30 Questions
What is the definition of ultrafiltration?
Movement of water across a membrane due to a pressure gradient without the need for dialysate
How do ultrafiltration and dialysis help manage blood volume and certain electrolyte concentrations?
By removing excess water and certain solutes from the blood
What is the impact of hemoconcentrators on circulating concentrations of drugs and ions during CPB?
They increase the circulating concentrations of drugs and ions
When is the use of the hemoconcentrator important in relation to CPB?
Before, during, and after CPB
What do several studies suggest about the effect of ultrafiltration and dialysis on systemic inflammatory response syndrome (SIRS)?
They may reduce mediators that initiate SIRS
What promotes capillary permeability and shifting of fluid to the extravascular space during CPB?
Exposure to foreign surfaces of the extracorporeal circuit and surgical trauma
What is the purpose of ultrafiltration and dialysis in relation to CPB and related extracorporeal technologies?
To manage blood volume, hemoglobin, protein, and certain electrolyte concentrations
What did Thomas Graham present a paper on in 1854?
Osmotic Force
Who conducted the first clinical dialysis procedure in 1924?
George Haas
What material did Willem Kolff use to build an artificial kidney in the 1940s?
Regenerated cellulose membrane
Who developed the flat or parallel plate dialyzer in 1947?
Leonard Skeggs and Jack Leonards
What is achieved through ultrafiltration?
Filtration of water across a semipermeable membrane
What occurs during ultrafiltration?
Solute removal called convection
What is the most widely used type of dialyzer and ultrafiltrator currently?
Hollow fiber dialyzer
What is the pressure gradient that transmembrane pressure (TMP) should not exceed?
500-600 mm Hg
What does the sieving coefficient ranging from 0 to 1.0 indicate?
The ability of a solute to be filtered through the ultrafiltrator membrane
What does ultrafiltration remove in equal concentration to the plasma water?
Plasma water and diffusible solutes
When using a centrifugal pump, where should the flow probe be located in relation to the ultrafiltrator shunt?
Distal to the ultrafiltrator shunt
What does ultrafiltration in bypass during cardiopulmonary bypass (CPB) remove?
Excess fluid
What factors does the rate of fluid removal during ultrafiltration depend on?
Membrane permeability, blood flow, TMP, and hematocrit
What are the positive effects of ultrafiltration in CPB?
Increase protein and red blood cell concentrations, decrease lung waters, reduce fluid balance, and improve perioperative hemostasis
What is the primary goal of ultrafiltration during cardiopulmonary bypass (CPB)?
To remove excess water and concentrate cellular elements and proteins in the blood
What is the purpose of continuous ultrafiltration during rewarming on CPB?
To attenuate the inflammatory response and lower cytokine and complement levels
What does Z-BUF (Zero-Balance Ultrafiltration) aim to correct in adults undergoing cardiac surgery?
Hyperkalemia, electrolyte, and acid-base disturbances
What is the purpose of Modified Ultrafiltration (MUF) in pediatric patients post-CPB?
To concentrate and transfuse residual circuit blood without the risk of hypervolemia
How does Z-BUF ensure stable potassium levels during ultrafiltration?
Ultrafiltrate potassium levels are always in equal concentration to the plasma
What can ultrafiltration efficiently remove compared to dialysis?
Middle-molecule uremic solutes
What challenge in managing hemodilution can be addressed through ultrafiltration during CPB?
Fluid shifts due to the systemic inflammatory response
What is the potential effect of ultrafiltration on direct thrombin inhibitors like bivalirudin for adults?
It can remove 45% to 65% of the drug using MUF or UF
What has shown improved post-CPB outcomes and reduced levels of inflammatory mediators?
Z-BUF in combination with MUF
Study Notes
Ultrafiltration and Modified Ultrafiltration in Cardiopulmonary Bypass
- Ultrafiltration during cardiopulmonary bypass (CPB) aims to remove excess water, concentrate cellular elements, and proteins in the blood, while maintaining the patient's plasma concentration of diffusible solutes.
- Continuous ultrafiltration during rewarming on CPB may attenuate the inflammatory response, as it can lower cytokine and complement levels, especially during this phase.
- To enable continuous ultrafiltration during rewarming, ultrafiltrate is replaced with a balanced electrolyte solution.
- Z-BUF (Zero-Balance Ultrafiltration) has been used to correct hyperkalemia, electrolyte, and acid-base disturbances in adults undergoing cardiac surgery.
- Z-BUF ensures that as blood volume is reduced by ultrafiltration, potassium levels remain stable, as ultrafiltrate potassium levels are always in equal concentration to the plasma.
- Modified Ultrafiltration (MUF) is a procedure used in pediatric patients to concentrate and transfuse residual circuit blood post-CPB without the risk of hypervolemia.
- MUF requires patients to remain cannulated for 10 to 20 minutes post-CPB termination, and protamine may not be administered during MUF to maintain circuit integrity.
- Ultrafiltration can remove direct thrombin inhibitors like bivalirudin, with the potential to remove 45% to 65% of the drug using MUF or UF for adults.
- CPB presents challenges in managing hemodilution, electrolyte levels, and fluid shifts due to the systemic inflammatory response, all of which can be addressed through ultrafiltration.
- Z-BUF, in combination with MUF, has shown improved post-CPB outcomes and reduced levels of inflammatory mediators.
- The conventional dialysis circuit can be simplified for use in the extracorporeal circuit to manage patient volume and electrolyte imbalances, similar to Z-BUF or hemofiltration.
- Ultrafiltration appears to efficiently remove middle-molecule uremic solutes compared to dialysis.
Test your knowledge of ultrafiltration and modified ultrafiltration in cardiopulmonary bypass with this quiz. Explore the uses, benefits, and techniques of ultrafiltration in managing hemodilution, electrolyte levels, and fluid shifts during CPB, as well as the application of Z-BUF and MUF in improving post-CPB outcomes.
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