Talk:Liquid breathing

Move to Liquid breathing ?
This should really be cleaned up and moved to Liquid breathing. Although this article uses the terms "liquid breathing" and "fluid breathing" to mean the same thing, it in fact is referring to the breathing of a liquid. Since all breathing is breathing of a fluid, the improper use of that term should be removed. If nobody else does this first, I'll get around to it eventually. Merenta 20:34, 10 November 2004 (UTC)


 * So what happened?, the Liquid breathing just redirects to this page. I agree that "fluid breathing" is a misnomer, as air is fluid--JinFX HuangDi 1968 06:12, 18 February 2005 (UTC)


 * Argh! Air... is... a... fluid... 24.218.139.205 05:53, 24 June 2005 (UTC)


 * Support, for the reasons suggested above. Alai 23:47, 27 August 2005 (UTC)
 * Support. You're absolutely right, of course, Merenta. &mdash; Knowledge Seeker &#2470; 00:34, 1 September 2005 (UTC)

This article has been renamed after the result of a move request. Dragons flight 22:47, 2 September 2005 (UTC)

Questions
After reading this fascinating article, I'm left with some questions. I don't know if the answers exist anywhere.


 * 1) Does the subject breathe, using the muscles around the lungs? There is a mention of a pump in some studies. But could the lungs actually work to inhale/exhale liquid?
 * 2) Has any subject been adult and conscious during any part of the process? Have their been any personal descriptions of the experience? I imagine that filling the lungs would be like drowning and very distressing, but what about the stable experience of breathing the liquid?
 * 3) "The animal was tilted for 15 seconds and the liquid drained from the lungs". Is it really that simple? I am thinking of the efforts involved (it would seem) after a person has water in their lungs from a near-drowning. Much pumping of the chest, coughing etc. Or is all that just Hollywood?

--Notinasnaid 17:31, 8 November 2005 (UTC)


 * A fetus actually builds its muscles by breathing amniotic fluid, and so the subject's lungs could work pretty well at this. The pump is to bring the liquid through the rebreathing apparatus that scavanges CO2 and replenishes O2.
 * As mentioned in a few places, people have been awake for the "mist" style of this therapy, but this is a gradual process of alveoli filling up, rather than bronchi etc.
 * Water has a fairly low vapor pressure, and doesn't allow oxygen to pass through very well. As in the more moderate types of therapy, the alveoli can stay filled as the perfluorocarbon evaporates.  However, in clinical trials, I'm sure that the animals cough and sputter, and the tilting is just to help with that process.  Researchers tend to overlook the work that animals themselves do...
 * --Joel 18:05, 8 November 2005 (UTC)

Perhaps I could add that after scouring the page, I have no good mental picture of how this works. Does the person stop moving their lungs and the liquid is pumped in and out by a machine, or does the person need to move their lungs normally? Is this a large apparatus, heavy, noisy? Would you be able to do normal activity or can you only lie there on a fancy table? 92.21.158.159 (talk) 13:31, 12 July 2012 (UTC)

- Experience:

I hope I'm adding this correctly. I have experienced liquid breathing as an adult, in 2015. I awoke in the ICU and my lungs were partially filled. (Between 30-40%) I then had to remain on the ventilator for another 24hr+ until I could be weaned off the machine. At first it felt like I was suffocating. I was in total panic mode. After much reassuring from my nurse, I calmed myself by relating the experience to using a trick I learned as a child. (When swimming underwater, I took tiny little micro breaths and was able to hold my breath longer.) After I accepted the fact that I was not being smothered to death, it was apparent that I was breathing fine and all would be okay. Very surreal! Reach me @leannebug13@gmail.com for additional info. — Preceding unsigned comment added by Leannebug (talk • contribs) 03:30, 4 November 2019 (UTC)

RD article
I'd read in a fairly recent article that one Dr. Shaffer of Temple University Hospital wanted to use PFC in premature babies since the procedure had worked fine in his experience. He claimed that his research was frustrated because he couldn't get the funding needed to apply for FDA approval. He said that the biggest reason critics object to its use is that it distracts from what causes much of premature births in the first place--drug and alcohol abuse by the mother. If this is a true claim by critics, its absurdity can be seen by all. --Jlujan69 22:25, 10 August 2006 (UTC)


 * Last I looked into this, the problem was that the FDA forced Alliance in the clinical trials to compare partial liquid ventilation PLV (used with regular ventilators), to gas-only ventilation using top of the line high frequency oscillating ventilators (HFOV). When the PLV didn't show any better results, instead of saying "Gee, that's remarkable, just putting in some PFC with a regular vent does as well as using a state of the art new HFOV ventiation system!", they closed the tests down and didn't approve Perflubron for any more trials. Alliance's stock went though the floor, they couldn't generate any new capital, and that was that. In a rational world they'd have tried comparing (say) HFOV with and without PLV. I am told, BTW, that HFOV works fine with PLV, so they're perfectly combatible.
 * If you want to look at real nuts and bolts social issues for why PLV gets little funding from drug developers (which is the seed money that provides the studies that attract federal funding), it has to do with general lack of funds for research and treatment in premature babies. It is prefectly true the premies have no money. And they are generally born to young people of very low socioeconomic class who have no money, either--- yep, that's also correct. This is not a promising market for a pharm developer. Give me a pill for rich and worried middle-aged former yuppie people, which they have to take every day for the rest of their lives. Crestor. If you think there's any comparitive incentive to develop liquid ventilation fluids which require the same drug approval process, considering how and in whom they will be used, think it out again. And yes, the Leftists are right about this. The Left can't be wrong ALL the time. -- S B Harris 22:50, 10 August 2006 (UTC)

