FDA revokes EUA protective barrier enclosures
The FDA revoked their EUA for passive protective barriers, see their letter dated 8/20/20
This effectively shuts down further study/use of this COVID Isolation Box unless we can argue otherwise with the FDA... a tall task.
The Begley study (cited in the FDA’s revocation letter) also addresses only usability and not infection control and employs a rigid box, the design of which we were also not satisfied with having tested it…. and that is in part he genesis of our current isolation box which addresses the shortfalls identified in this article. We feel strongly that this revocation is premature and is impeding efforts to study and fine tune the designs of these enclosures. To our knowledge, no adverse events reported have been reported in response to use of these boxes. One of the FDA cited studies in the EUA revocation letter is a bench study which we believe has significant design flaws in that it does't represent the real world use. The other is a series of only 36 intubations and identifies issues with the use of the “original” intubation box design, which has been abandoned by virtually all subsequent designs due to the aforementioned reasons.
We disagree with the FDA on their revocation of the EUA and believe that such revocation is harmful. The fact that they simply revoked the EUA for the non-negative pressure enclosures but not for negative pressure enclosures, without any further details is rather random. From our review of some of the negative pressure box designs, we have concerns about some of their ability to draw enough airflow to provide effective protection… the ones that use a single wall suction as their negative flow source. Additionally, flow into, within and out of an enclosure requires modeling and studying for optimum efficacy. Some of the designs (like PVC pipe with holes drilled into them and placed around the peripheral) are not likely effective. The CBA Negative Pressure Covid Box #1222 that was started involves such modeling (see issues section of that project)
Of note, we here at BMC have been very interested in optimizing a negative pressure enclosure for use. Our Equitable Healthcare Solutions Group, has at least 3 working prototypes. 2/3 of them look like the one published here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7413643/ It would be important to optimize designs for affordable accessible production-supply-use of these types of encolsures which could also be deployed for those requiring aeorsolizing procedures (including nebulizer treatments).