When diving underwater, oxygen is typically considered toxic at a partial pressure of 1.4. However, hyperbaric chamber treatment tables regularly require taking patients up to 60fsw on 100% O2, which translates to a partial pressure of 2.81. Why is the same amount of oxygen more toxic underwater than in the chamber, if the pressure exerted on both the body and the gas are the same in both scenarios? What variable when we’re “dry” allows us to tolerate more than double the amount of oxygen than when we’re “wet”?
In: Biology
When you’re in the hyperbaric oxygen tank, it’s for a limited time and with purpose. Typically we use it to enable healing of some wounds or for any type of poisoning by a chemical that binds to your hemoglobin better than oxygen (CO, NO, CO2, actually, almost every gas in existence binds to your hemoglobin better than O2). O2 treats these poisonings by basically forcing its way in via overwhelming numbers and attrition.
Oxygen for extended time at high concentrations is toxic though, regardless of environment. Too much O2 forces the N2 out which we also want in our lungs. N2 kind of acts as a lubricant for the air sacs.
Latest Answers