It was not a fall, but fainting: A case report of pulmonary embolism.

We encountered a case of pulmonary thromboembolism, in which an 84-year-old woman (body weight 62 kg, height 150 cm) fell in the ward eight days after upper arm surgery. In this event, she had fractured her ankle and hit her head, with transient loss of consciousness. She needed surgery for the ankle fracture under general anesthesia. Her anesthesia course was unstable, with heart rate varying between 95 and 140 bpm, systolic blood pressure between 70 and 110 mmHg, and oxygen saturation between 92 and 98%. Immediately after reversing anesthesia, we performed bedside ultrasound and diagnosed acute pulmonary embolism in the operating room. We assume that the event was not a simple fall, but pulmonary embolism-related fainting (syncope). This case and recent reports provide two lessons: (1) cases of syncope among postoperative patients may be reported as simple falls in the safety surveillance of hospitals, and (2) ultrasonography at the bedside plays a pivotal role in the diagnosis of pulmonary embolism in perioperative settings.

Cuff Failure of Spiral-Filled Polyvinyl Chloride Endotracheal Tube Immediately after Tracheal Intubation Using a Channeled Videolaryngoscope (Pentax Airway Scope).

We report on a case of mechanical damage to the spiral-filled polyvinyl chloride endotracheal tube that occurred shortly after tracheal intubation using a channeled videolaryngoscope (Pentax airway scope). We also found this problem in two other cases among 350 neurosurgery patients over the past 5 years. Prior to intubation, we did not observe any defect in the cuff. However, the cuff could not be filled with air immediately after the intubation. Anesthesiologists should be aware that, during tracheal intubation using an airway scope, friction between the endotracheal tube and inner surface of the introducer might result in sudden rupture of the cuff.

Successful perioperative management of a patient with erythropoietin-producing uterine myoma.

BACKGROUND: Erythropoietin-producing uterine myoma can cause various complications such as arterial or venous thrombosis and bleeding. Therefore, caution is required in the anesthetic management of affected patients. CASE PRESENTATION: A 57-year-old female was suspected to have an erythropoietin-producing uterine myoma and was scheduled to undergo an abdominal total hysterectomy and bilateral salpingo-oophorectomy. Preoperative levels of hemoglobin and erythropoietin were 21.9 g/dl (normal 11.5-15 g/dl) and 23.2 IU/ml (normal 4.2-23.7 IU/ml), respectively. Preoperative phlebotomy and isovolemic hemodilution were performed to prevent arterial and venous thrombosis, following previous evidence that a hemoglobin level < 16 g/dl reduces the occurrence of polycythemia vera-related complications. Fondaparinux 2.5 mg was subcutaneously injected once daily after the operation, resulting in a good perioperative course without major complications. CONCLUSION: Herein, we have described a successful perioperative management of a patient with erythropoietin-producing uterine myoma. Our findings in this case suggest that this combination of antithrombotic therapies can facilitate anesthetic management of patients with this disease.

In-hospital mortality does not increase in patients aged over 85 years after hip fracture surgery. A retrospective observational study in a Japanese tertiary hospital.

INTRODUCTION: Hip fracture is a common and serious orthopedic injury among the geriatric population, necessitating surgical treatment. We tested whether age is a significant risk factor for in-hospital mortality after surgery in this retrospective cohort study and, further, analyzed causes and pattern of death in those patients. METHODS: We queried the electronic hospital records of in-patients aged over 75 years who had undergone hip fracture surgery from the start of 2010 to the end of August 2016 in our hospital, a tertiary hospital on the main island of Japan. The extracted data included patient ID, age, gender, location of fracture, ASA-PS scores, types of anesthesia, durations of anesthesia and surgery, days of hospital stay after surgery, and outcomes at hospital discharge including in-hospital death. The extracted data were divided into two groups based on the patient's age at the time of surgery: the aged group (age of < 85) and the advanced age group (age of ≥ 85 years), and we compared patient characteristics and management variables and discharge disposition between the two groups. RESULTS: Eight hundred four patient records were extracted (360 in the aged and 444 in the advanced age groups). Although a smaller proportion of patients in the advanced age group could be discharged home, all-cause in-hospital mortality was also similar between the two groups (1.9 and 1.6%, aged and advanced age groups, respectively). Six patients died from advanced cancer, and five patients died of pneumonia resulting from aspiration. CONCLUSIONS: The results of this study suggest that age is not a clinically significant risk factor for in-hospital mortality. The possibility decreasing in-hospital mortality exists in identifying patients at risk of aspiration and preventing it.

