of sevoflurane preconditioning on ischemia-reperfusion injury in patients undergoing reconstructive plastic surgery with microsurgical flap, a randomized controlled trial

A systematic review of randomised controlled trials in breast reconstruction

BACKGROUND

For preference sensitive treatments, such as breast reconstructions, there are barriers to conducting randomised controlled trials (RCTs). The primary aims of this systematic review were to investigate what type of research questions are explored by RCTs in breast reconstruction, where have they been performed and where have they been published, and to thematise the research questions and thus create an overview of the state of the research field.

METHODS

Randomised controlled trials investigating any aspect of breast reconstructions were included. The PubMed database was searched with a pre-defined search string. Inclusion and data abstraction was performed in a pre-defined standardised fashion. For the purpose of this study, we defined key issues as comparison of categories of breast reconstruction and comparison of immediate and delayed breast reconstruction, when the thematisation was done.

RESULTS

A total of 419 abstracts were retrieved from the search. Of the 419, 310 were excluded as they were not RCTs concerning some aspect of breast reconstruction, which left us with 110 abstracts to be included in the study. The research questions of the included studies could more or less be divided into seven different themes inclusive of 2 key issues: Other issues - comparison of different categories of breast reconstruction, comparison of immediate and delayed breast reconstruction, surgical details within a category of breast reconstruction, surgical details valid for several categories of breast reconstruction, donor site management, anaesthetics, and non-surgical details. Only five studies compared key issues, and they all illustrate the challenges with RCTs in breast reconstruction.

CONCLUSIONS

A total of 110 publications based on RCTs in breast reconstruction have been published. Seven themes of research questions could be identified. Only five studies have explored the key issues. Better scientific evidence is needed for the key issues in breast reconstruction, for example by implementing a new study design in the field.

Practice Trends and Evidence-Based Practice in Microvascular Reconstruction

Microvascular and free flap reconstruction are important to the otolaryngology-head and neck surgery practice. Herein, the reader will find an up-to-date discussion of various evidence-based practice trends related to microvascular surgery, including surgical techniques, anesthetic and airway considerations, free flap monitoring and troubleshooting, surgical efficiency, and both patient-related and surgeon-related risk factors that may affect outcomes.

Impact of Anesthetic Agents on Endothelial Glycocalyx Injury during Total Knee Arthroplasty: Desflurane- vs. Propofol-Based Anesthesia-A Prospective Randomized Controlled Trial

Background

Ischemia-reperfusion injury and inflammation after tourniquet deflation in total knee arthroplasty are known to be associated with endothelial glycocalyx (EG) injury. This study is aimed at comparing EG injury between desflurane- and propofol-based anesthesia in patients undergoing total knee arthroplasty.

Materials and Methods

Patients were allocated to the desflurane group or propofol group. The opioid remifentanil was administered intraoperatively in both groups. Blood samples were obtained from the arterial line preoperatively, immediately before and 5 min after tourniquet deflation, and at 1, 6, and 24 h, postoperatively. Serum syndecan-1, cytokines (interleukin-1β, 6, 10, and tumour necrosis factor-α), and other laboratory values were investigated.

Results

Eighty patients were included in the final analysis. The change in syndecan-1 did not significantly differ between the desflurane and propofol groups (peak median level of syndecan-1; 754.5 pg/ml vs. 780.3 pg/ml, respectively, P = 0.512). Laboratory values (serum cytokines, creatinine phosphokinase, lactate dehydrogenase, and lactate levels) were also similar between the two groups. Pulmonary oxygenation was briefly improved after tourniquet deflation in the desflurane group but was similar between the two groups begging at 1 h, postoperatively.

Conclusions

The effect of desflurane was not superior to that of propofol in protecting the EG from ischemia-reperfusion injury during total knee arthroplasty. This trial is registered with Trial Registry Number NCT02756715 (http://clinicaltrials.gov).

Pharmacological preconditioning protects from ischemia/reperfusion-induced apoptosis by modulating Bcl-xL expression through a ROS-dependent mechanism

Myocardial ischemia/reperfusion (I/R) injury is a frequent perioperative threat, with numerous strategies developed to limit and/or prevent it. One interesting axis of research is the anesthetic preconditioning (APc) agent's hypothesis (such as sevoflurane, SEV). However, APc's mode of action is still poorly understood and volatile anesthetics used as preconditioning agents are often not well suited in clinical practice. Here, in vitro using H9C2 cells lines (in myeloblast state or differentiated toward cardiomyocytes) and in vivo in mice, we identified that SEV-induced APc is mediated by a mild induction of reactive oxygen species (ROS) that activates Akt and induces the expression of the anti-apoptotic protein B-cell lymphoma-extra large (Bcl-xL), therefore protecting cardiomyocytes from I/R-induced death. Furthermore, we extended these results to human cardiomyocytes (derived from induced pluripotent stem - IPS - cells). Importantly, we demonstrated that this protective signaling pathway induced by SEV could be stimulated using the antidiabetic agent metformin (MET), suggesting the preconditioning properties of MET. Altogether, our study identified a signaling pathway allowing APc of cardiac injuries as well as a rational for the use of MET as a pharmacological preconditioning agent to prevent I/R injuries.

