Diving with an Infectious Disease

If I have an infectious disease, should I dive?

There are two types of risks to consider with any infectious disease — those associated with the disease itself and the risk of transmission to other divers.

Many infectious diseases are characterized by disabling symptoms such as fatigue, fever, vomiting and dehydration. As long as these symptoms are present, diving is not recommended. In addition to their symptoms, divers should consider the medications they are taking. Doctors trained in dive medicine generally recommend that a diver take a medication for at least 30 days before considering diving with it to determine what, if any, side effects might occur and to ensure the dosage is correct. This also helps minimize the chances of side effects interfering with diagnosis of decompression sickness (DCS). It is theoretically possible that a drug’s action could be influenced by pressure, so any diving on medication should be conducted conservatively.

After recovery from an infectious disease, it is important your physician approves of your return to diving. In some cases an evaluation by a specialist is advisable. Lung infections, for example, might predispose divers to pulmonary barotrauma and should prompt a consultation with a doctor trained in diving medicine. Prolonged illness can result in significant deconditioning, characterized by muscle weakness, early fatigue and limited endurance. Exercise intolerance may be significant with some illnesses and is a common reason for physicians to recommend postponing diving. Divers must regain adequate physical fitness before returning to diving. If you need a referral to a diving medicine specialist in your area, call DAN at +1-919-684-2948, ext. 222.

The risk of disease transmission must be considered as well. DAN is not aware of any confirmed cases of divers contracting bacterial, viral or fungal infections from diving equipment; the most likely ways for an illness to be transferred between divers are by coughing, sneezing, close contact and lack of hand washing — the same ways diseases are transferred between people anywhere.

However, any diver who chooses to dive while potentially contagious should avoid sharing mouthpieces (except in an emergency) since transmission is still theoretically possible. Proper disinfection of equipment reduces the risk of disease transmission even further.

— John Lee, EMT, DMT, CHT, MSDT, DAN medical information specialist

How do air and enriched air (nitrox) compare with regard to DCS risk, and does the risk increase if I do nitrox dives and air dives on the same day?

At the 2000 DAN Nitrox Workshop, Michael Lang (see “Member Profile,” Page 20) remarked that “no evidence was presented that showed an increased risk of DCS from the use of nitrox versus compressed air” (Lang, MA [ed.]. Proceedings of the DAN Nitrox Workshop, 2001; Divers Alert Network, Durham, N.C.). Whenever nitrox is used, the diver should analyze his or her own cylinder so the actual oxygen percentage is known and the no-decompression limit (NDL) is calculated correctly. When usingText Box: eric do UGlas a computer, the diver should make sure to adjust the gas-mix setting for each dive to accurately reflect the gas in the cylinder. Although nitrox can be used to lower DCS risk, it is important to understand that nitrox dives are not inherently safer than air dives. They can be made safer (from a DCS-risk perspective) if the diver uses nitrox but dives within the NDL of an air dive to the same depth. On the other hand, nitrox can also be used to increase a diver’s bottom time, but this eliminates the protective effect. As for switching between gas mixes, if each dive is within the NDL of a dive computer or table and residual nitrogen is accounted for correctly, there is no reason to suspect that DCS risk would be elevated.

— Brian Harper, EMT, DMT, Alert Diver medical editor

What is the difference between a deco stop and a safety stop?

From time to time the DAN medical department receives calls from concerned divers who report having missed a “deco stop.” These divers are usually referring to a single three- to five-minute stop they had planned to do at 15 or 20 feet at the end of a recreational dive. Such a stop is generally a good idea but is not strictly necessary. These “safety stops” are done to minimize DCS risk, but in a context where the risk is already very low.

Recreational dives are defined in part by a diver’s ability to return (slowly) to the surface at any point during the dive without a decompression obligation. Dives requiring mandatory decompression should be done only by those with training in decompression diving. Obligatory “deco stops” are extremely important to keep DCS risk at an acceptably low level. If a deco stop is missed, the diver should abort subsequent dives and be monitored for any unusual symptoms. While these steps are generally not necessary in the case of a missed safety stop, the diver and his or her buddy should discuss why the dive plan was not followed and take steps to prevent similar errors on future dives.

— Brian Harper, EMT, DMT, Alert Diver medical editor

While on a liveaboard recently, I noticed one of the divers was using a scopolamine patch to combat motion sickness. In the middle of the week after replacing the patch, one of her pupils became much bigger than the other. Is this a side effect of the patch?

Woman stares at camera and her left pupil is dialated

Transderm Scōp has helped many divers; in fact, it’s even recommended in the U.S. Navy Diving Manual. The patch releases the drug scopolamine slowly through the skin and can be very effective against motion sickness.

Scopolamine is a prescription medication, and side effects are possible. Dry mouth occurs in more than half of users, and blurred vision after about 24 hours of use is common. Repeated applications can cause visual disturbance to increase. Symptoms may even persist for a short time after the patch is removed. Scopolamine can have other side effects that could impair one’s ability to dive safely, including drowsiness, dizziness and confusion. These side effects depend on the individual; there is no way to know in advance who will be affected. Before diving with the patch, try it for at least 24 hours on land in a situation where potential side effects will not cause harm. For some people who do not tolerate the patch, Scopace tablets are an alternative to Transderm Scōp. Benefits of the tablets may include faster onset of relief, dosage flexibility and fewer side effects than the patch. During application and removal of Transderm Scōp, avoid touching the inside of the patch. If some of the medication gets on a finger and then into an eye, the drug could cause the pupil to dilate. This may impair visual acuity temporarily, usually for no more than 12 to 24 hours. Flush the affected eye(s) with fresh water and postpone diving until vision returns to normal. Always wash your hands thoroughly after handling the patch.

— John Lee, EMT, DMT, CHT, MSDT, DAN medical information specialist

How clean should water be to use for wound cleaning?

If water is clean enough to drink, it is clean enough for wound care. In fact, potable water is often the only substance needed for irrigating a wound. There are several methods to make fresh water of uncertain cleanliness drinkable. These include boiling, filtration and the use of iodine tablets or chlorine dioxide drops. When applied forcefully, as with a syringe, a stream of water will effectively remove microorganisms and debris. When using boiled water, make sure it has cooled first. Wounds with an elevated risk of infection (e.g., bites, punctures and especially dirty wounds) may warrant irrigation with a mild solution of povidoneiodine, but these wounds should be given a final rinse with plain, potable water. This ensures none of the chemical agent remains in contact with wounded tissue.

— Brian Harper, EMT, DMT, Alert Diver medical editor

© Alert Diver — Q2 Spring 2011