Comments and Suggestions For Revision
It is interesting to see an article that is pretty factually accurate, but really misses the point in almost all the critical areas. I hate editing Wikipedia pieces (but don't mind writing the first one). If anyone is interested in "fixing" this piece, let me know - meanwhile here are some corrections and comments:

First, there is one critical missed point that renders much of the discussion and speculation about diving and space-flight applications moot. The major problem with TLV isn't simply the density of PFCs, but rather the fundamental physics of fluid flow. While different PFCs have differing viscosities, on average PFC is 80 times more viscous than air. Whether it is a mouse, a dog, or cat, if you look at the literature you will notice that 5-7 breaths a minute is the maximum achieveable (Shaffer T H, Forman DL, et al. Physiological effects of ventilation with liquid fluorocarbon at controlled temperatures. Undersea Biomed Res. 1984 Sep;11(3):287-98.). You cannot do more than 5-7 breaths a minute because the liquid is too viscous compared to air. Now, it would be possible to avoid the limitation on BPMs with PFCs in an animal thats use a flow-through system for respiration, such as fish, or birds. But not in most vertebrates.

In 1976, Miyamoto and Mikami (Maximum capacity of ventilation and efficiency of gas exchange during liquid breathing in guinea pigs. Jpn J Physiol. 1976;26(6):603-18.) calculated that the resting man normally produces 192 mL/min of CO2 (S.T.P.). This level of CO2 production would require TLV (PFC) ventilation volumes of about 4 L/min (or about 70 mL/kg/min). Although this is ~70% of the normal gas ventilatory flow for a resting adult, it is near the upper limit of flows that can be accomplished at normal pressures in TLV (Kylstra, 1974). The higher peak and mean ventilating pressures necessary to move the amount of liquid required for CO2 exchange in TLV would expose the lungs to an increased risk of barotrauma (pressure injury) and volu-trauma (over-distention injury).

During higher than normal CO2 production rates, such as physical exertion or illness, TLV would clearly not be adequate for CO2 removal. Some examples of high CO2 (hypercapnic) states are, 1) increased metabolic states (e.g. cancer, infection, burns), 2) states of physiologic stress (e.g. hyperthermia, agitation), 3) post-ischemic conditions where substantial metabolic debt has been incurred, and 4) physical exertion (such as swimming and diving). Under all these conditions the need to rapidly unload CO22 and deliver large amounts of O2 is essential. Such hypercapnic/hypercarbic states are also frequently present in shock due to sepsis or trauma, and thought to be due to both an increased production of CO2, and decreased elimination of CO2 due to low blood flow or pulmonary edema.

In anesthetized, paralyzed, normothermic dogs, TLV is capable of maintaining steady-state gas exchange with adequate O2 delivery and CO2 removal. However, TLV is not cannot deliver steady-state CO2 removal under basal metabolic conditions in smaller animals with higher specific metabolic rates, such as guinea pigs. As Matthews and co-workers document (Matthews WH, Balzer RH, et al. Steady-state gas exchange in normothermic, anesthetized, liquid-ventilated dogs. Undersea Biomed Res. 1978 Dec;5(4):341-54), the parameters for maintaining normocapnia in anesthetized beagles are narrow, even under basal normothermic metabolic conditions. In this study, as TLV rates were increased from 2.8 to 5.6 liquid breaths per minute, and alveolar ventilation was increased from 574 to 600 mL/min/animal (an increase of 4%), the pa CO2 continued to increase until dangerous hypercapnia occurred. The authors suggested that this increase was due to a 2% drop in liquid-alveolar ventilation, however using their own formulas and data, it easy to show by calculation that the dogs receiving higher ventilation rates actually have higher rates of alveolar ventilation (dVa/dt). These results would seem paradoxical until consideration is given to the inverse relationship of pa CO2 to alveolar ventilation, a relationship which holds only under equilibrium conditions. From a practical standpoint, this means TLV cannot be used in situations where humans or other mammals exert themselves. Under conditions of stress or exertion, respiratory rate increases dramatically. If a person or animal is running, or even engaging in normal activities, metabolic demands and CO2 generation will increase beyond the capability of TLV to provide adequate gas exchange.

The statement, “As in Kylstra's studies, Clark had problems due to the size of the animals' airways. The tiny size limited the amount of liquid that could get into the lungs. For that and other reasons, carbon dioxide tended to build up in the system and could not be removed fast enough," is incorrect. The “small size" of mouse airways is irrelevant to liquid distribution and to limitations on liquid breath rate. The small airways in a mouse are the same size as the small airways in a human or an elephant. PFCs have incredible spreading co-efficients and extraordinarily low surface tensions. They will get into almost any space, or through almost any hole. Indeed, they are used for leak-detection. The real limiting factor is that alveoli in both mice and men are scaled pretty much the same because of the physics of gas exchange. The same is true of capillaries in all mammals because of the physics of mass exchange and diffusion (Dawson, T. H. (1991). Engineering Design of the Cardiovascular System of Mammals. Prentice Hall Biophysics and Bioengineering Series (ed. A. Noordergraaf). Englewood Cliffs, NJ: Prentice Hall).

A capillary in a mouse is the same size as that in an elephant. Consequently, blood pressure, mean arterial pressure, and capillary opening pressure, are about the same for all mammals (giraffe's have their own issues). Resting blood pressure in a mouse and a man is virtually the same (Gregg, D. E., Eckstein, R. W. and Fineberg, M. H. (1937). Pressure pulses and blood pressure values in unanesthetized dogs, Am. J. Physiol. 118,399-410, and Woodbury, R. A. and Hamilton, W. F. (1937). Blood pressure studies in small animals. Am. J. Physiol. 119,663 -674.).

