Dysbarism

Dysbarism describes medical illnesses related to changes in pressure. The volume of a gas varies inversely with pressure. This can affect the following systems:

• Lungs. Rapid ascent can cause the lungs to expand too rapidly leading to serious conditions such as a pneumothorax ("punctured lung") and air embolism (gas in the veins - which can be fatal if it travels to the brain or heart). People with asthma are more susceptible to these complications
• Ears. Failure to equalise the pressure between the middle ear and surrounding structures and lead to increased pressure on the eardrum ("squeeze") or damage to the inner ear causing hearing loss and vertigo.
• Others. Other symptoms related to changes in pressure include headache, tooth pain and sinus pain.

Decompression Sickness

Decompression sickness results from the release of dissolved gas (mainly nitrogen) into the tissues and bloodstream due to the reduction in pressure while ascending.

• Type 1. Muscle, joint and tendon pains. Itch and skin rash.
• Type 2. Back pain, limb weakness or numbness . Visual disturbances, vertigo, nausea and confusion. Cough, chest discomfort and shortness of breath which can be severe, even fatal. Low blood pressure and the formation of clots in the blood vessels.

Treatment of decompression sickess in the field consists of

• Basic Life Support if required
• Administer 100% oxygen, aspirin (if not bleeding) and intravenous fluids.
• Transport to nearest hyperbaric unit for recompression therapy

Prevention

The risk of decompression sickess and dysbarism can be greatly reduced by diver eduction, ensuring good physical condition prior to diving, strict observation of decompression table limits and early recognition and management of symptoms.