Breathing by means of drowning is a little counter-intuitive, but it happens on occasion in hospitals across the country. Liquid ventilation (LV) is the process of partially filling the lungs with an oxygenated perfluorocarbon liquid as opposed to ventilating with a gas. The reason this works is that these perfluorocarbons have a carrying capacity for oxygen that is three times higher than blood (Tawfic and Kausalya, 2010). The applications of this technique are still be researched, but as of now, there is total liquid ventilation (which is still experimental) and partial liquid ventilation (which is already in use).
Total liquid ventilation (TLV) is the process of filling the entire lung volume, or functional residual capacity, with perfluorocarbons (PFC). Then, a liquid ventilator is attached to promote the tidal breathing with PFC. This continual flow keeps the fluid oxygenated and sustains the gas exchange necessary for survival. One possible benefit to TLV as opposed to partial liquid ventilation is that it might create a more uniform application of the PFC in the lung (Tawfic and Kausalya, 2010). But this method is still very much experimental.
Partial liquid ventilation (PLV) is similar, but the entire volume of the lung isn’t filled. In PLV, the lungs are only lined with PFC. One benefit of this treatment is that the liquid acts as an artificial surfactant (Tawfic and Kausalya, 2010). Over the past 40 years, much research has been done with liquid ventilation, each trial done with a different application of research.
One application for PLV treatment is in patients with extreme respiratory distress (Servaes and Epelman, 2009). The PFCs’ surfactant qualities help decrease the surface tension and the oxygenation of the PFCs help in the gas exchange process. For people who can’t properly inhale, or aren’t able to get the necessary gas exchange, this treatment can help.
PLV can also be used be used in the life support process of premature babies, but isn’t yet. There was a study with severely premature (gestational age 24 to 34 weeks) infants that tested this theory (Tawfic and Kausalya, 2010). This study showed improvement in the infants’ physiologic levels, including gas exchange and lung compliance (Tawfic and Kausalya, 2010). Unfortunately, the respiratory distress was so severe that none of the infants survived.
In conclusion, liquid ventilation still has a long way to go before it can be considered a viable and effective option for respiratory distress treatment in adults or infants, but the science is there and is being worked on.
References
Tawfic, Q.A. and Kausalya, R. (2010). Liquid ventilation. Oman Medical Journal, 26(1), 4-9. Doi: 10. 5001/omj.2011.02
Servaes, S. and Epelman, M. (2009). Perflubron residua: 12 years following therapy. Pediatric Radiology, 39, 393 – 395. Doi: 10.1007/s00247-008-1139-8
The main question that comes to mind in regards to this type of ventilation is what happens afterward? The post states that the perfluorocarbons have a higher carrying capacity for oxygen than does the blood. If the patient is able to go off of the total ventilation, and the liquid is removed from the lungs, will the patient have a difficult time re-adapting to normal respiration?
ReplyDelete