Hemodialysis

Indications

Metabolic Acidosis (see Metabolic Acidosis-Normal Anion Gap, [[Metabolic Acidosis-Normal Anion Gap]] or Metabolic Acidosis-Elevated Anion Gap, [[Metabolic Acidosis-Elevated Anion Gap]])

  • Lactic Acidosis (see Lactic Acidosis, [[Lactic Acidosis]])
    • Epidemiology: for severe cases

Intoxications

  • Barium Intoxication (see Barium, [[Barium]])
  • Ethylene Glycol Intoxicationb (see Ethylene Glycol, [[Ethylene Glycol]])
  • Metformin Intoxication (see Metformin, [[Metformin]])
  • Methanol Intoxication (see Methanol, [[Methanol]])
  • Iodine Intoxication (see Iodine, [[Iodine]])
    • Epidemiology: may be seen in burn patients
  • Isoniazid Intoxication (see Isoniazid, [[Isoniazid]])
  • Lithium Intoxication (see Lithium, [[Lithium]])
  • Salicylate Intoxication (see Salicylate, [[Salicylate]])
  • Valproic Acid Intoxication (see Valproic Acid, [[Valproic Acid]]): HD

Uremia

Other


Technique

Hemodialysis Access

Temporary (Non-Tunneled) Hemodialysis Catheters

  • Mahurkar Catheter Lengths: 13 cm, 16 cm, 20 cm, and 24 cm
    • IJ Site: use 13 or 16 cm catheter
    • Femoral Site: use 16 cm, 20 cm, or 24 cm catheter
  • Arrow Hemodialysis Catheter Lengths: 13 cm, 16 cm, and 19 cm
    • IJ Site: use 13 or 16 cm catheter
    • Femoral Site: use 16 or 19 cm catheter

Tunneled Hemodialysis Catheters

  • Permacath
  • Ash Split Cath

Arteriovenous Hemodialysis Fistula (see Arteriovenous Hemodialysis Fistula, [[Arteriovenous Hemodialysis Fistula]])

  • xxxx

Arteriovenous Hemodialysis Graft (see Arteriovenous Hemodialysis Graft, [[Arteriovenous Hemodialysis Graft]])

  • xxxx

Types of Renal Replacement Therapies (RRT)

Intermittent

  • Intermittent Hemodiafiltration
  • Intermittent Hemodialysis
    • Short: 2-4 hrs
    • Sustained Low-Efficiency Dialysis (SLED): 6-12 hrs

Continuous

  • Continuous Venovenous Hemodiafiltration (CVVHDF)
  • Continuous Venovenous Hemodialysis (CVVHD)
  • Continuous Venovenous Hemofiltration (CVVH)

Regional Anticoagulation

  • Rationale: often required with RRT to prevent circuit clotting (although patients with thrombocytopenia or coagulopathy may be managed without anticoagulation)
  • Agents
    • Citrate (see Sodium Citrate, [[Sodium Citrate]]): citrate is infused into afferent blood line and functions to bind calcium, preventing coagulation
      • Removal of Citrate is Dependent on the Dialysate Flow and/or Ultrafiltration Rate
      • Citrate May Enter the Systemic Circulation, Resulting in Hypocalcemia: may require intravenous calcium supplementation
      • Citrate Metabolism May Be Impaired in Patients with Liver Failure
      • Regional Citrate Anticoagulation (Trisodium Citrate) Has Been Studied in the L-CAT Trial with CCVHD in Patients with Liver Failure and is Considered Safe and Efficacious (Crit Care, 2015) [MEDLINE]
    • Heparin (see Heparin, [[Heparin]]): less commonly used, as compared to citrate

