Case Presentation 23 Sep 2024 (PDF)

NEPHROBERN Introduction to HD: Case Presentation Ariane Schweighauser Thierry Francey Drs. med. vet., Dipl. ACVIM (SAIM), ECVIM-CA, Founder ACVNU Small Animal Internal Medicine / Nephrology Department of Clinical Veterinary Medicine Vetsuisse Faculty University...

NEPHROBERN Introduction to HD: Case Presentation Ariane Schweighauser Thierry Francey Drs. med. vet., Dipl. ACVIM (SAIM), ECVIM-CA, Founder ACVNU Small Animal Internal Medicine / Nephrology Department of Clinical Veterinary Medicine Vetsuisse Faculty University of Bern (Switzerland) TF/AS-9/23/2024 Outline Indications Modality Prescription Anticoagulation Complications Outcome Duke Labrador Retriever, 3m, m Presented for vomiting, diarrhea, anorexia (x 3d) Diagnosed with - anuric AKI, grade 5 (5% overhydration) - hyperbilirubinemia (hepatic) - mild interstitial lung pattern Suspicion of severe acute leptospirosis (3 organ system involvements) Dialysis? Outline Indications Modality Prescription Anticoagulation Complications Outcome Indications for Hemodialysis Acute Kidney Injury (or ACKD) ❖ uremia expected to cause severe metabolic or organ dysfunction / damage ❖ directed to prevent rather than to resolve / ameliorate established morbidity ❖ ideally for AKI of caused by etiologies expected to be reversible (as "bridge to recovery") Chronic Kidney Disease ❖ CKD IRIS stage 4, when all other means of comprehensive medical management are not sufficient to control uremic manifestations Intoxication ❖ when no effective antidote or more effective therapeutic modality ❖ when suspected toxin concentration expected to cause morbidity, life-threatening risk, or tissue damage ❖ molecular characteristics of the toxin suggest removability: MW, protein binding, and VD Statement: Dialytic intervention is indicated in animals with AKI or acute-on-chronic kidney disease, when the uremia and retained uremia toxins are expected to cause severe metabolic or organ dysfunction or damage leading to multiorgan dysfunction. Dialytic intervention should be directed to prevent (preferentially) rather than to resolve or ameliorate established morbidity or systemic organ dysfunction secondary to the kidney injury. The main indications for dialytic intervention in AKI are: Serum creatinine exceeding 5 mg/dL (442 μmol/L) and trending higher in a hydrated animal. Persistent (>6 h) anuria or oliguria (1000 [1.0] 509-999 [1.69] ≤509 [3.44] model C Crea mg/dL ≤13.2 [1.0] >13.2 [2.26] Phos mg/dL ≤18.2 [1.0] >18.2 [3.13] Ca++ mmol/L >1.1 [1.0] 0.87-1.1 [1.99] ≤0.86 [4.16] AG mmol/L ≤18.2 [1.0] >18.2 [2.74] Alb g/dL >1.9 [1.0] ≤1.9 [2.52] ALAT U/L 1.31 [1.0] 0.10-1.31 [1.44] 0.00 [5.55] Resp No [1.0] Yes [2.48] Neuro No [1.0] Yes [3.76] DIC No [1.0] Yes [2.3] Total score: 17.2 Etiology Lepto [-8.46] EG [2.47] Neither [1.0]  Duke Segev score model C Total score: 17.2 Owners decide to go for dialysis… Outline Indications Modality Prescription Anticoagulation Complications Outcome Modality Intracorporeal RRT: Peritoneal dialysis (PD) (Enteral dialysis) Extracorporeal RRT: Intermittent hemodialysis (IHD) Continuous renal replacement therapy (CRRT) Hybrid forms different duration (PIRRT) different technique (HDF) PIRRT = prolonged intermittent renal replacement therapy Intra- vs extracorporeal RRT Peritoneal dialysis Hemodialysis/Hemofiltration thorough understanding of renal thorough understanding of renal pathophysiology and of the fluid, pathophysiology and of the fluid, electrolyte and acid-base electrolyte and acid-base physiology physiology reliable access to the peritoneal require specific medical cavity with a dedicated catheter equipment specifically composed fluids dedicated large-bore, double-lumen very careful attention to asepsis central venous catheters low-efficiency treatment Low to high efficiency treatment work-intensive Variable work-intensity  Kellum JA, Bellomo R, Ronco C. Continuous renal replacement therapy (2016) Hybrid therapies Share the characteristics of both intermittent and continuous techniques in terms of treatment frequency, duration, and modality Attempt to optimize the pros and cons of both