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Personal Protection Equipment and Slit-lamp Breath Shield in the Ophthalmology Office Setting
Investigative Ophthalmology and Visual Science ; 63(7):3378-A0165, 2022.
Article in English | EMBASE | ID: covidwho-2058212
ABSTRACT

Purpose:

COVID-19 pandemic has become a major global public health challenge. The ophthalmology office setting involves close encounters between the patient and the health care workers increasing risk of viral transmission. Use of PPE decreases risk of person-to-person viral transmission. The purpose of the study was to evaluate breath-induced air currents in subjects without a facemask, with a procedure mask, with an improvised face, and in the setting of slit-lamp examination.

Methods:

Breath-induced air currents were studied in healthy volunteers utilizing a vape pod system and videography during gentle and heavy breathing simulation. Video frames at 2 seconds after the initiation of expiration were captured and analyzed.

Results:

A total of 210 recordings were made for 7 settings. Without a face mask, the aerosol moved forwards and spread vertically and horizontally reaching a mean distance of 23.1 inches for gentle, and 36.1 inches for heavy breathing at 2 seconds (P< 0.001). Using PPE the airflow patterns included a) procedure mask- forward 0 cases, upward 19 (63%) cases, side 28 (93%) cases, downward 22 (73%) cases, and backward 22 (73%) cases. Adding a tape at the upper border of the mask eliminated upward flow in all cases. b) Improvised face mask- forward 0 cases, upward 0 cases, side 30 (100%) cases, downward 30 (100%) cases, and backward 17 (57%) cases. In 14 (47%) cases trace of aerosol was detected adjacent to the front surface of the mask. Adding a second layer eliminated the trace of aerosol in all cases. In the setting of simulated slit-lamp examination without the breath shield, the aerosol reached the chin rest in 9 (60%) cases during gentle breathing and in all cases during heavy breathing. The breath shield was effective in blocking forward airflow in all cases.

Conclusions:

Use of a procedure mask by patients, while effective in blocking forward breath-induced airflow, redirects the flow upwards, potentially increasing the risk of contamination during an office procedure. An improvised facemask alters breath-induced air currents favorably and partially absorbs respiratory droplets.
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Collection: Databases of international organizations Database: EMBASE Language: English Journal: Investigative Ophthalmology and Visual Science Year: 2022 Document Type: Article

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Collection: Databases of international organizations Database: EMBASE Language: English Journal: Investigative Ophthalmology and Visual Science Year: 2022 Document Type: Article