title: Foley catheter action in the nasopharynx: a cadaveric study.
abstract: OBJECTIVE
  To determine the action of the Foley catheter in the posterior nasal cavity in relation to balloon volume, and to deduce its implications in the treatment of posterior epistaxis.
  
  
  METHODS
  Human cadaveric study.
  
  
  METHODS
  Twenty nasal fossae of 10 adult cadavers.
  
  
  METHODS
  A Foley catheter (size 14) was inserted into the nasopharynx via each nostril. The catheter balloon was inflated to its recommended maximum volume with 15 mL of water. Firm traction was applied to the catheter. Colored liquid was instilled into the ipsilateral aspect of the nasal cavity, and liquid leakage into the contralateral side was monitored using a nasoendoscope. The balloon was reduced in volume by 1-mL steps, and the same fluid infusion and documentation procedures were performed for each reduced volume until the balloon slipped out of the nose. The procedure was repeated in the opposite nostril.
  
  
  METHODS
  Successful choanal sealing and anterior balloon shift into the nasal fossa in relation to the balloon size.
  
  
  RESULTS
  The Foley catheter balloon sealed the choana without any leakage of infused liquid into the contralateral side at appropriate inflation volumes in 17 (85%) of 20 nasal fossae. Complete sealing between volumes of 12 and 15 mL was achieved in 13 fossae (65%), between 11 and 15 mL in 10 nasal fossae (50%), and between 5 and 15 mL in 3 nasal fossae (15%). Failure to seal at any volume occurred in 3 nasal fossae (15%). Bimodal seal (ie, complete seal at high [15 mL] and low volumes [4-7 mL], but leakage in intermediate volumes) occurred in 3 nasal fossae (15%). The balloon remained in the nasopharynx under traction and did not slip past the choanal rim to encroach on the middle and inferior turbinates until the balloon volume was reduced to between 4 and 7 mL. The balloon slid out of the nose at a volume of 5 mL or less. The inflation volumes ranging from 8 to 12 mL were statistically more effective in sealing the choana than lower volumes (4-7 mL) (P<.002, chi(2) test).
  
  
  CONCLUSIONS
  At different inflation volumes, the Foley catheter balloon acts primarily (1) as a platform for an anterior gauze pack (at 4-15 mL); (2) as an effective seal of the choana (at 8-15 mL usually and at 4-7 mL occasionally); and (3) as a compressor of the region behind the middle and inferior turbinates (at 4-7 mL), provided that the balloon under traction does not slip out of the nose.
authors.affiliation: Division of Otorhinolaryngology, Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong.
authors.forename: W C
authors.initials: WC
authors.lastname: Lee
authors.forename: P K
authors.initials: PK
authors.lastname: Ku
authors.forename: C A
authors.initials: CA
authors.lastname: van Hasselt
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D002404:Catheterization / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009305:Nasopharynx