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.

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.

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.

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.

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.

A quality improvement project to reduce hypothermia in infants undergoing MRI scanning.

BACKGROUND: Hypothermia prevention strategies during MRI scanning under general anesthesia in infants may pose a challenge due to the MRI scanner's technical constraints. Previous studies have demonstrated conflicting results related to increase or decrease in post-scan temperatures in children. We noted occurrences of post-scan hypothermia in anesthetized infants despite the use of routine passive warming techniques. OBJECTIVE: The aims of our quality improvement project were (a) to identify variables associated with post-scan hypothermia in infants and (b) to develop and implement processes to reduce occurrence of hypothermia in neonatal intensive care unit (NICU) infants undergoing MRI. MATERIALS AND METHODS: One hundred sixty-four infants undergoing MRI scanning were prospectively audited for post-scan body temperatures. A multidisciplinary team identified potential variables associated with post-scan hypothermia and designed preventative strategies: protocol development, risk factor identification, vigilance and use of a vacuum immobilizer. Another audit was performed, specifically focusing on NICU infants. RESULTS: In the initial phase, we found that younger age (P = 0.002), lower weight (P = 0.005), lower pre-scan temperature (P < 0.01), primary anesthetic technique with propofol (P < 0.01), advanced airway devices (P = 0.02) and being in the NICU (P < 0.01) were associated with higher odds for developing post-scan decrease in body temperature. Quality improvement processes decreased the occurrence of hypothermia in NICU infants undergoing MRI scanning from 65% to 18% (95% confidence interval for the difference, 26-70%, P < 0.001). CONCLUSION: Several variables, including being in the NICU, are associated with a decrease in post-scan temperature in infants undergoing MRI scanning under sedation/general anesthesia. Implementation of strategies to prevent hypothermia in infants may be challenging in the high-risk MRI environment. We were able to minimize this problem in clinical practice by applying quality improvement principles.

Effects of Hypothermic Cardiopulmonary Bypass on Internal Jugular Bulb Venous Oxygen Saturation, Cerebral Oxygen Saturation, and Bispectral Index in Pediatric Patients Undergoing Cardiac Surgery: A Prospective Study.

The objective of this study was to evaluate the effect of hypothermic cardiopulmonary bypass (CPB) on cerebral oxygen saturation (rSO2), internal jugular bulb venous oxygen saturation (SjvO2), mixed venous oxygen saturation (SvO2), and bispectral index (BIS) used to monitor cerebral oxygen balance in pediatric patients.Sixty American Society of Anesthesiologists Class II-III patients aged 1 to 4 years old with congenital heart disease scheduled for elective cardiac surgery were included in this study. Temperature, BIS, rSO2, mean arterial pressure, central venous pressure, cerebral perfusion pressure (CPP), and hematocrit were recorded. Internal jugular bulb venous oxygen saturation and SvO2 were obtained from blood gas analysis at the time points: after induction of anesthesia (T0), beginning of CPB (T1), ascending aortic occlusion (T2), 20 minutes after initiating CPB (T3), coronary reperfusion (T4), separation from CPB (T5), and at the end of operation (T6). The effect of hypothermia or changes in CPP on rSO2, SjvO2, SvO2, and BIS were analyzed.Compared with postinduction baseline values, rSO2 significantly decreased at all-time points: onset of extracorporeal circulation, ascending aortic occlusion, 20 minutes after CPB initiation, coronary reperfusion, and separation from CPB (P < 0.05). Compared with measurements made following induction of anesthesia, SjvO2 significantly increased with initiation of CPB, ascending aortic occlusion, 20 minutes after initiating CPB, coronary reperfusion, and separation from CPB (P < 0.05). Compared with induction of anesthesia, BIS significantly decreased with the onset of CPB, aortic cross clamping, 20 minutes after initiating CPB, and coronary reperfusion (P < 0.05). Bispectral index increased following separation from CPB. There was no significant change in SvO2 during cardiopulmonary bypass (P > 0.05). Correlation analysis demonstrated that rSO2 was positively related to CPP (r = 0.687, P = 0.000), with a low linear correlation to temperature (r = 0.453, P = 0.000). Internal jugular bulb venous oxygen saturation was negatively related to temperature (r = -0.689, P = 0.000). Bispectral index was positively related to both temperature (r = 0.824, P = 0.000) and CPP (r = 0.782, P = 0.000). Cerebral oxygen saturation had a positive linear correlation with CPP and a low linear correlation to temperature. Internal jugular bulb venous oxygen saturation had a negative linear correlation to temperature.Pre-and and early postbypass periods are vulnerable times for adequate cerebral oxygenation. Anesthetic management must aim to optimize the supply and demand relationship.

