Continous renal replacement therapy in ICU

Summary

Highlights

• CRRT is broken down into methods like SCUF, CVVHF, and CVVHD. 🔍
• The video explains central processes like diffusion, ultrafiltration, and convection in CRRT. 🌊
• Michal discusses the importance of anticoagulation in CRRT to prevent clotting. 🩸
• Complications of renal replacement therapy are highlighted, including risks of hemodynamic instability. 🚨
• CRRT aids in stabilizing patients by reducing stress on the cardiovascular system in critical care. 🫀

Key Takeaways

• CRRT is essential in ICU for patients with kidney issues by providing continuous dialysis support. 🏥
• The therapy includes methods like SCUF, CVVHF, and CVVHD, each with specific applications. ⚙️
• CRRT minimizes cardiovascular stress compared to intermittent hemodialysis, making it more suitable for critically ill patients. 💓
• Anticoagulation is a critical component, with options like regional citrate and heparin. 🔄
• Renal replacement therapy complications range from hemodynamic instability to electrolyte imbalances. ⚠️

Overview

Chapters

• 00:00 - 01:00: Introduction to CRRT In the 'Introduction to CRRT' chapter, Mikhail Pasternik introduces continuous renal replacement therapy (CRRT) as a key form of renal replacement therapy used in intensive care units (ICU). The chapter highlights the main division of renal replacement therapies into three types: peritoneal dialysis, intermittent hemodialysis, and continuous renal replacement therapy.
• 01:00 - 02:00: Types and Indications of Dialysis The chapter discusses the various types of dialysis, focusing on continuous renal replacement therapy (CRRT) and intermittent hemodialysis. CRRT is subdivided into different forms including slow continuous ultrafiltration, CVH, CVHD, CVHDF, and SLED. These procedures share the same fundamental principle: blood is drawn from the patient, passed through a filter for purification, and returned to the bloodstream. Intermittent hemodialysis is highlighted for its ability to remove large amounts of water and solutes rapidly.
• 02:00 - 03:00: Dialysate and Fluid Components In this chapter, titled "Dialysate and Fluid Components," the discussion centers on dialysis, particularly focusing on the differences between continuous renal replacement therapy (CRRT) and peritoneal dialysis. CRRT is highlighted for its slow solute removal over extended periods, which mimics natural kidney function and imposes less stress on the cardiovascular system, making it suitable for certain patient populations. The chapter also touches on the limitations of peritoneal dialysis in critical care settings. It provides indications for dialysis in the intensive care unit (ICU), including scenarios like fluid overload not responsive to diuretic therapy, severe metabolic acidosis unmanageable by conventional medical treatments, and hyperkalemia that doesn't respond to standard therapies.
• 03:00 - 04:00: Mechanisms: Diffusion and Ultrafiltration The chapter discusses mechanisms such as diffusion and ultrafiltration as they relate to medical management. It addresses the management of uremic symptoms, poisoning with a dialysate drug or toxin, and electrolyte imbalances, especially in the context of acute kidney injury (AKI), progressive azotemia, or oliguria that does not respond to medical treatment, or hypothermia refractory to usual cooling techniques. The role of dialysate, a fluid used in dialysis, is explained, emphasizing its function in creating a diffusion gradient essential for filtration.
• 04:00 - 05:00: Convection and Hemofiltration The chapter "Convection and Hemofiltration" discusses the concentration of solutes within dialysate. Dialyzate contains sodium chloride and magnesium at levels similar to serum concentration. Solutes are only removed if their blood levels exceed normal concentrations. It mentions specific concentrations for potassium, bicarbonate, glucose, phosphate, and calcium, with a focus on cardiolysis and dialysis processes.
• 05:00 - 06:00: Anticoagulation Methods This chapter discusses anticoagulation methods in the context of kidney dialysis, particularly focusing on citrate solution and dialysate used in Continuous Venovenous Hemodialysis (CVHD) and Continuous Renal Replacement Therapy (CRRT). It highlights the importance of selecting the appropriate CVHD/CRRT access based on the dialysis technique and the duration of renal replacement therapy. The chapter also describes the structure and function of a dialysis catheter, which typically consists of two lumens, with one lumen designated for drawing blood from the patient.
• 06:00 - 07:00: Considerations for CRRT Dose The chapter titled 'Considerations for CRRT Dose' discusses the functioning of a device used as an external kidney. It is composed of a canister with many hollow fibers, which are semi-permeable. The process is described with specific mention of the color-coded lumens: one lumen, colored red, is responsible for drawing blood, while the other, colored blue, reinfuses the blood back into the bloodstream. The area of a typical continuous venovenous hemodialysis (CVHD) filter is noted to be approximately 1.8 square meters.
• 07:00 - 08:00: Specific Techniques and Modalities The chapter discusses the different compartments in medical procedures, specifically the blood compartment and drainage compartment. The drainage compartment can either be filled with dialysate or act as a drainage system for excess water. The chapter emphasizes the understanding of diffusion, which is the movement of particles from an area of higher concentration to an area of lower concentration across a semi-permeable membrane. It is noted that this movement is driven solely by concentration gradients.
• 08:00 - 09:00: Complications of Renal Replacement Therapy The chapter 'Complications of Renal Replacement Therapy' discusses the principles of diffusion in the context of removing small molecules and substances through renal replacement techniques. It explains that the effectiveness of diffusion is determined by the concentration gradient, which refers to the difference in concentration of particles in a solute between two sides of a membrane. The larger the concentration gradient, the greater the force driving diffusion. The chapter notes that particles smaller than 20 kilodaltons, such as certain waste molecules, can be effectively removed via diffusion. Furthermore, it details that factors like the amount of liquid present on either side of the membrane, the membrane's permeability, surface area, and the charge of particles also play crucial roles in the diffusion process and its efficiency in renal therapy.

