Marie-Hélène Tremblay

Cervical spine motion during tracheal intubation with manual in-line stabilization: direct laryngoscopy versus GlideScope videolaryngoscopy.

BACKGROUND: The optimal tracheal intubation technique for patients with potential cervical (C) spine injury remains controversial. Using continuous cinefluoroscopy, we conducted a prospective study comparing C-spine movement during intubation using direct laryngoscopy (DL) or GlideScope® videolaryngoscopy (GVL), with uninterrupted manual in-line stabilization of the head by an assistant. METHODS: Twenty patients without C-spine pathology were studied. After induction of general anesthesia with neuromuscular blockade, both DL and GVL were performed on every patient in random order. Cinefluoroscopic images of C-spine movement during GVL and DL were acquired and divided into four stages: a baseline image before airway manipulation, glottic visualization, insertion of the endotracheal tube into the glottis, and tracheal intubation. Peak segmental motion from the occiput to C5 was measured offline for each patient and each stage, averages were calculated, and movements induced by each instrument were compared using a two-way ANOVA. Also studied were the proportion of patients with occiput-C1 rotation exceeding 10, 15, or 20 degrees, and the quality of glottic visualization. RESULTS: No significant difference was found between DL and GVL regarding average segmental spine movement at any level (P values between 0.22 and 0.70). During both techniques, motion was mainly an extension concentrated in the rostral C-spine and occurred predominantly during glottic visualization. The proportion of patients with occiput-C1 extension of more than 10, 15, or 20 degrees was not significantly different. Glottic visualization was significantly better with GVL compared with DL. CONCLUSION: During intubation under general anesthesia with neuromuscular blockade and manual in-line stabilization, the use of GVL produced better glottic visualization, but did not significantly decrease movement of the nonpathologic C-spine when compared with DL.

Poor visualization during direct laryngoscopy and high upper lip bite test score are predictors of difficult intubation with the GlideScope videolaryngoscope.

BACKGROUND:The GlideScope® videolaryngoscope allows equal or superior glottic visualization compared with direct laryngoscopy, but predictive features for difficult GlideScope intubation have not been identified. We undertook this prospective study to identify patient characteristics associated with difficult GlideScope intubation. METHODS:Demographic and morphometric factors were recorded preoperatively for 400 patients undergoing anesthesia with endotracheal intubation. After induction, direct laryngoscopy was performed in all patients to assess the Cormack and Lehane grade of glottic visualization followed by GlideScope intubation. The number of attempts and time needed for intubation were recorded. Univariate and multivariate analyses were performed to identify the characteristics associated with difficult GlideScope intubation. RESULTS:Intubation required 1, 2, and 3 attempts in 342, 48, and 9 participants, respectively, with one failure. Mean time for intubation was 21 ± 14 s. After univariate analysis, the following characteristics were significantly correlated (P < 0.05) with longer time to intubate and/or multiple attempts: older age, male sex, history of snoring, high Mallampati class, small mouth opening, short sternothyroid and manubriomental distances, large neck circumference, high upper lip bite test score, and high Cormack and Lehane grade during direct laryngoscopy. However, after introducing these variables in nominal logistic and proportional hazard multiple regression models, only high Cormack and Lehane grade during direct laryngoscopy, high upper lip bite test score, and short sternothyroid distance were significantly associated with multiple attempts or lengthier intubations. CONCLUSION:Despite a high success rate, intubation with the GlideScope is likely to be more challenging in patients with high Cormack and Lehane grade during direct laryngoscopy, high upper lip bite test score, or short sternothyroid distance.

Effect of mutations K97A and E128A on RNA binding and self assembly of papaya mosaic potexvirus coat protein

Papaya mosaic potexvirus (PapMV) coat protein (CP) was expressed (CPΔN5) in Escherichia coli and showed to self assemble into nucleocapsid like particles (NLPs). Twenty per cent of the purified protein was found as NLPs of 50 nm in length and 80% was found as a multimer of 450 kDa (20 subunits) arranged in a disk. Two mutants in the RNA binding domain of the PapMV CP, K97A and E128A showed interesting properties. The proteins of both mutants could be easily purified and CD spectra of these proteins showed secondary and tertiary structures similar to the WT protein. The mutant K97A was unable to self assemble and bind RNA. On the contrary, the mutant E128A showed an improved affinity for RNA and self assembled more efficiently in NLPs. E128A NLPs were longer (150 nm) than the recombinant CPΔN5 and 100% percent of the protein was found as NLPs in bacteria. E128A NLPs were more resistant to digestion by trypsin than the CPΔN5 but were more sensitive to denaturation by heat. We discuss the possible role of K97 and E128 in the assembly of PapMV.

