What Is Blood Oxygenation?

Blood oxygen refers to the oxygen in the blood. The normal oxygen content of the human body is more than 95%. The higher the oxygen content in the blood, the better your metabolism. Of course, high blood oxygen content is not a good phenomenon. The blood oxygen in the human body has a certain degree of saturation. If it is too low, it will cause insufficient oxygen supply to the body, and if it is too high, it will cause cell aging in the body.

Blood oxygen

Blood oxygen refers to the oxygen in the blood. The normal oxygen content of the human body is more than 95%. The higher the oxygen content in the blood, the better your metabolism. Of course, high blood oxygen content is not a good phenomenon. There is a certain amount of blood oxygen in the human body.

Humans live on oxygen. After inhaling oxygen from the lungs, oxygen enters the blood through capillaries and is transmitted by blood to organs or cells in various parts of the body. The higher the oxygen content in the blood, the better your metabolism.

Of course, high blood oxygen content is not a good phenomenon. There is a certain amount of blood oxygen in the human body.

Partial oxygen pressure (PO2) refers to the tension produced by oxygen molecules dissolved in the plasma in a physical state (hence the name oxygen tension). Physically dissolved oxygen in 100 ml of blood at 37 ° C produces a partial oxygen pressure of 0.133 kPa (1 mmHg) per 0.003 ml. Normal people are breathing at sea level air, and the physical state of oxygen dissolved in arterial blood is about 0.3 ml%, the partial pressure of arterial blood oxygen (PaO2) is about 13.3kPa (100mmHg); the partial pressure of venous blood oxygen (PvO2) Normal is about 5.32kPa (40mmHg).

PaO2 mainly depends on the level of alveolar oxygen partial pressure (PAO2), the amount of oxygen diffused into the blood through the alveolar membrane, and the ratio of alveolar ventilation to pulmonary blood flow. If the external air oxygen pressure is low or the alveolar ventilation is reduced, the alveolar oxygen partial pressure is reduced, or the diffusion disorder, the ventilation / blood flow ratio is imbalanced, and the pulmonary arterial-venous blood functional or anatomical shunt is increased, which can reduce PaO2.

The oxygen content refers to the number of milliliters of oxygen contained in 100 milliliters of blood, including the oxygen actually bound to hemoglobin and the oxygen dissolved in the plasma. The normal arterial blood oxygen content is about 19.3 ml%, and the mixed venous blood oxygen content is about 12 ml%. Blood oxygen content mainly depends on the quality and quantity of PaO2 and hemoglobin. PaO2 significantly reduces or reduces the ability of hemoglobin to bind oxygen, reduces hemoglobin saturation, or decreases the amount of hemoglobin per unit volume of blood, which can reduce the oxygen content.

The oxygen content depends on the amount of hemoglobin per unit volume of blood and the ability of hemoglobin to bind oxygen. If the hemoglobin content decreases (anemia) or the ability of hemoglobin to bind oxygen (such as methemoglobin, carboxyhemoglobin) decreases, then the oxygen capacity decreases and the oxygen content It also decreased. If the amount and properties of hemoglobin per unit volume of blood are normal, it is only because the oxygen partial pressure decreases that the hemoglobin oxygen saturation decreases. The oxygen content decreases, but the oxygen capacity is normal.

Oxygen capacity refers to the amount of oxygen bound to hemoglobin in 100 ml of blood in vitro by a partial pressure of oxygen of 19.95kPa (150mmHg), a partial pressure of carbon dioxide of 5.32kPa (40mmHg), humidity of 38 ° C. Normal hemoglobin can bind 1.34 to 1.36 ml of oxygen per gram under the above conditions. If calculated based on 15 grams of hemoglobin per 100 ml of blood content, the oxygen capacity of arterial blood and venous blood is about 20 ml%.

Oxygen saturation is the percentage of hemoglobin that is saturated with oxygen. One gram of hemoglobin can be combined with up to 1.36 milliliters of oxygen with an oxygen saturation of 100%. Oxygen saturation can be expressed by the following formula:

Oxygen saturation (%) = actual 1 g of hemoglobin-bound oxygen (ml) /1.36 (ml) × 100

Normal arterial blood oxygen saturation is about 95 to 97%, and mixed venous blood oxygen saturation is about 75%.