Successful transtracheal lung ventilation using a manual respiration valve: an in vitro and in vivo study.
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.
Meissner
Konrad
K
Department of Anesthesiology and Intensive Care Medicine, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany. meissnek@wustl.edu
Iber
Thomas
T
Roesner
Jan-Patrick
JP
Mutz
Christian
C
Wagner
Hans-Erich
HE
Layher
Christina
C
Bartels
Utz
U
Gründling
Matthias
M
Usichenko
Taras I
TI
Wendt
Michael
M
Lehmann
Christian
C
Pavlovic
Dragan
D
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
D010100:Oxygen