General anesthetic agents induce neurotoxicity through oligodendrocytes in the developing brain.

General anesthetic agents can impact brain function through interactions with neurons and their effects on glial cells. Oligodendrocytes perform essential roles in the central nervous system, including myelin sheath formation, axonal metabolism, and neuroplasticity regulation. They are particularly vulnerable to the effects of general anesthetic agents resulting in impaired proliferation, differentiation, and apoptosis. Neurologists are increasingly interested in the effects of general anesthetic agents on oligodendrocytes. These agents not only act on the surface receptors of oligodendrocytes to elicit neuroinflammation through modulation of signaling pathways, but also disrupt metabolic processes and alter the expression of genes involved in oligodendrocyte development and function. In this review, we summarize the effects of general anesthetic agents on oligodendrocytes. We anticipate that future research will continue to explore these effects and develop strategies to decrease the incidence of adverse reactions associated with the use of general anesthetic agents.

Effect of General Anesthetic Agents on Microglia.

The effects of general anesthetic agents (GAAs) on microglia and their potential neurotoxicity have attracted the attention of neuroscientists. Microglia play important roles in the inflammatory process and in neuromodulation of the central nervous system. Microglia-mediated neuroinflammation is a key mechanism of neurocognitive dysfunction during the perioperative period. Microglial activation by GAAs induces anti-inflammatory and pro-inflammatory effects in microglia, suggesting that GAAs play a dual role in the mechanism of postoperative cognitive dysfunction. Understanding of the mechanisms by which GAAs regulate microglia may help to reduce the incidence of postoperative adverse effects. Here, we review the actions of GAAs on microglia and the consequent changes in microglial function. We summarize clinical and animal studies associating microglia with general anesthesia and describe how GAAs interact with neurons via microglia to further explore the mechanisms of action of GAAs in the nervous system.

Nd:YAG laser posterior capsulotomy performed under general anesthesia in the sitting position: a novel approach.

We present a novel approach for performing an Nd:YAG laser posterior capsulotomy under general anesthesia with the patent in a seated position. We illustrate this approach in 2 cases, a young child and an adult patient with developmental delay. This technique may facilitate YAG capsulotomy in patients who cannot sit for the procedure.

How to do a thoracoscopic-assisted oesophagectomy with oesophagogastric anastomosis using a circular stapler.

Thoracoscopic mobilization of the oesophagus during oesophagectomy has many advantages over the traditional open approach including less blood loss, reduced pulmonary complications and shorter hospital stay. Minimally invasive intrathoracic oesophagogastric anastomosis can be technically challenging, with several different techniques described in the literature. Here, we describe a nuanced technique to perform an intracorporeal anastomosis using a circular stapler.

A Multidisciplinary Approach to Expedite Surgical Hip Fracture Care.

INTRODUCTION: In 2014, we implemented a geriatric hip fracture patient care pathway at our institution which was designed to improve outcomes and decrease time to surgery. MATERIALS AND METHODS: We analyzed retrospective data from 463 patients, aged greater than 50, who had surgical treatment for a closed hip fracture due to a low-energy injury between 2013 and 2016 at an academic institution. Objective outcome measures included time to surgery, mortality rate, and total hospital length of stay. Our primary goal was to decrease the time to surgery for definitive fracture fixation to within 24 hours of admission to the hospital for patients who were medically fit for surgery. RESULTS: We implemented a multidisciplinary, collaborative approach to address the needs of this specific patient population. Prior to implementing the pathway in 2013, our baseline time to surgery within 24 hours was 74.67%. After implementation, we had incremental yearly increases in the percentage of patients operated on within 24 hours, 82.31% in 2014 (P = .10) and 84.14% in 2015 (P = .04). During the study period, our overall time to surgery was reduced by 27% with an initial average of 20.22 hours in 2013, decreasing to 15.33 hours in 2014, and 14.63 hours in 2015. Our mortality rate at 1 year was 16% in 2013, 17% in 2014, and 15% in 2015. CONCLUSION: With implementation of the pathway, we were able to expedite surgical care for our patients and demonstrate a 10% improvement in the percentage of patients able to have surgery within 24 hours over a 3-year period. Our mortality and hospital length of stay, however, remained the same. Through this collaborative process and system standardization, we believe we have significantly improved not only direct patient care but their overall hospital experience. We continue to make improvements in our pathway.

Anesthetic Management of Elderly Patients With Down Syndrome: A Case Report.

