Renal plasma flow measurement

Renal plasma flow, also known as renal plasma flow (RPF), refers to the amount of plasma flowing through the kidneys per unit time. If a substance in the blood can be filtered by both the glomerulus and the renal tubules, the clearance rate is a combined result of glomerular filtration and tubular excretion. If the substance is completely removed after 1 week of renal circulation, the plasma clearance of the substance is equal to the plasma flow within 1 min of the kidney. Renal plasma flow has a great influence on glomerular filtration rate, which mainly affects the position of filtration equilibrium. If the renal plasma flow is increased, the rate of increase of plasma colloid osmotic pressure in glomerular capillaries is slowed down, and the filtration balance is close to the exiting small arterial end. The effective filtration pressure and filtration area increase, and glomerular filtration The rate will increase accordingly. If the renal blood flow is further increased, the rate of increase of plasma colloid osmotic pressure will be further slowed down, the full length of glomerular capillaries will not reach the filtration balance, the whole length will be filtered, and the glomerular filtration rate will be further increased. . Conversely, when the renal plasma flow rate decreases, the plasma colloid osmotic pressure rises faster, and the filtration balance is close to the small arterial end. The effective filtration pressure and filtration area are reduced, and the glomerular filtration rate is reduced. In pathological conditions such as severe hypoxia and toxic shock, renal blood flow and renal plasma flow will be significantly reduced due to sympathetic excitation, and glomerular filtration rate will be significantly reduced. Basic Information Specialist classification: urinary examination classification: urine / kidney function test Applicable gender: whether men and women apply fasting: fasting Tips: Relax while checking and follow the doctor's arrangements. Normal value 600 ~ 800ml / min. Clinical significance 1, can judge kidney function and observe the effect. 2. Simultaneous determination of renal plasma flow rate and glomerular filtration rate can help to analyze the main parts of the lesion. 3. After renal transplantation, if the kidney map is abnormal and the renal plasma flow is normal, it indicates acute necrosis of the renal cortex and renal plasma flow is low, suggesting a rejection reaction. Low results may be diseases: malignant hypertensive small arteriosclerosis, acute renal failure, primary small vascular inflammatory renal damage considerations About 20% of the plasma is filtered through the glomerulus, and the resulting filtrate is about 120-160 ml/min. The amount of plasma fluid filtered out through the glomerulus per unit time (minutes) is called the glomerular filtration rate. Inspection process 1. On the morning of the test, rest on an empty stomach, drinking water at 500 ml at 7 o'clock, and indwelling the catheter. 2, 7:30 take urine 10ml, venous blood 2ml (test blank). 3. Immediately inject a sterile 200 g/LPAH solution into the mixture at a dose of 0.4 ml/kg body weight within 10 minutes, and then add 500 ml of physiological saline solution in a solution of 10 ml of a 200 g/LPAH solution for maintenance infusion. 4. At 8:30, clamp the catheter. At 8:50, 4 ml of venous blood was taken, followed by emptying the bladder and measuring the amount of urine. The bladder was rinsed with 20 ml of physiological saline, and 20 ml of air was injected to drain the fluid in the bladder. The rinse solution was combined with urine, mixed, and 10 ml was taken to determine the PAH content. 5, 9:10, the first repeated blood and urine samples; 9:20 second repeated blood and urine samples (same operation 4). 6. Determine the PAH concentration. Mix each time the reagent is added and place for 3 min. The color development was stable (10-15 min) and the blank tube was zeroed at 540 nm, and the absorbance values ​​of the tubes were read. 7. Determine renal plasma flow. Not suitable for the crowd It is not advisable for pregnant and lactating women to perform this test. Adverse reactions and risks A small number of people may have transient facial flushing, sore back, chest tightness, palpitations and other reactions.