Performance assessment of medical and non-medical CPAP interfaces used during the COVID-19 pandemic

TL;DR

This study evaluates the performance of medical and modified non-medical CPAP masks and helmets during COVID-19, focusing on pressure stability and the impact of antibacterial filters, highlighting the reliability of CPAP helmets and potential of modified masks.

Contribution

It provides the first experimental comparison of original and modified non-medical masks and helmets for CPAP use, assessing their pressure stability and effects of antibacterial filters during the pandemic.

Findings

CPAP helmet offers the most stable pressure performance.

Modified non-medical masks maintain near-regular pressure with moderate variations.

Antibacterial-viral filters significantly increase effective PEEP delivered.

Abstract

Background: At the beginning of 2020, a high number of COVID-19 cases affected Italy in a short period, causing a difficult supply of medical equipment. To deal with the problem, many healthcare operators readapted different masks to medical devices, but no experiment was conducted to evaluate their performance. The aims of our study were: to assess the performances of three masks and a CPAP helmet in their original configuration and after modifications, in the maintenance of mean pressure and half-amplitude variations using different PEEP valves and to analyse the impact of antibacterial (AB) or antibacterial-viral (ABV) pre-valve PEEP filters on the effective PEEP delivered to the patients. Four pressure ports were installed on each mask (three on helmet), mean values and half amplitudes of pressure were recorded. Tests were performed with any, AB, ABV filter before the PEEP valve. CPAP helmet was the most efficient interface producing more stable mean pressure and less prominent half-amplitude variations but the non-medical masks, especially after the modifications, maintained a stable mean pressure value with only a moderate increase of half-amplitude. The use of AB and ABV filters, produced respectively an increase of 2,23% and 16.5% in mean pressure, compared to no filter condition. CPAP helmet is the most reliable interface in terms of detected performance, but readapted masks can assure almost a similar performance. The use of ABV filters before the PEEP valve significantly increases the detected mean pressure while the AB filters have almost a neutral effect.