Technical Aspects of Hemodialysis

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Technical Aspects of Hemodialysis

• Saramma Mathew, RN,BSN,CNN
• Renal Educator
• Hackensack University Medical Center, Hackensack,
  NJ

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Anatomy

• Two Kidneys
• Two Ureters
• One bladder
• One Urethra

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Nephron

• Nephron functional unit of the kidney
• Filter the waste
• Kidney has lot of blood vessels-capillaries

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Kidney Physiology

• Glomerulus- ball of capillaries
• Bowmans capsule
• Selectively permeable
• Glomerular Filtration
• Tubule

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Functions of Kidneys

• Excretory Functions
• Gets rid of waste
• Endocrine functions
• Hormones
• EPO
• Calcitriol

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Principles of dialysis

• Solutions
• Solvent
• Solute
• Semi permeable membrane
• Ultra filtration

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First Principle of HD - Diffusion

• Solutes move from a region of higher
  concentration to a region of lower concentration
  until concentration is equal on either side.

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Factors affecting diffusion

• Concentration gradients
• Molecular weight of the solutes
• Temperature

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Factors affecting Diffusion

• Membrane permeability
• Surface area of the membrane
• Flow geometry

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2nd Principle of HD - Osmosis

• Osmosis is the movement of solvent through the
  semi permeable membrane from an area of lower
  concentration to an area of higher
  concentration.
• Ultra filtration

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Adequacy of Dialysis

• Formula for Urea Reduction Rate
• Pre Dial BUN - Post Dial BUN
• ________________________ x100
• Pre Dialysis BUN
• URR Calculation

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Adequacy - Kt/V

• K Dialyzer clearance
• T Length of dialysis time (in minutes)
• V Urea distribution volume in millimeters.
• Kt/V must be greater than 1.2

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Adequacy

• UKM Urea Kinetic Modeling
• Provides More Accuracy
• Measures Protein levels

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Machine alarms

• PRIORITY ALARMS
• Air detector alarm
• Blood leak detector
• Arterial pressure high/low alarm
• Venous pressure high/low alarm

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Technical Complications

• POTENTIAL PROBLEMS
• Air in Bloodlines
• Blood loss
• Clotting in extracorporeal circuit.

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Complications POTENTIAL PROBLEMS

• Dialyzer membrane leak
• Hemolysis
• Power failure

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Heparin Purposes in HD

• Function to prevent clotting
• Sensitivity
• Inadequate Heparin

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Heparin Protocols

• Heparin free
• Strength of Heparin
• Administering heparin
• Systemic
• Continuous infusion
• Intermittent
• Low-dose tight heparinization