Exceptional blood loss anaemia occurs when red blood cells are lost and oxygen delivery is compromised. Many patients cannot be treated by transfusion to restore red blood cell mass for medical or religious reasons. Medical reasons may include the inability to cross match blood. Some may refuse transfusions for fear of a communicable disease. Blood loss over a short period of time can reduce the amount of iron in the body, so much so that the bone marrow will no longer be able to increase production of new blood cells to replace the lost ones. In macrocytic anaemia the blood cells are larger than normal and can be caused by anaemia related to alcoholism and pernicious anaemia.

Benefits of HBOT :

Hyperbaric oxygen can temporarily support life without haemoglobin. The increased oxygen carrying capacity of blood during Hyperbaric Oxygen Therapy is enough to support basal metabolic needs at rest. The advantages of Hyperbaric Oxygen Therapy (HBOT) as an adjunct to cardiac surgery can be summarized as follows:

• HBOT increases the safe time of induced cardiac arrest under normothermia.
• HBOT reduces the impact of hypoxic complications and metabolic disturbances associated with cardiac surgery.
• HBOT enables surgery to be performed without blood transfusion in some cases.
• HBOT is the treatment of choice for air embolism as a complication of cardiac surgery.

Breathing Gas	Time to displace CO to O2
Air, 1 ATA	214 minutes
Oxygen, 1 ATA	43 minutes
Oxygen, 2.5 ATA	19 minutes