Reduction in bubble size may allow it to pass through the circulation, or at least travel into a smaller vessel which will reduce the size of any resulting infarction. This effect is useful in the management of gas embolism and decompression sickness. Flooding the body with oxygen forces the rapid elimination of other gases, thus reducing damage caused by toxic gases such as carbon monoxide. The elevated pressures used during hyperbaric oxygen therapy further accelerates the elimination process. Hyperbaric oxygen acts as an alpha-adrenergic drug.
Vasoconstriction can result in reduction of edema following burns or crush injuries.
Even with a reduction in blood flow, enough extra oxygen is carried by the blood so a net increase in tissue oxygen delivery occurs with hyperbaric oxygen. Anaerobic bacteria don't contain the natural defenses to protect them from the superoxides, peroxides and other compounds formed in the presence of high oxygen tensions. More important, many of the body's bacterial defense mechanisms are oxygen dependent. When tissue pO2 drops too low, effective ingestion and killing by phagocytic leukocytes is retarded. Reoxygenation of those tissues allows phagocytosis and other host defense mechanisms to come back into play.