Deep Vein Thrombosis and air travel for your patients: What you should know
M3 India Newsdesk Apr 16, 2018
According to the World Thrombosis Day Steering Committee, many people especially those who- are high risk, are recently operated on, or take long journeys are at risk of DVT, and in these cases, it is best to have experts who cannot only warn them about the condition but also diagnose and treat them quickly.
Long-distance flights are fraught with the risk of Deep Vein Thrombosis (DVT), a condition wherein blood clots form in deep veins owing to sitting immobile for a long time. Aviation medicine experts say any flight longer than 4 hours can pose a risk of DVT but the ones longer than 12 hours can be the trickiest.
In DVT, clots form in a deep vein, especially in the pelvis region, thigh or the lower part of the leg. It can occur in other parts of the body too, such as the liver vein, retinal vein, intestinal vein, brain vein and kidney vein, among others. The clot may break free from the vein wall and proceed toward lungs, blocking blood supply. This is a potentially fatal condition, called Pulmonary Embolism (PE).
In India, 1% population that's past the age of 40 years experiences DVT and about 20% of these patients need hospitalisation.
-The World Thrombosis Day Steering Committee
For healthcare professionals, it is critical to acknowledge that there exists is a risk of symptomatic venous thromboembolism from prolonged air travel.Though this risk is very low when flight time is less than 6 hours, it is progressively greater with longer-duration flights.
There is a 50% risk of DVT in the patients undergoing orthopaedic surgery, predominantly in those of hip and knee – while the patients undergoing thoracic or abdominal surgery have a 40% risk. In one in hundred cases, DVT patients develop PE, which is deadly. Reportedly, of all the hospitalised DVT patients in India, half are at high risk.
Dr. Sanjeev Sood empanelled medical examiner, Directorate General of Civil Aviation says, "During long-haul flights, those travelling in economy class in particular sit cramped up and don’t move, which causes slowing of blood circulation. There are other factors too, such as dehydration owing to the cabin's low relative humidity and less than optimum oxygen level, which make one prone to DVT."
Ex-Captain Arun Sahgal, Ethiopian Airlines (also served Indian Air Force as Wing Commander for 22 years and 17 years with Air India) says, "It is essential for passengers too to take a walk to the restroom whenever possible. Instead of pressing the button for water, they can walk up to the attendant. This helps break the confined posture."
What doctors need to caution their patients about
Doctors of patients with the following conditions should caution them about DVT so that the latter can plan their travel accordingly:
- Those with cardiovascular ailments
- Those older than 60 years
- Cancer patients undergoing chemotherapy
- Patients who underwent a surgery recently, particularly in the legs or pelvic region
- Patients with problems related to obesity
- Pregnant women
- Patients undergoing hormonal treatment
- Those with a hereditary condition of developing blood clots
If the patient has a personal history of venous thromboembolism and chronic venous disease, a full assessment by a vascular specialist is justified.
What doctors need to instruct their patients
If patients with any of the above condition need to take a long-distance flight, doctors can educate them about preventive measures. Experts highly recommend wearing compression stockings, especially the below-knee stockings, to mitigate the risk of DVT.
For long-distance travellers at increased risk of DVT, the American College of Chest Physicians suggest the use of a compression sock providing 15 to 30 mm Hg pressure at the ankle.
These stockings can help reduce the risk of swelling in the legs. The design of the stocking is such that it exerts a mild pressure on the ankle and assists the blood to flow at ease. Also called flight socks, the compression stockings come in various sizes and with different levels of compression.
Patients need to consult a medical expert before buying these stockings as a poorly-fitted stocking can increase the risk of DVT. Flight socks can also be purchased from pharmacies at airports and retail outlets.
What is the best possible treatment onboard
DVT and PE are closely related to heart attack and strokes. Experts say when there is a clot in a deep vein of the body, it may find its way into arteries. Automated External Defibrillators (AED) are excellent machines that can save lives in the event of a heart attack.
While some tier-1 airlines of the world mandatorily carry AEDs on the flight, there are still many who don’t. Owing to inconclusive scientific evidence, most airlines disclaim the responsibility. However, it is of paramount importance that airlines make it mandatory to incorporate AEDs, blood thinning and anti-coagulant drugs and other relevant medicines or equipment onboard that help treat any symptoms related to DVT, PE, heart attacks, and strokes.
Having said that, in general, it appears appropriate for travelers to engage in some DVT prophylaxis exercises, stay well hydrated, and avoid alcoholic beverages during flights.
Rajat Kalra is a freelance writer and a member of 101Reporters, a pan-India network of grassroots reporters.
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