Principles of Hemoperfusion Lecture Slides PDF

Principles of Hemoperfusion JD Foster, VMD, MS, DACVIM, DACVCP  Overview Limitations of solute removal in IHD/CRRT Rationale of hemoperfusion Relevant pharmacology  Solute Clearance in IHD/CRRT Solutes are cleared from intravascular space Properties of...

Principles of Hemoperfusion JD Foster, VMD, MS, DACVIM, DACVCP  Overview Limitations of solute removal in IHD/CRRT Rationale of hemoperfusion Relevant pharmacology  Solute Clearance in IHD/CRRT Solutes are cleared from intravascular space Properties of solute and membrane determine clearance Diffusion- based on concentration gradients  Diffusion Limitations Limited by pore size of dialyzer – Conventional (Low-flux): ~300 daltons – High-Flux: 12-15,000 daltons Clearance limited by Qb and Qd – IHD vs. CRRT PD has less clearance than that achieved with other ERRT  Molecular F3 F160 Size KOA urea 230 1064 K urea 60 da 125 194 (Qb 200, Qd 500) K creat 113 da 95 181 (Qb 200, Qd 500) K B12 1355 da 20 128 (Qb 200, Qd 500)  Limited Solute Clearance in IHD/CRRT Limited by pharmacokinetics of drug – Lipid solubility – Protein binding – Volume of distribution Convection- pressure applied to blood  Convective Therapies Diffusion and convection have similar clearance of smaller MW molecules (0.6L/kg suggests high lipophilicity, protein or tissue binding – In people, a Vd >1–2 L/kg is usually a deterrent to extracorporeal removal T ½- endogenous elimination Protein, lipid binding- reduces free solute Intercompartmental transfer rates Studied dose vs. toxic dose  Clinical Indications for HP of Toxins Winchester JF. Dialysis and hemoperfusion in poisoning. Adv Ren Replace Ther. 2002. 9 (1): 26- 30.  When to Choose HP Winchester JF. Dialysis and hemoperfusion in poisoning. Adv Ren Replace Ther. 2002. 9 (1): 26- 30.  Solute Kinetics in HP If no saturation of filter, 1st-order kinetics would occur Cartridge Saturation  Solute Kinetics in HP C = Qb (1 – Hct) x [(Ca – Cv)] Ca Qb= blood flow Ca= pre-cartridge concentration Cv= post-cartridge concentration Compartmental Kinetics One-compartment: body is single compartment -Vd is distribution volume -Occurs when Vd = treatment volume ---Drug found mostly within blood volume  Compartmental Kinetics Blood Fat Two-compartment: body is divided into multiple compartments -Blood, tissues, etc. -Solute moves between compartments ---Solute may be more concentrated in one compartment (e.g. fat) ---Solute removal may be limited by redistribution to intravascular space 2 Compartment Solute Kinetics Eq High intercompartmental transfer rate 2 Compartment Solute Kinetics Moderate peripheral compartment Large peripheral compartment  Cartridge Saturation Adsorba saturated after 1-6 hours for most solutes Atlas- higher surface area, longer to saturate DATA!!! Cartridges must be replaced when saturated  Adsorba Adsorba (Baxter) 150 – 110ml priming volume Tauk & Foster JVECC 2016 Hour Arterial Post Post Dialyzer % reduction % reduction Charcoal C D 0 228 1 139 149 147 7.19 1.34 2 56.2 106 161 [-88.61] [-51.88] 3.5 157 108 70.8 31.21 34.44 4.25 58 55.8 51 3.79 8.60 5 38.9 44.8 68.3 [-15.16] [-52.45] 6 47.6 43.6 39.1 8.40 10.32 Ibuprofen concentrations  Naproxen Concentrations During 5hr Charcoal Hemoperfusion Tx 120 Naproxen Concentration (ppm) 100 80 60 Arterial Blood 40 Concentration 20 0 0 20 40 60 80 100 120 140 Time (hours) Charcoal HP + HD Naproxen concentrations  AimaLojic Carbon Cartridges Atlas (150 - 5,000 Da) and Dublin (150 - 45,000 Da) – 100 and 300 size cartridges – 41mL and 165mL priming volumes – 55k m2 surface area (>10 football fields) 5.3 kg DSH 46 mg/kg naproxen ingestion Carbon HP started 8 hr after exposure AKI: sCr 3.5 → 1.3 Regenerative anemia: 2x pRBC 99% reduction  VetResQ Reduction in IL-6, IL-8, IL-1 Improved survival in non-controlled trials 300ml, 150ml, 50ml priming volumes  Cytokines Vetresq.com  IL-6 C-Reactive Protein Heymann Crit Care Med 2023  No survival benefit of CytoSorb® use in septic people at 28 - 30 days Saldaña-Gastulo Crit Care Sci 2023  Other Adsorptive Therapies Polymer sorbents – Can be customizable Albumin dialysis MARS (molecular adsorbent recirculating system) Prometheus MARS System Plasmapheresis & Adsorption  Prometheus and MARS Systems Prometheus MARS Tsipotis Adv Chronic Kidney Dis 2015 Questions?