In vivo assessment of a modification of a domiciliary ventilator which reduces oxygen consumption in mechanically ventilated patients.

There are instances where hospitals may experience a relative shortage of oxygen, for example, future pandemics, natural disasters or wartime. We developed a modification to a domiciliary ventilator that captures oxygen normally vented during expiration into the atmosphere, delivering it to the patient. The modification significantly increases PaO in mechanically ventilated patients at their baseline FiO and baseline FiO +1, +2 and +3 L/min compared to no modification. The modification reduces walled oxygen consumption by median (IQR) -1.0 (-1.25 to -1.00) L/min whilst maintaining PaO. This modification may be a valuable in circumstances where there is a relative shortage of oxygen.