Lungs were injured by many PFCs used in early liquid ventilation studies, because the vapor pressure was too high, and PFC that gets trapped in alveoli, or gets into the lung parenchyma, turns into gas. This PFC gas is not eliminated rapidly enough to avoid serious injury. If you inject 1 ml of FC-75 (vapor pressure of 30 torr at STP) into a mouse's peritoneum, the mouse inflates to about the size of a golf ball over a time course of several hours. A few days to a week later, the animal dies from starvation because its abdominal viscera are compressed (there is no fat on the animal at necropsy, and its organs are shrunken from starvation). Perflubron (perfluorooctylbromide) is the only molecularly consistent PFC. All others contain different chain lengths of the constituent perflurochemical. For example, the 3M Fluorinert compounds which were often used for early liquid ventilation experiments such as FC-75 (perfluoro(butyltetrahydrofuran), as previously noted, has a vapor pressure of 30 torr at STP and FC-77 (perfluorooctane) has a vapor pressure of 85 torr. Thus, the vapor pressure for a given PFC is the average of the molecular species present. As a consequence, even a little high vapor pressure PFC will cause lung injury. By contrast, the vapor pressure for perflubron which is the only PFC so far approved for clinical trials, is 11 torr and that is the “true” vapor pressure of perflubron since all molecules are of the same chain length.

These claims are largely incorrect and unsubstantiated:

"Profound expertise is mandatory to perform and maintain filling of the lung with perfluorocarbon to functional residual capacity (FRC). Disruption of PLV immediately deteriorates gas exchange. Incomplete filling of the lung has been shown to be less effective than filling the lung to functional residual capacity volume. Severe adverse events affecting gas exchange and pulmonary circulation limit the use of PLV."

First it is easy to maintain filling to FRC, and Alliance Pharmaceuticals had developed systems to measure the amount of PFC vaporized in real time, as well as to condense vaporized perflubron, measure it, and collect it for return the patient.

I don't know what "disruption" of PLV means, but PLV is only initiated in the first place because gas exchange is inadequate! Of course, if you stop adding perflubron, gas exchange will deteriorate -- it will go back to about what it was before -- unless the injury has improved or resolved. It is not easy to disrupt PLV because once the liquid is in the lungs it is in there until it vaporizes. The only way to get it out would be turn the patient upside down and attempt to drain it of out of him -- and even then you will still end up with pretty near FRC in the lungs. I know this because we tried to recover as much PFC from our experimental animals as possible in order to save money as all the PFCs are very expensive. The statement "Severe adverse events affecting gas exchange and pulmonary circulation limit the use of PLV," is totally unsupported and incorrect. There are no adverse hemodynamic effects, and the worst that can be said of PLV in clinical trials is that did little better, and maybe a bit worse, than gas ventilated patients AFTER the new lung protective ventilation strategies were adopted. Nobody ever tried PLV with the lower tidal volumes and lung protective ventilation strategies because Alliance ran out of money. Nor were there any clinical studies with high frequency oscillation ventilation (where PLV absolutely shines and all the issues of baro and volutrauma from liquid moving more slowly as the lungs are inflated and deflated go away). The tragedy of therapeutic PLV for respiratory distress syndrome is that the clinical trials were so badly designed and Alliance’s handling of the technology was even more poorly managed (Reiss SG. Understanding the fundamentals of perfluorocarbons and perfluorocarbon emulsions relevant to in vivo oxygen delivery. Artif Cells Blood Substit Immobil Biotechnol. 2005;33(1):47-63).

These incorrect statements should be supported by peer-reviewed references, or deleted.

Finally, the really important thing about Gas Liquid Ventilation (GLV) cooling or warming, and the major innovation, is that it uncouples heat exchange from gas exchange. Inducing hypothermia using TLV is problematic because PFC viscosity (pressure/flow) also places a limit on the rate at which heat can be extracted from an animal or patient using TLV. In addition to the CO2 diffusion limitation, there is indirect evidence suggesting that thermal equilibrium is not reached between blood and liquid in small airways at high TLV "alveolar ventilation" rates. Thus, there appears to be a heat-diffusion limitation to TLV that is analogous to the CO2 diffusion limitation.

This phenomenon may explain why Shaffer's TLV cat studies failed to achieve concurrent increases in the rates of animal core cooling, when significantly greater PFC temperature gradients were used (Shaffer T H, Forman DL, et al. Physiological effects of ventilation with liquid fluorocarbon at controlled temperatures. Undersea Biomed Res. 1984 Sep;11(3):287-98). Shaffer found that decreasing PFC infusion temperature from approximately 20.degrees C to about 10 degrees C (from ∆T =15.degrees C to ∆T =24.degrees C), resulted in cooling rates increasing from 0.13.degrees C/min (7.8 degrees C/hr) to 0.15.degrees C/min (9.0degrees C/hr) a change of only 15%. This 15% increase occurred despite an increase of ∆T equal to 60%. These results suggest a sharp decline in the efficiency of heat extraction with increased ∆T at higher TLV ventilation rates (in this experiment, rate was increased from 4.5 to 5.3 liquid breaths/min).

In Shaffer's study, the authors calculate from PFC inspiration and expiration temperature differences, a 96% increase in heat extraction per kg from their animals at the 10degrees C PFC infusion temperature versus that calculated at 20degrees C. However, the fact is that this increase in heat extraction does not show up in the rate of body core cooling (15%), to which it should be proportional. This indicates that Shaffer's calculations of heat removal performed on the basis of integrated measurements of expired fluid temperatures must have been in error. As further evidence of this error, calculations of expected cooling rates of animals used in this study (using a reasonable 0.8 cal/g/degrees C, or kcal/kg/.degrees C average specific heat capacity for the body), indicate that up to half of the heat extraction calculated by PFC temperature differences in this experiment are unaccounted for even at the fastest cooling rates. For example, an animal with an average 0.8 kcal/kg/.degrees C specific heat capacity, cooling at the reported rate of 9.0.degree. C/hr, could theoretically give up heat at a rate no faster than (0.8 kcal/kg/C)(4184 J/kcal)(9 C/hr)=30,124 J/kg/hr. However, Shaffer's experiment reports on the basis of temperature readings of PFC infused and expired, the extraction of 65,637 J/kg/hr. It is likely that the difficult integration of [expired fluid temperature] versus (fluid volume) curve for this experiment was in error by a factor of 2.0. For examples of experiments in which integrated cooling rates calculated from PFC temperature differences match actual animal body cooling, see: Harris SB, Darwin MG, et al. Rapid (0.5 degrees C/min) minimally invasive induction of hypothermia using cold perfluorochemical lung lavage in dogs. Resuscitation. 2001 Aug;50(2):189-204. The authors found that at rapid (machine-controlled) liquid infusion and removal rates, and peak fluid temperatures do not accurately reflect volume-averaged fluid temperatures, or fluid heats.

