Jet ventilation

Jet ventilation is a special type of mechanical ventilation for surgical operations in the airway. Jet ventilation (JV) is characterized by the insufflation of gas portions with high velocity into the airway. The latter has to be open to the atmosphere in order to allow an unhindered gas egress and therefore to avoid overdistention (barotrauma) of the lungs.

Indications

The rationale for JV is its property of being administered without an endotracheal tube, thus not requiring an airtight sealing of the airway. This feature allows maintenance of a sufficient gas exchange while the airway can be accessed, examined and operated with microsurgical endoscopic instruments.

Another advantage of this ventilation method during the use of surgical laser beams, is the avoidance of inflammable tubing material, as is usually applied for conventional intermittent positive pressure ventilation. JV can be applied either by simple manual devices or sophisticated electronically operated ventilators with various choices for ventilation settings as well as measuerement and display of applied and resulting parameters. A ventilation frequency below 1 Hz is called "low frequency jet ventilation" while above 1 Hz it is a "high frequency jet ventilation".

Procedure

The connection between the ventilator and the patient's airway can be established via a translaryngeal jet catheter (translaryngeal-infraglottic access), directly through the skin of the anterior neck into the trachea (transtracheal-infraglottic access) or through a nozzle which is located proximally and above the vocal cords (supraglottic access). Common ventilation settings in an adult patient are

• oxygen concentration: 30-100%
• driving pressure: 0.8-4 bar
• ventilation frequency: 150 cycles per minute
• I:E ratio of 1.0

Complications

Complications of JV may comprise hypoxaemia, hypercapnia, surgical emphysema and pneumothorax.

References

• High-frequency percussive ventilation during surgical bronchial repair in a patient with one lung at British Journal of Anaesthesia
• Comparison of double-lung jet ventilation and one-lung ventilation for thoracotomy Published online by Cambridge University Press 20Jun2007