In late 2009 I was talking to a friend who used to work at NASA. My office is in Clear Lake, Texas, just a short distance from Johnson Space Center. He mentioned a problem that NASA had been working on for the past 26 years. When some astronauts are in space, they get head swelling, visual changes, and some get increased pressure around the brain.

NASA had not been able to figure out the reason for this although a number of theories were proposed. A significant part of this problem is because the blood and fluids normally held in the legs due to gravity moves toward the center of the body and toward the head.

In my extensive training, part of which included general surgery residency, I was exposed to a diverse amount of problems in many patients. During my rotation at MD Anderson Cancer Center, on the thoracic surgery service, I saw a number of patients with a specific problem that made me think of the astronauts’ problem.

These patients had blockage of the main blood vessel draining blood from the head back to the heart, called Superior Vena Cava Syndrome.

The symptoms and signs were very similar to the astronaut problem. Over the next few weeks, I did some studies of anatomy and did ultrasound studies, and developed a hypothesis that a blockage was occurring in some of the veins draining blood out of the head in some astronauts in space. I coined the term “Space Obstructive Syndrome.”

NASA has continued to study the problem, and has come up with additional theories, none of which adequately answers the issues. Space Obstructive Syndrome has been studied by various researchers and also with research on the International Space Station.

Eventually, I predict, Space Obstructive Syndrome will be recognized as the main theory for this problem in spaceflight, which is important as missions stay longer and go deeper into space, such as Mars and beyond.

For a copy of the paper, you may download it at the publisher’s website:

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