Choice of Dialysis Technique for Renal Replacement Therapy

  • Preferred Hemodialysis Modality in Specific Clinical Scenarios
    • Burns (see Burns, [[Burns]]): protracted high-flux hemodialysis or hemodiafiltration (with high blood and dialysate flow) is recommended to remove iodine, which may accumulate in these patients (iodine molecular weight is 253, with similar clearance to that of small solutes such as urea)
    • Chronic Hyponatremia: low-efficiency RRT (CVVH) is recommended to avoid rapid changes in serum sodium
    • Ethylene Glycol Intoxication (see Ethylene Glycol, [[Ethylene Glycol]]): HD
    • Hepatorenal Syndrome (see Hepatorenal Syndrome, [[Hepatorenal Syndrome]]): no data exist to guide using one RRT modality over another
    • Iodine Intoxication (see Iodine, [[Iodine]]): HD
    • Isoniazid Intoxication (see Isoniazid, [[Isoniazid]]): HD
    • Lithium Intoxication (see Lithium, [[Lithium]]): HD
    • Metformin Intoxication (see Metformin, [[Metformin]]): HD
    • Methanol Intoxication (see Methanol, [[Methanol]]): HD
    • Ongoing Large Fluid Requirements: CVVHD is preferred over intermittent HD, due to the better ability to maintain fluid balance with CVVHD
    • Rhabdomyolysis (see Rhabdomyolysis, [[Rhabdomyolysis]]): intermittent HD is preferred ovr CVVHD, due to the more rapid solute removal with intermittent HD
    • Salicylate Intoxication (see Salicylate, [[Salicylate]]): HD may be used in patients with severe salicylate intoxication with fluid overload and cerebral edema
    • Severe Accidental Hypothermia: while cardiopulmonary bypass is the preferred modality, HD (without coagulation, as hypothermia is associated with coagulopathy) may alternately be used to warm a hemodynamically stable patient
    • Severe Cerebral Edema/Increased Intracranial Pressure (see Increased Intracranial Pressure, [[Increased Intracranial Pressure]]): CVVHD is preferred over intermittent HD, due to rapid solute changes and potential for hypotension in intermittent HD (which may exacerbate cerebral ischemia)
    • Severe Hyperkalemia (see Hyperkalemia, [[Hyperkalemia]]): intermittent HD is preferred ovr CVVHD, due to the more rapid solute removal with intermittent HD
    • Severe Lactic Acidosis (see Lactic Acidosis, [[Lactic Acidosis]]): CVVHD is preferred, as dialysis is more efficient in removing small molecules (such as lactate) and continuous method prevents intradialytic rebound
    • Valproic Acid Intoxication (see Valproic Acid, [[Valproic Acid]]): HD
  • Clinical Efficacy
    • French HEMODIAFE Multi-Center Randomized Trial of Intermittent vs Continuous Hemodialysis in AKI Associated with Multi-Organ Dysfunction in Critically Ill Patients (Lancet, 2006)
      • Provided That Precautions to Improve Tolerance and Metabolic Control are Used, Almost All Critically Ill Patients Can Be Dialyzed with Intermittent Hemodialysis with No Change in the Mortality Rate
        • Precautions: less aggressive ultrafiltration (with increased treatment duration and hemodynamic measurements to guide therapy), increasing dialysate sodium and calcium concentrations, adapting the dialysate temperature to obtain isothermic dialysis, connecting afferent and efferent bloodlines simultaneously at the start of the procedure, using low blood flow (<150 mL/min) and low dialysate flows, using biocompatible membranes, and using ultrapure water
    • Single Center Randomized CONVINT Trial of Intermittent vs Continuous Hemodialysis in AKI in Critically Ill Patients (Crit Care, 2014)
      • No Difference in Mortality Rate or Renal-Related Outcomes Between Intermittent and Continuous Hemodialysis

Timing of Initiation of Renal Replacement Therapy

  • Clinical Efficacy
    • AKIKI Trial Studying Early vs Delayed Renal Replacement Therapy for AKI in the ICU (NEJM, 2016) [MEDLINE]: multicenter randomized trial
      • No Difference in Mortality Between Early Initiation vs Delayed Initiation of Renal Replacement Therapy
    • ELAIN Trial of Early vs Delayed Renal Replacement Therapy for AKI in the ICU (JAMA, 2016) [MEDLINE]: single-center German randomized trial
      • Early Initiation of Renal Replacement Therapy in Critically Ill Patients Decreased the 90-Day Mortality Rate, as Compared to Delayed Initiation
      • More Patients in the Early Group Recovered Renal Function by 90 Days
      • Early Initiation Decreased the Duration of Renal Replacement Therapy and Hospital Length of Stay
      • Early Initiation Had No Effect on Requirement for Renal Replacement Therapy After 90 Days, Organ Dysfunction, and Length of ICU Stay
  • Recommendations
    • Timing of Initiation of Renal Replacement Therapy in Critically Ill Patients Remains Unclear: standard clinical indications should be used to determine the timing of initiation of hemodialysis in critically ill patients