Anesthetic Management of a Patient With Antimuscle-Specific Kinase Antibody-Positive Myasthenia Gravis Undergoing an Open Cholecystectomy: A Case Report.

Myasthenia gravis (MG) is an autoimmune disease characterized by the production of antibodies against the acetylcholine receptor, muscle-specific kinase (MuSK), or other proteins at the neuromuscular junction. MG with antibodies against MuSK (MuSK-MG) has been described recently. Here, we report the first case of anesthetic management of a patient with MuSK-MG undergoing an open cholecystectomy. In our case, propofol and remifentanil-based anesthesia were used for successful management without using muscle relaxants. Patients with MuSK-MG have predominantly ocular, bulbar, and respiratory symptoms that may increase the risk of aspiration. Anesthesiologists need to pay attention to perioperative respiratory failure and respiratory crisis.

Impaired glycinergic synaptic transmission and enhanced inflammatory pain in mice with reduced expression of vesicular GABA transporter (VGAT).

Loading of GABA and glycine into synaptic vesicles via the vesicular GABA transporter (VGAT) is an essential step in inhibitory neurotransmission. As a result of the evidence linking alterations in GABAergic and/or glycinergic neurotransmission to various pain disorders, we investigated the possible influence of down-regulation of VGAT on pain threshold and behavioral responses in mice. The phenotypes of heterozygous VGAT knockout [VGAT(+/-)] mice were compared with wild-type (WT) mice using behavioral assays. In addition, GABAergic and glycinergic miniature inhibitory postsynaptic currents (mIPSCs) were recorded in dorsal horn neurons. Western blot analysis confirmed significant reduction of VGAT protein levels in VGAT(+/-) mice. However, high-performance liquid chromatography revealed that glutamate, GABA, and glycine contents in the whole brain and spinal cord were normal in VGAT(+/-) mice. Behavioral analysis of VGAT(+/-) mice showed unchanged motor coordination, anxiety, memory performance, and anesthetic sensitivity to propofol and ketamine, although thermal nociception and inflammatory pain were enhanced. Patch-clamp recordings revealed that the frequency and amplitude of glycinergic mIPSCs in lamina II neurons were reduced in VGAT(+/-) mice. Genotype differences in glycinergic mIPSCs were more evident during sustained stimulation by solutions with high potassium levels, suggesting that the estimated size of the readily releasable pool of glycine-containing vesicles was reduced in VGAT(+/-) mice. These results provide genetic, behavioral, and electrophysiological evidence that VGAT-mediated inhibitory drive alters very specific forms of sensory processing: those related to pain processing. More close examination will be needed to verify the possibility of VGAT as a new therapeutic target for the treatment of inflammatory pain.

[Roles of glutamatergic and GABAergic nervous system in hypnotic and analgesic actions of general anesthetics].

General anesthetic-induced unresponsiveness covers a spectrum of different behavioral components, namely, (1) amnesia, (2) sedation/hypnosis, (3) analgesia, and (4) immobility. At the molecular and cellular level, anesthetic drugs have been shown to have effects on a wide rage of putative targets, such as ligand-gated ion channels (GABA, glycine, NMDA receptors), other ion channels (K+, Na+, Ca2+), and other intracellular functions. This mini-review summarizes recent topics in this research field focusing on NMDA and GABA receptors. Although ketamine blocks NMDA receptors as an open channel blocker, it has been recently shown that ketamine inhibits hyperpolarization-activated cationic currents (J Neurosci 2009) and also enhances GABA-induced currents in alpha6 GABA receptors (J Neurosci 2008). In addition, ketamine (0.5 microM, 24h) produces loss of phenotype of fast-spiking interneurons via NADPH-oxidase (Science 2007). These data suggests that ketamine have multiple molecular targets in hypnotic, analgesic and amnestic actions. Propofol has been shown to enhance two types of GABAergic inhibition: a synaptic form (phasic inhibition) regulating neural excitability via the activation of postsynaptic GABAA receptors by intermittent GABA release from presynaptic terminals ; and a persistent tonic form (tonic inhibition) generated by continuous activation of extrasynaptic GABAA receptors by low concentrations of ambient GABA. However, the roles of tonic inhibition in hypnotic actions of isoflurane and sevoflurane are less clear. In this mini review, the relative contributions of extrasynaptic GABA receptors in behavioral actions of isoflurane and sevoflurane will be discussed.

The influence of manipulations to alter ambient GABA concentrations on the hypnotic and immobilizing actions produced by sevoflurane, propofol, and midazolam.

