Figure 36-25 High-frequency jet ventilation. The jet is created when a high-pressure air-O₂ supply is rapidly modulated by the solenoid valve. Fresh inspired gas is from a low-pressure source, typically an anesthesia circuit. Drive pressure (PD) and jet pressure (PJ) are customarily monitored to detect solenoid or jet malfunction. An independent monitor of airway pressure (Paw), which can reliably detect overpressurization of the airway, circuit disconnection, or ventilator malfunction, should also be available.