Adverse Effects/Complications of Hemodialysis

Cardiovascular Adverse Effects/Complications

  • Arrhythmias
  • Hypotension (see Hypotension, [[Hypotension]])

Gastrointestinal Complications

  • Colonic Ischemia (Ischemic Colitis) (see Colonic Ischemia, [[Colonic Ischemia]]): due to underlying atherosclerosis, diabetes, and hemodialysis-induced hypotension
    • Usually non-occlusive

Pulmonary Adverse Effects/Complications

Air Embolism (see Air Embolism, [[Air Embolism]])

  • xxx

Hemodialysis-Associated Hypoxemia (see Hypoxemia, [[Hypoxemia]])

  • Physiology
    • Complement Activation by Bioincompatible Dialysis Membrane (Cuprophane): results in WBC aggregation within pulmonary microcirculation -> V/Q mismatch
    • Hypocapnia-Induced Hypoventilation: when acetate dialysate is used, there is net loss of bicarbonate from patient across dialyzer and also a flux of acetate into patient (decreasing respiratory quotient)
    • Induced Metabolic Alkalosis: use of dialysates with bicarbonate >37 mEq/L causes alkalemia -> decreases central respiratory drive
      • Not seen as much with dialysate bicarbonate <35 though
  • Prevention
    • Use Biocompatible Membranes: such as polyacrylonitrile/polysulfone/polymethyl methacrylate
      • Note: use of bioincompatible membranes may also prolong the course of AKI
    • Decrease Dialysate Bicarbonate to <35 mEq/L
    • Avoid Acetate-Based Dialysate: it also depresses myocardium and may increase hemodynamic instability

Other Adverse Effects/Complications

  • xxxxx
  • xxxxx
  • xxxxx

References

  • Hemodialysis-associated hypoxemia. Am J Nephrol. 1984;4(5):273-9 [MEDLINE]
  • Hemodialysis associated hypoxia extends into the post-dialysis period. Int J Artif Organs. 1997 Apr;20(4):204-7 [MEDLINE]
  • Hemodynamic tolerance of intermittent hemodialysis in critically ill patients. Usefulness of practice guidelines. Am J Respir Crit Care Med 2000, 162:197-202 [MEDLINE]
  • Continuous venovenous haemodiafiltration versus intermittent haemodialysis for acute renal failure in patients with multiple-organ dysfunction syndrome: a multicentre randomised trial. Lancet. 2006;368:379–385 [MEDLINE]
  • 84-year-old woman with hemodialysis-associated shortness of breath. Mayo Clin Proc. 2009 Feb;84(2):187-90; quiz 187-9. doi: 10.1016/S0025-6196(11)60827-6 [MEDLINE]
  • Clinical review: use of renal replacement therapies in special groups of ICU patients. Crit Care. 2012;16:201 [MEDLINE]
  • Temporary hemodialysis catheters: recent advances. Kidney Int. 2014 Nov;86(5):888-95. doi: 10.1038/ki.2014.162. Epub 2014 May 7 [MEDLINE]
  • The effect of continuous versus intermittent renal replacement therapy on the outcome of critically ill patients with acute renal failure (CONVINT): a prospective randomized controlled trial. Crit Care. 2014;18(1):R11. doi: 10.1186/cc13188 [MEDLINE]
  • Safety and efficacy of regional citrate anticoagulation in continuous venovenous hemodialysis in the presence of liver failure: the Liver Citrate Anticoagulation Threshold (L-CAT) observational study. Crit Care. 2015 Sep 29;19:349. doi: 10.1186/s13054-015-1066-7 [MEDLINE]
  • AKIKI Trial. Initiation Strategies for Renal-Replacement Therapy in the Intensive Care Unit. N Engl J Med. 2016 Jul 14;375(2):122-33. doi: 10.1056/NEJMoa1603017. Epub 2016 May 15 [MEDLINE]
  • ELAIN Trial. Effect of Early vs Delayed Initiation of Renal Replacement Therapy on Mortality in Critically Ill Patients With Acute Kidney Injury: The ELAIN Randomized Clinical Trial. JAMA. 2016;315(20):2190 [MEDLINE]