Using standard clinical components, a system of shared ventilation consisting of two ventilatory limbs was assembled and connected to a single ventilator. Individual monitors for each circuit were developed using widely available equipment and open source software.

System performance was determined under 2 sets of conditions. First, the effect of altering ventilator settings (Inspiratory Pressure, Respiratory rate, I:E ratio) on the tidal volumes delivered to each lung circuit was determined.

Second, the impact of altering the compliance and resistance in one simulated lung circuit on the tidal volumes delivered to that lung and the second lung circuit was determined. All measurements at each setting were repeated three times to determine the variability in the system.

The system permitted accurate and reproducible titration of tidal volumes to each lung circuit over a wide range of ventilator settings and simulated lung conditions.

Alteration of ventilator inspiratory pressures stepwise from 4-20cm H2O, of respiratory rates from 6-20 breaths/minute and I:E ratio from 1:1 to 1:4 resulted in near identical tidal volumes delivered under each set of conditions to each simulated lung.

Stepwise alteration of compliance and resistance in one test lung circuit resulted in reproducible alterations in tidal volume to the test lung, with little change to tidal volumes in the control lung (a change of only 6% is noted).

All tidal volumes delivered were highly reproducible upon repetition.

We demonstrate the reliability of a simple shared ventilation system assembled using commonly available clinical components that allows individual titration of tidal volumes. This system may be useful as a temporary strategy of last resort where the numbers of patients requiring invasive mechanical ventilation exceeds supply of ventilators.

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