The term was first coined in the late 1980s when it was observed that people undertaking long duration flights in the cramped conditions of economy class were vulnerable to enhanced risk of formation of blood clots
Merely travelling As a passenger in an airliner on a long duration flight can endanger one’s life? Unfortunately, yes. Although such incidents are rare when viewed against the multitude undertaking air travel, one cannot deny that the danger very much exists.
British medical journal Lancet records a rather shocking episode in September 2000 wherein a 28-year-old, apparently healthy lady passenger flew into Heathrow from Australia. She neither complained of discomfort nor displayed abnormal symptoms during the flight. But upon landing, she collapsed and died. The journal cites another case of a 68-year-old businessman, on a similar long-haul flight in November the same year, who complained of breathing difficulty in flight. After landing, he slipped into a coma and died in hospital five days later.
In both cases, it was discovered that blood clots had formed in some part of the body, most probably the lower limbs, and had travelled to the lung, impeding the passage of blood through it. As a result, the body was starved of oxygen and the individual literally choked to death. Obviously, the sudden death of a visibly healthy individual without any apparent cause would not only be sensational but also pose an enigma for medical science apart from being of concern to air passengers. This newly discovered threat to air passengers, the formation of killer blood clots in medical parlance, has come to be known as Deep Vein Thrombosis (DVT).
The occurrence of DVT in air passengers is also referred to as Economy Class Syndrome. The term was first coined in the late 1980s when it was observed that people undertaking long duration flights in the cramped conditions of the economy class were vulnerable to enhanced risk of formation of blood clots. This condition, however, is not limited to air travel. During the Second World War, British physicians observed this phenomenon among people crouching in overcrowded air-raid shelters for long hours during bombing raids by the Luftwaffe over London. This phenomenon is also referred to as Cattle Class Syndrome.
As more such cases came to light, victims or their well wishers began to drag airlines and aircraft manufacturers to court for compensation. However, it is not easy to hold airlines accountable as passengers are expected to be aware of any medical condition that might be aggravated by flight. If not, they themselves are responsible for obtaining the medical opinion of physicians regarding their fitness to travel by air prior to undertaking the flight.
The basic problem continues to be the lack of correct understanding of the problem. Many cases of DVT go undetected or unreported. Although there is little data available on the occurrence of DVT in the history of Indian aviation, in the West, an estimated one in ten thousand long-distance travellers is affected. One report claims, at London’s Heathrow Airport every month there is at least one passenger from long-haul flights who falls victim to DVT within minutes of landing. In Australia, one law firm alone has filed thousand DVT claims against six airlines in the course of the year. At Narita Hospital near Tokyo’s International Airport, records indicate that on an average, each year around 100 passengers are treated for DVT immediately upon arrival. Some 3 per cent of these succumb to the affliction.
What Is DVT?
Deep Vein Thrombosis is a blood clot that forms in the deep vein system of the lower leg, usually between the ankle and the upper calf. Symptoms, if they occur at all, might include muscle tension in the lower leg, a dull ache or sudden painful tear, or a cramp in the calf muscle with swelling and occasionally, elevated body temperature. The most common symptom is pain in the calf muscles developed during or shortly after a long duration flight. The pain, which sometimes could be mistaken for a muscle cramp, could be due to the formation of a deep vein clot resulting from sludging of blood in the veins of the calf muscle due to inactivity, dehydration or a pre-existing disease. More often than not, the clot dissolves and the pain subsides as the individual walks out of the aircraft after landing at destination. Fortunately, most passengers may never even be aware of having experienced the Economy Class Syndrome.
Alternatively, one might experience flu-like symptoms such as mild chest discomfort and the tendency to cough, which disappear in a day or two as the blood clots dissolve. Others may experience significant chest pain, sometimes misdiagnosed and treated as a heart attack.
The real danger lies wherein no symptoms are manifest. The clot may develop rapidly, detach from the wall of the vein and travel up the veins and get lodged usually in the lungs or sometimes in the heart. This is called Pulmonary Thrombosis and could result in sudden death. Even if the clot remains lodged in the leg veins, serious damage to the limb’s venous system may occur.
