Characterizing intubation practices in response to the COVID-19 pandemic: a survey of the Canadian COVID-19 Emergency Department Rapid Response Network (CCEDRRN) sites.

OBJECTIVE: The risk of occupational exposure during endotracheal intubation has required the global Emergency Medicine (EM), Anesthesia, and Critical Care communities to institute new COVID- protected intubation guidelines, checklists, and protocols. This survey aimed to deepen the understanding of the changes in intubation practices across Canada by evaluating the pre-COVID-19, early-COVID-19, and present-day periods, elucidating facilitators and barriers to implementation, and understanding provider impressions of the effectiveness and safety of the changes made. METHODS: We conducted an electronic, self-administered, cross-sectional survey of EM physician site leads within the Canadian COVID-19 Emergency Department Rapid Response Network (CCEDRRN) to characterize and compare airway management practices in the pre-COVID-19, early-COVID-19, and present-day periods. Ethics approval for this study was obtained from the University of Manitoba Health Research Ethics Board. The electronic platform SurveyMonkey ( www.surveymonkey.com ) was used to collect and store survey tool responses. Categorical item responses, including the primary outcome, are reported as numbers and proportions. Variations in intubation practices over time were evaluated through mixed-effects logistic regression models. RESULTS: Invitations were sent to 33 emergency department (ED) physician site leads in the CCEDRRN. We collected 27 survey responses, 4 were excluded, and 23 analysed. Responses were collected in English (87%) and French (13%), from across Canada and included mainly physicians practicing in mainly Academic and tertiary sites (83%). All respondents reported that the intubation protocols used in their EDs changed in response to the COVID-19 pandemic (100%, n = 23, 95% CI 0.86-1.00). CONCLUSIONS: This study provides a novel summary of changes to airway management practices in response to the evolving COVID-19 pandemic in Canada. Information from this study could help inform a consensus on safe and effective emergent intubation of persons with communicable respiratory infections in the future.

Intubation practices and outcomes for patients with suspected or confirmed COVID-19: a national observational study by the Canadian COVID-19 Emergency Department Rapid Response Network (CCEDRRN).

OBJECTIVE: Intubation practices changed during the COVID-19 pandemic to protect healthcare workers from transmission of disease. Our objectives were to describe intubation characteristics and outcomes for patients tested for SARS CoV-2 infection. We compared outcomes between patients testing SARS COV-2 positive with those testing negative. METHODS: We conducted a health records review using the Canadian COVID-19 Emergency Department Rapid Response Network (CCEDRRN) registry. We included consecutive eligible patients who presented to one of 47 EDs across Canada between March 1, 2020 and June 20, 2021, were tested for SARS-CoV-2 and intubated in the ED. The primary outcome was the proportion of patients experiencing a post-intubation adverse event during the ED stay. Secondary outcomes included first-pass success, intubation practices, and hospital mortality. We used descriptive statistics to summarize variables with subgroup differences examined using t tests, z tests, or chi-squared tests where appropriate with 95% CIs. RESULTS: Of 1720 patients with suspected COVID-19 who were intubated in the ED during the study period, 337 (19.6%) tested SARS-CoV-2 positive and 1383 (80.4%) SARS-CoV-2 negative. SARS-CoV-2 positive patients presented to hospital with lower oxygen levels than SARS-CoV-2 negative patients (mean pulse oximeter SaO2 86 vs 94%, p < 0.001). In total, 8.5% of patients experienced an adverse event post-intubation. More patients in the SARS-CoV-2 positive subgroup experienced post-intubation hypoxemia (4.5 vs 2.2%, p = 0.019). In-hospital mortality was greater for patients who experienced intubation-related adverse events (43.2 vs 33.2%, p = 0.018). There was no significant difference in adverse event-associated mortality by SARS-CoV-2 status. First-pass success was achieved in 92.4% of all intubations, with no difference by SARS-CoV-2 status. CONCLUSIONS: During the COVID-19 pandemic, we observed a low risk of adverse events associated with intubation, even though hypoxemia was common in patients with confirmed SARS-CoV-2. We observed high rates of first-pass success and low rates of inability to intubate. The limited number of adverse events precluded multivariate adjustments. Study findings should reassure emergency medicine practitioners that system modifications made to intubation processes in response to the COVID-19 pandemic do not appear to be associated with worse outcomes compared to pre-COVID-19 practices.