In 1930, the life expectancy of patients with Down syndrome was about 10 years; today, their life expectancy is more than 60 years. With aging, there is an increased need for anesthesia and surgery. There is, however, no published information regarding the anesthetic management of older adults with Down syndrome. In this report, we described the anesthetic management of a 50-year-old woman with Down syndrome undergoing major cervical spine surgery. Components of the anesthetic that we thought would be difficult such as intravenous line placement and endotracheal intubation were accomplished without difficulty. Despite our best efforts, our patient nevertheless experienced both emergence delirium and postoperative vomiting. We advocate that physicians, advanced practice providers, and registered nurses be aware of the unique perianesthesia needs of older patients with Down syndrome.

The Effects of Leukocyte Filtration on Cell Salvaged Autologous Blood Transfusion on Lung Function and Lung Inflammatory and Oxidative Stress Reactions in Elderly Patients Undergoing Lumbar Spinal Surgery.

BACKGROUND: This study was designed to investigate the effects of leukocyte filtration of autologous salvaged blood on lung function, lung inflammatory reaction, and oxidative stress reaction in elderly patients undergoing lumbar spinal surgery. MATERIALS AND METHODS: Sixty elderly patients undergoing lumbar spinal surgery were randomly divided into 2 groups: Leukocyte Filter group and Control group. Serum levels of inflammatory markers including white blood cell and polymorphonuclear count, neutrophil elastase, serum surfactant protein A, methane dicarboxylic aldehyde, superoxide dismutase, interleukin (IL)-6, IL-8, tumor necrosis factor-α, and respiratory function markers including dynamic respiratory system compliance, oxygenation index, and respiratory index were measured immediately before induction of anesthesia (T0), immediately before blood transfusion (T1), and 1 (T2), 6 (T3), and 12 hours (T4) after end of blood transfusion. RESULTS: The Leukocyte Filter group had higher dynamic respiratory system compliance at T2, oxygenation index at T2 and T3, respiratory index and superoxide dismutase at T2, T3, and T4 than those in the Control group (P<0.05). The Leukocyte Filter group had lower white blood cell, polymorphonuclear count, neutrophil elastase, serum surfactant protein A, methane dicarboxylic aldehyde, IL-6, IL-8, and tumor necrosis factor-α at T2, T3, and T4 than those in the Control group (P<0.05). There were no significant differences in adverse reactions related specifically to blood transfusion or postoperative respiratory complications within 72 hours. CONCLUSIONS: Salvaged autologous blood leukocyte filtration can improve ventilation, promote gas exchange and oxygenation, and inhibit lung inflammatory and oxidative stress reactions in elderly patients undergoing lumbar spinal surgery.

Role of autophagy in sevoflurane-induced neurotoxicity in neonatal rat hippocampal cells.

BACKGROUND: Sevoflurane has been extensively employed for induction and maintenance of general anesthesia. The effect of sevoflurane-induced apoptosis in developmental neurotoxicity has been appreciated for some time now, but the underlying mechanism of developmental neurotoxicity has not been established. The aim of our study is to evaluate the role of autophagy in sevoflurane-induced neurotoxicity through observing changes in the levels of autophagy in hippocampal neurons after exposure to sevoflurane. METHODS/MATERIALS: Primary cultured hippocampus neuronal cells were exposed to either 3.4% sevoflurane for 1 h (S1h group), 3 h (S3h group), 5 h (S5h group), or air (control group). We observed changes in autophagy proteins Beclin-1, LC3-II, p62, and Beclin-1mRNA, LC3mRNA and SQSTM1mRNA using Western Blot and QRT-PCR. We also determined the expression of LC3 using immunofluorescence staining, monitored the occurrence of autophagy using RFP-GFP-LC3 expression plasmid transient transfected hippocampal neuronal cells, detected the expression of LC3-II using siRNA Knockdown Beclin-1 and Atg5, and determined changes in cell apoptosis using Annexin V/PI staining and flow cytometry. RESULTS: After primary cultured hippocampal neuronal cells were exposed to 3.4% sevoflurane for 5 h, the expression level of Beclin-1 and LC3-II increased and p62 decreased in Western blotting. The expression of Beclin-1mRNA, LC3mRNA increased and SQSTM1mRNA decreased in QRT-PCR. LC3 increased with cell immunofluorescence staining, LC3 expression plasmid increased after mRFP-GFP-LC3 expression plasmid transient transfection and LC3-II decreased after transfection with siRNA Beclin-1 and siRNA Atg5. The apoptosis rate of primary cultured hippocampal neuronal cells increased in Annexin V/PI staining and flow cytometry analysis. CONCLUSION: This study demonstrates that sevoflurane may induce hippocampal neuron autophagy in primary cultured hippocampal neuronal cell and that Beclin-1 and Atg5 are involved in the process of sevoflurane-induced autophagy. Exposure of sevoflurane may not only induce autophagy of hippocampal neurons but also activate the apoptosis of hippocampal neurons. Autophagy may play an important role in sevoflurane-induced neurotoxicity in primary cultured hippocampal neuronal cells.