In TLV too few breaths and too little turbulence probably results in a lot of the liquid at the terminal end of the airways remaining there from one breath to the next. Heat exchange is very poor. In conclusion it is not possible to meet the gas exchange demands of a critically ill patient with TLV, nor is it possible to meet the gas exchange demands of humans under real-world conditions making TLV with currently available PFCs impossible for applications such deep sea diving or space travel. PLV remains a promising modality for the treatment of respiratory distress and for the induction of hyper- or hypothermia (Wauer RR, Gama de Abreu M. 4th European symposium on perfluorocarbon application. Eur J Med Res. 2006 Mar 16;11 Suppl 1:1-12).

Unmentioned in the Wikipedia article are potent anti-inflammatory and immune modulating properties of most PFCs, properties which undoubtedly contribute the salutary effects of PLV in the setting of lung injury (Haeberle HA, et al. Perflubron reduces lung inflammation in respiratory syncytial virus infection by inhibiting chemokine expression and nuclear factor-kappa B activation. Am J Respir Crit Care Med. 2002 May 15;165(10):1433-8, Forman MB, et al. Pharmacologic perturbation of neutrophils by Fluosol results in a sustained reduction in infarct size in the canine model of reperfusion. J Am Coll Cardiol. 1992 Jan;19(1):205-16 and Jiang L, et al. Effect of different ventilation modes with FC-77 on pulmonary inflammatory reaction in piglets after cardiopulmonary bypass. Pediatr Pulmonol. 2007 Feb;42(2):150).

--Necrobiologist 11:04, 3 February 2007 (UTC)

Space application not possible
I have added a paragraph about the impossibility of using liquid breathing to withstand high G-forces. Source: http://yarchive.net/med/liquid_breathe.html 17:47, 2 March 2006 User:71.247.67.39

Also, the trials by Alliance produced little results. I added the following sentence:

Unfortunately, results of the clinical trials were disappointing and Alliance is no longer pursuing partial liquid ventilation application.

-neolex 20:02, 2 March 2006 User:71.247.67.39


 * For the record, the space application is possible, just not with fluorocarbons. See the discussion in "Removed from Article" below. Cryobiologist 20:39, 17 January 2007 (UTC)

Removed from article
"However, while simultaneous immersion of the astronaut in a fluid filled chamber AND fluid breathing would mitigate G forces, the mass penalties of filling an entire space capsule with fluid would make its gross weight much higher than that of an air filled capsule, and thus the former would be less capable of high acceleration (due to lower thrust to weight) than the latter." Formatting is a bit odd, as is wording. Furthermore, the paragraph doesn't seem to have a point to make. Can anyone rewrite it, or comment on it? -- Ec5618 22:55, 2 June 2006 (UTC)
 * Yes, the idea is basically wrong. When you are floating in fluid you are no more weightless than when lying on a waterbed; you just happen to be a bit more well-supported. A watermattress which allows nearly total sinking should do almost as well as a tank, but it's not worth doing because the limiting factor to g's an astronaut can take is NOT the pressure he feels on his skin. Basically, g-load limit is due to blood pooling due to g-forces and fluid support doesn't change that. An astronaut subjected to "vertical" g's in liquid would still black out. Just as a scuba diver who has difficulty with head downward positions ala the "inversion table" will find that it's just as uncomfortable to be head downward while underwater (as I personally can testify). Again, fluid immersion is not weightlessness. Your internal organs can't tell whether you're floating in fluid or lying on a bed of nails-- it's all the same to them. 00:41, 3 June 2006 User:Sbharris


 * No, the idea is basically right. At high gees, there is no blood pooling in extremities without distention.  And there is no distention without pressure differential.  That is how anti-g suits (see g-suit) protect pilots from blacking out; they increase external pressure on lower parts of the body to counteract inreased internal pressure.  A new type of anti-g suit, the Libelle Suit, actually surrounds the pilot with water, allowing pilots to remain conscious at 12g.  The principle of zero-g equivalence with water suspension works, the only limitation being air cavities and tissues with density different from water. Cryobiologist 21:12, 12 December 2006 (UTC)
 * Okay, I admit that in the limit of suspension in an anti-acceleration fluid of the same density as blood, and with all vessels inside the body supported internally in the same way, you could take very high acceleration-- in theory all you like--- and wouldn't feel it. In practice, since blood and tissues do have different density (for example the brain would float in blood, so blood would pool at the bottom of the brain in verticle g-load), and there are some air spaces here and there, the relatively dense vessels have to be supported by bone, connective tissue, fat, etc. And the even denser bones in the same way. If you filled the lungs with a fluid of the density of blood, and the mediastenum also, you could in theory keep the aorta from tearing off the top of the heart with a big forward deceleration (as commonly happens). Fluids of near-blood different density should give some help there, but by the time you get to perfluorocarbons (PFC)s at 1.8 times the density of water, now your problem is even worse than before, since the ligaments which hold the lungs aren't designed to hold big heavy bags of PFC at high g, and their effective weight is the difference between water and PFC density, times volume. I suppose I'm saying that the problems of liquid-breathing have to be separated from the problems of high-g acceleration, and in any case, so long as we're talking about the perfluorocarbons or any fluid much different in density from water or blood, it doesn't work to fully ameliorate g-stress whether it's in the lungs or you're floating in it. For example, an astronaut with density of water, fully immersed in PFC with specific gravity 1.8, would be squashed against the roof of his tank with a weight equivalent to 0.8 g, and this would increase by 0.8 g for every g of acceleration, so no help there. But if you let him float freely at the surface of a tank of PFC, he'd have some part of his body (45% or something) above the PFC surface (presumably in gas), and that part of him in the air would get no help at all from g-effects. His lungs, of course, would be squashed by the differential weight of PFC, whether he were floating in PFC or not. S  B Harris 22:42, 13 December 2006 (UTC)