RéSUMé: OBJECTIF: Les pratiques d'intubation ont changé au cours de la pandémie de COVID-19 afin de protéger le personnel de santé contre la transmission de la maladie. Nos objectifs étaient de décrire les caractéristiques de l'intubation et les résultats pour les patients testés pour l'infection par le CoV-2 du SRAS. Nous avons comparé les résultats entre les patients testés positifs au SARS COV-2 et ceux testés négatifs. MéTHODES: Nous avons effectué un examen des dossiers de santé à l'aide du registre du Réseau canadien d'intervention rapide dans les services d'urgence pour la COVID-19 (RCIRSUC). Nous avons inclus les patients éligibles consécutifs qui se sont présentés à l'un des 47 services d'urgence du Canada entre le 1er mars 2020 et le 20 juin 2021, qui ont été testés pour le SRAS-CoV-2 et qui ont été intubés dans le service d'urgence. Le résultat principal était la proportion de patients ayant subi un événement indésirable après l'intubation pendant leur séjour aux urgences. Les critères de jugement secondaires comprenaient le succès du premier passage, les pratiques d'intubation et la mortalité hospitalière. Nous avons utilisé des statistiques descriptives pour résumer les variables avec des différences de sous-groupes examinées à l'aide de tests t, de tests z ou de tests du chi carré, le cas échéant, avec des IC à 95%. RéSULTATS: Sur les 1720 patients suspects de COVID-19 qui ont été intubés aux urgences pendant la période de l'étude, 337 (19,6%) ont été testés positifs au SARS-CoV-2 et 1383 (80,4%) négatifs au SARS-CoV-2. Les patients positifs au SRAS-CoV-2 se sont présentés à l'hôpital avec des niveaux d'oxygène inférieurs à ceux des patients négatifs pour le SRAS-CoV-2 (oxymètre de pouls moyen SaO2 86% contre 94%, p < 0,001). Au total, 8,5% des patients ont présenté un événement indésirable après l'intubation. Un plus grand nombre de patients du sous-groupe positif au SRAS-CoV-2 ont présenté une hypoxémie post-intubation (4,5% vs 2,2%, p = 0,019). La mortalité hospitalière était plus élevée chez les patients ayant subi des événements indésirables liés à l'intubation (43,2% vs 33,2%, p = 0,018). Il n'y avait pas de différence significative dans la mortalité associée aux événements indésirables selon le statut du SRAS-CoV-2. Le succès du premier passage a été obtenu dans 92,4% de toutes les intubations, sans différence selon le statut SARS-CoV-2 CONCLUSIONS: Pendant la pandémie de COVID-19, nous avons observé un faible risque d'événements indésirables associés à l'intubation, même si l'hypoxémie était fréquente chez les patients atteints de SRAS-CoV-2 confirmé. Nous avons observé des taux élevés de réussite du premier passage et des taux faibles d'incapacité à intuber. Le nombre limité d'événements indésirables a empêché les ajustements multivariés. Les résultats de l'étude devraient rassurer les praticiens de la médecine d'urgence que les modifications apportées aux processus d'intubation en réponse à la pandémie de COVID-19 ne semblent pas être associées à des résultats plus défavorables que les pratiques antérieures à la pandémie de COVID-19.

Predictors of Urgent Dialysis Following Ambulance Transport to the Emergency Department in Patients Treated With Maintenance Hemodialysis.

Background: Patients receiving maintenance hemodialysis frequently require ambulance transport to the emergency department (ambulance-ED transport). Identifying predictors of outcomes after ambulance-ED transport, especially the need for timely dialysis, is important to health care providers. Objective: The purpose of this study was to derive a risk-prediction model for urgent dialysis after ambulance-ED transport. Design: Observational cohort study. Setting and Patients: All ambulance-ED transports among incident and prevalent patients receiving maintenance hemodialysis affiliated with a regional dialysis program (catchment area of approximately 750 000 individuals) from 2014 to 2018. Measurements: Patients' vital signs (systolic blood pressure, oxygen saturation, respiratory rate, and heart rate) at the time of paramedic transport and time since last dialysis were utilized as predictors for the outcome of interest. The primary outcome was urgent dialysis (defined as dialysis in a monitored setting within 24 hours of ED arrival or dialysis within 24 hours with the first ED patient blood potassium level >6.5 mmol/L) for an unscheduled indication. Secondary outcomes included, hospitalization, hospital length of stay, and in-hospital mortality. Methods: A logistic regression model to predict outcomes of urgent dialysis. Discrimination and calibration were assessed using the C-statistic and Hosmer-Lemeshow test. Results: Among 878 ED visits, 63 (7.2%) required urgent dialysis. Hypoxemia (odds ratio [OR]: 4.04, 95% confidence interval [CI]: 1.75-9.33) and time from last dialysis of 24 to 48 hours (OR: 3.43, 95% CI: 1.05-11.9) and >48 hours (OR: 9.22, 95% CI: 3.37-25.23) were strongly associated with urgent dialysis. A risk-prediction model incorporating patients' vital signs and time from last dialysis had good discrimination (C-statistic 0.8217) and calibration (Hosmer-Lemeshow goodness of fit P value .8899). Urgent dialysis patients were more likely to be hospitalized (63% vs 34%), but there were no differences in inpatient mortality or length of stay. Limitations: Missing data, requires external validation. Conclusion: We derived a risk-prediction model for urgent dialysis that may better guide appropriate transport and care for patients requiring ambulance-ED transport.