Bedside ultrasound assessment of gastric content in children noncompliant with preoperative fasting guidelines: Is it time to include this in our practice?

Ultrasound assessment of gastric contents and volume is gaining popularity in adults and children. At present, a preoperative verbal check is used to determine the fasting status. Due to fear of delay or cancellation of surgery, parents may not disclose noncompliance with fasting guidelines. Pulmonary aspiration of gastric contents is a potential cause of morbidity and mortality. Ultrasound assessment of gastric contents is noninvasive and easy to learn. We present a series of three cases to demonstrate how the use of ultrasound to assess gastric contents in children can provide an objective means for decision-making and impact anesthetic management when preoperative fasting status is uncertain.

Efficacy of US-guided transversus abdominis plane block and rectus sheath block with ropivacaine and dexmedetomidine in elderly high-risk patients.

BACKGROUND: This study was designed to evaluate the effectiveness and safety of ultrasound-guided transversus abdominis plane (TAP) and rectus sheath (RS) blocks with ropivacaine and dexmedetomidine in elderly, high-risk patients undergoing emergency abdominal surgery. METHODS: Sixty elderly patients undergoing emergency abdominal surgery receiving both bilateral ultrasound-guided TAP and RS blocks were randomly divided into two groups: R+D (10 mL of 0.25% ropivacaine+0.5µg/kg dexmedetomidine) and R (10 mL of 0.25% ropivacaine). Pain scores (at rest and with movement) and overall analgesia satisfaction were assessed. The total amount of sufentanil administered postoperatively during the first 24 h, duration of sensory blockade, first time and total number of patient-controlled intravenous analgesia (PCIA) pump activations on the first postoperative day were recorded. RESULTS: The duration of sensory blockade and the first time to PCIA pump activation in the R+D group were longer than that of the R group (P<0.05). The total number of PCIA pump activations on the first postoperative day as well as the total amount of sufentanil administered during the first 24 h in R+D group were less than in the R group (P<0.05). VAS scores at rest and during activity in the R+D group were lower than those in the R group at 2, 6, and 12 h after surgery (P<0.05). CONCLUSIONS: Ultrasound-guided TAP and RS blocks with ropivacaine and dexmedetomidine are more effective in promoting block effect, prolonging the duration of analgesia, reducing postoperative pain in elderly high-risk patients undergoing emergency abdominal surgery.

Anesthetic Agents and Neuronal Autophagy. What We Know and What We Don't.

BACKGROUND: Ethanol is known to have both γ-Aminobutyric acid agonist and Nmethyl- D-aspartate antagonist characteristics similar to commonly used volatile anesthetic agents. Recent evidence demonstrates that autophagy can reduce the development of ethanol induced neurotoxicity. Recent studies have found that general anesthesia can cause longterm impairment of both mitochondrial morphogenesis and synaptic transmission in the developing rat brain, both of which are accompanied by enhanced autophagy activity. Autophagy may play an important role in general anesthetic mediated neurotoxicity. METHODS: This review outlines the role of autophagy in the development of anesthetic related neurotoxicity and includes an explanation of the role of autophagy in neuronal cell survival and death, the relationship between anesthetic agents and neuronal autophagy, possible molecular and cellular mechanisms underlying general anesthetic agent induced activation of neuronal autophagy in the developing brain, and potential therapeutic approaches aimed at modulating autophagic pathways. RESULTS: In a time- and concentration-dependent pattern, general anesthetic agents can disrupt intracellular calcium homeostasis which enhances both autophagy and apoptosis activation. The degree of neural cell injury may be ultimately determined by the interplay between autophagy and apoptosis. It appears likely that the increase in calcium flux associated with some anesthetic agents disrupts lysosomal function. This results in an over-activation of endosomal- lysosomal trafficking causing mitochondrial damage, reactive oxygen species upregulation, and lipid peroxidation. CONCLUSION: Autophagy may play a role in the development of anesthetic related neurotoxicity. Understanding this may lead to strategies or therapies aimed at preventing or ameliorating general anesthetic agent mediated neurotoxicity.

