Pulmonary edema, the accumulation of fluid in the lungs which can lead to respiratory failure, is not just a result of the inability of a person's lungs to clear alveolar fluid, according to researchers.
"We've found not only do they stop pumping fluid out as they're supposed to do, they've gotten confused and are actually pumping in the reverse direction, bringing fluid into the lungs," said Wolfgang M. Kuebler, PhD, MD, a physician at St Michael's Hospital in Toronto, Ontario, who was an author on the study.
The team believes the new findings have important implications for the treatment of lung edema. Stopping the pumping mechanism, although seemingly counterintuitive, is protective for the lung and important for effective treatment, according to the authors.
This new information also lends additional insight into the mechanism of action for Lasix, which was previously believed to work exclusively by targeting the kidneys. The team believes it also prevents the pumps from allowing fluid into the air spaces.
Kuebler points out that the mechanism of pumping fluid into the air spaces is similar to what happens in the fetal lung. In the womb, the lung works to pump fluids in and only after the baby is born, does that pumping mechanism reverse itself to pump fluid out.
"You can actually now interpret lung edema as a regression of the adult lung to a fetal stage," Kuebler said.