HF is a simulation device designed according to the glomerular filtration function. HF equipment consists of three parts: blood filter, blood pump, and negative pressure suction device.
(1) Methods
1. Establish arteriovenous vascular channels and heparinization method: the same as hemodialysis.
2. Blood filter device: Commonly used are polyacrylonitrile membrane multi-layer small flat filter (such as RP6 filter), polysulfone membrane hollow fiber filter (such as Diafilter TM30 Amicon) , polymethyl methacrylate membrane filters (such as Filtryzer B1 type, Gambro MF202 type), etc.
3. Connect the patient’s arterial and venous ends to the arterial and venous pipes of the hemofilter respectively, rely on the blood pump and the filter for intravenous examination, and collect the arterial pipe clamps to generate 13.33 on the blood side of the filter. ~26.66kpa (100~200mmHg) positive pressure, adjust the negative pressure device so that the negative pressure reaches 26.66kpa, then 60~100ml/min of filtrate can be obtained, and at the same time, the replacement fluid is replenished. If 1000ml of fluid is required to be removed from the body each time, the total volume of filtrate minus 1000ml is the input volume of replacement fluid.
4. The composition and input method of the replacement liquid: Na+140mmol/L, k+2.0mmol/L, Ca++1.85mmol/L, Mg++0.75~1.0mmol/L, Cl -105～110mmol/L, lactate 33.75mmol/L. It can be fed through the filter arterial line (pre-dilution type) or into the venous line (post-dilution type).
5. According to the patient’s condition, HF should be administered 2 to 3 times per week, 4 to 5 hours per time.
(2) Clinical significance
1. HF is slightly inferior to HD in clearing small molecular substances such as urea nitrogen and creatinine, but it can correct water and electrolytes in the clearance of medium molecular substances. and acidosis, but is better than HD in treating renal failure, pulmonary edema, pericarditis, and cerebral edema.
2. It can significantly improve anemia and triglycerideemia, and easily control high blood pressure.
3. The combination of HD and HF is called hemofiltration and dialysis, which can improve the efficiency of blood purification and shorten the dialysis time.
4. Inputting a large amount of replacement fluid can easily cause contamination and cause fever reaction and sepsis, so please be careful.