In easter 1999 I saw 'The Abyss'. When one of the characters where breathing liquid another wiever noticed that this is impossible. I corrected him. It is possible to breathe in liquid. We have all done so for nine months.

This kind of liquid got medical use. It's name is perflubron. When a respiratory failure occurs perflubron is used. Acute respiratory failure has many reasons, premature birth, infection, traumatic shock, severe burns, and inhalation of toxic substances. As the lung becomes less able to provide oxygen and remove carbon dioxide from the blood, acidosis and oxygen starvation threaten all organs. Respiratory distress syndrome (RDS), a severe, life-threatening form of respiratory failure, is characterized by loss of normal lung function. RDS affects approximately 200,000 patients annually in the United States.

The first reported "liquid breathing" experiments in the 1960's tried to make an alternative method for supporting distressed lungs. Researchers found that mice could survive several hours with their lungs filled with an oxygenated saline solution; subsequent use of oxygenated silicone oils met with some success, but these fluids were ultimately found to be toxic. The most significant finding of this period was the potential for use of perfluorochemical (PFC) liquids. These liquids are clear, colorless, odorless, no conducting, and nonflammable; they are approximately twice as dense as water, and are capable of dissolving large amounts of physiologically important gases (oxygen and carbon dioxide). PFCs are generally very chemically stable compounds, remaining unchanged in body tissues.

The first physiological tests of PFCs demonstrated that mice and rats submersed in oxygenated fluids could survive for long periods. These findings led to extensive lung physiology studies of liquid breathing using "tidal" or "total" liquid ventilation. This technique involves the complete filling of the lungs with a PFC and, by use of a special liquid ventilator machine, recirculation of the PFC between the patient's lungs and various mechanical components that perform gas exchange, filtration and temperature control. The first clinical study of premature babies was performed in 1989. While these studies demonstrated improvement in the patients' lung compliance and gas exchange, further clinical studies were not pursued due to the lack of a clinically applicable liquid ventilator system and a pharmaceutical-grade PFC.

A breakthrough occurred in 1991, when it was discovered that liquid ventilation could be performed effectively in normal pigs without the use of a liquid ventilator. Sustained, highly efficient gas exchange was achieved by simply filling the lung with a PFC to a prescribed level, and then reconnecting the conventional gas ventilator. This discovery, along with expanded studies sponsored by Alliance Pharmaceutical Corp., established the feasibility of a simplified, practical method of liquid ventilation that could lead to clinical applications. The PLV technique has now been shown to produce significant improvements in lung function and viability in numerous animal studies of diseased or injured lungs. By opening closed alveoli and keeping them open with lower ventilator pressures and reduced oxygen settings, and by increasing the flow of blood to the more open portions of the lung, selected PFCs can apparently minimize lung damage and enable earlier cessation of ventilator therapy.

If this technique could be perfected is could be useful for divers and submarine escape. As we have seen this liquid has an important medical use.

For medical use perflubron is sold by Alliance Pharmaceutical Corp. under the name LiquiVent.