Scuba Diving And Decompression Sickness

Cases of Decompression Sickness were first reported when the Brooklyn Bridge was built. The workers had to spend many hours in caissons - chambers filled with compressed air under the water and once out of the water, they experienced abdominal cramps, joint pain and sometimes death. This condition was called 'caissons disease'.

In scuba diving, when the diver is in water, nitrogen is breathed in and as the diver descends the nitrogen dissolves in the blood stream. When the diver ascends, as a result of low pressure, the nitrogen leaves the blood. The nitrogen shapes up into small bubbles which can become large if they are not re-absorbed by the blood or they are not exhaled out by the lungs. When these bubbles become large in number, symptoms of decompression sickness arise.

Dive Watch

Technically, what happens here is an example of the principal called Henry's Law. This law is taught in all diving courses. When there is change in pressure, dissolved gases present in the liquid bubble out, and it is exactly the same as when you open a soda can. How much gas is dissolved and how fast it is released is dependent on the pressure at every point when you dive.

Decompression can result in permanent health impairment even if the diver survives. One cannot play around with it, so the first lesson a diver must learn is to avoid it. Avoiding it is not very difficult with the aid of dive tables, a dive computer or a diving watch. When the diver ascends a certain amount of time is allowed where the diver can remain neutrally buoyant, which means not sinking nor floating while surfacing. The time spent at each level is dependent on the technique the diver uses to descend, on an average the time spent is about 2 to 3 minutes at ever 9 meters while the diver is coming up.

During short dives, the divers can come up continuously as long as they do not ascend quicker than 10 meters per minute for a dive that is deeper than 6 meters. A diver can perform a safety stop at 3 to 6 meters.

Deep dives need a lot more stops and the duration of the stops must be longer, especially when the diver has not spent a lot of time at one particular depth. Temperature, the physical condition of the diver, his body type (nitrogen is stored effectively in fat) and age are important factors to consider while diving.

The rate at which a diver ascends and the number of times he stops changes depending on the mixture of nitrogen, helium and oxygen that the tank contains. A dive computer may be programmed, and a wristwatch can check the dive and calculate a safe speed of ascent and the duration of the stops.

The new methods are more useful when compared to the older ones. The older ones depended on printed tables and plastic cards that were laminated or just based on experience. But, today, divers use both the methods. You cannot depend only on dive tables as they are based on assumptions called the 'square dive'. In a square dive the diver goes down straight and stays at a constant depth and then ascends.

The consequences could be serious, hence you must not hesitate to invest in a dive computer. Training from a skilled instructor is very essential and is best to prevent spoiling a good holiday.

Scuba Diving And Decompression Sickness