How Nitrous Oxide Works
Like other anaesthetics that we breathe, nitrous oxide depresses the normal function of the brain - depending on its dose or concentration. But exactly how nitrous oxide produces analgesia remains a mystery. Whatever the mechanism may be, it is necessary for the gas to reach the brain in a concentration which is sufficient to relieve pain. This is achieved via the lungs and bloodstream.
When nitrous oxide is inhaled, it mixes with the air already in our lungs and then passes into the circulation. This transfer to the bloodstream occurs easily and quickly. Once it enters the blood, incidentally, the gas goes into solution - it does not form bubbles! From the lungs, nitrous oxide starts to reach the brain (and other organs) within 15 seconds. The actual amount of gas which reaches the brain depends upon the concentration that is inhaled and how long it is breathed. When used in labour, the concentration of nitrous oxide reaching the brain rises rapidly
| |
|
|