Development of Fine Time Controller of a Transtracheal Jet Ventilator and Its Experimental Application

Kil, Hae Keum; Park, Wyun Kon; Roh, Jang Ho; Shim, Jae Kwang; Kim, Hoon Do; Ahn, Joo Hyun; Kim, Deok Won

Abstract

BACKGROUND: Transtracheal jet ventilation (TTJV) with a large-bore angiocath that is inserted through the cricothyroid membrane can provide immediate oxygenation from a high pressure-oxygen wall outlet, as well as ventilation by means of manual triggering. However, there is widespread agreement that TTJV with a high pressure oxygen system may induce numerous complications including tracheal hemorrhage/ulceration, subcutaneous/mediastinal emphysema, and barotrauma resulting in a pneumothorax. The goal of this study was to highlight the potential effectiveness of a TTJ-ventilator with an oxygen supply pressure lower than 50 psig for proper oxygenation and ventilation avoiding the possibility of complications from a high pressure oxygen supply system.
METHODS
Five mongrel dogs were intubated, paralyzed with vecuronium, and mechanically ventilated with enflurane in air maintaining the PaCO2 at 35 - 40 mmHg. A 16 G IV catheter was inserted percutaneously into the trachea below the tip of the endotracheal tube. We measured the injection volumes, entrained air volumes, and peak inflation pressures according to the changes of oxygen supply pressure (10 to 50 psig) with a fixed injection time (1 second). In addition, we evaluated the oxygenation effects of TTJV at 15 breaths per minute and an I : E 1 : 3 on 20 psig of oxygen supply pressure in hypoxic dogs.
RESULTS
A 16 G angiocath provided the injected volumes from 139 ml to 595 ml according to the changes of oxygen pressure from 10 to 50 psig. The entrained air volumes were 6.7 48% of total inspirated volumes. The PaO2 was elevated over 300 mmHg and the PaCO2 was reduced to 45 mmHg within 1 minute of TTJV in hypoxic dogs.
CONCLUSIONS
A TTJV system equipped with a time-controller and pressure-regulator can provide enough tidal volume to maintain oxygenation, and could minimize the volu/barotrauma of a conventional TTJV.