Hyperbaric

The so-called hyperbar vacuum filtration is a combination of vacuum and pressure filtration in a pull—push arrangement, whereby a vacuum pump of a fan generates vacuum downstream of the filter medium, while a compressor maintains higher-than-atmospheric pressure upstream. If, for example, the vacuum produced is 80 kPa, ie, absolute pressure of 20 kPa, and the absolute pressure before the filter is 150 kPa, the total pressure drop of 130 kPa is created across the filter medium. This is a new idea in principle but in practice requires three primary movers a Hquid pump to pump in the suspension, a vacuum pump to produce the vacuum, and a compressor to supply the compressed air. The cost of having to provide, install, and maintain one additional primary mover has deterred the development of hyperbar vacuum filtration only Andrit2 in Austria offers a system commercially. 

The low breathing resistance of helium—oxygen mixtures is of therapeutic advantage for patients suffering from asthma and other obstmctive respitatory difficulties. The mixtures have also been used for hyperbaric therapy. 

In the past, hyperbaric oxygenation as a medical procedure has received considerable attention. In this treatment the patient is given pure oxygen and may be placed in a pressurized chamber. In effect, the patient may thus receive >400 kPa (>4 atm) of pure oxygen. Beneficial results in cases of carbon monoxide poisoning, gangrene, severe bums, and other difficulties are often achieved as a result of this treatment. 

P. Wood, L. Spit2e, and T. Wydeven, The Use of Superoxidesfor Hyperbaric Air Kevitali tion, NASA Technical Briefs ARC-11695, 1986. 

Figure 7.7 The Hyperbaric Chromatography region, at temperatures above the 2-phase region and pressures below the locus of critical pressures. Reproduced by permission of the American Chemical Society.

Solubility affected by pressnre. (a) SCUBA divers must pay attention to the solubility of gases in die blood and die fact diat solubility increases with pressure, (b) A hyperbaric chamber. People who have problems breathing can be placed in a hyperbaric chamber where they are exposed to a higher partial pressure of oxygen. 

Increased pressure [hyperbaric chamber, respiratory ventilators (eg, PEEP or CPPB)] P02 polarographic electrode "error" due to halogenated hydrocarbons (eg, llalothane) t P02 usually <50... 

Burt JT, Kapp JP, Smith RR. Hyperbaric oxygen and cerebral infarction in the gerbil. Surg Neurol 1987 28 265-268. 

Lou M, Eschenfelder CC, Herdegen T, Brecht S, Deuschl G. Therapeutic window for use of hyperbaric oxygenation in focal transient ischemia in rats. Stroke 2004 35 578-583. 

Veltkamp R, Warner DS, Domoki F, Brinkhous AD, Toole JF, Busija DW. Hyperbaric oxygen decreases infarct size and behavioral deficit after transient focal cerebral ischemia in rats. Brain Res 2000 853 68-73. 

Sunami K, Takeda Y, Hashimoto M, Hirakawa M. Hyperbaric oxygen reduces infarct volume in rats by increasing oxygen supply to the ischemic periphery. Crit Care Med 2000 28 2831-2836. 

Schabitz WR, Schade H, Heiland S, Kollmar R, Bardutzky J, Henninger N, Muller H, Carl U, Toyokuni S, Sommer C, Schwab S. Neuroprotection by hyperbaric oxygenation after experimental focal cerebral ischemia monitored by mr-imaging. Stroke 2004 35 1175-1179. 

Roos JA, Jackson-Friedman C, Lyden P. Effects of hyperbaric oxygen on neurologic outcome for cerebral ischemia in rats. Acad Emerg Med 1998 5 18-24. 

Anderson DC, Bottini AG, Jagiella WM, Westphal B, Ford S, Rockswold GL, Loe-wenson RB. A pilot study of hyperbaric oxygen in the treatment of human stroke. Stroke 1991 22 1137-1142. 

Rusyniak DE, Kirk MA, May JD, Kao LW, Brizendine EJ, Welch JL, Cordell WH, Alonso RJ. Hyperbaric oxygen therapy in acute ischemic stroke results of the hyperbaric oxygen in acute ischemic stroke trial pilot study. Stroke 2003 34 571-574. 

Hyperbaric oxygen Hypertensive cerebrovascular injury Alcoholism... 

The nonpharmacologic treatment of diabetic foot ulcers may include off-loading, chemical or surgical debridement of necrotic tissue, wound dressings, hyperbaric oxygen, vascular or orthopedic surgery, and the use of human skin equivalents.30... 

There is no proven antidote for hydrogen sulfide poisoning. Treatment consists of supportive measures such as evaluating and supporting airway, breathing, and circulation (ATSDR 1994). Sodium nitrite may or may not be an effective antidote, but if proper precautions in administration are observed, intravenous administration of sodium nitrite may help some hydrogen sulfide poisoned persons (Hall 1996 Hall and Rumack 1997). Hyperbaric oxygen therapy is controversial, but it may be effective for patients not treated successfully by other measures (ATSDR 1994). 

Bitterman N, Talmi Y, Lerman A, et al. 1986. The effect of hyperbaric oxygen on acute experimental sulfide poisoning in the rat. Toxicol Appl Pharmacol 84 325-328. 

Smilkstein MJ, Bronstein AC, Pickett HM, et al. 1985. Hyperbaric oxygen therapy for severe hydrogen sulfide poisoning. J Emerg Med 3 27-30. 

Whitcraft DD III, Bailey TD, Hart GB. 1985. Hydrogen sulfide poisoning treated with hyperbaric oxygen. J Emerg Med 3 23-25. 

The effects of oxygen breathing on cognition in healthy people has only received limited attention. In the 1970s, Edwards and Hart examined the effects of hyperbaric oxygen administration on healthy elderly outpatients and found substantial... 

Edwards AE and Hart GM (1974). Hyperbaric oxygenation and the cognitive function of the aged. Journal of the American Geriatrics Society, 22, 376-379. 

Raskin A, Gershon S, Crook TH, Sathananthan G and Ferris S (1978). The effects of hyperbaric and normobaric oxygen on cognitive impairment in the elderly. Archives of General Psychiatry, 35, 50-56. 

Thom and coworkers published results on the stimulation of perivascular NO synthesis by oxygen [127], To perform this study a 200 pm diameter electrode (ISONOP200) was placed between the aorta and vena cava of anesthetized rats and mice (rodents) and then the rodents were placed inside a hyperbaric chamber. Inside the hyperbaric chamber the partial pressure of 02 was regulated/changed as NO concentration was monitored. Figure 1.11 shows that NO concentration increased as a function of 02 partial pressure. This experiment is important for understanding how NO synthesis, by NOS, is altered and regulated by 02. 

Continue oxygen therapy until patient is asymptomatic and blood carbon monoxide levels are below 10%. For individuals with blood carbon monoxide levels above 40%, consider transfer to a hyperbaric facility. 

McCormack, M., A.H.W. Nias, and E. Smith. 1990. Chronic anemia, hyperbaric oxygen and tumour radiosensitivity. Brit. Jour. Radiol. 63 752-759. 

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