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AN ASTRONAUT’S life is already fraught with danger, but two recent studies show that attempts to help astronauts who are injured in space may put them at even greater risk. A study with monkeys suggests that emergency surgery within hours of returning to Earth could prove fatal, while an international team of anaesthetists claims that medical equipment on the space shuttle for keeping an astronaut breathing in an emergency is inadequate.
Only the healthiest people can become astronauts. But during lengthy spells in space, for example on the International Space Station or on a mission to Mars, serious health problems and accidents are inevitable. “Send a few more John Glenns up there and someone is going to have a [heart attack],” says Michael Todd, an anaesthetist at the University of Iowa in Iowa City and the editor of the journal Anesthesiology.
Concerns about emergencies in space have been heightened following the joint Russian-American Bion 11 mission in 1997, in which two monkeys flew aboard the space shuttle. The monkeys were given a general anaesthetic on their first day back on Earth-something that had never been tried before. One monkey died and the other suffered serious complications.
Details of what triggered the complications are being prepared for publication. “The events could be explained if there was inadequate blood flow under anaesthesia, similar to that seen in a diabetic with severe nerve disorder,” says Ronald Merrell of the Medical College of Virginia in Richmond, who chaired the Bion task force for NASA. People take at least a day to regain control of their blood flow when they return to Earth from space.
If a seriously ill astronaut had to be rushed back to Earth for emergency treatment, “clinicians should be aware that there are potentially some unique anaesthetic risks involved,” says William Norfleet, a space medicine expert at NASA’s Johnson Space Center in Houston, Texas.
There is also plenty of scope for accidents on spacecraft, particularly fires which could release toxic fumes that stop an astronaut breathing. “Electrical fires are an ever-present hazard and there is nowhere to run,” says Norfleet. To find the best way to maintain an open passage to the lungs in microgravity, a team led by Joseph Brimacombe of the University of Queensland in Cairns and Christian Keller of the University of Innsbruck built a mock-up of the living quarters on the International Space Station and submerged it in a pool to simulate microgravity. Then the team, which included four anaesthetists, tested four different techniques on manikins.
They discovered that the equipment carried on the space shuttle-an endotracheal tube and a laryngoscope to insert it, similar to those commonly used on Earth-is likely to fail unless the patient is strapped down, which would take valuable time in an emergency.
Inserting an endotracheal tube requires two hands and considerable force. In space, this would push an unrestrained patient out of reach. The three other techniques tested by the researchers, all of which leave the doctor with a free hand to stabilise the patient’s head, worked well with or without restraints. The results will be published in the next issue of Anesthesiology.
“The space shuttle definitely does not have the appropriate equipment for airway management by inexperienced personnel like astronauts,” says Brimacombe.
Author: Rachel Nowak, Washington DC
New Scientist issue: 29th April 2000
