pregnant and lactating women, patients taking nitric oxide and nitrates, patients with reported allergy to milk proteins, patients with a previous history of bronchial hyperactivity and patients with pre-existing respiratory diseases. covid-19 patients requiring intensive care or mechanical ventilation were excluded.

pregnant and lactating women, patients taking nitric oxide and nitrates, patients with reported allergy to milk proteins, patients with a previous history of bronchial hyperactivity and patients with pre-existing respiratory diseases. covid-19 patients requiring intensive care or mechanical ventilation were excluded.