Space section is all wrong
The section on using this in space travel is based around a very common misconception. It contains this sentence, which seems to sum up the misconception:

"A person immersed in liquid of the same density as tissue has acceleration forces distributed around the body, rather than applied at a single point such as a seat or harness straps. This principle is used in the Libelle G-suit, which allows aircraft pilots to remain conscious and functioning at more than 10 G acceleration by surrounding them with water in a rigid suit."

The problem here is that a G-suit works because it applies unequal pressure to a pilots body; it squeezes the legs and lower abdomen (but not upper body) so that blood can't pool in the lower body during high-g maneuvers. If the suit applied the same pressure evenly across the pilots body, it would be useless. The particular flight suit linked to in the article is simply a regular flight suit that has a system to automatically change the pressure being applies across different parts of the pilot's body, allowing it to provide optimal support during different types of maneuvers - but it still works on the principle of applying unequal pressure to prevent blood from pooling in different parts of the body.

Being immersed in a fluid would not magically protect you from acceleration forces. For example, if a person were standing immersed in a tank of fluid and the entire tank began accelerating upward, the person’s blood would still pool in his lower body and eventually cause a blackout. His lower body would get slightly larger as it fills with blood and his upper body would get slightly smaller as the blood drains out. Since the fluid is applying pressure evenly across his entire body surface, it wouldn't do him any good.

20:39, 14 February 2007 User:128.227.142.57


 * The space section is correct, and is supported by an authoritative secondary source (Textbook of Medical Physiology). The reason fluid immersion prevents blood pooling is because hydrostatic pressure is NOT the same at all points on the body when g forces are applied.  At one gee, water pressure increases by 0.5 psi per foot of depth.  At 10 gees, water pressure increases by 5 psi per foot of depth.  Under water, at 10 gees, a seated pilot's legs will experience an external pressure of 15 psi relative to the head, which exactly counterbalances internal pressures that would otherwise distend the legs and cause blood pooling.  Think of a bag of water immersed in a tank of water.  There's no force to change the shape of the bag regardless of gees.


 * The Libelle G-suit, by the way, is a purely passive device. The only "automatic" change in pressure applied to different parts of the pilot's body is due to the water bladders which experience passive hydrodrastic pressure gradients by the mechanism described above.  Please see the review article Current Concepts in Acceleration Physiology Cryobiologist 23:33, 14 February 2007 (UTC)

Fiction
I remember an episode of Captain Simian and the Space Monkeys in which they crashed onto a water-planet, and were concerned with drowning until they realized they could breathe the "water" and called it "wet air." 05:48, 19 February 2007 User:75.72.21.221

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . For addition to the Fiction section: There is a children's series called "Dark Life" by Kat Falls (ages 8-12). The characters inhale a liquid substance called Liquigen that allows them to breathe underwater without additional breathing apparatuses.

Falls, K. (2010). Dark life. New York: Scholastic Press.

When fifteen-year-old Ty, who has always lived on the ocean floor, joins Topside girl Gemma in the frontier's underworld to seek and stop outlaws who threaten his home, they learn that the government may pose an even greater threat. (WorldCat)

Falls, K. (2011). Rip tide. New York: Scholastic Press.

Ty discovers an entire township chained to a sunken submarine, its inhabitants condemned to an icy underwater grave. It's only the first clue to a mystery that has claimed hundreds of lives and stands to claim two more -- - lives very precious to Ty and his Topsider ally, Gemma. (WorldCat)

66.65.47.62 (talk) 22:58, 2 November 2013 (UTC)

Filling all air-filled cavities
I have reverted the recent edit that said reducing the physical stress of G forces requires "filling all normally air-filled body cavities with liquid." This is not necessary for the mere reduction of the stress of G forces. As the article explains, simple water immersion does reduce the stress of G forces, allowing tolerance up to 15 or 20 Gs. It is the near-elimination (as opposed to reduction) of the stress of G forces that requires both water immersion and filling of the major air-filled cavities with a similar liquid, which is where the role of liquid breathing comes in. Cryobiologist 17:18, 18 March 2007 (UTC)
 * Although this comment is extremely dated, it should be noted that bones also contain air filled cavities that cannot have fluid replace the air by the nature of their nature. One would have to find a fluid that preferentially replaces air, fails to displace oxygen, be of a similar density and mass of water *and* be delivered by the blood stream within the individual's lifetime. That'd qualify as unobtainium.Wzrd1 (talk) 07:57, 20 August 2015 (UTC)

