Lack of effect of an in-line filter on cardiopulmonary exercise testing variables in healthy subjects

Abstract

Purpose: Pathogen transmission during cardio-pulmonary exercise testing (CPET) is caused by carrier aerosols generated during respiration.

Methods: Ten healthy volunteers (age range: 34 ± 15; 4 females) were recruited to see if the physiological reactions to ramp-incremental CPET on a cycle ergometer were affected using an in-line filter placed between the mouthpiece and the flow sensor. The tests were in random order with or without an in-line bacterial/viral spirometer filter. The work rate aligned, time interpolated 10 s bin data were compared throughout the exercise period.

Results: From rest to peak exercise, filter use increased only minute ventilation ([Formula: see text]_E) (Δ[Formula: see text]_E = 1.56 ± 0.70 L/min, P < 0.001) and tidal volume (V_T) (ΔV_T = 0.10 ± 0.11 L, P = 0.014). Over the entire test, the slope of the residuals for [Formula: see text]CO₂ was positive (0.035 ± 0.041 (ΔL/L), P = 0.027). During a ramp-incremental CPET in healthy subjects, an in-line filter increased [Formula: see text]_E and V_T but not metabolic rate.

Conclusion: In conclusion, using an in-line filter is feasible, does not affect appreciably the physiological variables, and may mitigate risk of aerosol dispersion during CPET.

Keywords: Aerosol-generating procedures; COVID-19; Cardiopulmonary exercise testing; In-line filter; Respiratory viruses; Ventilation.