Recommended approaches to minimize aerosol dispersion of COVID during noninvasive ventilatory support can deteriorate ventilator performances: a benchmark comparative study

Abstract

<b>Introduction:</b> Various circuit setups have been described in order to reduce COVID&nbsp;aerosolisation. We aimed to assess the consequences of these setup on ventilator9s efficacy. <b>Method:</b> 8&nbsp;circuit setups were evaluated on a bench made of a 3D printed head and an artificial lung. Setups were a dual-limb (DL)&nbsp;circuit with an oronasal mask, a DL&nbsp;circuit with a helmet interface, a single-limb (SL) circuit with a passive exhalation valve, 3 SL circuits with custom-made additional leaks and 2&nbsp;SL circuits with exhalation valves. All setups were evaluated during NIV and CPAP. We measured: the inspiratory flow preceding trigger of the ventilator, the inspiratory effort required to trigger the ventilator, the triggering delay, the maximal inspiratory pressure delivered by the ventilator, the tidal volume (Vt), the total work of breathing (WOB) and the pressure time product to trigger the ventilator (PTPt). <b>Results:</b> With NIV, the type of circuit setup had a significant impact on inspiratory flow preceding the trigger of the ventilator (p&lt;0.0001), the inspiratory effort required to trigger the ventilator (p&lt;0.0001), the triggering delay (p&lt;0.0001); the maximal inspiratory pressure (p&lt;0.0001), the Vt (p:0.0008), the WOB (p&lt;0.0001), the PTPt (p&lt;0.0001). Similar differences were seen with CPAP as well as with the addition of bacterial filters. Best performance was achieved using a DL&nbsp;circuit with an oronasal mask. Worst performance was achieved using a DL&nbsp;circuit with a helmet interface. <b>Conclusion:</b> Ventilator performance is significantly impacted by the circuit setup. DL circuit with oronasal mask should be used preferentially.