Nitrogen Narcosis and Scuba diving
Nitrogen narcosis is a dangerous condition that can affect scuba
divers, especially when diving deeper than 30 meters. The exact
mechanisms behind nitrogen narcosis are still to be explored,
but it has to do with nitrogen gas affecting the nerve
transmissions in the body during high pressure. Nitrogen is not
the only gas capable of affecting the nerve transmissions when
the body experience high pressure; the same state of
intoxication can for instance be caused by hydrogen and argon.
Since the air inhaled by scuba divers contains a large amount of
nitrogen (just like the air that we breathe above the surface
every day), nitrogen narcosis was the first type of gas narcosis
experienced by scuba divers, hence the name. Today, the
condition is also referred to as Inert Gas Narcosis.
The effects of nitrogen narcosis are similar to the effects of
anesthetic gas or alcohol. The well known diver Jacques Cousteau
expressed it as the "rapture of the deep". Since a diver needs
to be focused and act responsible - and even more so at great
depths - nitrogen narcosis can have disastrous effect. A diver
can for instance forget to check how much air he or she has
left, stay down to long or forget to do safety stops when
ascending to the surface. Some divers have even begun to take
off their equipment or tried to share their mouth piece with a
fish. Nitrogen narcosis can also be lethal due to nitrogen
poisoning.
It can be hard for the effected diver to realize that he or she
is developing nitrogen narcosis, since the level of intoxication
will increase gradually. It is therefore always important to
keep an eye on your partner during the dive and try to detect
illogical behaviors. Many divers regularly check the mental
state of their buddy by showing the buddy a number of fingers.
Before the dive, the divers have agreed that when 3 fingers are
displayed, the buddy must respond by showing 2 fingers, when 8
fingers are displayed the buddy should hold up 7 fingers and so
on. A diver suffering from nitrogen narcosis might calculate the
wrong number, or display a number of fingers that is not
coherent with the number that he or she calculated. The diver
can also loose interest in carrying out these safety checks and
ignore the buddy.
If you suspect that you or your buddy is suffering from nitrogen
narcosis, you should immediately begin your ascent to shallower
depts. Never panic and head for the surface as quickly as
possible, safety stops are imperative. The effects of nitrogen
narcosis will usually wear of as soon as you reach shallower
depths, even if they are far from the surface. Sometimes an
affect buddy can be very reluctant to ascend, since he or she is
not aware of the problem. Before embarking on a deep dive, it
can be a good idea to agree on a sign that means "Nitrogen
narcosis, we must ascend".
Never dive below 20 meters unless you have completed your
deep-dive training. During the training, you will learn more
about how to avoid nitrogen narcosis. A rapid descent should be
avoided since it will make the pressure increase very quickly
and nitrogen gas dissolves more slowly in the blood than many
other gases. Nitrogen narcosis seems to be more common during
dives where the diver has made a rapid descent, but it can occur
even after a very slow descent. Many experienced divers
recommend a descent at a very steady pace when deep-diving,
since this will prevent any sudden changes and unbalanced
solution of gas in the blood. This method has however not been
scientifically proven.
Never use sedating drugs, including alcohol and marijuana,
before you go scuba diving. Any sedating drugs will increase the
risk of nitrogen narcosis. Keep in mind that THC is stored in
your body for long periods of time. Sedating medications should
also be avoided prior to dives, even when prescribed by a
physician.