Different method
Would it be possible to get the same benefits of a liquid breathing apparatus by simply filling the lungs with saline or whatever, and then pumping oxygenated blood directly into the user from some outside source? Thanks! --TotoBaggins 15:44, 2 August 2007 (UTC)
 * You mean as regards acceleration, diving, and so on? The answer is yes. The technology is called ECMO, and I suspect, due to the CO2 problem, some form of ECMO will replace or augment lung ventilation, if liquid-filled lungs are ever used to allow humans direct access to the deep oceans (abysal plain). S  B Harris 17:43, 2 August 2007 (UTC)
 * Thanks for the response. This approach seems a lot more feasible than pumping liquid through the lungs, etc.  It occurred to me after reading about athletes using their own fresh & oxygenated blood in blood doping.  --TotoBaggins 18:05, 2 August 2007 (UTC)

Broken Link
The link in the acknowledgement seems to be broken on my end. Could somebody verify this and repair or delete the input. Carnelain 21:52, 16 August 2007 (UTC)

Context / gaps
There seems to be a bit of a disconnect or of missing information, especially between the lede and the first sections. While "perfluorocarbon" is linked, and a more detailed discussion should be at the linked article, it really needs some more expansion here before the methods of application are detailed. The article needs to be able to stand on its own, at the moment, this doesn't seem to be quite given to me as a non-expert. Ingolfson 09:37, 8 September 2007 (UTC)

Needs cite
A new editor who states he is a developer of TLV has made some good-faith edits about TLV and how workable it is, compared with standard gas ventilation. Here's one: "the necessity for the liquid filled tube system that contains pumps and heater and membrane oxygenator to deliver and remove tidal volume aliquots of conditioned perfluorocarbon to the lungs is a great disadvantage .very similar to the control of respiratory parameters during assisted gas ventilation." In fact, I do not believe this, as a membrane oxygenator is lot harder to manage than a simple gas blender. So these kinds of things need a cite (such as the idea that tidal volumes are easier to control with liquid than gas, with new technology), and I'll explain need for such citations on the new user's talk page. S B Harris 21:30, 26 January 2008 (UTC)

New IP editor may be a known authority!
user:71.224.14.76 says he did the only human study, and cites T. H. Shaffer. That means he's actually claiming to be Shaffer, since to date Shaffer is the only person ever to try this on a human (the subject died shortly thereater, probably not as a result of the liquid ventilation). So don't WP:BITE the new user and let's see if he can learn to cite. If he IS Professor Thomas H. Shaffer, it would be an honor to see what he says, and to get his comments into Wiki-shape. That doesn't mean I think he's reversion-proof. But be VERY sure to WP:AGF with this guy, who may be the closest we've seen here to a living historical figure and authority as regards the development of the subject at hand. S B Harris 02:14, 27 January 2008 (UTC)
 * I can't agree. The editor blatantly violated many rules of Wiki, after being warned many times. I don't see how we would have "egg on our faces", as you mentioned on my talk page; it is not my responsibility to assume that an unregistered user is in any sort of "higher" position than anyone else. He claims to be a developer? Fine, then it should be a simple matter for him to become a registered user, do a couple quick reads on the policies that we told him about, and do it correctly. I do typically assume good faith, a quick scroll through my contributions would verify that. However, I'm not going to give this IP address preferential treatment until he/she follows Wikipedia policies. I'm aware that there are some gray areas, but this certainly isn't one of them. See WP:COS. Tanthalas39 (talk) 16:30, 27 January 2008 (UTC)

Sorry for creating so many issues around my lack of knowledge on this site. I have attempted to cite articles which I believe supports my point. Hopefully, they will be organized in the text properly, so that readers can see them. T.H.Shaffer —Preceding unsigned comment added by 199.254.17.254 (talk) 20:59, 28 January 2008 (UTC) Thanks to Sbharris, I have a log in and can provide a signature(THSHAFFER)--Thshaffer (talk) 21:46, 28 January 2008 (UTC). However, at the moment, I am quite limited in what I can add to the site. Thanks Thshaffer (talk) 21:46, 28 January 2008 (UTC)
 * You're doing fine. I've added a template to your TALK and USER pages with a pointer to the manual of style and other useful links. Please read them. I fixed up your references, and you might note how I did that. I've also got some comments on liquid ventilation which I left on your TALK page, but which could as easily go here. In fact, in future we should discuss your editing learning on your TALK page, and liquid ventilation questions HERE, rather than the other way around, if you see my point. But I'll put this here for now to preserve it as a record. S  B Harris 22:01, 28 January 2008 (UTC)

TLV vs. gas ventilation
Dr. Shaffer: I've fixed up the references you added: please see how it was done. I disagree with you that some aspects of total liquid ventilation are easier than gas: it most definitely IS harder to oxygenate and scrub fluorocarbon than it is to simply blend ingoing oxygen, and remove CO2 by simple ventilation and exhaust to the air (whereas liquid must be recycled as in a rebreather or anesthesia circuit). However, you may be right that control of volumes is inherently easier than with a gas. Could you explain why? S B Harris 21:57, 28 January 2008 (UTC)


 * Thanks for the help with the references. Regarding TLV, for infants, we have gone back to the concept of ventilating with pre-oxygenated, warmed PFC which has plenty of oxygen(one-way system) and no carbon dioxide(Lancet, 1989). To ventilate infants, it takes less than a liter of pre-oxygenated PFC to effectively recruit alveoli and stabilize the infant's under-inflated lungs during a transient period of TLV.  After returning to gas ventilation (some would call this PLV), our PFC sensors in the expired gas line indicate the amount of PFC which is required to maintain an effective PFC volume in the lung.  In the intensive care setting, determination of effective lung volume (FRC) is one of the most difficult variables to assess, but not for PFC in the lung. Also using TLV circuits for larger patients, using microprocessor controlled ventilators, we can carefully control tidal volume and FRC during each phase of ventilation as described in the Heckman et al. article. As compared to our early ventilators, we no longer use patient weight as a measure of PFC in the lungs, we have the membrane and PFC loss technology greatly improved. There is a significant amount of technology and TLV results published (PubMed), but it is difficult to get all of this information across at once.--Thshaffer (talk) 00:15, 29 January 2008 (UTC)

