A new study found that simulating high altitude could help older patients who are at risk of health complications after surgery. A randomized trial of eight volunteers spent a week in a residential hypoxia facility exposed to reduced oxygen levels that simulated high altitude to see if breathing less oxygen could benefit their physical health.
Researchers from King’s College London, Royal Melbourne Hospital, Oxford University Hospitals NHS Foundation Trust, Beth Israel Deaconess Medical Center, and the University of Limerick published their findings in Anaesthesia.
Many patients awaiting major surgery have low levels of fitness, a high BMI, sedentary lifestyles, or anemia, all of which are linked to higher rates of complications and death after surgery. Anaesthetists are working hard to develop more effective methods of improving fitness before operations, known as prehabilitation, in order to reduce this risk.
Whilst this study suggests that simulated altitude exposure may have potential advantages for older and sedentary patients, further studies are needed to explore this for home-based altitude prehabilitation.
Professor Thomas Smith
Altitude training is known to improve fitness and increase blood levels (haemoglobin, which carries oxygen in the body) in athletes by exposing them to low oxygen levels (hypoxia), which are similar to the conditions passengers experience during an airline flight. A low-oxygen environment stimulates an increase in haemoglobin, which allows athletes to carry more oxygen throughout the body and perform better in low-altitude environments.
The concept of ‘altitude prehabilitation’ was introduced by researchers who questioned whether exposure to simulated high altitude could benefit older people who face a risk of complications prior to surgery. To put this to the test, they recruited eight sedentary volunteers with an average age of 64 to spend two weeks living in the National Altitude Training Centre in Ireland, a ‘hypoxic house’ with tightly controlled oxygen levels in the air.
During one week, the house had normal air, while the oxygen levels were mildly reduced (similar to conditions on an airline flight, equivalent to about 2438 m or 8000 ft). Cardiopulmonary exercise tests were performed on volunteers before and after each week-long exposure.
The researchers discovered that simulated high altitude increased participants’ hemoglobin levels but had no effect on their aerobic fitness. This increase in hemoglobin could be clinically beneficial prior to surgery.
In practice, small scale hypoxic canopies could be provided to patients to use while sleeping in the weeks preceding surgery. Hypoxic technology is also already widely used, as hypoxic rooms or tents are available in high-end gyms and professional sports clubs, and similar hypoxic air systems are used to prevent fires on a larger scale, such as in warehouses and library archives. As the technology becomes available, hospitals may be able to create small or large hypoxic spaces for patients prior to surgery.
“We know that athletes can use hypoxic canopies over their beds to simulate altitude exposure and that altitude can induce performance benefits after two to three weeks even in people who are extremely fit,” said lead author Professor Thomas Smith, a Consultant Anaesthetist and Head of Aerospace Medicine Research at King’s College London. We were curious whether this approach could also benefit older patients prior to major surgery, who are more at risk of negative postoperative outcomes due to sedentary lifestyles and low levels of fitness.
“Whilst this study suggests that simulated altitude exposure may have potential advantages for older and sedentary patients, further studies are needed to explore this for home-based altitude prehabilitation.”
