title: In vitro study investigating post neck surgery haematoma airway obstruction.
abstract: OBJECTIVE
  To investigate whether the possible pressure produced by a haematoma in the neck would be sufficient to directly compress the trachea to the point of airway obstruction.
  
  
  METHODS
  In vitro study.
  
  
  METHODS
  Varying pressures were applied over the second and third cartilaginous rings of 10 pig tracheas in vitro and the anterior-posterior compression was measured.
  
  
  RESULTS
  At pressures of 257 mmHg, equivalent to the maximum possible pressure in the neck (i.e. systolic blood pressure), there was an average compression of 20.8 per cent of the original anterior-posterior tracheal diameter.
  
  
  CONCLUSIONS
  This study suggests that the pressures in haematomas observed after neck surgery would not be sufficient to cause airway obstruction due to direct pressure on the trachea. Therefore, the most likely cause of airway obstruction would be supraglottic oedema secondary to venous obstruction.
authors.affiliation: Department of Ear, Nose & Throat Surgery, Derbyshire Royal Infirmary, Derby, UK. esmond@doctors.org.uk
authors.forename: E R M
authors.initials: ER
authors.lastname: Carr
authors.forename: E
authors.initials: E
authors.lastname: Benjamin