Many people regain their physical fitness after cardiovascular diseases such as heart attacks, strokes or venous thromboembolism thanks to medical advances and lifestyle changes - often even to the point where they can dive again. At the same time, however, their situation requires the lifelong use of blood thinners (anticoagulants).
This raises important questions: Is diving while on anticoagulants safe? What specific risks are associated with these medications when diving? And, perhaps most importantly, what impact do the underlying medical conditions that necessitate taking the medication have on diving safety?
This article highlights the particular aspects that divers on anticoagulation should be aware of. It is aimed not only at those affected themselves, but also at their diving partners. A sound understanding of the risks and considerations when diving with blood thinners helps to ensure that everyone involved is well prepared for potential problems.
Categories
Anticoagulants:
They interfere with the coagulation factors in the blood by inhibiting their production or activity.
Common examples are:
Vitamin K antagonists: tablets. These include Marcoumar (phenprocoumon, US warfarin). Requires frequent monitoring of anticoagulation using INR (International Normalized Ratio, formerly “Quick” value) to ensure therapeutic values.
Direct oral anticoagulants (DOACs): Tablets. These include agents such as rivaroxaban (Xarelto), apixaban (Eliquis) and dabigatran (Pradaxa), which provide a more predictable effect without routine monitoring.
Heparin and low-molecular-weight heparin (e.g. enoxaparin): Subcutaneous application by injection. Often used in the short term, especially in hospital or to prevent thrombosis on long-haul flights.
Platelet-inhibitors:
They prevent the blood platelets from clumping together, an early step in clot formation.
Common examples are:
Aspirin: Tablet. Often used for the long-term prevention of strokes and heart attacks.
Clopidogrel (Plavix): Tablet. Often prescribed after the insertion of a stent in the coronary arteries (mesh tube after ballooning of a stenosis).
Ticagrelor (Brilique) and prasugrel (Efient): Tablet. Stronger options. Often prescribed after stent implantation or for heart attacks.
The underlying disease: the real challenge
Although blood anticoagulation itself carries risks, it is important to realize that in most cases the underlying medical condition requiring such therapy is the more critical factor in diving safety. A previous heart attack, stent implantation, coronary bypass surgery, atrial fibrillation, deep vein thrombosis, pulmonary embolism or stroke can impair physical performance or lead to medical complications during diving.
1. Cardiovascular diseases:
Conditions such as atrial fibrillation or heart attacks require anticoagulation or platelet inhibition to prevent the formation of blood clots. However, they can also indicate reduced cardiac performance, which can affect divers' ability to respond to stress underwater.
2. Venous thromboembolism (VTE):
Individuals with a history of venous thrombosis or pulmonary embolism have an increased risk of recurrence of clots, especially during long flights or car rides to dive sites. In addition, dehydration increases the risk of thrombosis. For this reason, long journeys after diving are also more risky and those affected must pay particular attention to sufficient fluid intake.
3. Strokes:
Divers who have suffered a stroke may have impaired motor or cognitive skills. These can be very subtle and negligible in everyday life, but can become a problem in challenging situations, which can occur at any time when diving.
4. Mechanical heart valves or other heart implants:
These may require anticoagulation to prevent clot formation. The above applies here with regard to physical resilience and adjustment of coagulation when traveling.
Specific diving risks of blood thinners
1. Barotrauma of the paranasal sinuses (sinus barotrauma)
A common diving injury caused by a lack of pressure equalization in the paranasal sinuses. Although sinus barotrauma is usually minor, it can lead to severe nosebleeds that can last longer in people taking blood thinners.
Bleeding into the paranasal sinuses or the middle and inner ear can lead to severe pain, displacement with obstruction of pressure equalization or even emergencies (e.g. dizziness and disorientation).
Injuries
Cuts, abrasions or bruises caused by diving or handling equipment can lead to excessive bleeding and make wound care more difficult. Consider, for example, a cut during a wreck dive or a bruise when getting out of a boat.
3. Decompression sickness
The formation of bubbles during decompression can cause micro-bleeding. Normally, blood coagulation controls this. This is impaired under anticoagulants. As a result, decompression incidents involving the spinal cord, for example, can become more serious.
4. Mistaking it for other problems
Symptoms of internal bleeding such as dizziness or shortness of breath can be mistaken for decompression sickness or other diving-related illnesses, which can delay appropriate treatment.
When using anticoagulants, bleeding can usually only be controlled by applying pressure to the wound. This is not possible with internal bleeding. This is why common barotraumas can easily become a real medical emergency.
Precautions and recommendations
1. Medical clearance
Advice from a diving physician strongly recommended This may include the following:
Review reason for anticoagulation.
Assess the stability of the condition.
Assess the person's risk factors, including previous bleeding events.
Assess the ability to dive as a whole.
2. Diving profile
Maintain conservative dive profiles to minimize the risk of barotrauma.
Limit depth and bottom time.
Descend and ascend slowly and buoy carefully.
Take care in special circumstances such as wreck dives (sharp edges) or overhead environments (bruising).
Take care during decompression dives
3. Dealing with medication
Vitamin K antagonists (Marcoumar, warfarin or similar):
Ensure that the INR value is within the therapeutic range. Avoid diving if the INR value is too high (e.g. >3.0), as the risk of bleeding increases considerably. Ensure that the INR value is reliably monitored when traveling.
DOAC and platelet aggregation inhibitors:
Take medication reliably. Do not skip any doses.
4. Preparedness for emergencies
It is advisable to carry a medical ID card with a list of medications and diagnoses.
Buddies and instructors should be aware of the condition and blood thinning and be trained to recognize potential bleeding emergencies.
Think about how to access emergency medical care, especially at remote dive sites.
5. No diving with active or recent bleeding
Any signs of active bleeding, such as a recent heavy nosebleed or blood in the urine or stool, should be checked by a doctor before diving.
6. Caring for the sinuses and hydration
Adequate hydration and the use of nasal ointments can reduce the likelihood of nasal dryness and irritation, which can cause bleeding.
Hydration helps to prevent decompression sickness.
7. Pay attention to your diet
People taking vitamin K antagonists such as Marcoumar or warfarin should be aware that changes in the vitamin K content of food can affect blood clotting. This is particularly relevant when traveling, as the change to unfamiliar food, especially during longer stays, can promote such fluctuations.
“Dive your plan, plan your dive” and level-appropriate diving
apply more than ever when diving with blood thinners.
Comments