Contents 1 Pinyin 2 English reference 3 Definition and overview 4 Indications and contraindications 5 Pre-treatment patient assessment 6 Treatment modalities and prescriptions 7 For vascular access, see the vascular access chapter 8 Anticoagulation 9 Monitoring and monitoring of anticoagulation therapy Treatment of complications 10 Hemofilter selection 11 Replacement fluid 11.1 Composition of replacement fluid 11.2 Preparation of replacement fluid 12 Operating procedures and monitoring 12.1 Item preparation 12.2 Power-on self-test 12.3 Installation of hemodialysis filter and pipeline 12.4 Closed pre-flush 12.5 Establishment Extracorporeal circulation (on the machine) 12.6 Blood return (off the machine) 13 Complications and treatment 13.1 Reverse ultrafiltration 13.2 Protein loss 13.3 Deletion syndrome 14 Source 1 Pinyin
xuè yè tòu xī lǜ guò 2 English reference
p>hemodiafiltration 3 Definition and Overview
Hemodiafiltration (HDF) is a combination of hemodialysis and hemofiltration. It has the advantages of both treatment modes and can be treated through two mechanisms: diffusion and convection. It removes solutes and removes more small and medium molecule substances per unit time than hemodialysis or hemofiltration alone. 4 Indications and Contraindications
(1) The indications for hemodiafiltration are similar to those of hemofiltration.
(2) The contraindications for hemodiafiltration are the same as those for hemodialysis. 5 Pre-treatment patient assessment
Same as hemodialysis and hemofiltration. 6 Treatment methods and prescriptions
(1) Treatment methods
Pre-dilution replacement method, post-dilution replacement method and mixed dilution method.
(2) Prescription
1. Faster blood flow rate (recommended >250ml/min) and dialysate flow rate (500~800ml/min) are often required to remove the appropriate amount of solute.
2. The amount of replacement fluid to be replenished is 15 to 25L for the post-dilution and replacement method, and 30 to 50L for the pre-dilution and replacement method. In order to prevent transmembrane pressure alarm, the replacement volume setting needs to be adjusted according to the blood flow speed. 7 For vascular access, see the vascular access chapter
Same as hemodialysis and hemofiltration. 8 Anticoagulation
(1) For the assessment of the patient’s coagulation status and the selection of anticoagulant drugs before treatment, please refer to the anticoagulation treatment chapter of blood purification.
(2) Anticoagulation regimen
1. The usual initial dose of unfractionated heparin is 0.3 to 0.5 mg/kg, with additional doses of 5 to 10 mg/h, intermittent intravenous injection or continuous intravenous injection Infusion (commonly used); stop adding 30 to 60 minutes before the end of hemodialysis. The dose should be adjusted individually based on the patient's coagulation status.
2. Low molecular weight heparin is generally selected at 60-80IU/kg. It is recommended to inject intravenously 20-30 minutes before treatment without additional dose.
3. The concentration of local citrate anticoagulant citrate is 4 to 46.7. Taking the commonly used clinical method of generally giving 4 sodium citrate as an example, 4 sodium citrate 180ml/h is continuously injected in front of the filter. , control the free calcium ion concentration after the filter to 0.25~0.35mmol/L; give 0.056mmol/L calcium chloride saline (10 ml of calcium chloride added to 1000ml of saline) 40ml/h at the intravenous end to control the free calcium ions in the patient's body The calcium ion concentration is 1.0~1.35mmol/L; until the blood purification treatment is completed. It can also be implemented using citric acid replacement solution.
Importantly, when applying local citrate anticoagulation clinically, the actual blood flow of the patient needs to be considered, and the dosage of sodium citrate (or citrate replacement solution) and calcium chloride saline should be adjusted accordingly based on the detection of free calcium ions. Enter speed.
4. The general initial dose of argatroban is 250 μg/kg, the additional dose is 2 μg/(kg·min), or 2 μg/(kg·min) is continuously administered before the filter. It should be based on the partial activation of the patient's plasma. Monitor prothrombin time and adjust dosage.
5. Before treatment without anticoagulants, pre-flush with 4 mg/dl heparin normal saline, retain the perfusion for 20 minutes, and then give 500 ml of normal saline for flushing; every 30 to 60 minutes during blood purification treatment, give 100 ~200ml saline to flush the lines and filter. 9 Monitoring of anticoagulant therapy and treatment of complications
Refer to anticoagulant therapy for blood purification 10 Selection of hemofilters
The dialyzer used in HDF is similar to the dialyzer used in HF and is a high Flux dialyzer or filter. 11 Replacement fluid 11.1 Composition of replacement fluid
1. Sterile, non-pyrogenic replacement fluid, endotoxin <0.03EU/ml, bacterial count <1×106 cfu/ml.
2. The composition of the replacement fluid should be consistent with that of the extracellular fluid. Try to achieve individualized treatment and adjust sodium and calcium. Common replacement fluid formula (mmol/L): sodium 135~145, potassium 2.0~3.0, calcium 1.25~1.75, magnesium 0.5~0.75, chlorine 103~110, bicarbonate 30~34. 11.2 Preparation of replacement fluid
The replacement fluid for hemofiltration must be sterile, virus-free and pyrogenic. There are two preparation methods:
1. Online method ) is the current main method. Reverse osmosis water and concentrated liquid are diluted in proportion to prepare a replacement liquid, which is then filtered and injected into the body.
