Changes

* An automated machine check could calculate the amount of circuit leak you have, separate from any patient leak.

* An automated machine check could calculate the amount of machine leak you have in the circuit, separate from any patient leak. Just occlude the Y-piece and run the vent while comparing your VTI - VTE. Average 20 breaths or so and likely there is a delta of a few ml with each breath accounting for air lost from circuit connections, internal machine leaks, tubing, etc. Variability may also be due to measurement error from the flow meters used.

* VTI - VTE gives the total volume lost per breath, which could be used to calculate patient side leaks.

* Once connected to the patient, VTI - VTE gives the total volume lost per breath. Subtract the machine leak found above and this gives you the patient side leaks (air lost from around the ETT cuff, volume lost to chest tubes, etc)

* FiO2 * FGF = VdotO2

* FiO2 * FGF = VdotO2