Flying After Diving: A Threat Worse than the Bends

In an earlier issue of Undercurrent, I commented on the death of a healthy 28-year-old woman who, following a dive trip to Australia, died from a deep vein thrombosis (DVT) during her long return flight. DVT, an inactivity-related blood clot in the deep veins of the calf or the thigh that works its way to the lungs or heart, can be caused by sitting in the cramped seat of a plane for an extended period. Among the signs of DVT are calf pain upon extension of the foot, redness and hardness at the site of the clot, and swelling of the lower extremity.

The February issue of Chest, the journal of the American College of Chest Physicians (ACCP), contains an article that revisits DVT and makes revised recommendations for prevention. The authors suggest that the common usage of the term "economy-class syndrome" to describe this condition is inaccurate, as there is no definitive evidence to support that simply traveling in economy class can lead to the malady. Evidence does, however, support the danger of remaining immobile for long periods of time, no matter which class of seat you are flying.

The article also indicates that while flying-related DVT is quite unlikely in the healthy traveler, odds of an event are increased by a history of previous DVT, malignant cancer, recent surgery or trauma, advanced age, use of estrogen or oral contraceptives, pregnancy, obesity, immobility and sitting in a window seat (most likely because you don't get up as often).

In terms of prevention, keeping the legs active tops the list. On flights of six hours or more, the ACCP recommends that individuals who have an increased risk for DVT frequently stretch their calf muscle and walk around, sit in an aisle seat if possible, and hydrate regularly. Also recommended are below-the-knee graduated compression stockings. Aspirin or more powerful anticoagulants may be prescribed for flyers at significant risk. The ACCP does not recommend compression hose, aspirin or other anticoagulants for those who do not have one or more of the above risk factors.

For those of us who enjoy an alcohol beverage while flying, happily the article notes that the evidence does not support a recommendation of abstinence.

- - Doc Vikingo

"New DVT Guidelines: No Evidence to Support 'Economy- Class Syndrome,'" Chest, February 2012, volume 141.