Recent studies have suggested that extrasynaptic GABA(A) receptors, which contribute tonic conductance, are important targets for general anesthetics. We tested the hypothesis that manipulations designed to alter ambient GABA concentrations (tonic conductance) would affect hypnotic (as indicated by loss of righting reflex, LORR) and immobilizing (as indicated by loss of tail-pinch withdrawal reflex, LTWR) actions of sevoflurane, propofol, and midazolam. Two manipulations studied were 1) the genetic absence of glutamate decarboxylase (GAD) 65 gene (GAD65-/-), which purportedly reduced ambient GABA concentrations, and 2) the pharmacological manipulation of GABA uptake using GABA transporter inhibitor (NO-711). The influence of these manipulations on cellular and behavioral responses to the anesthetics was studied using behavioral and electrophysiological assays. HPLC revealed that GABA levels in GAD65-/- mice were reduced in the brain (76.7% of WT) and spinal cord (68.5% of WT). GAD65-/- mice showed a significant reduction in the duration of LORR and LTWR produced by propofol and midazolam, but not sevoflurane. NO-711 (3 mg/kg, ip) enhanced the duration of LORR and LTWR by propofol and midazolam, but not sevoflurane. Patch-clamp recordings revealed that sevoflurane (0.23 mM) slightly enhanced the amplitude of tonic GABA current in the frontal cortical neurons; however, these effects were not strong enough to alter discharge properties of cortical neurons. These results demonstrate that ambient GABA concentration is an important determinant of the hypnotic and immobilizing actions of propofol and midazolam in mice, whereas manipulations of ambient GABA concentrations minimally alter cellular and behavioral responses to sevoflurane.

Alignment-retainable nitrogenation of cylindrical carbon nanotubes by thermal reaction with ammonia following UV oxidation: chemical alteration effects on electrical conductivity.

Cylindrical carbon nanotubes (CNTs) pretreated by UV irradiation were able to react with NH(3) to give nitrogen-containing CNTs without destroying their vertically aligned morphology. This process provided incorporation of nitrogen mostly at pyridinic and pyrrolic sites and promoted disordering, which was correlated with decreased electrical conductivity of CNT yarns.

Regurgitant leak from the area between the stent post and the sewing ring of a stented bovine pericardial valve implanted in the aortic valve position.

Biologic valves can sometimes have a small closure or leakage backflow jet originating from the central coaptation point. This is physiologic regurgitation that usually only requires monitoring, and not treatment.Another non-central transvalvular leakage is occasionally seen in both porcine and pericardial valves and originates from the base of the stent post. Typically, it spontaneously decreases or even disappears by the end of the surgery, after administration of protamine. This leak, however, needs to be distinguished from abnormal paravalvular leakages, especially if the regurgitation is relatively large, as this may require an extra cardio-pulmonary bypass (CPB) run.In our case with stented bovine pericardial valves, detailed transesophageal echocardiography (TEE) examination immediately after CPB showed oblique and turbulent flow, which originated from the base of the stent post and flowed toward the anterior mitral leaflet. An extra CPB run, assessment of the cause of the leakage, and restoration if necessary, might have been required if the leakage did not improve or was exacerbated, because contact of the anterior mitral valve leaflet by the oblique flow is associated with the risks of infective endocarditis and hemolysis. Detailed TEE examination accurately delineated the site of the leak, which was subsequently found to originate from the site between the anterior stent post and the sewing ring. The leakage in this case was classified as non-paravalvular, non-central leakage within the sewing ring. Accurate diagnosis of the leakage by intra-operative TEE led to the decision to administer protamine and to adopt a wait-and-watch approach.

[Removal of sevoflurane and nitrous oxide from waste anesthetic gases by using Anesclean, the system for treating waste anesthetic gases].

BACKGROUND: The system for treating waste anesthetic gases, Anesclean, has been developed recently. This system can collect volatile anesthetics from waste anesthetic gases, and then decompose nitrous oxide (N2O) into N2 and O2 immediately. The purpose of this study was to investigate the efficacy of this treating system, Anesclean, on removal of greenhouse effect gases in our university hospital. METHODS: The concentrations of sevoflurane and N2O from an outlet of the system were measured using gas-chromatography. The total amount of sevoflurane consumed in the past two years and the amount of sevoflurane collected by Anesclean in the same period were measured to calculate collection rate. RESULTS: The concentrations of anesthetics in the outlet were very low, suggesting that the system works effectively. The amount of sevoflurane consumed was 606.51, and 245.31 was collected. Thus, calculated collection rate was 40.4%, indicating that approximately 60% of sevoflurane is not collected in our current situation. CONCLUSIONS: The waste anesthetic gas treating system, Anesclean, was effective to some degree in collection of sevoflurane and decomposition of N2O. However, in order to increase collection rate of sevoflurane, we need to pay more attention to minimize gas leak during anesthetic procedure.

