Dr. Chris Imray, a member of the Xtreme Everest 2007 training expedition on Cho Oyu, scans a mountaineer with the SonoSite MicroMaxx system and P-17 probe.

Hand-carried ultrasound system provider SonoSite said at RSNA 2006 that the Xtreme Everest 2007 expedition will bring its MicroMaxx hand-carried ultrasound system to perform cerebral perfusion studies for its research on human performance at extreme altitudes. The goal of the project is to place a medical and scientific team on the summit of Mount Everest in the spring of 2007 to study the effects of oxygen deprivation on the human body, the company said.

According to Anne M. Bugge, vice president of the company’s Corporate Affairs, the expedition picked the MicroMaxx because, among other reasons, it was the only system that seemed to be able function at such a high altitude and extreme conditions.
 
Coordinated by the Centre for Aviation, Space and Extreme (CASE) Environment Medicine in London, the Everest ascent is the core of an extensive research program studying human performance at extreme altitude aimed at improving the care of the critically ill. The study will consist of examining more than 200 volunteers as they climb progressively higher into the thin atmosphere.

 “One of the major areas of interest is cerebral perfusion, the supply of blood to the brain, since we know that this can be seriously affected at high altitude,” said Chris Imray, MD, consultant vascular surgeon and Hon Reader in Surgery Warwick Medical School and member of the training team.  “We were looking for a robust, portable transcranial Doppler system that would be simple to use and reliable in an extreme environment.  I used the MicroMaxx on the rehearsal climb to the summit of Cho Oyu in Tibet this autumn and it performed beautifully. We performed scans up to 21,000 feet on battery power and in temperatures as low as -20°C; the system was operable within seconds of booting up and the images produced were very high quality,” he said.

The expedition team hopes to show parallels between the human body pushed to its limits during critical illness and changes that occur in extreme environments.

The expedition has thus far had some surprises. In August during a rehearsal expedition to Cho Oyu (the sixth highest mountain in the world) the MicroMaxx system was unexpectedly used to examine an emergency casualty, when a North American mountaineer from another climbing party was suspected of having a stroke. The team converted their DRASH (Deployable Rapid Assembly Shelter) laboratory into a high dependency unit, allowing Imray to examine the climber using the system with the P-17 probe.

“We used the SonoSite equipment to transmit sound waves through the thin part of his skull and look for blood flow to the brain,” Imray said. “We were able to image his brain and see that on one side blood flow was absolutely normal and on the other side there was virtually no flow at all.”

The team was able to confirm the occurrence of the stroke the man was stabilized and brought down the mountain safely and is currently in recovery.

For more information about the project visit: http://www.xtreme-everest.co.uk