A team of researchers, including several from UBC’s Okanagan campus, have determined that providing extra oxygen to patients with chronic obstructive pulmonary disease (COPD) may help reduce the risk of developing dementia.
Professor Phil Ainslie, who teaches in UBC Okanagan’s School of Health and Exercise Sciences, recently published a study demonstrating how oxygen therapy is beneficial to people with COPD. A Canada Research Chair in Cerebrovascular Physiology in Health and Disease, Ainslie and his team travelled to Croatia to conduct research at the Split Clinical Hospital Centre for Pulmonary Diseases.
Their tests concluded that oxygen therapy, used on people with COPD, does improve the delivery of oxygen to the brain and can lower the risk of diseases such as stroke, mild cognitive impairment and dementia.
Study first author Ryan Hoiland, who recently completed his PhD with Ainslie, says patients with moderate to severe COPD endure a state of chronic hypoxaemia (lower levels of oxygen in the blood) due to suboptimal oxygen gas exchange.
In the 1980s it was demonstrated that oxygen supplementation reduces the risk of mortality. But the theory that oxygen can help COPD patients reduce the risk of other disease development has not been fully investigated.
“People with COPD may experience lower than normal blood oxygen levels on a consistent basis due to reduced lung function,” Ainslie said. “While COPD is a respiratory disease, the low oxygen levels cause problems throughout the body, including impacting the health of the heart and brain.”
Chronic COPD patients also deal with issues that can lead to blocked airways, leading to a low concentration of oxygen in the blood, or high carbon dioxide, affecting blood flow to the brain which can contribute to dementia over a period of time.
“Some evidence suggests oxygen therapy reduces the risk of cognitive impairment and by association, potentially dementia, but there is no research into exactly how the oxygen supplementation may be benefiting these particular patients relative to the function of blood vessels in the brain.”
During their tests, researchers used ultrasound to measure blood flow to the brain of the study participants. Patients rested while they were administered oxygen for 30 minutes. The next step was for participants to spend 30 seconds reading standardized material to stimulate brain activity and then 30 seconds with their eyes closed. While this was happening, ultrasound measurements tracked changes in blood flow to the brain.
The results demonstrated that oxygen therapy improved oxygen delivery to the brain. It also improved what is called neurovascular function, the ability of blood vessels in the brain to work with neurons and other cells to ensure the right amount of oxygen is being delivered to the brain during changes in brain activity.
“This particular aspect of brain and neurovascular function is extremely important, with impaired neurovascular function implicated in the development and progression of diseases such as dementia,” said Hoiland. “This improvement in cerebral oxygen delivery and neurovascular function might provide a physiological link between oxygen therapy and a reduced risk of certain brain diseases for people with COPD.”
While the research was promising, Hoiland says very little research on how altered resting arterial blood gases affect cognitive brain function has been conducted in COPD patients and more is needed.
The paper was recently published in Experimental Physiology.
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