Effects of saline nebulisation on SARS-CoV2 spreading and exhaled bio-aerosol particles in hospitalised COVID-19 patients

Francesca Buttini¹, Leonardo Gori², Fabio Morecchiato², Andrea Bartolini², Gian Maria Rossolini,² Alessandro Bartoloni², Jessica Mencarini², Ruggero Bettini¹ and Federico Lavorini²

¹Food and Drug Department, University of Parma, Parco Area delle Scienze 27A, Parma, 43124, Italy

²Department of Experimental Medicine, University of Florence, Largo Brambilla 3, Florence, 50134, Italy

Summary

Nebulised therapy is the mainstay for treating obstructive airway diseases, but there is heightened particular concern about the potential risk for SARS-CoV2 transmission during nebulisation in COVID-19 patients. In 10 patients (6 females, mean age 63±4 yr) hospitalised for COVID-19 we investigated the effects of 0.9% saline nebulisation on SARS-CoV2 spreading. In 5 out of the 10 patients we also ascertained whether saline nebulisation changed the number of exhaled particles. Air samples were collected by using suction pumps equipped with 0.45µ PTFE filters and positioned around the patient’s bed. Exhaled particles were quantified by using an optical particle counter. At baseline (i.e. before nebulisation) SARS-CoV2 was detected more in the pumps close to the patient than in those far away. In the pumps close to the patient, detection of SARS-CoV2 was similar after saline nebulisation compared to baseline. In the pumps far from the patient saline nebulisation slightly but not significantly increased SARS-CoV2 detection compared to baseline. Overall, no significant changes in the SARS-CoV2 detection was observed after saline nebulisation. At baseline, we found a large variability among patients in the exhaled particles emission, with 2 patients showing higher emission of particles than the remaining patients. Saline nebulisation induced a marked decrease in exhaled particles in the 2 patients who displayed high emission at baseline, whereas no changes was observed in the remaining. Of note, the patients who displayed high emission at baseline showed a reduction in the number of pumps positive for SARS-CoV2 after saline nebulisation. This pilot study shows that saline nebulisation does not significantly change SARS-CoV2 spreading. Thus, there is no compelling reason to alter aerosol delivery devices for patients with established nebuliser-based regimens.

Key Message

Saline nebulisation does not change SARS-CoV2 spreading.