Dr. Harris, I am looking to put some up data on the liquid page. I hope you would be willing to collaborate. I put another note in Wikopedia, but it may be in the wrong place. In the meantime, I will try to track down your contact information through other sources. THSThshaffer (talk) 01:31, 8 November 2008 (UTC)

Libelle G-suit
It seems that the Libelle G-suit hyperlink in the space travel section is broken. Vsst (talk) 18:58, 22 August 2008 (UTC)

Dispute page
This article, in the lead, says that liquid breathing is used for medical treatment. This assertion is unreferenced in the Medical Treatment section. From google searching, LiquiVent was a failure. Alliance is a penny stock. Looks like the best they have is Oxygent sp? which is in clinical trials in China. Clinical trials do not equal medical treatment, in my opinion. This has led me to totally dispute the neutrality of this page. -Shootbamboo (talk) 05:05, 27 December 2008 (UTC)

Title dispute
This article would be better titled Liquid breathing research, IMHO. The current title implies too strongly the feasibility of total liquid ventilation, instead of characterizing it as an investigative field. -Shootbamboo (talk) 20:43, 1 January 2009 (UTC)

Cleanup
I've tried to clean this page up as much as possible, but the technical parts really require someone with more knowledge of the subject. Hopefully, at the very least, the pov dispute's resolved. I think the article's pretty clear now that the technique remains unrealized. LSD (talk) 01:45, 15 January 2009 (UTC)
 * In the absence of any disagreement, I've removed the POV tag. LSD (talk) 19:17, 3 February 2009 (UTC)

Fiction section
I'm tempted to delete the whole section, since it's bascially irrelevent to the article, but at the very least it needs to be trimmed up.LSD (talk) 02:00, 15 January 2009 (UTC)
 * Deleted. LSD (talk) 19:19, 3 February 2009 (UTC)

Article "reads like a review??"
What the devil does that mean? And how is it problem, seeing as a well done review article is suitable for an encyclopedia (though it may have more citations than the average wikipedia article, for sure). However, as soon as I remove citations, I have no doubt somebody will stick up an "inadequate citations" tag. So just what is it that is wanted? S B Harris 20:41, 10 July 2009 (UTC)
 * In general, I think the article has too many primary sources inserted by potentially conflicted editors that make it unlike an encyclopedia article. -Shootbamboo (talk) 00:24, 11 July 2009 (UTC)

Maintenance templates
Looking at the request for third-party reliable sources, I feel that this article now has plenty of them, so I've removed the Primary sources template.

I can't see how the Review template is helpful here, so I've removed that.

I do see that some parts of the article may need further referencing, so I've added a Refimprove template.

I think it would be more helpful in improving the article if any specific requests for citation were flagged in-line using fact and any specific problems with the style of the article were discussed here to allow contributors to meet concerns. Thanks --RexxS (talk) 18:03, 8 September 2009 (UTC)

Dan Brown
The article, in the section Examples in Fiction, lists breathable liquid as being used in the book THE LOST SYMBOL... TWICE. One should be deleted. If I did it myself, someone would have like sent me some message saying that my improvement was not constructive. —Preceding unsigned comment added by 76.71.131.15 (talk) 23:58, 20 October 2009 (UTC)


 * Shouldn't someone put a spoiler warning on it? Or at least truncate the message so it doesn't ruin the story for people who haven't read it? (Minutes (talk) 23:22, 14 February 2010 (UTC))


 * I request that the Dan Brown reference come with a plot spoiler warning before it. In one sentence the last few chapters of the book have lost three major climax points. Knowing that robert Langdon does not die, would completely ruin the book for someone who has not read it yet.

— Minty (talk) 09:47, 21 March 2010 (UTC)

David Blaine claims to have tried breathing with "Preflubron"
In this video David Blaine claims to have "filled his sink with Perflubron" and tried to breathe it. I am skeptical of his story. —Preceding unsigned comment added by 76.126.242.132 (talk) 01:15, 20 January 2010 (UTC)

diaphragm
I suppose someone should add this into the lead of the article. I don't have a source, but a medical expert will tell you that breathing fluids isn't exactly good for your diaphragm. It takes a lot more force to pull and push out a fluid than it does a gas. That is why lungs don't work like gills... Anyway, I think it's important enough for the lead, so yeah. —Preceding unsigned comment added by 68.89.219.173 (talk) 22:32, 21 September 2010 (UTC)

Removed text -- density issues for use in space travel
I have removed the following text added in this 2009 edit:


 * On the other hand, although perfluorochemicals are denser than water, lung tissue floats within the PFC filled lungs, and if the lungs are not over-filled, there is no compromise in pulmonary or systemic blood flow. Therefore, if the astronaut is immersed in liquid and his lungs are filled with liquid PFC, he should not experience adverse effects, in spite of the almost twofold density difference. Based on interviews with adult patients that experienced partial liquid ventilation, when they became conscious they were unaware that 20-30 ml/kg of PFC was in their lungs during recovery.


 * As noted earlier, the density of the fluid is an issue for the extreme acceleration protection application. A body floating in a heavy liquid will be squished against the "roof" of the tank as surely as the one in air will be squished against the "floor". The whole scheme depends on surrounding the body and filling its cavities with a liquid of the same average density of the body, and even then differing densities withing the body will still cause there to be an upper acceleration limit. -- ToE 10:54, 31 December 2011 (UTC)

Removal of "redundant text" from the Partial liquid ventilation section
71.104.179.19 did edits in the Partial liquid breathing section, later commenting that "The last paragraph of this section was redundant. I just repeated the information from the first paragraphs in the section. I left the references, which were helpful, but the repetitive information was not helpful". I reverted those edits because I perceived them to be partial section blanking, & suspected vandalism because of the combination of an IP address & because there was a blank reason for editing.