Contexte: Les patients sous hémodialyse chronique doivent souvent être transportés au service des urgences par ambulance (transport ambulance-SU). Il est important pour les prestataires de soins de santé que l'on détermine les facteurs prédictifs des résultats après un transport ambulance-SU, en particulier le besoin de dialyze d'urgence. Objectifs: Cette étude visait à établir un modèle de prédiction du risque pour une dialyze d'urgence après un transport ambulance-SU. Type d'étude: Étude de cohorte observationnelle. Participants et cadre de l'étude: Tous les transports ambulance-SU de patients incidents et prévalents recevant une hémodialyse chronique affiliée à un program régional de dialyze (zone desservant environ 750 000 personnes) entre 2014 et 2018. Prédicteurs: Les signes vitaux du patient (pression artérielle systolique, saturation en oxygène, fréquence respiratoire et fréquence cardiaque) au moment du transport par ambulance et le temps écoulé depuis la dernière dialyze. Résultats: La dialyze d'urgence (définie comme une dialyze en environnement monitoré dans les 24 heures suivant l'arrivée aux urgences ou une dialyze dans les 24 heures avec une première mesure du taux de potassium sanguin aux urgences supérieure à 6,5 mmol/L) pour une indication non programmée. Résultats secondaires: hospitalization, durée du séjour à l'hôpital et mortalité à l'hôpital. Méthodologie: Un modèle de régression logistique a servi à prédire le résultat de dialyze d'urgence. La discrimination et la calibration ont été évalués à l'aide de la statistique C et du test Hosmer-Lemeshow. Résultats: Parmi les 878 visites aux urgences, 63 (7,2 %) ont nécessité une dialyze d'urgence. L'hypoxémie (rapport de cote [RC]: 4,04; IC à 95 %: 1,75-9,33) et des périodes de 24 à 48 heures (RC: 3,43; IC à 95 %: 1,05-11,9) et de plus de 48 heures (RC: 9,22; IC à 95 %: 3,37-25,23) depuis la dernière dialyze sont les facteurs qui ont été les plus fortement associés à une dialyze d'urgence. Un modèle de prédiction du risque intégrant les signes vitaux du patient et le temps depuis la dernière dialyze a présenté une bonne discrimination (statistique C: 0,8217) et une bonne calibration (qualité de l'ajustement selon Hosmer-Lemeshow: P =,8899). Les patients qui avaient reçu une dialyze d'urgence étaient plus susceptibles d'être hospitalisés (63% contre 34%), mais aucune différence n'a été observée pour le taux de mortalité ou la durée du séjour en milieu hospitalier. Limites: Données manquantes, validation externe requise. Conclusion: Nous avons dérivé un modèle de prédiction du risque de dialyze d'urgence susceptible de mieux guider le transport et les soins appropriés pour les patients nécessitant un transport ambulance-SU.

Diagnostic yield of screening for SARS-CoV-2 among patients admitted to hospital for alternate diagnoses: an observational cohort study.

OBJECTIVES: To determine the diagnostic yield of screening patients for SARS-CoV-2 who were admitted with a diagnosis unrelated to COVID-19 and to identify risk factors for positive tests. DESIGN: Cohort from the Canadian COVID-19 Emergency Department Rapid Response Network registry. SETTING: 30 acute care hospitals across Canada. PARTICIPANTS: Patients hospitalised for non-COVID-19-related diagnoses who were tested for SARS-CoV-2 between 1 March and 29 December 2020. MAIN OUTCOME: Positive nucleic acid amplification test for SARS-CoV-2. OUTCOME MEASURE: Diagnostic yield. RESULTS: We enrolled 15 690 consecutive eligible adults who were admitted to hospital without clinically suspected COVID-19. Among these patients, 122 tested positive for COVID-19, resulting in a diagnostic yield of 0.8% (95% CI 0.64% to 0.92%). Factors associated with a positive test included presence of fever, being a healthcare worker, having a positive household contact or institutional exposure, and living in an area with higher 7-day average incident COVID-19 cases. CONCLUSIONS: Universal screening of hospitalised patients for COVID-19 across two pandemic waves had a low diagnostic yield and should be informed by individual-level risk assessment in addition to regional COVID-19 prevalence. TRIAL REGISTRATION NUMBER: NCT04702945.

