Liquid breathing is a type of respiration where people breathe an oxygenated liquid, rather than air. Long the stuff of science fiction, liquid breathing has a number of useful applications in the real world, and it has been the subject of extensive research. One obvious use is in diving, where it can assist with adjustments to pressurized environments. Doctors can also use liquid breathing in medical treatment of premature infants and people with lung damage caused by severe infections, smoke inhalation, and similar events.
In liquid breathing, the patient breathes a perfluorocarbon mixture with high oxygen concentrations. The mixture is heavy, sinking to the bottom of the lungs. It will open up the alveoli, allowing for gas exchange to take place. Typically, the entire lung is not filled, with the breathing mixture instead filling only a portion of the lung. When it is time to stop the liquid breathing, the patient's breathing apparatus can stop introducing fluid, allowing the existing perfluorocarbon to evaporate away so the patient can breathe air again.
In diving, using incompressible liquids can make diving at great depths safer. It can also prevent the need for extended decompression stops to allow a diver's body to adjust to lower pressures. People who dive and surface too quickly are at risk of serious medical problems caused by dissolved gases in the bloodstream, and some of these issues can be addressed with liquid breathing. While breathing liquid can be traumatic at first, most people grow accustomed.
In medical care, liquid breathing can help keep the lungs open. It is possible to mix medications into the liquid to treat issues like infection. Fluids such as water, pus, and so forth will rise to the top of the perfluorocarbon solution because they are lighter, allowing doctors to suction them out more easily to clear the patient's lungs. Many liquid ventilator systems can use existing medical technology, requiring no special retrofitting for a hospital to provide breathing treatments to patients with lung problems.
Accessibility of liquid breathing technology varies. Some of the most extensive research takes place in military settings, where divers can experiment with different kinds of breathing systems as part of their work. Military medical research also tends to be highly advanced, and the applications of this technique to treatment of lung trauma and damage are of particular interest in battlefield medicine, where affordable and easily-implemented treatments can greatly increase the quality of patient care.