title: Reusable Laryngeal Mask Airways can be used more than 40 times.
abstract: OBJECTIVE
  To compare the mechanical properties of classic, reusable Laryngeal Mask Airways (LMAs) that have been used more than 100 times with one unused LMA.
  
  
  METHODS
  Laboratory testing of devices used clinically.
  
  
  METHODS
  Metropolitan university hospital.
  
  
  METHODS
  Cuff and tube specimens from LMAs that had been used at least 100 times were tested for elongation, tensile strength, stiffness, and tear strength using standard American Society of Testing and Materials protocols. Samples from an unused LMA were analyzed in the same manner for comparison.
  
  
  RESULTS
  Tensile strength of the cuff samples was found to increase by approximately 25%. There was an increase in cuff stiffness and decreased tear strength similar to the manufacturer-reported trends. Cuff elongation decreased by 30%. Results for the LMA tube differed depending on whether the samples were taken in the machine direction or transverse direction. Tensile strength decreased by 30% in machine direction and, on average, very little in transverse direction.
  
  
  CONCLUSIONS
  The material in reusable classic LMAs does not lose its strength after 100 uses to the extent that its manufacturer claims. At least 100 uses may be considered safe for these devices.
authors.affiliation: Department of Anesthesiology and Department of Macromolecular Science, Case Western Reserve University Schools of Medicine and Engineering, Cleveland, OH, USA. evan.goodman@uhhs.com
authors.forename: Evan J
authors.initials: EJ
authors.lastname: Goodman
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Christenson
authors.forename: Allen M
authors.initials: AM
authors.lastname: Douglas
authors.forename: E Jane
authors.initials: EJ
authors.lastname: Ziegler
authors.forename: Bradley R
authors.initials: BR
authors.lastname: Lewis
mesh_terms: D004209:Disposable Equipment; D017743:Equipment Reuse; D017214:Laryngeal Masks / Q000706:statistics & numerical data*; D017550:Spectroscopy, Fourier Transform Infrared; D013314:Stress, Mechanical; D013718:Tensile Strength