Predictors of Hyperkalemia among Patients on Maintenance Hemodialysis Transported to the Emergency Department by Ambulance.

Background: Hyperkalemia is common among patients on maintenance hemodialysis (HD) and is associated with mortality. We hypothesized that clinical characteristics available at time of paramedic assessment before emergency department (ED) ambulance transport (ambulance-ED) would associate with severe hyperkalemia (K≥6 mmol/L). Rapid identification of patients who are at risk for hyperkalemia and thereby hyperkalemia-associated complications may allow paramedics to intervene in a timely fashion, including directing emergency transport to dialysis-capable facilities. Methods: Patients on maintenance HD from a single paramedic provider region, who had at least one ambulance-ED and subsequent ED potassium from 2014 to 2018, were examined using multivariable logistic regression to create risk prediction models inclusive of prehospital vital signs, days from last dialysis, and the presence of prehospital electrocardiogram (ECG) features of hyperkalemia. We used bootstrapping with replacement to validate each model internally, and performance was assessed by discrimination and calibration. Results: Among 704 ambulance-ED visits, severe hyperkalemia occurred in 75 (11%); 26 patients with ED hyperkalemia did not have a prehospital ECG. Younger age at transport, longer HD vintage, more days from last hemodialysis session (OR=49.84; 95% CI, 7.72 to 321.77 for ≥3 days versus HD the same day [before] ED transport), and prehospital ECG changes (OR=6.64; 95% CI, 2.31 to 19.12) were independently associated with severe ED hyperkalemia. A model incorporating these factors had good discrimination (c-statistic 0.82; 95% CI, 0.76 to 0.89) and, using a cutoff of 25% probability, correctly classified patients 89% of the time. Conclusions: Characteristics available at the time of ambulance-ED were associated with severe ED hyperkalemia. An awareness of these associations may allow health care providers to define novel care pathways to ensure timely diagnosis and management of hyperkalemia.

Development of the Canadian COVID-19 Emergency Department Rapid Response Network population-based registry: a methodology study.

BACKGROUND: Emergency physicians lack high-quality evidence for many diagnostic and treatment decisions made for patients with suspected or confirmed coronavirus disease 2019 (COVID-19). Our objective is to describe the methods used to collect and ensure the data quality of a multicentre registry of patients presenting to the emergency department with suspected or confirmed COVID-19. METHODS: This methodology study describes a population-based registry that has been enrolling consecutive patients presenting to the emergency department with suspected or confirmed COVID-19 since Mar. 1, 2020. Most data are collected from retrospective chart review. Phone follow-up with patients at 30 days captures the World Health Organization clinical improvement scale and contextual, social and cultural variables. Phone follow-up also captures patient-reported quality of life using the Veterans Rand 12-Item Health Survey at 30 days, 60 days, 6 months and 12 months. Fifty participating emergency departments from 8 provinces in Canada currently enrol patients into the registry. INTERPRETATION: Data from the registry of the Canadian COVID-19 Emergency Department Rapid Response Network will be used to derive and validate clinical decision rules to inform clinical decision-making, describe the natural history of the disease, evaluate COVID-19 diagnostic tests and establish the real-world effectiveness of treatments and vaccines, including in populations that are excluded or underrepresented in clinical trials. This registry has the potential to generate scientific evidence to inform our pandemic response, and to serve as a model for the rapid implementation of population-based data collection protocols for future public health emergencies. TRIAL REGISTRATION: Clinicaltrials.gov, no. NCT04702945.

CO-aVoID: coronavirus outbreak affecting variability of presentations to a local emergency department.