Hemoglobin levels and transfusions in neurocritically ill patients: a systematic review of comparative studies

IntroductionAccumulating evidence suggests that, in critically ill patients, a lower hemoglobin transfusion threshold is safe. However, the optimal hemoglobin level and associated transfusion threshold remain unknown in neurocritically ill patients.MethodsWe conducted a systematic review of comparative studies (randomized and nonrandomized) to evaluate the effect of hemoglobin levels on mortality, neurologic function, intensive care unit (ICU) and hospital length of stay, duration of mechanical ventilation, and multiple organ failure in adult and pediatric neurocritically ill patients. We searched MEDLINE, The Cochrane Central Register of Controlled Trials, Embase, Web of Knowledge, and Google Scholar. Studies focusing on any neurocritical care conditions were included. Data are presented by using odds ratios for dichotomous outcomes and mean differences for continuous outcomes.ResultsAmong 4,310 retrieved records, six studies met inclusion criteria (n = 537). Four studies were conducted in traumatic brain injury (TBI), one in subarachnoid hemorrhage (SAH), and one in a mixed population of neurocritically ill patients. The minimal hemoglobin levels or transfusion thresholds ranged from 7 to 10 g/dl in the lower-Hb groups and from 9.3 to 11.5 g/dl in the higher-Hb groups. Three studies had a low risk of bias, and three had a high risk of bias. No effect was observed on mortality, duration of mechanical ventilation, or multiple organ failure. In studies reporting on length of stay (n = 4), one reported a significant shorter ICU stay (mean, -11.4 days (95% confidence interval, -16.1 to -6.7)), and one, a shorter hospital stay (mean, -5.7 days (-10.3 to -1.1)) in the lower-Hb groups, whereas the other two found no significant association.ConclusionsWe found insufficient evidence to confirm or refute a difference in effect between lower- and higher-Hb groups in neurocritically ill patients. Considering the lack of evidence regarding long-term neurologic functional outcomes and the high risk of bias of half the studies, no recommendation can be made regarding which hemoglobin level to target and which associated transfusion strategy (restrictive or liberal) to favor in neurocritically ill patients.

INFLAMMATION-INDUCED LEUKOCYTE ACCUMULATION IN INJURED SKELETAL MUSCLE : ROLE OF MAST CELLS

Inflammation consequent to muscle damage is characterized by an accumulation of leukocytes. Our aim in this study was to determine whether mast cells can modulate inflammation‐induced leukocyte trafficking. One approach consisted of giving rats a mast cell–degranulating agent, CMP 48/80, prior to a protocol of lengthening contractions inducing inflammation without neutrophil accumulation; in parallel, other rats were given the mast cell–stabilizing agent, cromolyn, prior to injecting muscle with bupivacaine, which induces neutrophil accumulation. Damage was evaluated through measurement of contractile force and inflammation using histochemical and immunohistochemichal methods. Stimulation with CMP 48/80 increased the proportion of degranulated mast cells significantly and neutrophil accumulation occurred with lengthening contractions. With bupivacaine, accumulation of neutrophils decreased by 70% when degranulation was inhibited. These results indicate that mast cells are important in the process governing leukocyte trafficking in skeletal muscle trauma and that targeting their inhibition could be an attractive alternative for control of inflammation. Muscle Nerve, 2008

Mast cell tryptase stimulates myoblast proliferation; a mechanism relying on protease-activated receptor-2 and cyclooxygenase-2