Effects of Ginkgo biloba extract on cerebral oxygen and glucose metabolism in elderly patients with pre-existing cerebral ischemia.

SPECIFIC AIM: Cerebral injury caused by hypoperfusion during the perioperative period is one of the main causes of disability and death in patients after major surgery. No effective protective or preventative strategies have been identified. This study was designed to evaluate the effects of Ginkgo biloba extract on cerebral oxygen and glucose metabolism in elderly patients with known, pre-existing cerebral ischemia. METHODS: Sixty ASA (American Society of Anesthesiologists) II-III patients, diagnosed with vertebral artery ischemia by transcranial Doppler ultrasonography (TCD), and scheduled for elective total hip replacement surgery, were enrolled in the study. They were randomly allocated to receive either 1mg/kg Ginkgo biloba extract (G group n=30) or normal saline (D group n=30) after induction of anesthesia. Blood samples were collected from radial artery and jugular venous bulb catheters for blood gas analysis and determination of glucose and lactate concentrations preoperatively, before surgical incision, at the end of surgery, and on post-op day 1. Arterial O2 content (CaO2), jugular venous O2 content (CjvO2), arteriovenous O2 content difference (Da-jvO2), cerebral oxygen extraction rate (CEO2), and arteriovenous glucose and lactate content differences (Da-jvGlu and Da-jvLac) were calculated. RESULTS: There were no significant differences in CaO2 or Da-jvGlu during surgery between groups (p>0.05). However, the Ginkgo group had higher CjvO2, internal jugular venous oxygen saturation (SjvO2) and lower CEO2, Da-jvO2 and Da-jvLac at the end of surgery (T2) and on post-op day 1 (T3) than those in the control group (p<0.05). CONCLUSION: Ginkgo biloba extract can improve cerebral oxygen supply, decrease cerebral oxygen extraction rate and consumption, and help maintain the balance between cerebral oxygen supply and consumption. It has no effect, however, on cerebral glucose metabolism in elderly patients with known, pre-existing cerebral ischemia.

Transversus abdominis plane block as the primary anesthetic for laparotomy.

Elderly patients undergoing emergency intra-abdominal surgery are at high risk for morbidity and mortality. The risks and side-effects associated with intubation and mechanical ventilation or neuraxial anesthesia must be balanced against the need to maintain hemodynamic stability while maximizing pain control. Providing anesthesia and analgesia without either of these techniques can be a difficult prospect. We present three cases of ultrasound guided transversus abdominis plane (TAP) block as the primary anesthetic for laparotomy in elderly patients with multiple comorbidities. We have demonstrated the efficacy of and recommend the use of TAP blocks as the primary surgical anesthetic in a selected group of patients undergoing laparotomy.

Does dexmedetomidine have a cardiac protective effect during non-cardiac surgery? A randomised controlled trial.

This study was designed to determine the effects of dexmedetomidine on perioperative myocardial injury by observing peripheral circulatory changes in response to tracheal intubation and extubation, myocardial enzyme levels, myocardial ischaemia improvements, cardiovascular adverse events and cytokines in patients with coronary heart disease (CHD) undergoing non-cardiac surgery. This study was a prospective, randomized, double-blind trial. Eighty patients having CHD were scheduled for elective hip-replacement surgery and randomly allocated to receive a loading dose of 1 µg/kg dexmedetomidine followed by a 0.2 µg/kg per h infusion (Dex group; n = 40) or normal saline (control group; n = 40). Systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, rate-pressure product and changes in ST-T segment on the electrocardiogram were recorded every 5 min during surgery. Serum creatine kinase-MB (CK-MB), cardiac troponin I (cTnI), glycogen phosphorylase BB (GP-BB), interleukin (IL)-6 and tumour necrosis factor (TNF)-α protein levels were determined preoperatively, at the end of surgery and 12 and 24 h after surgery. The improvement rate of myocardial ischaemia was higher in the Dex than control group (87.5% vs 32.5%, respectively; P < 0.05). In addition, the Dex group had lower serum CK-MB, IL-6, cTnI and GP-BB concentrations than the control group (P < 0.05). There was no significance difference in TNF-α between the two groups (P > 0.05). Dexmedetomidine can reduce myocardial injury and cytokine levels in patients with CHD undergoing non-cardiac surgery.

Transient unilateral brachial plexopathy and partial Horner's syndrome following spinal anesthesia for cesarean section.

