Evaluation of Aerosol-Laden Plumes Generated by Jet Ventilation Using Background Oriented Schlieren

The risk of viral infection to healthcare workers during aerosol-generating procedures (AGPs) is an area of significant concern within the medical community. In this work, we analyze the flow patterns created by jet ventilation, a type of AGP used in laryngeal surgery, both qualitatively and quantitatively to assess the effects associated with commonly used jet ventilation settings.

We apply background oriented schlieren (BOS) imaging to visualize and analyze the aerosol-laden plume. Simultaneous direct measurements of aerosol content were performed using an optical particle sizer (OPS). Twelve configurations for jet ventilation were studied, varying the jet frequency, placement within the airway, and level of suction, and the aerosol contained in the plume was quantitatively evaluated.

Low-frequency supraglottic ventilation exhibits the lowest total signal, approximately 50% lower than the high-frequency cases and less than 10% of the low-frequency infraglottic case. The highest signal magnitude was seen in low-frequency infraglottic ventilation, 20% higher than the next highest signal with no suction. The use of suction was observed to reduce the signal by 40%-100%, with a stronger effect in the SG configuration.

Both BOS and OPS measurements reveal that a supraglottic arrangement with a pulse frequency of 0.2 Hz produces the lowest amount of plume extent and aerosol content, and that the use of suction considerably reduces the amount of aerosol content present in the plume. Qualitative agreement was observed between the BOS data and the OPS in terms of the relative signal between configurations, but not quantitatively.

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