Tales of “the bends” are often the first horror stories many divers hear before they first enter into the world of SCUBA. While the stories are justified, the condition can have severe and lasting implications on the body. It’s important to know that if you dive safely, you can avoid it entirely.
Decompression sickness (DCS), known as “the bends,” is a rare condition ( 3 or 4 cases per 10,000 dives) that happens when there is too much nitrogen in the diver’s body and too little time to get rid of it.
While underwater, your body absorbs nitrogen from breathing compressed gas. If you speed to the surface too quickly, your body can’t adjust and “off gas” or dissolve the nitrogen. The result is nitrogen bubbles in your tissues, which causes DCS.
Even on the safest of dives, you will have a residual amount of nitrogen in your body and can get DCS from diving too much. With each dive, more nitrogen is left over.
Decompression sickness is part of a larger term called decompression illness (DCI), which also includes Arterial Gas Embolism (AGE). An embolism occurs when nitrogen bubbles enter the lung circulation and go into the arteries, blocking blood flow. This happens when divers hold their breath on ascent to the surface.
The condition was first identified during the construction of the Brooklyn Bridge in 1878. DCS was originally called “Casisson Disease,” named after the large chambers workers used to stay dry underwater while building bridges and tunnels — “caisson” is French for “big box,” which is what the underwater chambers were called. When workers ascended to the surface after being underwater for hours in the chambers, many experiencd DCS symptoms. The reason decompression sickness is called “the bends” is because when nitrogen bubbles start to form near or inside joints, it causes pain. Sufferers doubled over, or leaned forward due to the pain. Their posture mimicked a popular women’s fashion of the time called the “Grecian Bend.”
French physiologist Paul Bert was the first to realize that breathing under pressure increased the amount of nitrogen in the blood. Workers did not do “safety stops” to allow the nitrogen to dissolve. Workers found that if they descended again, they tended to feel better. After Bert’s discovery and recommendation to ascend slowly, fewer workers were affected, although many still were. Recompression chambers, chambers that mimicked the underwater pressure (known today as hyperbaric chambers) were built and installed at construction sites to treat workers beginning in 1879.
Later in 1907, English physiologist Dr. J.S. Haldane was conducting experiments with the Royal Navy. He discovered that instead of ascending slowly but continually as recommended by Bert, ascending in gradual stages prohibited nitrogen bubbles from forming in body tissue — hence, the “safety stop.” Using what he learned, Haldane created the first set of dive tables.
Symptoms usually begin within 15 minutes to 12 hours after surfacing. Some common DCS signs and symptoms are:
Some signs of an Arterial Gas Embolism can be similar to the “bends,” but also can include:
DCI manifests in varying degrees of severity. The first step is to determine how serious the symptoms are, and if life-threatening, immediately begin CPR and administer oxygen if possible. Arrange to have the diver evacuated. Call the Divers Alert Network (DAN) to find out where the nearest hyperbaric chamber is located. DAN experts can also provide advice on what to do next.
For less severe cases of decompression sickness, fluids and 100% oxygen should be administered as soon as possible in a medical facility.
In some cases, even after treatment, there may be residual effects. Depending on the severity, these symptoms may last a few hours or they may require additional treatment.
The good news is that most victims of DCS and DCI can find relief of symptoms.
If you’re in the Dallas metro area, we here at Scuba Toys offer a Nitrox course – learn more about breathing oxygen enriched air while diving.
Stop by our shop in Carrollton, TX, call us at 877-728-2243 or visit us at ScubaToys.com!
Have you ever experienced (or witnessed others) decompression sickness? Let us know in the comments section below!
Image Attribution: https://www.flickr.com/photos/chadlathe/