title: Using the inflating syringe as a safety valve to limit laryngeal mask airway cuff pressure.
abstract: OBJECTIVE
  Hyperinflation of the laryngeal mask airway (LMA) cuff is thought to be the etiology underlying many of the complications associated with the use of this device. Until now, there has not been a clinically acceptable method (besides direct measurement) to assure that the cuff pressure is maintained less than the recommended maximum value of 44 mm Hg (60 cm H(2)O).
  
  
  METHODS
  We inflated sizes #2 and #5 LMAs with air to 40, 60, or 120 mm Hg starting pressures, using 30- and 60-ml BD™ and B Braun™ syringes; we then allowed the syringe plungers to recoil to equilibrium before removing the syringe from the LMA inflation port. Residual LMA cuff pressures following complete passive recoil were measured and recorded.
  
  
  RESULTS
  A number of combinations of syringes (30 and 60 ml) and starting pressures (40, 60, 120 mm Hg) resulted in safe residual (#2 and #5 LMA) cuff pressures of <44 mm Hg.
  
  
  CONCLUSIONS
  When using specific combinations of syringes, LMA sizes and inflation pressures, these data demonstrate an efficient, practical and easy method to achieve an initial equilibrium recoil LMA cuff pressure that is less than, or very near to, the recommended upper safe limit of 44 mm Hg.
authors.affiliation: Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL 32610-0254, USA. mrice@anest.ufl.edu
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Rice
authors.forename: Nikolaus L
authors.initials: NL
authors.lastname: Gravenstein
authors.forename: Sorin J
authors.initials: SJ
authors.lastname: Brull
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Morey
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Gravenstein
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D004869:Equipment Safety / Q000295:instrumentation*; D017214:Laryngeal Masks; D008365:Manometry / Q000295:instrumentation*; D011312:Pressure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013594:Syringes
references.citation: Anaesthesia. 1991 Jul;46(7):589-90
references.pmid: 1862907
references.citation: Paediatr Anaesth. 2008 Oct;18(10):952-6
references.pmid: 18647269
references.citation: Anaesthesia. 2005 Mar;60(3):278-82
references.pmid: 15710013
references.citation: Anaesthesia. 2008 Jul;63(7):738-44
references.pmid: 18582260
references.citation: Br J Anaesth. 1996 Aug;77(2):295-6
references.pmid: 8881646
references.citation: Can J Anaesth. 2005 Oct;52(8):878-82
references.pmid: 16189342
references.citation: Br J Anaesth. 2004 Sep;93(3):476-7
references.pmid: 15304422
references.citation: Anesthesiology. 1995 Mar;82(3):787-8
references.pmid: 7879948
references.citation: Anesth Analg. 1997 Sep;85(3):687-90
references.pmid: 9296432
references.citation: Anaesthesia. 1996 Jun;51(6):603
references.pmid: 8694225
references.citation: Paediatr Anaesth. 2006 Jan;16(1):25-30
references.pmid: 16409525
references.citation: Anaesthesia. 1994 Mar;49(3):251-4
references.pmid: 8147523
references.citation: Anaesthesia. 1996 Sep;51(9):869-70
references.pmid: 8882254
references.citation: Anesth Analg. 1996 Dec;83(6):1335-6
references.pmid: 8942611
references.citation: Anesthesiology. 2010 Mar;112(3):652-7
references.pmid: 20179502