Propofol-based total intravenous anesthesia decreases the incidence of postoperative nausea and vomiting without affecting flap survival in free flap breast reconstruction

Background

Postoperative nausea and vomiting (PONV) may cause undesirable effects after microsurgical breast reconstruction. Although total intravenous anesthesia (TIVA) with propofol has been demonstrated to be effective in reducing PONV, it has not been assessed in autologous free flap breast reconstruction. The purpose of this study was to investigate the antiemetic prophylaxis effect and safety of TIVA in microvascular breast reconstruction.

Methods

Eighty-three patients undergoing microsurgical breast reconstruction with propofol (31 patients) or sevoflurane (52 patients) were retrospectively reviewed. The incidence of PONV was assessed at 2, 6, and 24 hours after surgery. Mean arterial blood pressure (MAP) was compared at T₁ (after flap elevation but before transfer), T₂ (15 minutes after revascularization), and T₃ (at the end of surgery).

Results

The incidence of nausea was significantly reduced in the TIVA group over 0 to 2 hours period (P=0.017), and over 2 to 6 hours period (P=0.033). The incidence of vomiting was significantly reduced in the TIVA group over 0 to 2 hours period (P=0.006), and over 2 to 6 hours period (P=0.005). MAP was higher in the TIVA group at T₁ (P=0.018), T₂ (P=0.005), and T₃ (P=0.007). The incidence of flap failure was similar between the two groups (P=0.373).

Conclusions

Compared with sevoflurane maintaining anesthesia, propofol-based TIVA improves PONV with less fluctuation of MAP, and did not affect flap survival.

Sevoflurane Pre-conditioning Ameliorates Diabetic Myocardial Ischemia/Reperfusion Injury Via Differential Regulation of p38 and ERK

Diabetes mellitus (DM) significantly increases myocardial ischemia/reperfusion (MI/R) injury. During DM, cardioprotection induced by conventional pre-conditioning (PreCon) is decreased due to impaired AMP-activated protein kinase (AMPK) signaling. The current study investigated whether PreCon with inhaled anesthetic sevoflurane (SF-PreCon) remains cardioprotective during DM, and identified the involved mechanisms. Normal diet (ND) and high-fat diet (HFD)-induced DM mice were randomized into control and SF-PreCon (3 cycles of 15-minute period exposures to 2% sevoflurane) groups before MI/R. SF-PreCon markedly reduced MI/R injury in DM mice, as evidenced by improved cardiac function (increased LVEF and ±Dp/dt), decreased infarct size, and decreased apoptosis. To determine the relevant role of AMPK, the effect of SF-PreCon was determined in cardiac-specific AMPKα2 dominant negative expressing mice (AMPK-DN). SF-PreCon decreased MI/R injury in AMPK-DN mice. To explore the molecular mechanisms responsible for SF-PreCon mediated cardioprotection in DM mice, cell survival molecules were screened. Interestingly, in ND mice, SF-PreCon significantly reduced MI/R-induced activation of p38, a pro-death MAPK, without altering ERK and JNK. In DM and AMPK-DN mice, the inhibitory effect of SF-PreCon upon p38 activation was significantly blunted. However, SF-PreCon significantly increased phosphorylation of ERK1/2, a pro-survival MAPK in DM and AMPK-DN mice. We demonstrate that SF-PreCon protects the heart via AMPK-dependent inhibition of pro-death MAPK in ND mice. However, SF-PreCon exerts cardioprotective action via AMPK-independent activation of a pro-survival MAPK member in DM mice. SF-PreCon may be beneficial compared to conventional PreCon in diabetes or clinical scenarios in which AMPK signaling is impaired.

Sevoflurane Ameliorates Myocardial Cell Injury by Inducing Autophagy via the Deacetylation of LC3 by SIRT1

Misfolded and aberrant proteins have been found to be associated with myocardial cell injury. Thus, increased clearance of misfolded or aggregated proteins via autophagy might be a potential option in preventing myocardial cell injury. Sevoflurane may ameliorate myocardial cell injury by affecting sirtuin 1- (SIRT1-) mediated autophagy. Rat models with myocardial cell injury were induced by limb ischemia reperfusion. The model rats received different treatments: sevoflurane, nicotinamide, and autophagy inhibitor 3-methyladenine (3-MA). Autophagy was observed by SEM. The levels of SIRT1 and microtubule-associated protein 1A/1B-light chain 3 (LC3) were measured. Present findings demonstrated that limb ischemia reperfusion induced autophagy. Sevoflurane increased the level of SIRT1, which deacetylated LC3 and further increased autophagic rates. On the other hand, the autophagy was inhibited by sevoflurane and or the inhibitors of SIRT1 and LC3. Present results demonstrated a novel molecular mechanism by which sevoflurane induced autophagy by increasing the level of SIRT1 and reducing the acetylation of LC3.