title: Successful transtracheal lung ventilation using a manual respiration valve: an in vitro and in vivo study.
abstract: BACKGROUND
  Lung ventilation through a thin transtracheal cannula may be attempted in patients with laryngeal stenosis or "cannot intubate, cannot ventilate" situations. It may be impossible to achieve sufficient ventilation if the lungs are spontaneously emptying only through the thin transtracheal cannula, which imposes high resistance to airflow, resulting in dangerous hyperinflation. Therefore, the authors describe the use of a manual respiration valve that serves as a bidirectional pump providing not only inflation but also active deflation of the lungs in case of emergency transtracheal lung ventilation.
  
  
  METHODS
  The effectiveness of such a valve was tested in vitro using mechanical lungs in combination with two different cannula sizes and various gas flows. The valve was then tested in five pigs using a transtracheal 16-gauge cannula with three different combinations of inspiratory/expiratory times and gas flows and an occluded upper airway.
  
  
  RESULTS
  In the mechanical lungs, the valve permitted higher minute volumes compared with spontaneous lung emptying. In vivo, the arterial oxygen and carbon dioxide partial pressures increased initially and then remained stable over 1 h (arterial oxygen tension, 470.8 +/- 86.8; arterial carbon dioxide tension, 63.0 +/- 7.2 mmHg). The inspiratory pressures measured in the trachea remained below 10 cm H2O and did not substantially influence central venous and pulmonary artery pressures. Mean arterial pressure and cardiac output were unaffected by the ventilation maneuvers.
  
  
  CONCLUSIONS
  This study demonstrated in vitro and in vivo in adult pigs that satisfactory lung ventilation can be assured with transtracheal ventilation through a 16-gauge cannula for a prolonged period of time if combined with a bidirectional manual respiration valve.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany. meissnek@wustl.edu
authors.forename: Konrad
authors.initials: K
authors.lastname: Meissner
authors.forename: Thomas
authors.initials: T
authors.lastname: Iber
authors.forename: Jan-Patrick
authors.initials: JP
authors.lastname: Roesner
authors.forename: Christian
authors.initials: C
authors.lastname: Mutz
authors.forename: Hans-Erich
authors.initials: HE
authors.lastname: Wagner
authors.forename: Christina
authors.initials: C
authors.lastname: Layher
authors.forename: Utz
authors.initials: U
authors.lastname: Bartels
authors.forename: Matthias
authors.initials: M
authors.lastname: Gründling
authors.forename: Taras I
authors.initials: TI
authors.lastname: Usichenko
authors.forename: Michael
authors.initials: M
authors.lastname: Wendt
authors.forename: Christian
authors.initials: C
authors.lastname: Lehmann
authors.forename: Dragan
authors.initials: D
authors.lastname: Pavlovic
mesh_terms: D000402:Airway Obstruction / Q000628:therapy; D000818:Animals; D001187:Artificial Organs; D004867:Equipment Design; D005260:Female; D066298:In Vitro Techniques; D007442:Intubation, Intratracheal / Q000295:instrumentation* / Q000379:methods; D008168:Lung; D010100:Oxygen / Q000097:blood; D012121:Respiration, Artificial / Q000379:methods*; D013552:Swine
chemical_list: D010100:Oxygen