What is the difference between saturation and oxygen tension?
The problem we face in advocating proper usage of oxygen involves confusion between saturation and oxygen tension, 100% vs.. 100 mmHg. Only dissolved oxygen contributes to the tension (or partial pressure). Study the figures for oxygen transported by plasma (liquid) vs.. hemoglobin (one gram hemoglobin can only combine with 1.34 ml oxygen) – in 100ml of healthy blood there is 19ml oxygen as oxyhemoglobin and 0.3ml oxygen in liquid solution, here the hemoglobin is near maximum saturation (98%) and the pressure or tension of oxygen in the liquid solution is initially 95mmHg and downline tissue levels drop to 39mmHg or less. Breathing pure oxygen at 2.5 times atmospheric pressure increases the amount of oxygen in (plasma) liquid solution to about 6 ml per 100ml blood. This increased oxygen volume measurably increases the oxygen tension and downline tissue levels can rise upwards of 200mmHg.
Oxygen given with increased pressure can correct many serious health problems. Hyperbaric oxygenation helps the body heal from conditions that have low oxygen in the tissues causing or complicating the outcome. Repetitive hyperbaric sessions can help many different conditions; let’s mention the first few ABC’s such as anemia, burns and crush injuries. Compromised skin grafts often improve with hyperbaric oxygenation. Difficult to heal infections treated with hyperbaric oxygenation has attracted interest lately as antibiotic therapy can fail to clear today’s resistant strains of pathogens. Treatable infections include such diverse situations as actinomycosis, osteomyelitis, diabetic wounds, gangrene and related deadly tissue infections. In the last four decades hyperbaric oxygenation research has raised the value of this unique therapy. Doctors used to ask, “Can it work?” now they ask, “How much is needed to completely work?”