A manikin-based evaluation of a teaching modality for ultrasound-guided infraclavicular longitudinal in-plane axillary vein cannulation in comparison with ultrasound-guided internal jugular vein cannulation: A pilot study.

BACKGROUND AND AIMS: Ultrasound (US)-guided infraclavicular approach for axillary vein (AXV) cannulation has gained popularity in the last decade. MATERIAL AND METHODS: In this manikin study, we evaluated the feasibility of a training model for teaching AXV cannulation. The learning pattern with this technique was assessed among attending anesthesiologists and residents in training. RESULTS: A faster learning pattern was observed for AXV cannulation among the attending anesthesiologists and residents in training, irrespective of their prior experience with US. It was evident that a training modality for this technique could be easily established with a phantom model and that hands-on training motivates trainees to embrace US-based central venous cannulation. CONCLUSION: A teaching model for US-guided infraclavicular longitudinal in-plane AXV cannulation can be established using a phantom model. A focused educational program would result in an appreciable change in preference in embracing US-based cannulation techniques among residents.

African Americans have a lower prevalence of portal vein thrombosis at the time of liver transplantation.

BACKGROUND: Perioperative vascular thrombotic events in patients undergoing liver transplantation (LT) are associated with significant morbidity and mortality. METHODS: In this retrospective UNOS database analysis, we evaluated the prevalence of portal vein thrombosis (PVT) and factors contributing to PVT development in different ethnic groups. RESULTS: Of the 47 953 LT performed between 2002 and 2015, we identified 3642 cases of PVT. African Americans (AA) had a significantly lower prevalence of PVT compared to other ethnic groups (p = 0.0001). Multivariable regression analysis confirmed that AA were less likely than other ethnicities to have PVT (OR = 0.6). AA cohort was more likely to have infectious or autoimmune causes of liver failure (OR = 1.6, 1.7 respectively) as well as higher creatinine and INR compared to other groups (OR = 1.6, 1.3 respectively). AA's were less likely to have encephalopathy, ascites, or variceal bleeding, which might indicate lower portal pressures. AA's were listed for LT later than other ethnicities and had both a lower functional status and higher MELD score at the time of registration. DISCUSSION: AA's had a significantly lower prevalence of preoperative PVT despite having a greater number of factors predisposing to thrombosis. This predisposition should be considered before instituting perioperative antithrombotic therapy.

Successful Liver Transplant Complicated by Severe Portopulmonary Hypertension After an Initial Aborted Attempt: Case Report and Review of Treatment Options.

Good right ventricular function and responsiveness to vasodilator therapy are the most important prerequisites for successful liver transplant in patients with portopulmonary hypertension. A patient with portopulmonary hypertension and good right ventricular function presented for deceased-donor liver transplant. Pulmonary arterial pressure was controlled with epoprostenol and sildenafil preoperatively. After anesthesia induction, pulmonary arterial pressure increased significantly and the procedure was aborted. Additional medical treatment included aggressive vasodilator therapy and the transplant was successfully performed 1 month later. During the procedure, elevations in pulmonary arterial pressure responded to a combination of inhaled nitric oxide, intravenous milrinone and nitroglycerin, and optimization of mechanical ventilation.

A Prospective Randomized Study to Evaluate a New Learning Tool for Ultrasound-Guided Regional Anesthesia.

Objective: To evaluate the effectiveness of a new learning tool for needle insertion accuracy skills during a simulated ultrasound-guided regional anesthesia procedure. Methods: Thirty participants were included in this randomized controlled study. After viewing a prerecorded video of a single, discreet, ultrasound-guided regional anesthesia task, all participants performed the same task three consecutive times (pretest), and needle insertion accuracy skills in a phantom model were recorded as baseline. All participants were then randomized into two groups, experimental and control. The experimental group practiced the task using the new tool, designed with two video cameras, a monitor, and an ultrasound machine where the images from the ultrasound and video of hand movements are viewed simultaneously on the monitor. The control group practiced the task without using the new tool. After the practice session, both groups repeated the same task and were evaluated in the same manner as in the pretest. Results: Participants in both group groups had similar baseline characteristics with respect to previous experience with ultrasound-guided regional anesthesia procedures. The experimental group had significantly better needle insertion accuracy scores ( P < 0.01) than the control group. Using the new learning tool, inexperienced participants had better needle insertion accuracy scores ( P < 0.01) compared with experienced participants. Conclusions: This study demonstrates that the use of this new learning tool results in short-term improvement in hand-eye, motor, and basic needle insertion skills during a simulated ultrasound-guided regional anesthesia procedure vs traditional practice methods. Skill improvement was greater in novices compared with experienced participants.

