During the corona virus pandemic, preventing contamination of the anesthesia machine, critical to avoid cross‐contamination between patients, has proven challenging when treating premature infants and neonates. While attaching a HEPA filter to the endotracheal tube will protect the anesthesia machine and the gas sampling line from contamination, this contributionto the dead space makes ventilation of these small patients challenging. Direct filtration of the gas sampling line eliminates this problem;however, appropriate filters are not readily available.
Identify a small filter capable of filtering outparticles of a size similar to the SARS‐CoV‐2 virus for the gas sampling line.
We used fluorescence microspheres suspended in a solution for a challenge test to determine the filtration efficiency of various filters. The microspheres varied in diameter (0.02 µm, 0.042 µm, 0.109 µm and 0.989 µm). A fluorescence plate reader was used to evaluate the degree of fluorescence intensity in the flow‐through from various filters and referenced to the fluorescence intensity of the input.
AHEPA filter,as recommended as an anti‐viral filter, effectively filtered all the particles tested. The B. Braun PERIFIX Flat Epidural Filter was the second most effective filter, filtering particleslarger than 0.042 µm.Other filters tested did not filter fluorescence microspheres equivalent in size to a single coronavirus particle (0.07 µm).