Hyperbaric chamber

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... 

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. 

Both decompression sickness and air embolism can be treated by placing the victim in a hyperbaric chamber. Hyper ... 

Lillo, R.S., Morris, J.W., Caldwell, J.M., Balk, D M., Flynn, E.T. (1990) Atmosphere contamination following repainting of a human hyperbaric chamber complex. Undersea biomed. Res., 17, 437 51... 

Oxygen Carbon monoxide Give 100% by high-flow nonrebreathing mask use of hyperbaric chamber is controversial but often recommended for severe poisoning. 

Divers who ascend too quickly can develop the bends, a condition caused by the formation of nitrogen bubbles in the blood. Treatment involves placement in this high-pressure tank called a hyperbaric chamber, and a slow, controlled change to atmospheric pressure. 

CO is bound to hemoglobin and does not allow it to carry oxygen. Oxygen under high pressure in the hyperbaric chamber is dissolved in the plasma and is carried to the tissues without the aid of hemoglobin. 

Pseudoephedrine is often used by scuba divers to avoid ear barotrauma. The psychometric and cardiac effects of pseudoephedrine have been evaluated at 1 atmosphere (100 kPa, sea level) and 3 atmospheres (30 kPa, 20 m) in a double-blind, placebo-controlled, crossover study in 30 active divers in a hyperbaric chamber (253). Pseudoephedrine did not cause significant alterations in psychometric performance at 3 atmospheres. 

The binding of CO to hemoglobin is fully dissociable, and dissociation requires ventilation. After removal from exposure to CO, administration of O reverses CO binding to hemoglobin. Utilization of 100 percent accelerates the washout of CO. Use of hyperbaric chambers with pressures up to 2 atmospheres speeds up the CO washout process even more. Addition of 5 to 7 percent CO to the O is sometimes used as a prompt to ventilatory exchange. One disadvantage of the addition of CO is the serious acidosis that results when the respiratory acidosis produced by CO inhalation is added to the metabolic acidosis produced by O deprivation in the tissues because of CO poisoning. 

Carbon monoxide poisoning is treated by administration of pure O2 which promotes the shift of the above equilibrium to the left. This can be made even more effective by placing the victim in a hyperbaric chamber in which the pressure of O2 can be made greater than 1 atm. 

The CO diffusing capacity, DPco, of sheep was measured at various 02 tensions in a hyperbaric chamber using a method similar to that outlined above (12). DPco varied as a function of the oxygen tension. In Figure 2 the reciprocal of DPco is plotted as a function of the reciprocal of the diffusing capacity of the maternal and fetal red blood cells. From the plot the slope is the reciprocal of the value of V, the maternal and fetal capillary blood volume while the intercept is the reciprocal of Dmco- From these studies we calculated that the resistance of maternal and fetal red blood cells was approximately one-third of the total resistance while the resistance of the placental membrane per se was about two-thirds of the total resistance to 02 diffusion (12). This is in contrast to previous studies which assumed that the placental membrane per se constituted the total resistance to diffusion. 

Figure 1 During HBOT, the patient iies in a hyperbaric chamber. A technician controls the pressure and oxygen levels.

If a diver does surface too quickly, some hospitals have hyperbaric chambers, where the sea depth pressures are reapplied and slowly reduced while the victim breathes oxygen as pure as 100 percent. 

A December 2002 ice storm in the southeastern United States knocked out electricity for millions of people. About 150 people were hospitalized and treated in hyperbaric chambers where they could breathe much higher than normal concentrations of oxygen several people died. Use your chemical literacy to decide which of the following scenarios probably led to this. 

Victims of carbon monoxide poisoning are placed in a hyperbaric chamber where the pressure is raised above 1 atm and a richer oxygen environment exists. If the pressure is raised from 1 atm to 3 atm, what will be the proportional change in oxygen solubility in blood Use Henry s law and assume blood behaves like water. 

Hyperbaric chambers in medical facilities for performing certain procedures operate under elevated atmospheric pressure. They are another example of high pressure environments. Some hyperbaric chambers have solid enclosures and some are simply plastic bubbles. The thicker the walls of the enclosure, the greater the pressure it can contain. Medical hyperbaric chambers have uses in elevated oxygen therapy for bmns, gangrene, air embolisms, and other diseases and conditions. 

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