Can I dive after being treated for cancer?
That depends on a number of factors. Cancer varies widely in location, severity, and treatment. For example, surgical excision of tumors in the sinuses or lungs can create air pockets that may not be well-vented, in which case they could be damaged by pressure changes during descent and ascent. On the other hand, if a diver undergoes a simple in-office procedure to remove a small basal cell carcinoma (a form of skin cancer), he or she can normally return to diving as soon as the incision has completely healed. Some chemotherapy agents react adversely with hyperbaric oxygen (HBO2). Most people who are actively receiving chemo are too ill to dive; however, chemo/HBO2 interaction could become problematic if a diver needed to be treated for DCS. Similarly, most people undergoing radiation therapy are too ill to dive. Radiation can also cause long-term damage to surrounding tissue, theoretically increasing the risk of decompression sickness in that area. In general, it’s necessary to obtain clearance to dive by your oncologist and, if needed, a qualified diving physician.
Which are safer, dive computers or traditional no-decompression/decompression tables?
Vann and colleagues (Vann et al, 1989) found that there is no direct evidence of a higher incidence of decompression sickness (DCS) among divers who use computers. Beyond that, there is not much to indicate that computers are either safer or less safe than decompression tables in terms of risk of DCS.
I’ve been treated for decompression sickness or arterial gas embolism. Can I start diving again right away?
We advise divers who’ve been treated for DCS or AGE to wait 90 days after all of their symptoms have resolved before they return to diving. However, your diving physician may advise you differently based on your symptom presentation and treatment outcome. Divers who’ve had DCS with spinal cord involvement are not usually able to safely return to diving. Sometimes, a diver can suffer DCS or AGE even with a seemingly normal dive profile that’s within no-decompression limits. We call this an “undeserved” or “unexpected” hit. If your symptoms were particularly severe or unexpected, your physician may want to perform an echocardiogram to rule out patent foramen ovale (see below). If you’ve suffered from AGE, further studies may be needed to ensure that you do not have any residual lung damage or underlying conditions that may precipitate another gas embolism.
What are the main symptoms of decompression sickness?
Decompression sickness is rare, and serious DCS is even more so. When DCS does occur, it’s usually after long, deep dives, repetitive dives, or if a diver fails to follow established decompression procedures or no-decompression limits. Any system in the body can be affected by DCS. The location of the bubble(s) determines the symptom presentation. Traditionally, DCS symptoms have been divided into two types, Type I and Type II. Type I symptoms are less severe and include joint pain; itching skin; reddened, hive-like skin rash; and swelling of a limb or limbs. Type II symptoms are more severe and potentially life-threatening. Neurological DCS involves the brain and/or spinal cord. Symptoms can include numbness, weakness, paralysis, altered level of consciousness or loss of consciousness, loss of speech, bladder paralysis, and bowel incontinence. Inner ear DCS can cause vertigo, nausea, vomiting, tinnitus (ringing in the ears) and hearing loss. Pulmonary DCS is the most immediately life-threatening; symptoms include difficulty breathing, unconsciousness and death. Other symptoms classified as Type II include trunk pain and cutis marmorata, or “marbling” of the skin that appears as a streaky reddish-blue rash. Decompression illness that occurs when bubbles in the veins cross into the arterial circulation through some sort of arteriovenous shunt such as a patent foramen ovale (PFO) or intrapulmonary shunt is sometimes referred to as Type III DCS.
What is the treatment for decompression sickness?
Decompression sickness is treated in a hyperbaric chamber using oxygen. At Duke, we normally use treatment protocols established by the U.S. Navy. A diver is compressed to a depth equivalent of 60 feet and given 100% oxygen in 20-minute periods. These O2 breathing periods are separated by “air breaks” where the diver breathes chamber air to help avoid oxygen toxicity. The diver is then slowly decompressed to 30 feet, given additional oxygen, and then slowly brought to the surface. This normally takes just under five hours but can take longer if the diver’s symptoms are slow to resolve. If symptoms persist after the first treatment, a diver may undergo additional hyperbaric oxygen therapy until the symptoms either resolve completely or “plateau” (cease improving with treatment). Symptoms that remain after treatment frequently improve over time.