For patients struggling to breathe because of acute respiratory failure, clearing mucus from the airways is a routine part of treatment. Mucoactive agents are widely used for this purpose. But after years of clinical use, one question remains: Do mucoactive agents actually help?
To figure this out, researchers designed a large study called the MARCH (Mucoactives in Acute Respiratory Failure: Carbocisteine and Hypertonic Saline) randomized trial, which included nearly 2,000 adults across 71 hospitals in the United Kingdom who were on ventilators and having trouble clearing mucus. The focus of the study was to determine the effectiveness of two widely used mucoactive agents: carbocisteine and hypertonic saline (HTS).
The drugs did not deliver the hoped-for benefits. Those who were on carbocisteine spent about the same amount of time on the ventilator as those who didn’t get any treatment, and the same was true for HTS. Instead, the medications appeared to do more harm than good. Patients treated with these mucoactive agents had side effects like bleeding in the stomach, tightened airways and a drop in blood oxygen levels.