Continous renal replacement therapy in ICU Transcription

• 00:00 - 00:30 [Music] hi guys welcome back to prague icu i'm mikhail pasternik and in this presentation i will give you the most important information about continuous renal replacement therapy in icu renal replacement therapy can be divided into three main types peritoneal dialysis intermittent hemodysis and continuous renal replacement therapy
• 00:30 - 01:00 crt is then divided to slow continuous ultrafiltration cvh cvhd cvhdf and sled intermittent hemodialysis or continuous renal replacement therapy circuits utilize the same principles blood is removed from the patient blood is pumped through a filter and purify blood is then returned to the bloodstream intermittent hemodialysis removes large amount of water and solutes in a short period of time in
• 01:00 - 01:30 contrast crt removes solutes in a slow rate for a long time stimulating properly in function it represents less stress to cardiovascular system peritoneal dialysis is not used in critical care indications for dialysis in the icu are fluid overload resistant to diuretic therapy profound metabolic acidosis refractory to medical management hyperkalemia refractory to medical
• 01:30 - 02:00 management uremic symptoms or signs poisoning with a dialysal drug or toxin electrolyte arrangements in the setting of aki progressive asotemia or oliguria without response to medical management or hypothermia refractory to regular cooling techniques dialysate is a fluid that is pumped into the filter canister surrounding the hollow fibers diffusion gradient is determined by the
• 02:00 - 02:30 concentration of solutes within dialysate dialyzate contains sodium chloride and magnesium levels that are similar to serum concentration their removal is observed only in case if the blood level exceeds normal concentration potassium two or four millimeters per liter in c cardiolysis bicarbonate 20 millimoles per liter in sica dialysis glucose and sometimes in addition phosphate and calcium
• 02:30 - 03:00 on this slide you can appreciate components of citrate solution and dialysate used in cvhd crt access depends on the type of dialysis technique and duration of renal replacement therapy dialysis catheter has usually two lumens the first lumen is pulling blood from the patient is
• 03:00 - 03:30 usually marked with red color in contrast the second lumen is reinfusing the blood into the bloodstream it's usually marked with blue color so how does it work external kidney is enclosed canister with a lot of hollow tubules called hollow fibers hollow fibers are made of semi-permeable membrane area of cvhd filter is usually 1.8 square meters
• 03:30 - 04:00 it determined by two compartments first blood compartment and drainage compartment which can be filled with flowing dialysate or can serve as a waste or surplus water drainage what are the principles of crt you need to be aware and understand the term diffusion diffusion is a movement of particles across semi-permeable membrane from the side with higher concentration of particles to the site with lower concentration the only force that makes
• 04:00 - 04:30 diffusion possible is concentration gradient the bigger the concentration difference of particles in solute is the bigger will be the force of diffusion it's effective at removal of small molecules substances less than 20 kilodaltons can be removed amounts of liquids on both sides of membrane is constant depends on the concentration gradient membrane permeability surface size of membrane and charge of particles
• 04:30 - 05:00 concentration gradient is enhanced with the counter current direction of blood and alizate that flow against each other like in native renal parenchyma ultrafiltration is a movement of water across a semi-permeable membrane due to a pressure gradient difference of solute pressures between two compartments the difference between the blood pressure in the hollow fibers and surrounding pressure is called transmembrane pressure that determines the ultrafiltrate