modalities efficient solute removal slower ultrafiltration rates for hemodynamic stability less anti-coagulant exposure lower costs decreased "nurse" workload / improved ICU workflow One concept of longer duration treatments – many names: Prolonged intermittent daily renal replacement therapy (PIRRT) Sustained low-efficiency dialysis (SLED) Slow low-efficiency extended daily dialysis (SLEDD)... and others! Typical duration of treatments IHD I PIRRT I CRRT... Start 5h 10h 15 h 20h 25 h Choice of modality Dictated by medical considerations degree of azotemia, fluid overload Dictated by availability of platform (different machines) expertise of staff manpower of staff equipment (expected duration of treatment vs number of patients) Also dictated by expected duration of dialysis- dependent time  Choice of modality – based on duration of treatment AKI AKD CKD IHD x x x CRRT x ((x)) PD x ((x)) AKI: acute kidney injury Lakhmir et al, Nat Rev Nephro 2017 AKD: acute kidney disease CKD: chronic kidney disease  PD Membrane – the Peritoneal dialysis (PD) peritoneal membrane Infusion and drainage of dialysate through a dedicated peritoneal catheter Hemodialysis (HD) Blood Dialysate Artificial kidney = Dialyzer Fiber bundle Hollow fiber HD Dialysate HCO3- Blood Glucose Ca++ Glucose Na+… HCO3- Ca++ K+ Na+ Creatinine PO4- Urea Diffusion  What else can we achieve... Ultrafiltration -1.4 l of fluid post HD Removal of excessive fluid by Ultrafiltration (UF) 15% fluid overload HD Dialysate HCO3- Blood Glucose Ca++ Glucose Na+… HCO3- Ca++ K+ Na+ Creatinine PO4- Urea UF (increased TMP) Diffusion  Purely convective therapy Fluid not replaced Slow continuous ultrafiltration Acierno, Comp cont edu 2008 Hemodialysis (HD) Treatment based on diffusion and removal of low molecular weight solutes across a semi-permeable membrane. Removal efficacy depends on the concentration gradient across the membrane and on the molecular weight of the solute to be removed. Cutoff approximately 500 - 1’000 Da. Urea (60 Da) Creatinine (113 Da) Blood Dialysate Gambro CVVHD Primarily diffusive therapy Continuous venovenous hemodialysis Acierno, Comp cont edu 2008 Hemofiltration (HF) Treatment based on convective removal of solutes across a semi-permeable membrane. Removal efficacy extended to larger molecules. Cutoff approximately 10’000 – 50’000 Da. β2-microglobulin (11’800 Da) Leptin (16’000 Da) IL6 (24’500 Da) Blood Filtrate Gambro  Convective therapy Fluid replaced Continuous venovenous hemofiltration (HF) Acierno, Comp cont edu 2008 Hemodiafiltration (HDF) Treatment based on both diffusive and convective removal of solutes across a semi-permeable membrane. Low MW solutes removed mostly by diffusion and larger MW solutes by convection. Urea (60 Da) IL6 (24’500 Da) Blood Dialysate + Filtrate Gambro  CVVHD (diffusion) + CVVH (convection) Continuous venovenous hemodiafiltration Acierno, Comp cont edu 2008  Different methods of extracorporeal RRT Hemodialysis (HD) Hemofiltration (HF) Based on various physical principles Uses convection and solvent drag Uses diffusion along a concentration Basis of continuous renal replacement gradient through a semi-permeable therapies (CRRT) membrane performed for extended periods of typically used for intermittent several days treatments of 4-5 hours duration each Hybrid therapies combine diffusive and convective techniques (HDF) can be performed either as intermittent, prolonged intermittent (PIRRT), or continuous therapies Hybrid therapies Diffusion Convection Short tx Long tx Discontinuous tx Continuous tx Dialysate generation Dialysate in bags Water treatment No water treatment Gambro AK200 Ultra Gambro Prismaflex Fixed machine Mobile machine Qb > Qd Intermittent hemodialysis Continuous Renal Replacement Therapy (IHD) (CRRT) Blood purification strategies IHD Intermittent Intermittent hemodialysis Diffusive Hybrid therapies Convective (Hemodialyisis, HD) (PIRRT, iHDF...) (Hemofiltration, HF) CVVHF Continuous Continuous hemofiltration Duke, 10 kg dog, 1st treatment goals tx: URR 40%, fluid removal 500ml in 5h Choice of modality? Qb (blood flow) limiting efficacy Qd (dialysate flow) in excess Qb