title: The efficacy of spontaneous and controlled ventilation with various cricothyrotomy devices: a quantitative in vitro assessment in a model lung.
abstract: BACKGROUND
  Guidelines for the management of a difficult airway recommend performing a cricothyrotomy in a "can't intubate/can't ventilate" situation. We investigated the tidal volumes delivered by controlled and spontaneous ventilation by seven commercially available cricothyrotomy sets (cuffed: Quicktrach II, Portex Cricothyroidotomy Kit, and Melker cuffed cannula and uncuffed: Airfree, 4.0-mm ID Quicktrach, 6.0-mm inner diameter Melker, and 13-gauge Ravussin cannula) and two improvised devices (14-gauge intravenous cannula and spike and drip chamber device).
  
  
  METHODS
  A LS800 model lung, set at different values for compliance and resistance and modified with different upper airway diameter, was ventilated via the respective cricothyrotomy device mechanically and using a self-inflating bag. With the 13-gauge Ravussin cannula and the 14-gauge intravenous cannula, a Manujet injector was used for jet ventilation. Spontaneous ventilation was simulated with a Michigan 560i lung.
  
  
  RESULTS
  During controlled or manual ventilation, all cuffed cricothyrotomy devices yielded adequate tidal volumes. Uncuffed devices provided tidal volumes≥300 mL only with an upper airway diameter of ≤3 mm. With a Manujet injector, adequate tidal volumes required an upper airway diameter between 3 mm and 5 mm. A spike and drip chamber device does not provide suitable emergency airway access. Spontaneous ventilation at adequate inspiratory pressure levels required a device inner diameter of at least 4 mm.
  
  
  CONCLUSIONS
  As expected, cuffed cricothyrotomy devices yield the best results during controlled, manual, and spontaneous ventilation. With uncuffed cricothyrotomy devices, ventilation becomes ineffective when the upper airway obstruction allows for an upper airway diameter>3 mm.
authors.affiliation: Department of Special Anaesthesia and Pain Therapy, Medical University of Vienna, Vienna General Hospital, Vienna, Austria. andrea.michalek-sauberer@meduniwien.ac.at
authors.forename: Andrea
authors.initials: A
authors.lastname: Michalek-Sauberer
authors.forename: Marcus
authors.initials: M
authors.lastname: Granegger
authors.forename: Hermann
authors.initials: H
authors.lastname: Gilly
mesh_terms: D003413:Cricoid Cartilage / Q000601:surgery; D004638:Emergency Treatment / Q000379:methods*; D006801:Humans; D008168:Lung / Q000502:physiology*; D008953:Models, Anatomic; D012119:Respiration; D012121:Respiration, Artificial / Q000379:methods*; D012143:Respiratory Physiological Phenomena; D013957:Thyroid Cartilage / Q000601:surgery; D013990:Tidal Volume; D014139:Tracheostomy / Q000295:instrumentation / Q000379:methods*