A technique known as cryotherapy, where liquid nitrogen at nearly minus 200oC is sprayed into the airways to destroy malfunctioning nerves, is being tested in a trial involving several British hospitals, according to a report by The Daily Mail.

The new treatment, which is being tested on chronic bronchitis, targets the thickened airway tissue by freezing it. The tissue is first rapidly frozen then allowed to thaw before it’s frozen again.

In the procedure, a catheter is inserted into the airway via the throat and navigated to where airways are thickened (as seen from a prior MRI scan). Once in place, liquid nitrogen is sprayed through a small device inserted via the catheter.

The sprayed area is allowed to thaw naturally in minutes, then blasted repeatedly until the target tissue is destroyed.

According to the article, the cycle of freezing and thawing destroys the tissue, allowing healthy cells to develop in their place, and improves breathing. The cycle can be repeated several times.

The flash-freeze and slow thaw of tissue has been shown to destroy targeted cells, but doesn’t affect collagen, the tough fibrous protein that provides a scaffold for healthy tissue to regrow.

The report noted that the approach has been used to treat a pre-cancerous disease caused by chronic acid reflux called Barrett’s esophagus, and esophageal cancer.