Comparative bench study evaluation of a modified snorkeling mask used during COVID-19 pandemia and standard interfaces for Non-Invasive Ventilation

Background COVID-19 infection has put enormous pressure on the healthcare systems worldwide and especially on Intensive Care Units (ICUs). In this particular situation, a modified snorkeling mask into a mask for non-invasive continuous positive airway pressure (nCPAP) and non-invasive ventilation (NIV), with the help of 3D printers, has been proposed for clinical use. We designed a bench study to compare a Helmet (H), a Full face mask (RFF) and a modified full face snorkeling mask (MFF) for delivering nCPAP and NIV in pressure support mode (PSV). Methods A mannequin was connected to an active lung simulator. The inspiratory and expiratory variations in airways pressure observed with a high simulated effort (Pmus), were determined relative to the preset CPAP level. NIV was applied in PSV at two simulated respiratory rates and two cycling-off flow thresholds. During the bench study we measured the variables defining patient-ventilator interaction and performance. Results During nCPAP, the MFF presented significantly lower values of ΔPawi and ∆Pawe compared to the other interfaces tested (H and RFF). During NIV, the MFF demonstrated a better patient-ventilator interaction compared to RFF, as shown by significantly shorter Timepress and Delaytrexp (p < 0.01), but no significant differences were found in terms of Delaytrinsp and Timesync between the interfaces tested. At RR 20sim, the MFF presented the shorter ΔPtrigger (p < 0.01), moreover during all the conditions tested the MFF showed the longer PTP 200, 300 and 500 compared to RFF (p < 0.01). A major limitation of MFF is that during NIV with this interface it is possible to reach at maximum 18 cmH2O of peak inspiratory pressure. Over this pressure value, the presence of air leaks determined important asynchrony phenomena. For this reason, our test was limited to one pressure support and PEEP set (PS 10 cmH2O and PEEP 8 cmH2O). Conclusions The modified full face snorkeling mask can be used as an acceptable alternative to other interfaces for both nCPAP and NIV in emergency situations.