Astronauts face a similar danger during a space walk. It is necessary to reduce the pressure within the space suit from 14.7 psi to only 4 psi when the hatch out into space is opened. The suit pressure must be reduced to this level to prevent ballooning of the suit in the vacuum of space which would make the astronaut unable to bend his/her arms or legs. The only way this can be done is if the astronauts breath pure oxygen for 2 hours prior to donning their space suit. This ‘off-gasses’ the nitrogen from their tissues. After two hours the astronauts can tolerate the rapid reduction of atmospheric pressure from 14.7 to 4 psi without the formation of lethal nitrogen emboli. Without nitrogen off-gassing, an immediate pressure drop this great would result in crippling or lethal gaseous emboli.
Perfusion Theory is an educational platform for the Oxygen Pressure Field Theory (OPFT). August Krogh’s theoretical concept of the oxygen pressure field is explained and then applied to clinical applications in perfusion practice.