Oxygen physiological effects

Asphyxiation and Toxicity Hazards An asphyxiant is a chemical (either a gas or a vapor) that can cause death or unconsciousness by suffocation (BP, Hazards of Nitrogen and Catalyst Handling, 2003). A simple asphyxiant is a chemical, such as N2, He, or Ar, whose effects are caused by the displacement of 02 in air, reducing the 02 concentration below its normal value of approximately 21 vol %. The physiological effects of oxygen concentration reduction by simple asphyxiants are illustrated in Table 23-18 (BP, Hazards of Nitrogen and Catalyst Handling, 2003). 

Note that C02 acts as neither a simple asphyxiant (like N2) nor a chemical asphyxiant (like CO). The normal concentration of C02 in air is approximately 300 ppm (0.03 vol %). Table 23-19 (Air Products, Carbon Dioxide, Safetygram 18, 1998) illustrates that exposure to air diluted by 5 vol % C02 (yielding an oxygen concentration of 21 x 0.95, or approximately 20 vol %) prompts physiological effects that are more severe than those inferred from Table 23-18 for dilution by the same amount of nitrogen. 

Burrow GE, Liu DHW, Way JL. 1973. Effect of oxygen on cyanide intoxication V. physiologic effects. J Pharmocol Exp Ther 184 739-748. 

By resonance Raman methods, Wang and coworkers105 showed NO bound to both ferric and ferrous heme of bNOS. Hurshman and Marietta106 used iNOS and spectrophotometric methods to show similar reactions, although the physiological effects will depend on the effects of arginine and oxygen in vivo. 

It is important to note that there have been no harmful physiological effects observed in infants bom to mothers who are administered nitrous oxide and oxygen during labor itself, as the gas is quickly metabolized. However, a few long-term studies have shown a possible link between heavy nitrous oxide use during labor and... 

Propane is not considered to be inherently toxic to humans. Air concentrations up to 10 000 ppm (10%) for a few minutes will only produce slight dizziness in humans. At high concentrations, it may have a narcotic effect but at concentrations below 100 ppm, propane causes no physiological effects in humans. However, it will cause chemical suffocation at concentrations that are high enough to displace oxygen. 

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