Subsequent to 71.104.179.19's reversion of my reversion, & this time leaving a reason for editing, I do think that this user has a point. However, this leaves some things out of the article.

Outside of this section, Liquivent (see by l-dictionary.thefreedictionary.com/perflubron) is only mentioned in the references. Should it be referred to earlier in the article?

The following seems germane to the article but misplaced in the Partial liquid breathing section.

"The liquid has some unique properties. It has a very low surface tension, similar to surfactant, a substance that is produced in your lungs and prevents the alveoli from collapsing and sticking together during exhalation. It also has a high density, oxygen readily diffuses through it, and it may have some anti-inflammatory properties."

The following seems germane to the Partial liquid ventilation section & is not discussed elsewhere.

"The hope is that the liquid will help the transport of oxygen to parts of the lung that are flooded and filled with debris, help remove this debris and open up more alveoli improving lung function. The study of PLV involves comparison to protocolized ventilator strategy designed to minimize lung damage.The hope is that the liquid will help the transport of oxygen to parts of the lung that are flooded and filled with debris, help remove this debris and open up more alveoli improving lung function. The study of PLV involves comparison to protocolized ventilator strategy designed to minimize lung damage."

While I am not knowledgeable about Liquid breathing or Partial liquid ventilation, I am not totally disinterested, as my mother died of acute respiratory distress syndrome (ARDS) a couple of decades ago. Such a therapy may help, or eventually help, others with ARDS.

I hope I did not offend anyone with my reversion or inadvertantly set off an edit war. Again, I reverted because I perceived: Peaceray (talk) 05:39, 6 July 2012 (UTC)
 * partial section blanking
 * Lack of an edit summary
 * Anonymous editing by an IP address, which can sometimes be a sign of vanadlism, but not inherently per se.

-ize suffix

 * What does "protocolize" mean hereinabove?? Wiktionary says that "protocolize" = "notarize", and that "notarize" = (transitive) "to be witness of the authenticity of a document and its accompanying signatures in one's capacity as notary public", but that meaning does not fit here. Anthony Appleyard (talk) 07:56, 6 July 2012 (UTC)


 * I think "protocolize" in this context has a medical treatment meaning. I work most Saturdays at a library that specializes in nursing, so I will check a medical dictionary while I am there. Peaceray (talk) 08:02, 6 July 2012 (UTC)


 * If "protocolized" = "made into protocol", "protocolized ventilator strategy" could become "a standardized way of using the ventilator" or similar, to become understandable. Anthony Appleyard (talk) 04:56, 7 July 2012 (UTC)

protocolize seems to be standard medical jargon
In medicine, to protocolize means to develop a precise & detailed plan or procedure for a therapeutic regimen or a biomedical research problem. Coincidentally, I happened to find a lot of links to ventilation treatment & research when searching for "protocolize".

examples


The root context appears to be proto- (first, primitive, original) + col (from kolla, glue) + -ize (to become or produce).

Peaceray (talk) 02:10, 8 July 2012 (UTC)
 * But "protocolize" needs properly defining in Wikipedia, else it is another specialized jargon word which the general public will not know. See http://www.wordnik.com/words/protocol . Anthony Appleyard (talk) 20:38, 9 July 2012 (UTC)

There are over 700 ize ending words in US and Canadian English. []. Though all end in -use in UK English. The ending makes adjectives and verbs into nouns. The sense is "made into". When "protocolized" is defined here that will be the final step and the use will be finalized. Finalization on WP is good. All definitions must eventually be finalizationalized. And while we are at it, we encourage protocolization wherever possible, also. All scientific actions must be protocolizationalated, and resistance is futile. Has been futilized. S B Harris 17:32, 2 August 2013 (UTC)

liquid breathing
couldn't this also be used for Firefighters with scorched lungs? — Preceding unsigned comment added by 99.122.86.208 (talk) 18:37, 13 May 2014 (UTC)
 * This is also a bit dated, but deserves an answer. *If* they can get the bloody thing to work without damaging already damaged tissues, deliver oxygen and remove carbon dioxide in a manner that the body requires. In short, it'll work once they get all of the major kinks worked out, some kinks being bent 180 degrees around, others more manageable. It's still a bit of a new technology, with few willing to risk expenses on a thus far lossy return.Wzrd1 (talk) 08:04, 20 August 2015 (UTC)

Anime (Aldnoah) example
I'm not really certain this belongs here. This sounds more like someone drowning, than someone liquid breathing, given that the fluid had to be "kissed" out to save his life.64.180.221.163 (talk) 12:47, 3 March 2015 (UTC)

Sinus passageways? Inner ear cavity?
Why is there no discussion of the sinus and inner ear passageways inside a human skull?

In order for liquid breathing to be fully functional to protect against diving depth compression, not only do the lungs need to fill with liquid, but so do all these air spaces inside the skull to prevent implosion damage.

How long does it take to for these inner skull spaces to fill with liquid and then to be drained afterward?

Due to the layout of some air spaces being more like pockets with a single entry vent channel (inner ear space and the Eustachian tube) natural direct filling and emptying seems impossible without some sort of inserted capillary vent tube to aid the process.

-- DMahalko (talk)

I Have To Ask...
...because the article doesn't seem to mention it. Wouldn't this be incredibly painful?

Can someone with some knowledge of this field address that?

*Septegram*Talk*Contributions* 22:11, 25 April 2016 (UTC)

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Theoretical or practical?
This article doesn't make it clear. Kortoso (talk) 21:48, 15 December 2016 (UTC)

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How?
how do you breathe it in? Anytime I accidently inhale water, I cough and choke 2601:1C0:4D7F:D7A0:705F:C903:B0A7:4A8E (talk) 01:28, 10 July 2023 (UTC)