• 05:00 - 05:30 production ultrafiltration depends on tmp surface size of a membrane and hydraulic permeability of membrane ultrafiltration is connected with another physical principle convection convection is the transport of a solute across the membrane along with solvent by so-called solvent drag a collective movement of molecules within fluids solute molecule is swept through a membrane by a moving
• 05:30 - 06:00 stream of ultrafiltrate convective transport is independent of solute concentration gradient across the membrane positive pressure is generated in the blood compartment by increasing the hydrostatic pressure in the blood compartment increasing the rate of blood flow to the membrane and negative pressure in the dialysate compartment that facilitates ultrafiltration created by decreasing the oncotic pressure of plasma by pre-dilution it's useful for small and middle-sized molecules clearing
• 06:00 - 06:30 also middle-sized molecules such as mediators in sepsis are removed hemofiltration technique enhances the loss of water causing hypovolemia any water removed must be returned to the blood via the replacement fluid replacement fluid is present only in cvh and cvhdf replacement fluid is sterile electrolyte levels are similar to plasma
• 06:30 - 07:00 the fluid can be replaced pre-filter or post filter this table summarizes advantages and disadvantages of pre-lotion and post-dilution how is it with anticoagulation crt can be either anticoagulation free regional with heparin anticoagulation or citrate anticoagulation or systemic
• 07:00 - 07:30 no anticoagulation is indicated in patients with a high risk of bleeding impaired hemophilia survival can be prolonged by diminishing hematocrit within the filter by predilution maintaining a filtration fraction less than 20 percent and achieving high blood flow rates it's indicated for patients on therapeutic anticoagulation for another indication nonetheless regional citrate anticoagulation
• 07:30 - 08:00 is the first choice in icu in regional heparin anticoagulation there is a prefilter infusion of unfraction heparin and post filter neutralization is represented by protamine there is shorter hemo filter survival compared to regional citrate anticoagulation regional citrate anticoagulation decreases the risk of bleeding and it's also prolonged hemophilia patency in contrast there is a risk of electrolytic disbalance risk of metabolic alkalosis
• 08:00 - 08:30 or metabolic acidosis and when trisodium citrate is used there is increased sodium load to the patient how does the citrate anticoagulation work citrate is a calcium calata unizide calcium is important for proper function of coagulation cascade calcium bonds on clotting proteins decreased level of ionoside calcium leads to inhibition in thrombin formation citrate is a strong anion and is administered mostly in a form of
• 08:30 - 09:00 trisodium citrate to minimize your differences we need to be aware of citrate toxicity as some proportions of infused citrate is removed by the crt circuit with bonded calcium ions the rest of citrate calcium complexes return into the bloodstream and undergo metabolization liver kidney and muscles bonded calcium is released citrate is then transformed to three bicarbons in patients with normal liver function
• 09:00 - 09:30 we can subsequently observe metabolic alkalosis in this case we can either decrease blood flow or increase dialysate flow in patients with liver dysfunction we can observe metabolic acidosis in this case we can decrease blood flow treat life-threatening hypocalcemia with iv calcium or switch to regional heparin anticoagulation alternatively we can use systemic
• 09:30 - 10:00 anticoagulation confraction heparin infusion is managed if regional citrate and accumulation is contraindicated hyperinduced thrombocytopenia can develop within five to ten days of vapor in use low molecular weight heparin administration lowers the risk of hit low molecular weight heparin use is slightly superior to unfraction heparin in hemophilia survival hit requires discontinuation of heparin further systemic anticoagulation is
