RESUMO
BACKGROUND: Transtracheal jet ventilation (TTJV) has been used for 'Cannot Ventilate/Cannot Intubate' situation, lefe-saving situations, by simply introducing an IV catheter (angiocatheter) through the cricothyroid membrane. To decrease the occurrence of barotrauma caused by a continuous high pressure oxygen supply while applying TTJV, it would be ideal to have a TTJV system equipped with an inspiration time adjustable function which any currently commercially available TTJV does not have. METHODS: Recently, we made a prototype of an inspiration time adjustable TTJV and measured the corresponding injection volumes and peak inflation pressures according to the changes of oxygen supply pressure and inspiration time using catheters ranging from 14 to 20 G in a simulated human adult trachea-lung model. RESULTS: A 16 G angiocatheter provided 465 +/- 5 ml of injected volume with a peak inflation pressure of 25 cmH2O under a 50 psi oxygen supply at 1 second of inspiration, which would be adequate for an adult tidal volume. When a 14 G catheter was used under the same conditions as above, the injected volume was 1128 +/- 9 ml. All injected volumes were under 310 ml when 18 and 20 G angiocathers were used at variosus driving pressures (10 - 50 psi) and inspiration time (0.5, 0.75, and 1 s). CONCLUSIONS: An inspiration time adjustable TTJV can easily provide enough tidal volume to maintain oxygenation, and could be expected to prevent or reduce barotraumatic complications such as pneumothorax.