What is pulmonary embolism and why the risk is greater on flights – 03/13/2024 – Balance

Pulmonary embolism is a condition that occurs when a thrombus, that is, a blood clot, forms in the veins and migrates from one region to another, obstructing the passage of blood to important organs, such as the lungs or heart. The condition can be fatal and is related to mobility restrictions, but may have a genetic origin or be aggravated by atmospheric pressure, common on flights. In this case, some care can make a difference.

“We hear about embolism during plane trips. This happens because passengers spend most of their time sitting in the same position, resulting in reduced mobility. Added to this is the decrease in atmospheric pressure in aircraft, so the thrombus formation and migration can happen”, says doctor Bruno Nanni, vascular surgeon at the Marcelino Champagnat and Cajuru hospitals, in Curitiba.

He explains that the best-known pulmonary embolism is of thrombotic origin, that is, after a venous thrombosis, most often in the legs, the clot moves to the lung. “The legs are the most common place for venous thrombosis, as it is in the lower limbs that thrombus formation begins.”

This is because, when the blood descends to the legs during circulation, it needs muscular strength to return, which is impaired by the lack of mobility. “There is a chance that the blood will become more retained, causing swelling and discomfort, and eventually the formation of clots.”

The main symptoms, notes the surgeon, are: swelling in the legs, reduced saturation, sudden shortness of breath and the presence of chest pain, like a stab wound.

Although, in most cases, they are not fatal, massive embolisms can cause death. “In the hospital we can help with anticoagulant medications, catheterization or surgery. On a flight, however, it is practically impossible”, emphasizes Nanni. “Although flight crews are prepared to provide first aid to patients with pulmonary embolism, sometimes the embolism is too large and there is nothing they can do.”

The risks increase in cases of very long flights, lasting more than four hours. “It rarely happens on short trips.”

Another aggravating factor of the flight is the decrease in atmospheric pressure, which makes venous return from the lower limbs to the upper limbs difficult. “This can cause venous stasis and favor the formation of thrombi and obstruction of pulmonary vessels, making gas exchange in the lungs very difficult and, in more serious cases, leading to death.”

In addition to these risk factors, venous thrombosis can also occur in patients with vein damage, genetic predisposition (such as thrombophilia) or post-operatively (due to lack of mobility).

Although possible, the incidence of thromboembolic events on flights is not high, and some precautions can be taken to minimize these risks, highlights the doctor.

Precautions include: moving during the flight and wearing compression stockings. “In cases with previous thrombosis or pulmonary embolism, we can use anticoagulants prophylactically.”

This week, it was reported on news sites that a Brazilian woman had died of a pulmonary embolism during a flight to Tokyo, Japan. The report attempted to contact the woman’s family, but received no response until the publication of this edition.

The surgeon points out, however, that although there are reports of embolisms on flights, they are rare. “Most people will fly and won’t have any complications.”