• 10:00 - 10:30 needed either argatrobin or donoperoid transmembrane pressure is hydrostatic pressure gradient across the membrane rise of tmp is gradual throughout the life of a filter membrane sudden rise of tmp with normal value of retinal pressure signifies clotting the limit of filter is approximately 450 millimeters mercury filtration fraction is a percentage of
• 10:30 - 11:00 plasma that is being removed from blood during outer filtration filtration fraction above 25 percent can lead to increased risk of clotting for diminish we can either increase predilution rate or reduce replacement pump rate scaf slow continuous ultra filtration is rarely used in icu it's carried out with high flux membranes and the objective is to achieve volume control
• 11:00 - 11:30 in patients with severe diuretic resistant volume overload by ultra filtration of excess fluid without metabolic imbalance because of low filtration rates this method is not so effective as the blood purification modality its indication include fluid removal without significant electrolyte imbalance cvvh continues venovenous hammer filtration is rarely used in icu it works on the
• 11:30 - 12:00 basis of convection and ultrafiltration convection is used for the purpose of clearing wastes by removal of large amounts of fluid across the filter membrane the volume of removed fluid is greater than surplus water hence must be restored via replacement fluid the amount of fluid in the affluent bag is equal to amount of fluid removed from patient plus the volume of replacement fluid administered indications include uremia acid-base
• 12:00 - 12:30 imbalance electrolyte imbalance or need of large molecular weights particles removal cvhd works on the basis of diffusion and ultrafiltration cvhd is the most frequently used method in icu removal of waste is caused by diffusion counter current dialysate flow mechanism enhances the concentration gradient hence there is a greater clearance the
• 12:30 - 13:00 dialysate determines what type of solute is going to be removed by its own concentration of solutes if concentration of some particle is higher in dialysate this particle will diffuse into bloodstream indications include uremia severe acid-base disbalance or severe electrolyte based disbalance cvhdf continuous venovenosaur modal filtration
• 13:00 - 13:30 is rarely used in ico nowadays it works on the basis of convection diffusion and ultrafiltration this technique uses both modalities dialysis with diffusion and hemofiltration using convection this therapy includes replacing the fluids through the pre-dilution or post-dilution and a dialysate solution canister divided into two compartments by semi-permeable membrane has one side with high concentration and
• 13:30 - 14:00 pressure of solute and the second with low concentration and pressure thus maintaining the concentration gradient for dialysis and tmp for ultrafiltration circuit can be altered for cvh by removing the administration of dialysate or for cvhd by removing the administration of pre-blood pump fluid and post-dilution replacement fluid sled is sustained low efficiency
• 14:00 - 14:30 dialysis it's a hybrid technique of renal replacement therapy that proceeds from intermittent hemolysis and crt it requires 6 to 12 hours to run a day which can be done overnight it offers significant breaks between treatments and mobilization of patient so diagnostic and therapeutic work can be done euro clearance is 80 milliliters per minute there is a crt in which is 30 milliliters per minute
• 14:30 - 15:00 patient can profit from the shorter duration of exposure to anticoagulant otherwise saline flashes can be used instead of anticoagulation drug or citrate solution sled offers faster removal of wastis and lower cost compared to crt it might be three times cheaper than crt in contrast we can observe worse hemodynamic stability after the procedure but it's still better than intermittent hemodialysis