BackgroundMast cells contribute to tissue repair in fibrous tissues by stimulating proliferation of fibroblasts through the release of tryptase which activates protease-activated receptor-2 (PAR-2). The possibility that a tryptase/PAR-2 signaling pathway exists in skeletal muscle cell has never been investigated. The aim of this study was to evaluate whether tryptase can stimulate myoblast proliferation and determine the downstream cascade.MethodsProliferation of L6 rat skeletal myoblasts stimulated with PAR-2 agonists (tryptase, trypsin and SLIGKV) was assessed. The specificity of the tryptase effect was evaluated with a specific inhibitor, APC-366. Western blot analyses were used to evaluate the expression and functionality of PAR-2 receptor and to assess the expression of COX-2. COX-2 activity was evaluated with a commercial activity assay kit and by measurement of PGF2α production. Proliferation assays were also performed in presence of different prostaglandins (PGs).ResultsTryptase increased L6 myoblast proliferation by 35% above control group and this effect was completely inhibited by APC-366. We confirmed the expression of PAR-2 receptor in vivo in skeletal muscle cells and in satellite cells and in vitro in L6 cells, where PAR-2 was found to be functional. Trypsin and SLIGKV increased L6 cells proliferation by 76% and 26% above control, respectively. COX-2 activity was increased following stimulation with PAR-2 agonist but its expression remained unchanged. Inhibition of COX-2 activity by NS-398 abolished the stimulation of cell proliferation induced by tryptase and trypsin. Finally, 15-deoxy-Δ-12,14-prostaglandin J2 (15Δ-PGJ2), a product of COX-2-derived prostaglandin D2, stimulated myoblast proliferation, but not PGE2 and PGF2α.ConclusionsTaken together, our data show that tryptase can stimulate myoblast proliferation and this effect is part of a signaling cascade dependent on PAR-2 activation and on the downstream activation of COX-2.

Simulation-based assessment of anesthesiology residents’ competence: development and implementation of the Canadian National Anesthesiology Simulation Curriculum (CanNASC)

The specialty of anesthesiology will soon adopt the Competence By Design (CBD) approach to residency education developed by the Royal College of Physicians and Surgeons of Canada (RCPSC). A foundational component of CBD is frequent and contextualized assessment of trainees. In 2013, the RCPSC Anesthesiology Specialty Committee assembled a group of simulation educators, representing each of the 17 Canadian anesthesiology residency programs, to form the Canadian National Anesthesiology Simulation Curriculum (CanNASC) Task Force. The goals were to develop, implement, and evaluate a set of consensus-driven standardized mannequin-based simulation scenarios that every trainee must complete satisfactorily prior to completion of anesthesiology residency and certification. Curriculum development followed Kern’s principles and was accomplished via monthly teleconferences and annual face-to-face meetings. The development and implementation processes included the following key elements: 1) Curriculum needs assessment: 368 of 958 invitees (38.4%) responded to a national survey resulting in 64 suggested scenario topics. Use of a modified Delphi technique resulted in seven important and technically feasible scenarios. 2) Scenario development: All scenarios have learning objectives from the National Curriculum for Canadian Anesthesiology Residency. Standardized scenario templates were created, and the content was refined and piloted. 3) Assessment: A validated Global Rating Scale (GRS) is the primary assessment tool, informed by using scenario-specific checklists (created via a modified Delphi technique) and the Anesthesia Non-Technical Skills GRS. 4) Implementation: Standardized implementation guidelines, pre-brief/debrief documents, and rater training videos, guide, and commentary were generated. National implementation of the scenarios and program evaluation is currently underway. It is highly feasible to achieve specialty-based consensus on the elements of a national simulation-based curriculum. Our process could be adapted by any specialty interested in implementing a simulation-based curriculum incorporating competency-based assessment on a national scale.RésuméLa spécialité de l’anesthésiologie adoptera prochainement une approche de La compétence par conception (CPC) à la formation en résidence, mise au point par le Collège royal des médecins et chirurgiens du Canada (CRMCC). Une des compétences fondamentales de la CPC est l’évaluation fréquente et contextualisée des stagiaires. En 2013, le Comité de spécialité en anesthésiologie du CRMCC a réuni un groupe d’enseignants en simulation, chacun représentant l’un des 17 programmes canadiens de résidence en anesthésiologie, afin de créer le Groupe de travail sur le Programme national de simulation en anesthésiologie au Canada (CanNASC). Les objectifs de ce groupe de travail étaient de mettre au point, mettre en œuvre et évaluer un ensemble de scénarios de simulation sur mannequin; ces scénarios seraient standardisés et approuvés par consensus, et chaque stagiaire devrait les compléter de façon satisfaisante avant de pouvoir terminer sa résidence et sa certification en anesthésiologie. La mise au point du programme s’est fondée sur les principes de Kern et s’est faite par l’entremise de téléconférences mensuelles et de réunions annuelles en personne. Les éléments clés suivants ont fait partie des processus de mise au point et de mise en œuvre: 1) Évaluation des besoins du programme: 368 personnes sur 958 personnes invitées (38,4%) ont répondu à un sondage national qui a donné jour à 64 sujets de scénario proposés. Grâce à une méthode de Delphes modifiée, sept scénarios importants et réalisables d’un point de vue technique ont vu le jour. 2) Mise au point des scénarios: Tous les scénarios comportent des objectifs d’apprentissage tirés du Programme national pour la résidence en anesthésiologie au Canada. Des modèles de scénario standardisés ont été créés, et le contenu a été peaufiné et soumis à des essais pilotes. 3) Évaluation: Une Échelle d’évaluation globale (ÉÉG) validée constitue le principal outil d’évaluation; elle s’appuie sur des listes de contrôle spécifiques à chaque scénario (créées grâce à une méthode de Delphes modifiées) et l’EEG des compétences non techniques en anesthésie. 4) Mise en œuvre: Des directives de mise en œuvre standardisées, des documents préparatoires et de rétroaction, et des vidéos de formation, un guide et des commentaires destinés aux évaluateurs ont été générés. La mise en œuvre nationale des scénarios et l’évaluation du programme est en cours. Il est tout à fait possible d’atteindre un consensus dans la spécialité quant aux éléments d’un programme national de simulation. Notre processus peut être adapté à chaque spécialité intéressée à mettre en œuvre un programme fondé sur la simulation et intégrant une évaluation fondée sur les compétences à l’échelle nationale.

