How long does it take to complete the plasma transfusion

Many patients with blood diseases need to rely on plasma transfusions to achieve an improvement effect, and patients with severe anemia also need to rely on this treatment method to achieve a cure. Therefore, the speed of plasma infusion should be determined according to their physical condition. If the body is weak, the infusion should not be too fast to avoid the body being unable to bear it.

Plasma infusion rate

Functional speculation

By measuring GFR and the plasma clearance rate of other substances, it is possible to infer which substances can be reabsorbed by the renal tubules and which are secreted by the renal tubules. Of course, these substances must be able to pass freely through the filter membrane. If the plasma clearance rates of urea and glucose are both less than Cl, urea is 70 ml/min, and glucose is 0, it means that part of the urea is reabsorbed, while all of the glucose is reabsorbed.

However, it cannot be inferred from this that the substance is not secreted. As long as the reabsorption amount exceeds the secretion amount, its plasma clearance rate may still be less than 125 ml/min; if the reabsorption amount is equal to the secretion amount, its plasma clearance rate may also be equal to 125 ml/min; if the reabsorption amount of a substance is less than the secretion amount or there is no reabsorption, the plasma clearance rate of the substance is greater than 125 ml/min.

Renal blood flow measurement

If a substance in plasma (whose concentration is P) can be completely cleared after one cycle of renal circulation through the processes of filtration and secretion, that is, the concentration of the substance in the renal venous blood is close to 0, the amount of the substance excreted from the urine per minute (U·V) should be equal to the amount of the substance contained in the plasma passing through the kidneys per minute, that is, X represents the plasma flow of the kidney.

For example, ioretinol and sodium p-aminohippurate are substances that meet this condition. Therefore, the plasma clearance rate of these two substances can represent the plasma flow. It is calculated that the human renal plasma flow is about 660ml/min. The ratio of GFR to renal plasma flow is called the filtration fraction.

From the renal plasma flow, based on the hematocrit, the renal blood flow can be calculated.

Renal blood flow is about 1200 ml/min, accounting for about 1/5 to 1/4 of cardiac output.

It should be pointed out here that the so-called number of ml of plasma that completely clears a substance per minute is only a theoretical estimated value. In fact, the kidneys do not necessarily completely eliminate a substance in a milliliter of plasma. They may only eliminate part of it. It is just that the amount of the substance eliminated by the kidneys each minute is equivalent to the amount of the substance contained in a certain number of milliliters of plasma.