A healthy 21-year-old primigravida presented for elective cesarean section. At 45 min after intrathecal (IT) injection of bupivacaine, morphine and fentanyl she developed dysphagia, right sided facial droop, ptosis and ulnar nerve weakness. This constellation of signs and symptoms resolved 2 h later. Based on the time course and laterality of her symptoms, as well as the pharmacologic properties of spinal opioids, we believe her symptoms can be attributed to the IT administration of fentanyl.

Coronary responses to cold air inhalation following afferent and efferent blockade.

Cardiac ischemia and angina pectoris are commonly experienced during exertion in a cold environment. In the current study we tested the hypotheses that oropharyngeal afferent blockade (i.e., local anesthesia of the upper airway with lidocaine) as well as systemic ß-adrenergic receptor blockade (i.e., intravenous propranolol) would improve the balance between myocardial oxygen supply and demand in response to the combined stimulus of cold air inhalation (-15 to -30°C) and isometric handgrip exercise (Cold + Grip). Young healthy subjects underwent Cold + Grip following lidocaine, propranolol, and control (no drug). Heart rate, blood pressure, and coronary blood flow velocity (CBV, from Doppler echocardiography) were continuously measured. Rate-pressure product (RPP) was calculated, and changes from baseline were compared between treatments. The change in RPP at the end of Cold + Grip was not different between lidocaine (2,441 ± 376) and control conditions (3,159 ± 626); CBV responses were also not different between treatments. With propranolol, heart rate (8 ± 1 vs. 14 ± 3 beats/min) and RPP responses to Cold + Grip were significantly attenuated. However, at peak exercise propranolol also resulted in a smaller ΔCBV (1.4 ± 0.8 vs. 5.3 ± 1.4 cm/s, P = 0.035), such that the relationship between coronary flow and cardiac metabolism was impaired under propranolol (0.43 ± 0.37 vs. 2.1 ± 0.63 arbitrary units). These data suggest that cold air breathing and isometric exercise significantly influence efferent control of coronary blood flow. Additionally, ß-adrenergic vasodilation may play a significant role in coronary regulation during exercise.

The use of a double-lumen central venous catheter for airway management in pediatric patients undergoing laryngeal papillomatosis surgery.

PURPOSE: To evaluate the efficacy and safety of a spontaneous ventilation anesthesia technique with insufflation of oxygen and volatile agent through a double-lumen central venous catheter (DLCVC) in pediatric patients undergoing suspension laryngoscopic surgery for laryngeal papillomatosis. METHODS: Thirty-six pediatric patients with laryngeal papillomatosis undergoing suspension laryngoscopic surgery were anesthetized with oxygen and volatile anesthetic insufflation while spontaneously breathing. Anesthesia was induced by inhalation of 8% sevoflurane in oxygen by mask. Atropine, dexamethasone, lidocaine, and midazolam were administered intravenously. The tip of a 7Fr DLCVC was inserted below the glottis after placement of the laryngoscope and establishing suspension. Anesthesia was maintained with insufflation of 4-6% sevoflurane and oxygen with a total fresh gas flow of 6 l·min(-1) through the 14G (larger lumen) of the DLCVC. Endtidal carbon dioxide tension (PetCO2) was monitored using the other lumen of the DLCVC, which was connected to the CO2 sampling line. Duration of the procedure as well as total anesthesia time was recorded. Electrocardiography (ECG), heart rate (HR), mean arterial pressure (MAP), oxygen saturation (SpO2), and PetCO2 were also monitored. Arterial blood was sampled for blood gas analysis including pH, PaO2 , PaCO2 , and actual base excess (ABE). Complications, including intraoperative patient movement, hypoxemia (SpO2 < 95% during oxygen insufflation), nausea, vomiting, bronchospasm, and arrhythmias, were recorded. RESULTS: There was a significant increase in PetCO2 and PaCO2 (P values <0.05) as well as a decrease in ABE, pH, and PaO2 (P values <0.05) in samples collected before and after surgery. MAP, HR, and SpO2 after surgery were not significantly different from after induction values (P values >0.05). During surgery, SpO2 < 95% in three cases and body movements in three cases were observed. No patient had any other of the complications previously described. Furthermore, no postsurgical endotracheal intubation was needed in any patient. CONCLUSION: After establishing an adequate depth of anesthesia, a spontaneous ventilation anesthesia technique with insufflation of oxygen and volatile agent through a DLCVC is feasible in pediatric patients undergoing suspension laryngoscopic surgery for laryngeal papillomatosis.