CJEM Articles: Roland C. Merchant

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  • Bedside ultrasonography detects significant femoral vessel overlap: implications for central venous cannulation
    July 2011 13 4
    Fenwick Gardiner, Francesca L. Beaudoin, James Lincoln, Jamieson Cohn, Otto Liebmann, Roland C. Merchant

    Objective: Our goal was to gain a better understanding of the femoral vessel anatomy as it relates to central venous cannulation. The primary objective of this study was to use bedside ultrasonography to determine the amount of exposed femoral vein at three sites corresponding to surface anatomy of the landmark-based procedure.
    Methods: This cross-sectional study enrolled a random sample of 180 adult patients presenting to a large urban academic emergency department. Subjects underwent standardized ultrasonography to identify and measure the depth and diameter of the femoral vessels and amount of exposed femoral vein at the level of the inguinal ligament (0 cm) 2 cm and 4 cm below. Repeated measures analysis of variance was used to determine significant relationships between vessel measurements and distance from the inguinal ligament.
    Results: The median age was 44.5 (range 19–90) years; 101 patients were male. The mean (± SD) percentage of exposed vein at the inguinal ligament was 83% (± 21). This decreased significantly (p < 0.01) with increasing distance from the inguinal ligament: 65% (± 25) at 2 cm and 56% (± 30) at 4 cm. At every distance away from the inguinal ligament, there were some subjects with no vein exposed.
    Conclusion: This study demonstrates significant overlap of the femoral vessels at sites where landmark-based femoral vein cannulation is often attempted. Our results suggest that ultrasound guidance would be beneficial as femoral vein cannulation may be difficult or impossible in certain individuals owing to anatomic variations.

  • Factors associated with delay to emergency department presentation, antibiotic usage and admission for human bite injuries
    November 2007 9 6
    Bruce M. Becker, Christopher P. Zabbo, Kenneth H. Mayer, Roland C. Merchant

    Objectives: Evidence and consensus on best practices on the management of human bite injuries is lacking. Our objective was to identify factors that are associated with delay to emergency department (ED) presentation, antibiotic usage and patient admission.

    Methods: We present a retrospective chart review of adults treated for human bites. Multivariable logistic regression models used demographic characteristics and bite circumstances and characteristics as factors associated with ED presentation more than 24 hours after the bite, antibiotic usage and hospital admission.

    Results: Of the 388 patients evaluated for a human bite, 66.5% were bitten during an altercation; 23.8% presented more than 24 hours after the bite; 50.3% were bitten on the hands or fingers, 23.5% on an extremity and 17.8% on the head or neck. Only 7.7% of all patients sustained closed-fist injuries; the majority had occlusional or other kinds of bites. The majority of patients (77.3%) received antibiotics and 11.1% were admitted to hospital. Patients who had greater odds of presenting more than 24 hours after the bite were black (odds ratio [OR] 1.79, 95% confidence interval [CI] 1.02-3.13), Hispanic (OR 2.68, 95% CI 1.22-5.89) and those who had a non-occupational bite (OR 3.87, 95% CI, 1.68-8.90). Patients had a greater chance of receiving antibiotics if they were bitten during an altercation (OR 1.87, 95% CI, 1.09-3.20) and were bitten on the hands or fingers (OR 2.23, 95% CI 1.31-3.80). Patients had a greater chance of being admitted to the hospital if they were bitten during an altercation (OR 4.91, 95% CI 1.65-14.64), bitten on the hands or fingers (OR 5.26, 95% CI, 1.74-15.87) and if they presented ≥ 24 hours after the bite.

    Conclusion: Most patients presented to the ED within 24 hours of their injury and received antibiotics. The circumstances surrounding the bite appeared to be associated with delay to ED presentation, receipt of antibiotics and admission to the hospital. There are ethnic background differences in delay to ED presentation. ED clinicians in our study favour antibiotic usage and admission based on the body location of the bite, despite little evidence to support these practices.