Esmolol infusion versus propranolol infusion: effects on heart rate and blood pressure in healthy volunteers.

Despite its widespread clinical use, the ß1-adrenergic receptor antagonist esmolol hydrochloride is not commonly used in human physiology research, and the effective dose of esmolol (compared with the nonselective ß-blocker propranolol) is unclear. In four separate studies we used cycle ergometry exercise and infusions of isoproterenol and epinephrine to test the heart rate (HR)-lowering effect of esmolol compared with propranolol and saline in healthy humans. In cohort 1, both esmolol (ΔHR 57 ± 6 beats/min) and propranolol (ΔHR 56 ± 7 beats/min) attenuated exercise tachycardia compared with saline (ΔHR 88 ± 17 beats/min). In cohort 2, we found that the HR response to exercise was similar at 5 min (ΔHR 57 ± 9 beats/min) and 60 min (ΔHR 55 ± 9 beats/min) after initiation of the esmolol maintenance infusion. In cohort 3, we confirmed that the HR-lowering effect of esmolol disappeared 45 min after termination of the maintenance infusion. In cohort 4, changes in femoral blood flow and hematological parameters in response to epinephrine infusion were not different between esmolol and saline infusion, indicating that our esmolol infusion paradigm does not block ß2-receptors. Collectively, our data indicate that infusion of ~160 mg of esmolol (range 110-200 mg in the 5 min before exercise) acutely and selectively blocks ß1-receptors in healthy humans. Additionally, ß1-receptors remain blocked 60 min later if a maintenance infusion of ~0.2 mg·kg total body mass-1·min-1 continues. The current data lay the foundation for future studies to evaluate ß1- vs. ß2-receptor control of the circulation in humans.NEW & NOTEWORTHY We used cycle ergometry exercise and infusions of isoproterenol and epinephrine to test the heart rate-lowering effect of esmolol compared with propranolol and saline in healthy humans. Collectively, our data indicate that infusion of ~160 mg of esmolol (range 110-200 mg in the 5 min before exercise) acutely and selectively blocks ß1-adrenergic receptors. These infusion parameters can be used in future experiments to evaluate ß1- vs. ß2-receptor control of the circulation in humans.

Hepatic resection is associated with reduced postoperative opioid requirement.

BACKGROUND AND AIMS: Postoperative pain can significantly affect surgical outcomes. As opioid metabolism is liver-dependent, any reduction in hepatic volume can lead to increased opioid concentrations in the blood. The hypothesis of this retrospective study was that patients undergoing open hepatic resection would require less opioid for pain management than those undergoing open pancreaticoduodenectomy. MATERIAL AND METHODS: Data from 79 adult patients who underwent open liver resection and eighty patients who underwent open pancreaticoduodenectomy at our medical center between January 01, 2010 and June 30, 2013 were analyzed. All patients received both general and neuraxial anesthesia. Postoperatively, patients were managed with a combination of epidural and patient-controlled analgesia. Pain scores and amount of opioids administered (morphine equivalents) were compared. A multivariate lineal regression was performed to determine predictors of opioid requirement. RESULTS: No significant differences in pain scores were found at any time point between groups. Significantly more opioid was administered to patients having pancreaticoduodenectomy than those having a hepatic resection at time points: Intraoperative (P = 0.006), first 48 h postoperatively (P = 0.001), and the entire length of stay (LOS) (P = 0.002). Statistical significance was confirmed after controlling for age, sex, body mass index, and American Society of Anesthesiologists physical status classification (adjusted P = 0.006). Total hospital LOS was significantly longer after pancreaticoduodenectomy (P = 0.03). A multivariate lineal regression demonstrated a lower opioid consumption in the hepatic resection group (P = 0.03), but there was no difference in opioid use based on the type of hepatic resection. CONCLUSION: Patients undergoing open hepatic resection had a significantly lower opioid requirement in comparison with patients undergoing open pancreaticoduodenectomy. A multicenter prospective evaluation should be performed to confirm these findings.