Monoamine-dependent, opioid-independent antihypersensitivity effects of intrathecally administered milnacipran, a serotonin noradrenaline reuptake inhibitor, in a postoperative pain model in rats.

The neurotransmitters serotonin (5-HT) and noradrenaline (NA) have important roles in suppressing nociceptive transmission in the spinal cord. In the present study, we determined the efficacy and nature of the antihypersensitivity effects of milnacipran, a 5-HT and NA reuptake inhibitor (SNRI), in the spinal cord in a rat model of postoperative pain. Sprague-Dawley rats were used in all experiments. An incision was made on the plantar aspect of the hind paw. Mechanical hypersensitivity was measured by determining the withdrawal threshold to von Frey filaments applied to the paw. Drugs were administered intrathecally 24 h after paw incision. Microdialysis studies of the dorsal horn of the lumbar spinal cord were also performed to measure 5-HT and NA levels after systemic injection of milnacipran. Milnacipran (1-30 microg) produced dose-dependent antihypersensitivity effects. The effect lasted 6 h after the 30-microg injection. Doses of 30 microg or less produced no abnormal behavior. The peak antihypersensitivity effect of 10 microg of milnacipran was blocked by intrathecal pretreatment with antagonists of the alpha(2)-adrenoceptor (idazoxan; 30 microg) or 5-HT receptors (methysergide; 30 microg). Intrathecal pretreatment with 30 microg of naloxone, a mu-opioid receptor antagonist, did not reverse the effect of milnacipran. Isobolographic analysis indicated antinociceptive synergism between milnacipran and morphine. Microdialysis studies revealed that milnacipran increased both 5-HT and NA levels in the spinal dorsal horn. These findings suggest that the antihypersensitivity effect of intrathecal milnacipran in the postoperative pain model is monoamine-mediated. Combined administration of an SNRI with morphine might be a promising treatment to suppress postoperative hypersensitivity.

Anti-agglomerating effect in vertically aligned carbon nanotubes derived by antisolvent precipitation of naphthalene.

We developed a novel anti-agglomeration method that enables preservation of the vertical alignment of carbon nanotubes (CNTs) during desiccation of wet CNTs by utilizing antisolvent precipitation and sublimation of naphthalene (Nap). Moreover, we succeeded in depositing Pt nanoparticles onto CNTs without collapse of the vertically aligned morphology by this method.

Tracheal intubation with the PENTAX-AWS (airway scope) reduces changes of hemodynamic responses and bispectral index scores compared with the Macintosh laryngoscope.

The PENTAX-AWS, a novel video laryngoscope, allows indirect visualization of the vocal cords on a color monitor display and enables tracheal intubation without upward lifting force required to expose the glottis. This study compared hemodynamic changes, bispectral index scores, and postoperative sore throat before and after laryngoscopy between the Macintosh laryngoscope and the airway scope (AWS). Forty patients (American Society of Anesthesiologists I-II), randomly assigned to either the Macintosh group (n=20 each) or AWS group, were enrolled in this study. After induction with fentanyl (0.001 mg/kg), propofol (1.5 mg/kg), and vecuronium (0.1 mg/kg), tracheal intubation was performed. Hemodynamic parameters were compared before and after laryngoscopy. Patients were assessed for postoperative sore throat at 24 hours after extubation. No significant differences in patient characteristics were observed between groups. Significant increases in both systolic blood pressure (P<0.05 vs. baseline) and heart rate (P<0.001 vs. baseline) after laryngoscopy were seen using the Macintosh blade, whereas the AWS provided no increases in either parameter. The AWS also caused a lesser increase in bispectral index (P<0.05 vs. Macintosh group). Postoperative sore throat was observed in both groups (2 out of 20 in AWS and 6 out of 20 in Macintosh), although this difference did not reach statistically significant level (P=0.23). In conclusion, the AWS offers a reduced degree of hemodynamic stimulation compared with the Macintosh laryngoscope, suggesting that tracheal intubation with the AWS is advantageous to prevent hypertension after laryngoscopy in neurosurgical patients.

Thermal hyperalgesia via supraspinal mechanisms in mice lacking glutamate decarboxylase 65.