Survey of neuroanesthesia fellowships in Canada

To the Editor, In the recent article by Kahn et al, we read with interest that 70% of Canadian anesthesia residents plan to pursue fellowship training. A recent survey of the membership of the Society of Neuroanesthesia and Critical Care (SNACC) demonstrated interest in pursuing accreditation, following which SNACC developed curriculum guidelines for neuroanesthesia fellowships. Although neuroanesthesia fellowships are offered in Canada, the prevalence and content are unknown. Given the lack of standardization of goals or objectives for neuroanesthesia fellowships in Canada, the content and structure may vary significantly. In addition, the support for accreditation in Canada is unclear. Our objectives were to determine the prevalence and characteristics of Canadian neuroanesthesia fellowships, identify barriers to the establishment of programs, and determine the level of support for standardization and accreditation of these fellowships. Following approval from the University of British Columbia Behavioral Research Ethics Board (H1501640), we conducted a cross-sectional survey of all anesthesia departments with membership in the Association of Canadian University Departments of Anesthesia. We developed a web-based survey (http:// www.simplesurvey.com/) and e-mailed the survey link to the Neuroanesthesia Program Director identified on the respective university anesthesia department website between September 22, 2015 and November 2, 2015. If a Program Director was not identified, we instead contacted the Department Chair. We included questions about the presence and characteristics of a neuroanesthesia fellowship program, support for standardization of goals and objectives, and accreditation of neuroanesthesia fellowship programs in Canada (Appendix; available as Electronic Supplementary Material). Of the 17 anesthesia departments contacted, ten (59%) responded, including five of the eight (63%) identified as having a neuroanesthesia fellowship on the Internet. Of note, 50% of the responding departments did not have a fellowship program. Among those with a fellowship, most had been active for more than ten years (80%, n = 4). All of the fellowships lasted one year and typically included a mix of clinical exposure to neuroanesthesia (two to three days/week) and research/academic activities (one day/ week), although the clinical exposure varied (Table 1). The programs were designed to accommodate one (60%), two (20%), or four (20%) fellows per year. Program Directors thought that the number of applicants each year was either constant (n = 2) or increasing (n = 3). Barriers to program development were most frequently insufficient faculty (40%), low departmental interest (30%), low clinical volume (30%), and remuneration (30%). Although 80% (n = 4) of Fellowship Directors thought the development of Electronic supplementary material The online version of this article (doi:10.1007/s12630-016-0751-6) contains supplementary material, which is available to authorized users.