• 15:00 - 15:30 once deciding on the modality of choice a dose must be chosen a dose of effluent flow rate in milliliters per hour it's a flow rate of ultrafiltrate and dialyzate together and effluent those calculated in milliliters per kilogram per hour which is normalized effluent flow rate to patient body weight the dose of crt can be thought of as the volume of blood purified per unit time typical dose of crt is 25 to 30 milliliters per kilogram per
• 15:30 - 16:00 hour it's calculated as ultra filtration rate in cvh deliver dialysis flow rate in cvhd and both for cvhdf higher dose haven't found no significant difference for mortality or rate of renal recovery these patients with more intensive crt had significantly higher rates of hypophosphatemia furthermore receiving high doses of crt
• 16:00 - 16:30 decreases the plasmatic concentration of several drugs in bloodstream eg antibiotics how to prescribe crt crt dose is quantified by the effluent dose 25 milliliters per kilogram per hour how is it with blood flow rate and allies outflow rate in cvhd diligent flow rate is calculated as blood flow rate times 20. blood flow
• 16:30 - 17:00 in a patient with 80 kilograms is usually 100 milliliters per minute diligent flow rate in this patient is then 2 000 milliliters per hour cvh and cvhdf are nowadays rarely used in icu bicarbonate buffer solutions are preferred over lactate buffered solutions for rca we always use calcium three dialysate fluid removal depends on clinical
• 17:00 - 17:30 situation such as pulmonary edema etc we avoid very high ultrafiltrate rates this is an overview of original citrate dialysis we administer citrate solution before the filter citrate binds to calcium dilysate flow which is running into counter direction to blood flow effluent is containing citrate and calcium
• 17:30 - 18:00 behind the filter we administer calcium infusions and you can also observe that there is still some citrate remaining that is returning to the bloodstream of the patient so how do we prescribe citrate cvhd which is the most frequently used method of crt in icu in an 80 kilogram patient we usually start with diazide flow rate
• 18:00 - 18:30 of 2000 milliliters per hour blood flow rate 100 milliliters per minute citrate dosage is 4 millimoles per liter and calcium dosage is 1.5 millimeters per liter in a patient with 100 kilograms we usually start with 2400 milliliters per hour diesel flow rate 120 milliliters per minute of blood flow rate and citrate and calcium dosage is the same the white arrow points on a site from
• 18:30 - 19:00 which we withdraw samples for determination of post-filter unizide calcium with just the citrate dose depending on the levels of post-filter calcium as displayed in the table moreover we also need to focus on systemic uranized calcium levels where they just depose filter calcium rate depending on their levels
• 19:00 - 19:30 how can we affect acid-base balance in cvhd horizontal axis represent zika dialysate flow in milliliters per hour vertical line represents blood flow in milliliters per minute the numbers from 30 to 18 represent expected concentration of bicarbonate in serum in millimeters per liter to correct an acidosis we can either decrease the dialysate flow or increase
• 19:30 - 20:00 the blood flow rate whereas in patients in alkalosis we can either increase dialysate flow or decrease the blood flow rate finally what are general complications of renal replacement therapy complications related to excess such as bleeding vessel damage bloodstream or localized infection or air embolism respiratory complications include hypoxia or hypocapnia circulatory complications
• 20:00 - 20:30 include hemodynamic instability or hypothermia neurological complications are represented by dialysis disequilibrium syndrome also we can observe gastrointestinal complications such as malnutrition moreover there could be renal electrolyte or hematological complications thank you for watching prague icu and stay tuned for next interesting
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