Recommended Approaches to Minimize Aerosol Dispersion of SARS-CoV-2 During Noninvasive Ventilatory Support Can Cause Ventilator Performance Deterioration

Abstract

Background SARS-CoV-2 aerosolization during noninvasive positive pressure ventilation may endanger healthcare professionals. Various circuit setups have been described in order to reduce virus aerosolization. However, these setups may alter ventilator performances. Research question What are the consequences of the different suggested circuit setups on ventilator’s efficacy during continuous positive airway pressure (CPAP) and noninvasive ventilation (NIV)? Study Design and Method Eight circuit setups were evaluated on a bench made of a 3-D printed head and an artificial lung. Setups were a dual-limb circuit with an oro-nasal mask, a dual-limb circuit with a helmet interface, a single-limb circuit with a passive exhalation valve, three single-limb circuits with custom-made additional leaks and two single-limb circuits with active exhalation valves. All setups were evaluated during NIV and CPAP. The following variables were recorded: 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 (V t ) generated to the artificial lung, the total work of breathing (WOB) and the pressure time product to trigger the ventilator (PTPt). Results With NIV, the type of circuit setup had a significant impact on inspiratory flow preceding the trigger of the ventilator (p<0.0001), the inspiratory effort required to trigger the ventilator (p<0.0001), the triggering delay (p<0.0001); the maximal inspiratory pressure (p<0.0001), the V t (p:0.0008), the WOB (p<0.0001), the PTPt (p<0.0001). Similar differences and consequences were seen with CPAP as well as with the addition of bacterial filters. Best performance was achieved using a dual limb circuit with an oro-nasal mask. Worst performance was achieved using a dual-limb circuit with a helmet interface. Interpretation Ventilator performance is significantly impacted by the circuit setup. The use of dual-limb circuit with oro-nasal masks should be used preferentially.

ERS International Congress 2020 Virtual: highlights from the Respiratory Intensive Care Assembly

“… A noninvasive ventilation circuit used to minimise viral aerosolization. Reproduced from and evaluated in [ 79 ]. …”

Addition of bacterial filter alters positive airway pressure and non-invasive ventilation performances

“…The manufacturer and some healthcare regulatory agencies advocated, as a temporary solution, to modify PAP and NIV circuits by adding an inline bacterial filter in order to reduce the risk of inhalation [ 2 ]. However, changing ventilator circuits can alter ventilator performances during PAP and NIV [ 3 ].…”

Circuit Set-ups to Reduce Virus Aerosolization During Noninvasive Positive Pressure Ventilation

“…In this issue of CHEST , Patout et al 8 need to be commended for setting up such detailed and interesting bench study, to better clarify the impact of such modifications.…”

“…The bench study of Patout et al, 8 who used a precise method, analyzed eight different circuit set-ups that were evaluated both during noninvasive positive pressure ventilation and CPAP with the Astral 150 ventilator version 0601 (ResMed, San Diego, CA). In their experiment, the best performance was achieved with the use of a dual-limb circuit with an oronasal mask, whereas the worst performance was achieved with the use of a dual-limb circuit with a helmet interface.…”

“…While we wait for new real world data, with the use of different ventilator models and nonvented oronasal masks with or without antiasphyxia valve, the article from Patout et al 8 should serve as an useful guide for performing the best NRST delivery during COVID-19 pandemic.…”