BACKGROUND: The impact of the COVID-19 pandemic on public health, specifically on patients presenting to the emergency department (ED) with non-COVID-related diseases, remains largely undocumented. OBJECTIVE: This study explored how overall rates of presentations to the emergency department were impacted immediately after the declaration of the COVID-19 pandemic, and specifically how key presenting symptoms representing emergency, standard and low-acuity conditions were impacted. METHODS: A sequential modified Delphi survey and cross-sectional analysis of administrative census data from a tertiary care center in New Brunswick, Canada, were performed. Details of ED presentations for emergency, standard and low-acuity conditions from February 1 to April 30, 2020, were compared to data from previous years. RESULTS: There was a significant decrease in the number of patients visiting the ED with emergency, standard and low-acuity complaints immediately after March 13, 2020, compared to 2019. The proportion of females and males remained similar, with a median age of 48 years in 2020 and 44 years in 2019. Total presentation patterns to the ED (registrations, admissions to hospital and left without being seen numbers) decreased, compared to previous years. CONCLUSIONS: We report a predictable decrease in patient visits to the ED with minor, non-life-threatening conditions during a pandemic. However, we also report a decrease in presentations for emergency and standard conditions. Improved messaging highlighting the need to seek help for "true" emergencies, while providing non-ED options for minor, non-life-threatening conditions, may be helpful under normal circumstances and during future pandemics.

RéSUMé: CONTEXTE: L'impact de la pandémie COVID-19 sur la santé publique, en particulier sur les patients se présentant aux services d'urgence (SU) avec des maladies non liées à la COVID, demeure en grande partie non documenté. OBJECTIF: Cette étude a exploré la façon dont les taux globaux de présentations au service des urgences ont été touchés immédiatement après la déclaration de la pandémie de COVID-19, et plus particulièrement la façon dont les principaux symptômes représentant des conditions d'urgence, standard et de faible acuité ont été touchés. MéTHODES: Une enquête Delphi séquentielle modifiée et une analyse transversale des données du recensement administratif provenant d'un centre de soins tertiaires du Nouveau-Brunswick, au Canada, ont été réalisées. Les détails des présentations du SU pour les conditions d'urgence, standard et de faible acuité du 1er février au 30 avril 2020 ont été comparés aux données des années précédentes. RéSULTATS: Il y a eu une diminution significative du nombre de patients se rendant au service d'urgence avec des plaintes d'urgence, standard et de faible gravité immédiatement après le 13 mars 2020, par rapport à 2019. La proportion de femmes et d'hommes est demeurée semblable, avec un âge médian de 48 ans en 2020 et de 44 ans en 2019. Le nombre total de modèles de présentation à l'urgence (inscriptions, admissions à l'hôpital et nombre laissé sans être vu) a diminué par rapport aux années précédentes. CONCLUSIONS: Nous faisons état d'une diminution prévisible des visites de patients aux urgences pour des affections mineures qui ne mettent pas leur vie en danger pendant une pandémie. Toutefois, nous signalons également une diminution des présentations pour les situations d'urgence et les conditions normales. Des messages améliorés soulignant la nécessité de demander de l'aide pour les urgences « réelles ¼, tout en offrant des options non urgentes pour des conditions mineures et qui ne mettent pas la vie en danger peuvent être utiles dans des circonstances normales et lors de futures pandémies.

Optimal Transport Scenario With Rotary Air Transport for Access to Endovascular Therapy Considering Patient Outcomes and Cost: A Modeling Study.

Background and Purpose: For an ischemic stroke patient whose onset occurs outside of the catchment area of a hospital that is capable of Endovascular Treatment (EVT) and whose stroke is suspected to be caused by a large vessel occlusion (LVO), a transportation dilemma exists. Bypassing the nearest stroke hospital will delay Alteplase but expedite EVT. Not bypassing allows for confirmation of an LVO diagnosis before transfer to an EVT-enabled facility, but ultimately delays EVT. Air transport can reduce a patient's overall time to treatment however, it is costly. We expanded on an existing model to predict where Drip-and-Ship vs. Mothership provides better outcomes by including rotary air transport, and we also included prediction of where either the transport method was most cost effective. Methods: An existing model predicts the outcome of patients who screen positive for an LVO in the field based on how they were transported, Drip-and-Ship (alteplase-only facility first, then EVT-enabled facility) or Mothership (direct to EVT-enabled facility). In our model, the addition of rotary wing transportation was conditionally applied to inter-facility transfer scenarios where it provided a time advantage. Both patient outcome and transport cost functions were developed for Mothership and Drip-and-Ship strategies including transfers via either ground or air depending on the conditional probabilities. Experiments to model real world scenarios are presented by varying the driving time between the alteplase-only and EVT-enabled facility, time to treatment efficiencies at the alteplase-only facility, and EVT eligibility for LVO patients. Patient outcome and transport costs were evaluated for Mothership and Drip-and-Ship strategies. Results: The results are presented in temporospatial diagrams that are color coded to indicate which strategy optimizes the objectives. In most regions, there was overall agreement between the optimal solution when considering patient outcomes or transport costs. Small regions exist where outcome and cost are divergent; however, the difference between the divergence in Mothership and Drip-and-Ship in these regions is marginal. Conclusions: The optimal transport method can be optimized for both patient outcomes and transport costs.

