Realtime, Qualitative Imaging Of Exhaled Airflow Patterns And The Impact Of Infection Control Measures On These

Image and analyse exhaled airflow patterns with respiratory activities in a clinical scenario and the impact of infection control practices in context of COVID19 pandemic.

 

Iladevi Cataract & IOL Research Centre and Raghudeep Eye Hospital

10 patients attending ophthalmic outpatient clinic(OPD) and operating room(OR) were included. Using Schlieren imaging, exhaled airflow patterns were documented with/without an N95 mask or face shield during respiratory activities. Recordings were performed with and without room air conditioning turned on. Exhaled airflow patterns in OPD and OR when using versus not using these infection control measures, as well as the impact of room air circulation on these were compared.

There was a forward stream of exhaled air from the patient’s mouth/nose during all respiratory activities. An N95 mask dampened its intensity and forward transmission. Taping the mask around the nasal bridge further reduced airflow leakage. A mechanical barrier in front of the patient’s face blocked forward propagation of the exhaled airflow. Turning on a forceful and direct draft of air over the surgeon’s working area dampened and diverted the exhaled airflow away from the surgeons’ breathing area. This effect was particularly pronounced in the OR, with the overhead laminar airflow.

 

Using masks /mechanical barriers and taping the mask reduces potential dissemination of aerosols and thereby human and surface contamination. Using a high force airflow with the draft facing downwards can dampen and divert the exhaled airflow away from healthcare providers. These simple interventions can be very useful for clinical practices.