What is “economy-class syndrome”? Economy class syndrome describes the situation of patients who suffer potentially serious blood clots that can lead to potentially fatal blockages in the lungs (pulmonary embolism) following prolonged immobility in a long distance flights. What is Deep vein thrombosis (DVT)? Deep vein thrombosis or DVT is when blood clots form in a deep vein , most commonly affects the leg veins or deep veins in the pelvis. It can cause pain and swelling in the leg but in some cases there may be no symptoms. What is a pulmonary embolism (PE)? A sudden blockage in a lung artery. It usually happens when a blood clot breaks loose and travels through the bloodstream to the lungs. PE is a serious condition that can cause Permanent damage to the lungs ,low oxygen levels in your blood and damage to other organs in your body from not getting enough oxygen. PE can be life-threatening, especially if a clot is large, or if there are many clots. When was the economy class syndrome discovered? The first reference to the association between immobility and the risk of deep vein thrombosis (DVT) dates from 1940 when cases of pulmonary embolism were reported in persons who had spent long periods of almost total immobility in subterranean air raid shelters during the bombing raids on London during WWII. The association between travel and DVT was first reported in 1954 with a description of 5 cases, and soon the phrase “economy-class syndrome” appeared to describe the problems of venous return that occur in passengers on long distance flights in seats with evident restrictions of space and few opportunities to move their lower limbs. Since then, there have been several published case series involving patients who have taken long-distance flights and later developed DVT and/or pulmonary embolism, but few authors have associated those 2 conditions with overland travel by car, coach, lorry, or train. What are the risk factors for developing economy class syndrome? The guidelines looked at a range of risk factors for the development of DVT in long-distance travelers . They conclude that developing DVT or pulmonary embolism from a long-distance flight is generally unlikely, but that the following factors increased people’s risk:
Having a history of blood clots or having cancer
Having a known thrombophilic disorder -- a medical disorder that predisposes you to forming blood clots
Undergoing a recent surgery
Use of oral contraceptives or other estrogen treatments
Sitting in a window seat if this prevents getting up and moving around
advanced ageWhat are the symptoms of DVT?About half of people with DVT have no symptoms at all. The following are the most common symptoms of DVT that occur in the affected part of the body (usually the leg or arm):
Swelling of your leg or arm
Pain or tenderness that you can’t explain
Skin that is warm to the touch
Redness of the skinWhat are the symptoms of Pulmonary Embolism (PE)?You can have a PE without any symptoms of a DVT. Symptoms of a PE can include:
Difficulty breathing
Faster than normal or irregular heartbeat
Chest pain or discomfort, which usually worsens with a deep breath or coughing
Anxiety
Coughing up blood
Lightheadedness, or faintingHow can we prevent DVT from developing during travelling?
Keep moving : Don’t sit in a cramped position for too long. Wriggle your toes and work those ankles and knees. Make an effort to stand up and walk along the aisle to get the blood pumping. If possible, ask for an aisle seat. Studies have shown that passengers in window seats have double the risk of developing DVT.
Sit right, not tight: Don’t cross your legs or sit on the edge of the seat. Wear loose clothing, and avoid stockings or socks with tight bands.
Avoid alcohol and caffeine on board: Don’t let yourself be intoxicated or dehydrated before and during a long-haul flight. Instead, drink water at regular intervals.
No sleeping pills either: This encourages immobility and increases the risk of DVT.How can we diagnose DVT?
Duplex ultrasonography: is an imaging test that uses sound waves to look at the flow of blood in the veins. It can detect blockages or blood clots in the deep veins. It is the standard imaging test to diagnose DVT.
A D-dimer blood test measures a substance in the blood that is released when a clot breaks up. If the D-dimer test is negative, it means that the patient probably does not have a blood clot.
Contrast venography is a special type of X-ray where contrast material (dye) is injected into a large vein in the foot or ankle so that the doctor can see the deep veins in the leg and hip. It is the most accurate test for diagnosing blood clots but it is an invasive procedure, which means it is a medical test that requires doctors to use instruments to enter the body. Therefore this test has been largely replaced by duplex ultrasonography, and it is used only in certain patients.
Magnetic resonance imaging (MRI)—a test that uses radio waves and a magnetic field to provide images of the body—and computed tomography (CT) scan—a special x-ray test—are imaging tests that help doctors diagnose and treat a variety of medical conditions. These tests can provide images of veins and clots, but they are not generally used to diagnose DVT.How can we diagnose PE?
Computed tomographic pulmonary angiography (CTPA) is a special type of X-ray test that includes injection of contrast material (dye) into a vein. This test can provide images of the blood vessels in the lungs. It is the standard imaging test to diagnose PE.Ventilation-perfusion (V/Q) scan is a specialized test that uses a radioactive substance to show the parts of the lungs that are getting oxygen (ventilation scan) and getting blood flow (perfusion scan) to see if there are portions of the lungs with differences between ventilation and perfusion. This test is used when CTPA is not available or when the CPTA test should not be done because it might be harmful to the particular patient. Pulmonary angiography is a special type of X-ray test that requires insertion of a large catheter (a long, thin hollow tube) into a large vein (usually in the groin) and into the arteries within the lung, followed by injection of contrast material (dye) through the catheter. It provides images of the blood vessels in the lung and it is the most accurate test to diagnose PE. However, it is an invasive test so it is used only in certain patients. Magnetic resonance imaging (MRI) How can we Treat DVT and PE? Anticoagulants
Anticoagulants (commonly referred to as “blood thinners”) are the medications most commonly used to treat DVT or PE. Although called blood thinners, these medications do not actually thin the blood. They reduce the ability of the blood to clot, preventing the clot from becoming larger while the body slowly reabsorbs it, and reducing the risk of further clots developing.
The most frequently used injectable anticoagulants are
Unfractionated heparin (injected into a vein),
Low molecular weight heparin (LMWH) (injected under the skin), and Fondaparinux (injected under the skin).
All of the anticoagulants can cause bleeding, so people taking them have to be monitored to prevent unusual bleeding.Thrombolytics Thrombolytics (commonly referred to as “clot busters”) work by dissolving the clot. They have a higher risk of causing bleeding compared to the anticoagulants, so they are reserved for severe cases. Inferior vena cava filter When anticoagulants cannot be used or don’t work well enough, a filter can be inserted inside the inferior vena cava (a large vein that brings blood back to the heart) to capture or trap an embolus (a clot that is moving through the vein) before it reaches the lungs. Thrombectomy/Embolectomy In rare cases, a surgical procedure to remove the clot may be necessary. Thrombectomy involves removal of the clot in a patient with DVT. Embolectomy involves removal of the blockage in the lungs caused by the clot in a patient with PE.