Tight space, fatal clot
The common practice of packing hundreds of airline passengers into tight quarters without much legroom spawned the term “economy-class syndrome” to describe the blood clots that can form in the legs during prolonged periods of inactivity. While the syndrome is linked most often to flying, the condition can occur in any situation where people are cramped for hours in tight quarters, such as a tank or other military vehicles on the battlefield.
The death last week of David Bloom, the NBC newsman, drew attention to the problem. The 39-year-old reporter died of a pulmonary embolism while reporting from Iraq, and his death has been linked to the syndrome.
Bloom had spent long hours reporting from a Bradley fighting vehicle and slept, by his own description, with his knees gathered up close to him. For several days before his death, colleagues said he reported leg cramping and pain behind his knees from sitting in one position for hours in the tank. These are key symptoms of phlebitis, an inflammation of blood vessels that can lead to clots in the legs, known as deep vein thromboses. Bloom reportedly took aspirin for the pain and kept working until his death. In otherwise healthy people, inactivity or sitting in a cramped position for a prolonged period of time can cause blood to pool in the legs and form clots in the veins of the calves, thighs or pelvis. If those clots break off, they can pass through the heart and lodge in the lungs, cutting off the body’s supply of oxygen-filled blood, sometimes leading to death.
About 600,000 people suffer a pulmonary embolism each year, and about 60,000 of them die, according to the American Heart Assn. Deep vein thromboses, which can create pulmonary emboli if untreated, are much more common, suffered by about one in 1,000 people. Increasingly, doctors are treating patients who have developed the condition from extended immobility.
Had Bloom sought medical help when he first noticed the leg pain, doctors might have been able to use ultrasound to diagnose a deep vein thrombosis in his legs and provide treatment, said Dr. David J. Ross, a UCLA pulmonologist. Working in the desert, Bloom also may have suffered the complicating effects of dehydration, which can raise the risk of blood clots, Ross said.
Studies have shown that aspirin, although it does thin the blood, doesn’t help thwart or dissolve leg clots. But twice-daily injections of the anticoagulant drug heparin can prevent these clots from breaking off and traveling to the lungs, Ross said. Such treatment might not have been an impossibility for Bloom. Although heparin used to be administered only in hospitals, patients today can give themselves twice-daily shots of a long-acting form of heparin, called low-molecular-weight heparin, that’s dosed based on body weight and then injected just under the skin. Such injections might have stabilized Bloom’s condition and allowed him to travel to a hospital for further care.
When patients develop deep vein clots in the legs, doctors also typically prescribe several months of treatment with another anticoagulant called warfarin (Coumadin), which must be monitored to make sure the drug helps prevent further clot formation without causing internal bleeding. In some cases, doctors may insert filters to keep clots from reaching the heart and lungs, and in other cases, they may perform surgery to remove the clot.
Once a clot travels to the lungs, symptoms can include shortness of breath or sudden chest pain, dizziness and fainting, but doctors may be able to treat it successfully with clot-busting drugs such as streptokinase or t-PA, which are used to treat strokes, Ross said.
Untreated, 30% of people with pulmonary emboli die; treatment reduces the mortality rate to between 2% and 8%.
In addition to travelers and those who are immobilized, others at risk of blood clots in the legs include surgical patients -- about 5% of hernia repair patients and up to 75% of hip replacement patients; cancer patients; those with a hip fracture, severe varicose veins or phlebitis; women taking birth control pills or using hormone replacement therapy; those who have suffered trauma; and people who have inherited clotting problems. Occasionally, clots develop in weightlifters who have damaged veins in their upper extremities, Ross said.
Although clots in the legs are most frequently seen in post-surgical patients, Ross said they are becoming more common in healthy people who travel frequently on cross-country and overseas flights. He recently treated a Japanese automobile executive in his 40s who had suffered a pulmonary embolism after a long flight to Los Angeles. He was effectively treated with drugs.
Doctors recommend that passengers on long airline flights get up frequently to stretch their legs and walk for a while. The movement aids in blood circulation through the legs.
