Decompression Sickness

Understanding the Bends Decompression Sickness and Scuba Diving

Knowing the facts about decompression sickness (DCS) and providing the proper treatment quickly can help prevent this diving condition from becoming fatal.

Diving DCS, also known as the bends, is a diver's worst nightmare. If the conditions are severe enough they can prevent a diver from diving after the bends. Divers learn in a basic open water certification course about decompression theory and how to manage nitrogen in the body while diving.


Caisson Disease (The Bends)

DCS was first seen in the 19th century. Huge chambers or caissons where being used to build bridge footings and excavate tunnels. The caissons allowed several men to work at depth. Air would be pumped into the caisson to keep the water out.

Many of the workers would become ill after their shift. This illness became know as Caissons Disease. Today we know this illness as DCS.


How DCS Happen

DCS (the bends) normally occurs when a diver ascends too quickly. This causes a rapid change in the pressure around the diver. When this happens the nitrogen in the body turns into bubbles in body tissue and blood vessels.

Nitrogen is usually expelled from the body during an exhale. When breathing compressed air while under pressure, nitrogen remains in the body. As the pressure around the diver decreases, the nitrogen will start to off gas from the body.

Nitrogen bubbles can form under the skin or in the blood stream. This causes a restriction in the blood flow to the lungs. This will cause lowing of blood pressure, slower breathing and shock. It extreme cases nitrogen bubbles can show up in the brain or spinal column. This can cause paralysis and even death.


Predisposing Factors to DCS

There are predisposing factors to DCS and they can affect whether a diver suffers from the bends. A safe diver plans dives with these factors in mind.

• Fat Tissue: Fat tissue holds a high amount of nitrogen.


• Age: Age inevitably changes circulation and respiration, which interferes with nitrogen leaving the body.


• Dehydration: Dehydration reduces the amount of blood available for gas exchange. This slow down nitrogen removal from the body.
  

• Illness and Injury: A healed injury can cause problems with local circulation, and an illness cause a loss of circulation efficiency. Either of these can affect nitrogen removal from the body.


• Alcohol: Alcohol will accelerate circulation and cause tissue to carry more nitrogen during a dive.


• Carbon Dioxide: Higher amounts of carbon dioxide from skip breathing will cause slower nitrogen removal from the body.


• Cold Water: Diving in cold water will change the body's normal circulation as it takes action to conserve heat.


• Flying After Diving: Problems may occur of a diver ascends above sea level before nitrogen is completely removed from the body.

Symptoms of decompression sickness normally appear between one and six hours after diving. Sometimes it can take up to 24 hours for symptoms to show up. They usually start as mild pain in the joints and itching. In mild cases of DCS they will disappear in a few hours. In more severe cases they are followed by severe complications.

Treatment off DCS is very important. How quickly the treatment is started is vital. Diver's Alert Network's recommended first aid for DCS is:

• Request emergency medical attention.


• Administer 100% oxygen to a breathing patient.
  

• A breathing patient should lie down on their left side, a non-breathing patient should be laid on their back for CPR.


• Transfer the patient to a recompression facility for medical attention.


• The patients airway and circulation should be monitored until EMS arrives.

Dan's emergency hotline: 1-919-684-4DAN(4326)

Non-emergency medical questions: 1-919-684-2948

DAN Travel Assist: 1-800-326-3822

There are no dive tables or dive computers that can guarantee a diver will not get DCS. But if a diver learns how to calculate dive time properly, stays within safe depth limits and ascends slowly from every dive they can lessen their chance of getting the bends.

Plan the Dive and Dive the Plan