Oxygen and the Brain
It gives long-overdue recognition of the brilliant Scottish scientist John Scott Haldane, who pioneered many of the discoveries that today we take for granted. For example, Haldane showed that, curiously, it is carbon dioxide, not lack of oxygen, that drives breathing: A sudden reduction of oxygen level, in fact, increases cardiac output and blood flow, not breathing. He also advocated giving oxygen as a treatment, not simply as a supplement.1
Oxygen is probably the most widely prescribed agent in medical practice, but it is only to ensure “saturation” of the oxygen reservoir hemoglobin: in other words, to ensure that blood is as red as possible.² The book points out that blood oxygen levels can be normal when a patient has a heart attack or a stroke because of a reduction of blood flow in an artery and because cells may die of lack of oxygen, which is called anoxia. The pathology caused by lack of oxygen extends well beyond the volume where cells die because of the localized tissue swelling known as edema.
Oxygen is poorly soluble in water. Cells in this zone are short of oxygen — not dead, but sleeping. Loss of function may be due to the death of cells or simply due to lack of sufficient oxygen to maintain their normal activity, a condition known as hypoxia (hypo meaning below and oxia obviously is oxygen).
These two states are widely separated in the brain but cannot be differentiated on clinical examination. The objective of using a high level of oxygen as a treatment, that is, “hyperoxia” — usually delivered in a room at increased pressure known as a hyperbaric chamber — is to allow cells to recover function from an inactive state.
The highlight of the book is an account of the astonishing research showing that oxygen actually controls our most important genes. Beginning with the creation of blood vessels in the embryo, a mechanism that continues throughout life in healing wounds³ from skin to the brain. It ranks in importance with the determination of the structure of DNA.
Research into the effects of lack of oxygen is beginning to be featured in prestigious journals, such as the New England Journal of Medicine (NEJM). A nine-page review in the NEJM in 2011 highlighted the close relationship between cellular hypoxia and inflammation,4 and the latest review published in the journal on May 18, 2017, details the physiological effects of chronic hypoxia.5 The author advocates oxygen conditioning of rooms at altitude by pumping oxygen in from an atmospheric oxygen concentrator, comparing it with air conditioning, suggesting it would improve boardroom decisions.
Tissue hypoxia affects us whenever we are ill or injured. Higher levels of oxygen are needed in treatment, especially for injuries and disease of the brain. It is the next frontier for mainstream medicine.
- Haldane JS. The therapeutic administration of oxygen. Br Med J. 1917; i:181-183.
- British Thoracic Society guideline for emergency oxygen use in adult patients. Thorax. 2008; 63:Supplement VI.
- Semenza G. Oxygen sensing homeostasis and disease. N Eng J Med 2011; 365:537-47.
- Eltzschig HK, Carmeliet P. Hypoxia and inflammation. N Eng J Med 2011;364:656-64.
- West JB. Physiological effects of chronic hypoxia. N Eng J Med. 376:1965-71.
- Burman F, Sheffield R, Posey K. Decision process to assess medical equipment for hyperbaric use. Undersea Hyperb Med. 2009; May-Apr;36(2):137-44.