ABSTRACT
High-frequency jet ventilation (HFJV) was first developed in clinical anesthesia to provide small tidal volume ventilation for procedures involving the larynx and tracheobronchial tree where the ability to achieve a normal CO2 with low airway pressures provided ideal operating conditions. Although HFJV and HFOV operate on the same physiological principles of very small tidal volumes delivered at high rates, they should not be considered as merely two variations on the same theme. HFJV uses a high-pressure gas source to deliver small tidal volumes at frequencies of 1-5 Hz. Apart from the slower rates used in HFJV, the other major difference is that expiration is passive in the former while it is active in HFOV. The published experience with jet ventilation in acute hypoxemic respiratory failure (AHRF) is considerably less than oscillation and until recently only documented its use as rescue therapy in patients with either hypoxemia despite high PEEP or an established air leak. The rationale for the switch is usually the avoidance of further barotrauma by the use of smaller tidal volumes while maintaining a high mean airway pressure, but with lower peak airway pressures. Improvements in oxygenation can be obtained by driving up the MAP but this usually involves some compromise to cardiovascular function because of the transmitted pressure. A randomized, controlled clinical trial of HFJV in neonates with pulmonary interstitial emphysema (PIE) has shown an improvement in PIE and lower mortality rate in infants treated with HFJV compared to conventional ventilation.45
