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2729272 
Technical Report 
Therapeutic Gases: Oxygen, Carbon Dioxide, And Helium 
Lambertsen, CJ 
1971 
NIOSH/00135408 
s Pharmacology in Medicine 
1145-1179 
The therapeutic uses of oxygen (7782447), carbon-dioxide (124389), and helium (7440597) are reviewed. Factors underlying the pulmonary gas exchange, blood gas transport, and control of respiration are summarized. The varied causes of anoxia are classified as a basis for discussion of oxygen therapy. Conditions leading to clinical anoxia include coronary occlusion, barbiturate poisoning, asthma, cardiac shunt, carbon-monoxide (630080) poisoning, and cyanide (57125) poisoning. The benefits of oxygen administration are not uniform for all of these conditions, because anoxia is produced by different mechanisms. The effects of oxygen inhalation on respiration and circulation in normal humans are reviewed. At moderate tensions, oxygen has few direct effects on normal processes. The responses to oxygen administration in anoxia are primarily due to relief of a deficiency state. Sustained oxygen inhalation at greater than normal oxygen pressures can have toxic effects, including convulsions due to effects on the central nervous system, pulmonary damage, and retinal damage in premature infants. The toxic effects result from the action of oxygen on cellular metabolic processes, including enzyme activity. Carbon-dioxide is therapeutically useful only in a few special circumstances and then only for short periods of time. Its clinical importance is related not only to its use as a drug but to the occurrence of excessive or deficient concentrations of naturally produced carbon-dioxide following failure of the normal regulation of respiration. Helium is of value in treating respiratory obstructive conditions and during exposure to very high ambient pressures in diving. Because of the high cost, use of oxygen/helium mixtures usually is limited to treatment of acute inflammatory obstructions, such as those produced by pulmonary burns, infection, instrumentation, or inhalation of irritating vapors.