respiratory
Research

Respiratory extremes at the top of the world


How far would you go to advance respiratory science? Professor Mike Grocott, leader of the Xtreme Everest Oxygen Research Consortium and anaesthetist and the University of Southampton, UK, has been to the roof of the world and back – twice.

Delegates at the British Thoracic Society Winter Meeting heard him describe the challenges of conducting science on the world’s highest mountain, including hypoxic blood gas measurements “unknown in clinical medicine” taken at 8,400m, just below the summit.

Professor Grocott said research at extreme altitude could be “a good model for understanding hypoxia in critical illness”, for example when treating critically ill patients with acute respiratory distress syndrome in intensive care. “It’s difficult [with ICU patients] to separate out the effects of hypoxia,” he said.

Findings included a suggestion that the ACE II gene allele helped elite climbers adapt better to altitude – and also reduced mortality in critically ill ARDS patients. Physical fitness at sea level, however, doesn’t seem to help – indeed, they found a “slight inverse relationship between fitness and ability to adapt to hypoxia.”

Their most recent research, published this summer in PNAS, found metabolic adaptations, underpinned by genetic differences, in Sherpas who lived at high altitudes in the Himalayas. He showed slides demonstrating that Sherpas – unlike the researchers – showed no difference in microcirculation at high altitude. Microcirculation scans for the researchers showed microcirculation that “looks like heart failure.”

Professor Grocott described the challenges of conducting exercise tests with Sherpas who had never ridden a bicycle before. “We used a lot of gaffer tape,” he said.

The respiratory research might be helpful in determining personalised oxygen delivery for people in long-term intensive care, and in congenital heart conditions where people have become acclimatised to lower cardiac output, said Professor Grocott.