title: Effect of tracheal tube cuff shape on fluid leakage across the cuff: an in vitro study.
abstract: BACKGROUND
  This study compared the fluid leakage in the new 'tapered' shaped against the classic 'cylindrical' shaped tracheal tube cuffs when placed in different sized tracheas.
  
  
  METHODS
  The 7.5 mm internal diameter (ID) tracheal tube cuffs-Tapered Seal Guard (TSG), Standard Seal Guard (SSG), Hi-Lo, Microcuff, Ruesch, and Portex Profile-were compared in an in vitro apparatus. Vertical artificial tracheas with 16, 20, and 22 mm ID were intubated, 5 ml clear water was applied above the unlubricated tube cuffs, and fluid leakage was measured up to 60 min. Data of tapered vs non-tapered tube cuffs (16 observations) were compared for each tracheal diameter using the Mann-Whitney test.
  
  
  RESULTS
  Median (range) fluid leakage (ml) at 60 min was 2.14 (0.05-4.88), 1.14 (0.00-4.84), and 0.13 (0.00-1.32), respectively, for 16, 20, and 22 mm tracheas in the TSG tube studies when compared with 4.58 (0.44-4.88), 2.21 (0.00-4.81), and 0.00 (0.00-4.81) in the SSG tube and 4.54 (1.54-4.82), 0.90 (0.00-4.49), and 4.85 (4.40-4.99) in the Microcuff tube studies. Leakage in all polyvinylchloride (PVC) tube cuffs was almost complete (5 ml) within 5 min (P<0.001).
  
  
  CONCLUSIONS
  The tapered PU tube cuff was as effective as the cylindrical PU cuffs in smaller tracheal diameters and was more efficient than the cylindrical Microcuff PU tube cuff in larger tracheal diameter in preventing subglottic fluid leakage across the tube cuff tested in this in vitro study. PVC tube cuffs leaked much more and faster than PU cuffs.
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Steinwiesstrasse 75, CH 8032 Zurich, Switzerland. mital.dave@kispi.uzh.ch
authors.forename: M H
authors.initials: MH
authors.lastname: Dave
authors.forename: A
authors.initials: A
authors.lastname: Frotzler
authors.forename: N
authors.initials: N
authors.lastname: Spielmann
authors.forename: C
authors.initials: C
authors.lastname: Madjdpour
authors.forename: M
authors.initials: M
authors.lastname: Weiss
mesh_terms: D004867:Equipment Design; D004868:Equipment Failure; D005122:Exudates and Transudates; D007442:Intubation, Intratracheal / Q000009:adverse effects / Q000295:instrumentation*; D008953:Models, Anatomic; D011015:Pneumonia, Aspiration / Q000209:etiology / Q000517:prevention & control; D011143:Polyvinyl Chloride; D011897:Random Allocation; D018709:Statistics, Nonparametric
chemical_list: D011143:Polyvinyl Chloride