Saturday, March 8, 2008

"Economy class syndrome": What you need to know

Economy class syndrome has been all over the newspaper and TV headlines for the past several years, with little insight given to this problem other than press releases by the major airline carriers, who are in denial over fear of numerous lawsuits, should they discuss in any detail. We are told it is just something that happens to folks who are immobile for long times in the economy class section of the aircraft.

Let's focus on what Economy Class Syndrome really is and what it is not. First of all, Economy Class Syndrome is a misnomer as it also occurs in first class and among flight attendants and even pilots. It refers to DVT, or deep vein thrombosis, where the blood pools in the deep veins of the legs and then clots. Sometimes these clots can break off and travel to the lungs or heart, causing a pulmonary embolism or myocardial infarction, also known as a heart attack. Risk factors include clotting factor abnormalities which are inherited, smoking (nicotine promotes blood clots), illness with cancer, dehydration and prolonged immobility.

Blood travels quickly through arteries, which actively pump the blood to all parts of the body. Veins, on the other hand, are passive and blood flow relies on a one-way valve system. Whenever the muscles are flexed or arms or legs moved, it causes the muscles to squeeze the veins, causing blood to flow back to the heart. If there is prolonged immobility, then the blood can clot. Usually these clots, if they are in the deep veins of the lower legs (behind the calf), will dissolve on their own, but sometimes they will break free and can then travel to the lungs and cut off the blood supply there. That is a pulmonary embolism and is often fatal without immediate medical treatment using "clot-busting" (thrombolytic) medication.

The advice given by the airlines and most general practitioners is to wiggle your toes from time to time and do other in-seat exercises to keep blood flowing. Getting up to walk around the cabin is also recommended every hour or so. Drink plenty of fluids and avoid alcohol or caffeinated beverages as these have a diuretic effect, further dehydrating you. Blood is much more sticky when one is dehydrated.

Now, we go on to examine why folks in business class and flight attendants, who are neither in cramped conditions nor immobile (in the latter case) still get deep vein thrombosis (DVT), or the so-called "Economy Class Syndrome".

A few articles appeared on the web a number of years ago, written by a few doctors and a pilot, stating that the cause is due to rapid compression and decompression, especially the rapid decompression experienced on takeoff. Most airlines pressurize their cabin to be the equivalent of 8000 feet above sea level because it is just not possible to keep the plane pressurized to sea level at the high altitudes they fly. The plane's body, or fuselage, simply isn't strong enough.

I know, you're thinking, "8000 feet? That's like living up in the mountains!". You're right. The amount of oxygenation _and_ pressurization is equivalent to living up in the mountains at a high elevation of 8000 feet. Oxygen content is far less than it is on the ground, although most folks in good health can tolerate this. Folks with heart ailments may be wise to avoid flying altogether or use supplementary oxygen while onboard the flight.

Low oxygen, dry air, immobility and low air pressure all contribute to the increased risk of DVT. In fact, there was a study done where some patients sat in a crowded theater for 8 hours. Examinations were done to look for blood clots. None were found. However, on an airplane flight, it is quite different. One in 10 passengers form clots, but almost all of these dissolve on their own without further complications. This lends more fuel to the fire that there's something about being on an airplane that triggers clots, or causes preexisting clots to dislodge and travel to the lungs or heart.

With all factors analyzed, the only thing that sticks out is low air pressure and sudden decompression and recompression. The airlines don't want you to know this, because I'm sure they know and to admit any fault would mean endless lawsuits or one heck of a class action against them.

The rapid decompression of flying is somewhat like a diver coming out of the water. Divers can experience blood clots if they surface too quickly or fail to undergo proper decompression shortly after surfacing. The same concept applies to flying. Surely it can trigger blood clots and usually these clots don't break off until there is recompression upon landing and deplaning.

In conclusion, it is most likely the rapid decompression on takeoff - a decompression from sea level to 8000 feet in a matter of seconds - that triggers clots and this explains why flight attendants and other active members of the cabin experience the same problem as the rest of us. It is not just long haul flights either. Now it is known that several short flights seem to be just as risky. This is likely due to the compression/decompression at work on producing and loosening up clots.

What is the best prevention? Wear compression stockings. Your doctor will be familiar with those and can recommend to you the right size and compression. Drinking just 4 ounces of tomato juice also has a potent blood-thinning effect (e.g. there is a brand called Cardioflow), along with drinking plenty of water and getting up every hour to walk around.

I have a feeling the airlines will never come forward with the truth. My friend is a long haul pilot for a major parcel service and knows this, so why not spread the news? It might save your life.

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