Predictors of Prehospital On-Scene Time in an Australian Emergency Retrieval Service.

INTRODUCTION: Prehospital physicians balance the need to stabilize patients prior to transport, minimizing the delay to transport patients to the appropriate level of care. Literature has focused on which interventions should be performed in the prehospital environment, with airway management, specifically prehospital intubation (PHI), being a commonly discussed topic. However, few studies have sought additional factors which influence scene time or quantify the impact of mission characteristics or therapeutic interventions on scene time.Hypothesis/Problem:The goal of this study was to identify specific interventions, patient demographics, or mission characteristics that increase scene time and quantify their impact on scene time. METHODS: A retrospective, database model-building study was performed using the prehospital mission database of South Australian Ambulance Service (SAAS; Adelaide, South Australia) MedSTAR retrieval service from January 1, 2015 through August 31, 2016. Mission variables, including patient age, weight, gender, retrieval platform, physician type, PHI, arterial line placement, central line placement, and finger thoracostomy, were assessed for predictors of scene time. RESULTS: A total of 506 missions were included in this study. Average prehospital scene time was 34 (SD = 21) minutes. Four mission variables significantly increased scene time: patient age, rotary wing transport, PHI, and arterial line placement increased scene time by 0.09 (SD = 0.08) minutes, 13.6 (SD = 3.2) minutes, 11.6 (SD = 3.8) minutes, and 34.4 (SD = 8.4) minutes, respectively. CONCLUSION: This study identifies two mission characteristics, patient age and rotary wing transport, and two interventions, PHI and arterial line placement, which significantly increase scene time. Elderly patients are medically complex and more severely injured than younger patients, thus, may require more time to stabilize on-scene. Inherent in rotary wing operations is the time to prepare for the flight, which is shorter during ground transport. The time required to safely execute a PHI is similar to that in the literature and has remained constant over the past two years; arterial line placement took longer than envisioned. The SAAS MedSTAR has changed its clinical practice guidelines for prehospital interventions based on this study's results. Retrieval services should similarly assess the necessity and efficiency of interventions to optimize scene time, knowing that the time required to safely execute an intervention may reach a minimum duration. Defining the scene time enables mission planning, team training, and audit review with the aim of improved patient care.

Are all pulmonary embolism clinical decision rules equal?

CLINICAL QUESTION: Are four common clinical decision rules, in combination with normal D-dimer results, comparable in their ability to clinically exclude the diagnosis of pulmonary embolism? ARTICLE CHOSEN: Douma RA, Mos ICM, Erkens PMG, et al. Performance of 4 clinical decision rules in the diagnostic management of acute pulmonary embolism: a prospective cohort study. Ann Intern Med 2011;154:709-18. OBJECTIVE: To directly compare the performance of four different clinical decision rules, the Wells rule, revised Geneva score, simplified Wells rule, and simplified revised Geneva score, in combination with D-dimer results, to exclude pulmonary embolism.

The Coxsackie and adenovirus receptor binds microtubules and plays a role in cell migration.

The Coxsackie and adenovirus receptor (CAR), a cell adhesion molecule of the immunoglobulin superfamily, inhibits cell growth of a variety of tumors. The cytoplasmic domain of CAR has been implicated in decreased invasion and intracerebral growth of human U87 glioma cells. Using affinity binding, we identified tubulin as an interaction partner for the cytoplasmic domain of CAR. The interaction was specific; CAR and tubulin co-immunoprecipitated in cells expressing endogenous CAR and partially co-localized in situ. The binding of CAR to tubulin heterodimers and to microtubules was direct, with dissociation constants of approximately 1 mum for tubulin and approximately 32 nm for in vitro assembled microtubules. Whereas CAR-expressing U87 glioma cells had decreased migration in a chemotactic assay in Boyden chambers as compared with control cells, an effect that depended on the presence of the cytoplasmic domain of CAR, the difference was abrogated at low, non-cytotoxic doses of the taxane paclitaxel, a microtubule-stabilizing agent. These results indicate that CAR may affect cell migration through its interaction with microtubules.