The arterioven oxygen difference , or a-vO 2 diff , is the difference in the oxygen content of blood between the arterial blood and the blood vein. This is an indication of how much oxygen is removed from the blood in the capillaries when blood circulates in the body. The output of a-vO 2 and cardiac output are the major factors that allow variation in total body oxygen consumption, and are important in measuring VO 2 . The-vO 2 diff is usually measured in milliliters of oxygen per 100 milliliters of blood (mL/100 mL).
Video Arteriovenous oxygen difference
Measurement
Arteriovenous oxygen difference is usually taken by comparing differences in oxygenated oxygen concentrations in the femoral, brachial, or radial arteries and oxygen concentration in deoxygenated blood from a mixed supply found in the pulmonary artery (as an indicator of a typical mixed vein supply).
Put into simple terms: a diff = C a - C v
- where:
- C a = oxygen concentration of arterial blood (oxygenated blood)
- C v = oxygen concentration of venous blood (deoxygenated blood)
The ordinary unit for a-vO 2 diff is milliliters of oxygen per 100 milliliters of blood (mL/100 mL), but, especially in medical use, other units can be used, such as micromoles per milliliter (? ).
In practice, a-vO 2 diff can be determined by using the Fick Principle rather than by taking a direct blood sample. To do so the oxygen consumption (VO 2 ) can be measured using a spirometer to detect the gas concentration in the exhaled air compared to the inhaled air, while cardiac output can be determined using Doppler ultrasound.
Arterial blood generally contains an oxygen concentration of about 20 mL/100 mL. Venous blood with a concentration of 15 mL/100 mL of oxygen will cause the typical values ​​of a-vO 2 diff on the remaining about 5 mL/100 mL. During intense exercise, however, a-vO 2 diff can increase to as much as 16 mL/100 mL because the muscles that work extract far more oxygen from the blood than they do at rest.
Alternatively, to find the efficiency of the lungs in filling blood oxygen levels, a-vO 2 diff can be taken by comparing blood from the pulmonary artery and pulmonary vein; in this case the negative value for a-vO 2 diff will be obtained because the oxygen content of the blood will increase.
Maps Arteriovenous oxygen difference
Impact of exercise
Physical exercise leads to increased arteriovenous oxygen difference in all individuals. As the intensity of the exercise increases, the muscles increase the amount of oxygen they extract from the blood and this results in a further increase in a-vO 2 diff.
The maximum difference a-vO 2 is also usually greater in trained athletes than in untrained individuals. This is the result of aerobic exercise that leads to hypertrophy of slow twitch muscle fibers primarily due to increased capillaryization. The increase in capillary bed in muscle means that the blood supply to the muscle can be larger and the diffusion of oxygen, carbon dioxide, and other metabolites increases. By exercising the muscles also improve their ability to extract oxygen from the blood and process oxygen, possibly due to mitochondrial adaptation and increased muscle myoglobin content.
Research has shown that after the start of the exercise there is a delay in the increase of a-vO 2 diff, and that a-vO 2 diff has only a marginal effect in total change VO 2 in the early stages of the exercise. Much of the initial increase in oxygen consumption after abrupt changes in exercise levels is a result of increased cardiac output. It has also been found that the maximum increase of a-vO 2 diff resulting from adaptation to a physical training program can account for most of the differences in VO 2 max in the subjects participating in the exercise sub-max.
In medicine
Arteriovenous oxygen differences are also used in other fields of study such as medicine and medical research. For example, a-vO 2 diff has been used to measure cerebral blood flow in coma patients, aiding their diagnosis and treatment. The-vO 2 diff has also been used to determine the effects of physical exercise on coronary patients.
See also
- Blood gases
- oxygen saturation
References
Source
-
Malpeli, Robert; et al. (2010). Physical Education: Unit VCE 3 & amp; 4 (5th ed.). South Melbourne, Victoria: Cengage Learning Australia. ISBN 978-0-17-018692-6.
Source of the article : Wikipedia
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