The Model 73X from Impact Instrumentation is the first self-contained portable ventilator developed specifically for transport and mass casualty care. The "X" may be used with external oxygen but more importantly it is operable via its own internal compressor. In addition, the "X" automatically switches to compressor operation should oxygen supplies become exhausted and simultaneously triggers an alarm to alert the caregiver. The "X" has a simple user interface that's easily managed by personnel with limited mechanical ventilation experience. It uses adult and pediatric disposable circuits, operates for about six hours between battery recharges, interfaces with industry-standard HEPA or chemical/biologic filters, and includes a digital airway pressure display, alarms suite, airway pressure limiting, continuous operation from external power, and more.