Gamma-aminobutyric acid, which is synthesized by two isoforms of glutamate decarboxylase (GAD), inhibits the transfer of nociceptive signals from primary afferent fibers to the central nervous system. However, the roles of a 65-kDa isoform of GAD (GAD65)-mediated GABA in nociceptive processing are less clear. This study tested whether partial reductions in GABAergic inhibitory tone by GAD65 gene knockout [GAD65(-/-)] would contribute to the regulation of pain threshold in mice. Experiments were performed on male wild-type (WT) mice and GAD65(-/-) mice. Acute nociception and inflammatory pain tests were compared between WT mice and GAD65(-/-) mice. GABA(A) receptor-mediated inhibitory postsynaptic currents were also examined by use of the whole-cell patch-clamp method in somatosensory cortical neurons in brain slices. In the hot plate test, which reflects supraspinal sensory integration, a significant reduction in the latency was observed for GAD65(-/-) mice. Intraperitoneal administration of the GABA transporter 1 inhibitor, 1-[2-[[(diphenylmethylene)imino]oxy]ethyl]-1,2,5,6-tetrahydro-3-pyridinecarboxylic acid hydrochloride (C(21)H(22)N(2)O(3).HCl; NO-711), dose-dependently prolonged the latency in both genotypes, suggesting that GABA concentration contributes to acute thermal nociception. However, there was no genotype difference in responses to the tail-immersion test or the von Frey test, indicating that spinal reflex and mechanical nociception are kept intact in GAD65(-/-) mice. There was no genotype difference in responses to chemical inflammatory nociception (formalin test and carrageenan test). Although properties of the phasic component of inhibitory postsynaptic currents were similar in both genotypes, tonic inhibition was significantly reduced in GAD65(-/-) mice. These results support the hypothesis that GAD65-mediated GABA synthesis plays relatively small but significant roles in nociceptive processing via supraspinal mechanisms.

[Perioperative management of a case of myasthenic crisis with unexpected difficult airway].

Myasthenia gravis (MG) is an autoimmune disorder characterized by loss of acetylcholine receptors (AChR) due primarily to the production of anti-AChR autoantibodies. We report here a case of anesthetic management of MG patient associated with difficult airway. A 58-year-old woman, 150 cm in height and 43 kg in weight, was scheduled for elective thymectomy. Preoperative evaluation using Mallampati classification, mouth opening, and thyromental distance did not predict airway difficulty. After anesthetic induction with propofol and sevoflurane, mask ventilation was performed easily. However, tracheal intubation using Macintosh type laryngoscope was unexpectedly difficult. This was largely due to transformation of the epiglottis and thereby Cormack classification was grade III. Tracheal intubation was eventually performed by blindly with a gum elastic bougie after some trials. Postoperative day two, she was diagnosed as postoperative myasthenic crisis and needed re-intubation. We used fiberscope intubation for her because it was difficult to intubate."Cannot intubate, cannot ventilate (CICV)" scenario is very rare, but it sometimes leads to serious morbidity and mortality. Therefore, we need to deal with this emergency situation by using a variety of equipments and techniques. Careful examination of the airway and a carefully considered plan for re-intubation are prerequisites for this type of surgery.

Altered responses to propofol, but not ketamine, in mice deficient in the 65-kilodalton isoform of glutamate decarboxylase.

GABA is synthesized by two isoforms of glutamate decarboxylase (GAD), GAD65, and GAD67. However, the relative contributions of GAD65-mediated GABA synthesis to the in vivo actions of anesthetics remain unknown. To address this issue, we used mice deficient in the 65-kDa isoform of GAD and tested the hypothesis that partial reduction of GABA content in GAD65-deficient mice [GAD65(-/-)] would contribute to hypnotic and immobilizing actions of the anesthetics. The open field test, loss of righting reflex (LORR), loss of tail-pinch withdrawal response (LTWR), and locomotor activity were compared between wild-type (WT) mice and GAD65(-/-) mice. Effects of general anesthetics on both phasic and tonic GABAergic currents were examined using the patch-clamp method in frontal cortex pyramidal neurons in brain slices. The duration of propofol (100 mg/kg i.p.)-induced LORR and the duration of propofol (150 mg/kg i.p.)-induced LTWR in GAD65(-/-) mice were significantly reduced compared with WT mice. In contrast, no difference was seen for ketamine. Preinjection of the GABA transporter 1 inhibitor, NO-711 (C(21)H(22)N(2)O(3).HCl) (0.75 mg/kg i.p.), reinstated diminished actions of propofol in GAD65(-/-) mice. Cortical pyramidal neurons in GAD65(-/-) mice had smaller tonic conductances, and propofol-induced enhancement of tonic inhibition was smaller than in WT mice, suggesting that genotype differences in GAD65-mediated GABAergic inhibitory tone may be, at least in part, a cellular basis underlying behavioral differences. In conclusion, GAD65(-/-) mice show a diminished response to propofol, but not ketamine, indicating that GAD65-mediated GABA synthesis plays an important role in hypnotic and immobilizing actions of propofol.