2. Intravenous infusion preparations are prepared according to the above-mentioned replacement fluid ingredients and adjusted according to the specific conditions of the patient. They are expensive and are basically not used in clinical practice. 12 Operating procedures and monitoring 12.1 Item preparation
Hemodialysis filter, hemodiafiltration line, safety catheter (hydration device), puncture needle, sterile treatment towel, normal saline, disposable flushing tube , disinfection items, tourniquets, disposable gloves, dialysate, etc. 12.2 Power-on self-test
1. Check whether the power cord of the dialysis machine is connected normally.
2. Turn on the main power switch of the machine.
3. Carry out machine self-inspection as required. 12.3 Installation of hemodialysis filter and pipeline
1. Check whether the hemodialysis filter and pipeline are damaged and whether the outer packaging is intact.
2. Check the validity date and model number.
3. Operate according to the principle of asepsis.
4. Install the pipelines in sequence according to the blood flow direction of the extracorporeal circulation.
5. The replacement fluid connecting pipe should be installed in the order of the replacement fluid flow direction. 12.4 Closed pre-flush
1. Start the blood pump of the dialysis machine at 80-100ml/min, and use physiological saline to drain the gas in the pipeline and the blood chamber (in the membrane) of the hemodialysis filter first. The flow direction of normal saline is arterial end → dialyzer → venous end, and reverse preflushing is not allowed.
2. Adjust the pump speed to 200~300ml/min, connect the dialysate connector and the hemodialysis filter bypass, and drain the gas from the dialysate chamber (outside the membrane) of the dialyzer.
3. The machine is pre-flushed online through the replacement fluid connecting tube, using the replacement fluid generated online by the machine, and flushing in a closed manner according to the direction of the extracorporeal circulation blood flow.
4. The priming volume of normal saline should be strictly in accordance with the requirements in the instructions of the hemodiafilter; if closed circulation or heparin priming with normal saline is required, it should be carried out after the priming volume of normal saline is reached.
5. It is recommended that the pre-filled physiological saline flow directly into the waste liquid collection bag, and the waste liquid collection bag is placed on the liquid rack of the machine, not lower than the operator’s waist; it is not recommended that the pre-filled normal saline flow directly into the waste liquid collection bag In an open waste tank.
6. After flushing, set the treatment parameters according to the doctor’s instructions. 12.5 Establish extracorporeal circulation (on the machine)
1. Vascular access preparation
(1) Arteriovenous fistula puncture
1) Check the vascular access: whether it is present Redness, swelling, bleeding, and induration; and find out the direction and pulse of blood vessels.
2) After selecting the puncture point, disinfect the puncture site with iodophor.
3) Select the puncture needle according to the thickness of the blood vessel and blood flow requirements.
4) Use steps, buttons and other methods to puncture blood vessels at appropriate angles. First puncture the vein, then the artery. It is advisable to keep the arterial puncture point at least 3cm away from the arteriovenous fistula opening and the arteriovenous puncture point at least 10cm away. Fix the puncture needle. Inject the first dose of heparin according to the doctor's advice (low molecular weight heparin is used as an anticoagulant and should be injected intravenously in one go before boarding the machine according to the doctor's advice).
(2) Central venous indwelling catheter connection
1) Prepare iodophor disinfectant swabs and medical garbage bags.
2) Open the outer dressing of the intravenous catheter.
3) Turn the patient’s head to the opposite side and place a sterile treatment towel under the intravenous catheter.
4) Remove the inner dressing of the intravenous catheter and place the catheter on a sterile treatment drape.
5) Sterilize the catheter and catheter clip respectively and place them in a sterile treatment towel.
6) First check that the catheter clamp is in a closed state, and then remove the catheter heparin cap.
7) Disinfect the catheter connectors separately.
8) Use a syringe to withdraw heparin from the sealed tube in the catheter, and inject it onto the gauze to check whether there is a clot. The amount withdrawn is about 2 ml each in the arterial and venous tubes. If the blood flow from the catheter is not smooth, carefully search for the cause and do not use a syringe to forcefully inject into the catheter lumen.
9) Inject the first dose of heparin from the venous end of the catheter according to the doctor’s instructions (when using low molecular weight heparin as an anticoagulant, it should be injected intravenously once according to the doctor’s instructions before getting on the machine), and connect to the extracorporeal circulation.
10) Medical waste should be placed in medical trash cans.
