Effects of saline nebulization on SARS-CoV-2 RNA spreading and exhaled bio-aerosol particles in COVID-19 patients

Abstract

Nebulised therapy is the mainstay for treating obstructive airway diseases, but there is heightened concern about the potential risk for SARS-CoV-2 transmission during nebulisation in COVID-19 patients. We investigated the effects of 0.9% saline nebulisation on SARS-CoV-2 RNA spreading in 11 COVID-19 patients (5 females, mean age 62.45±9.31 yr). In 6 out of the 11 patients we also ascertained whether saline nebulisation changed the number of exhaled bioaeroosl particles. Air samples were collected using suction pumps equipped with 0.45μm 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-CoV-2 was detected more frequently in the pumps close to the patient than in those far away. After saline nebulisation, the detection of SARS-CoV-2 in the pumps close to the patient was comparable to that observed at baseline. In the pumps far from the patient, saline nebulisation slightly, but not significantly, increased SARS-CoV-2 RNA detection compared to baseline. Overall, no significant changes in the SARS-CoV-2 RNA detection were observed after saline nebulisation. At baseline, exhaled particles emission varied among patients, with two of them 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 were observed in the remaining patients. Saline nebulisation did not significantly change SARS-CoV-2 RNA spreading. Thus, there is no compelling reason to alter aerosol delivery devices for patients with established nebuliser-based regimens.