Aerosol generation with the use of positive pressure ventilation via supraglottic airway devices: an observational study

Abstract

The amount of aerosol generation associated with the use of positive pressure ventilation via a supraglottic airway device has not been quantified. We conducted a two-group, two-centre, prospective cohort study in which we recruited 21 low-risk adult patients scheduled for elective surgery under general anaesthesia with second-generation supraglottic airway devices. An optical particle sizer and an isokinetic sampling probe were used to record particle concentrations per second at different size distributions (0.3–10 μm) during use as well as baseline levels during two common activities (conversation and coughing). There was a median (IQR [range]) peak increase of 2.8 (1.5–4.5 [1–28.1]) and 4.1 (2.0–7.1 [1–18.2]) times background concentrations during SAD insertion and removal. Most of the particles generated during supraglottic airway insertion (85.0%) and removal (85.3%) were < 3 μm diameter. Median (IQR [range]) aerosol concentration generated by insertion (1.1 (0.6–5.1 [0.2–22.3]) particles.cm−3) and removal (2.1 (0.5–3.0 [0.1–18.9]) particles.cm−3) of SADs were significantly lower than those produced during continuous talking (44.5 (28.3–70.5 [2.0–134.5]) particles.cm−3) and coughing (141.0 (98.3–202.8 [4.0–296.5]) particles.cm−3) (p < 0.001). The aerosol levels produced were similar with the two devices. The proportion of easily inhaled and small particles (<1 μm) produced during insertion (57.5%) and removal (57.5%) was much lower than during talking (99.1%) and coughing (99.6%). These results suggest that the use of supraglottic airway devices in low-risk patients, even with positive pressure ventilation, generates fewer aerosols than speaking and coughing in awake patients.