2. Monitoring during hemodiafiltration
(1) After the extracorporeal circulation is established, immediately measure blood pressure and pulse, ask the patient about his or her feelings, and record the details in the hemofiltration record On the list.
(2) Self-checking:
1) Check the connections and openings of the extracorporeal circulation pipeline system in sequence according to the direction of the extracorporeal circulation pipeline. The pipe opening used should be in a double-safe state of sealing with a cap and a pipe clamp.
2) Check the machine treatment parameters according to the doctor’s instructions.
(3) Double check: After self-check, check the above content again with another nurse at the same time and sign on the treatment record sheet.
(4) During hemofiltration treatment, carefully ask the patient how they feel every hour, measure blood pressure and pulse, observe whether there is bleeding at the puncture site, whether the puncture needle has prolapsed or shifted, and record it accurately .
(5) If the patient's blood pressure, pulse and other vital signs change significantly, they should be monitored at any time and ECG monitoring should be provided if necessary. 12.6 Blood return (off the machine)
1. Basic method
(1) Disinfect the saline bottle stopper and bottle mouth used for blood return.
(2) Insert a large sterile needle and place it on the top of the machine.
(3) Adjust blood flow to 50~100ml/min.
(4) Turn off the blood pump. Clamp the arterial puncture needle clip, pull out the arterial needle, and press the puncture site.
(5) Unscrew the puncture needle and connect the arterial line to the large sterile needle on the physiological saline.
(6) Turn on the blood pump and use normal saline to return blood throughout the process. During the blood return process, you can use your hands to rub the blood filter, but you must not squeeze the venous end pipe with your hands; when the normal saline is returned to the venous pot and the safety clip is automatically closed, stop returning blood; it is not advisable to remove the pipe from the safety clip. Forcibly remove the fluid from the tube and completely return the fluid to the patient (otherwise, blood clots or air embolism may easily occur).
(7) Close the venous line clamp and the venipuncture needle clamp, pull out the venous needle, and compress the puncture site for about 2 to 3 minutes. Use an elastic bandage or tape to bandage the arterial and venous puncture sites for 10 to 20 minutes, check that there is no bleeding or oozing at the arterial and venous puncture needle sites, and then loosen the bandage.
(8) Organize supplies. Measure vital signs, record treatment orders, and sign.
(9) After treatment, the patient is asked to lie down for 10 to 20 minutes. The vital signs are stable, there is no bleeding at the puncture site, and the internal fistula murmur is good on auscultation.
(10) Explain the precautions to the patient and send the patient to leave the blood purification center.
2. Closed blood return (off the machine) is recommended
(1) Adjust the blood flow to 50~100ml/min.
(2) Open the preflush side tube at the arterial end, and use physiological saline to return the blood remaining in the arterial side tube to the arterial pot.
(3) Turn off the blood pump, and rely on gravity to inject the blood from the proximal side of the arterial tube back into the patient's body.
(4) Clamp the arterial line clamp and the arterial puncture needle clamp.
(5) Turn on the blood pump and use normal saline to return blood throughout the process. During the blood return process, you can use your hands to rub the filter, but you must not squeeze the venous end tube with your hands. When the physiological saline is returned to the intravenous pot and the safety clip is automatically closed, blood return will stop. It is not advisable to forcibly remove the pipeline from the safety clip and completely return the pipeline liquid to the patient (otherwise, clots may enter the blood or air embolism may occur).
(6) Clamp the intravenous line and the venipuncture needle.
(7) First pull out the arterial fistula needle, then pull out the intravenous fistula needle, and compress the puncture site for 2 to 3 minutes. Use an elastic bandage or tape to bandage the arterial and venous puncture sites for 10 to 20 minutes, check that there is no bleeding or oozing at the arterial and venous puncture needle sites, and then loosen the bandage.
(8) Organize supplies. Measure vital signs, record treatment orders, and sign.
(9) After treatment, the patient is asked to lie down for 10 to 20 minutes. The vital signs are stable, there is no bleeding at the puncture point, and the internal fistula murmur is good on auscultation.
(10) Explain the precautions to the patient and send the patient to leave the blood purification center. 13 Complications and treatment 13.1 Reverse ultrafiltration
1. When the reason is low venous pressure, low ultrafiltration rate or a dialyzer with high ultrafiltration coefficient is used, at the outlet of the dialyzer, The pressure on the blood side may be lower than that on the dialysate side, resulting in reverse ultrafiltration, which may cause pulmonary edema in severe cases.
Clinically uncommon.
2. Prevent and adjust appropriate TMP (100~400mmHg) and blood flow (normal gt; 250ml/min). 13.2 Protein loss
The application of high-flux dialysis membrane makes albumin easy to lose. During HDF treatment, albumin
loss increases, especially the post-dilution replacement method. 13.3 Deletion syndrome
High-flux hemodialysis can increase the loss of soluble vitamins, proteins, trace elements, small molecule peptides and other substances
. Therefore, nutrition should be supplemented in time during hemodiafiltration treatment. 14 sources