Haemoperfusion

OVERVIEW

Renal replacement therapy (RRT) using an adsorbent cartridge to remove circulating toxins

USE

Hemoperfusion may be considered for agents with high volumes of distribution if:

• agent is not cleared by liver or kidneys, or clearance is impaired by organ failure
• agent is not removed by dialysis or hemofiltration
• agent causes significant illness

Indications are controversial

• Toxicology: anti-epileptic drugs (e.g. carbamazepine, valproate, phenytoin, barbiturates), theophyline
• renal failure with aluminum intoxication

Many other agents bind hemoperfusion cartridges in vitro and in animal models but clinical utility is not established. Similarly, for endotoxin, superantigens and harmful cytokines.

DESCRIPTION

• RRT with an adsorbent charcoal cartridge or an ion exchange resin (e.g. XAD 4 amberlite)
• Charcoal hemoperfusion results in irreversible binding
• resin hemoperfusion reversibly binds toxins via hydrogen bonds and Van Der Waal’s forces
• charcoal is coated with an ultrathin film to prevent hypersensitivty reactions and charcoal embolisation (major problems with early hemoperfusion cartridges)

METHOD OF USE

• blood flow rate typically 150-300 mL/min
• standard CVVH circuit with an adsorbant cartridge instead of a semi-permeable filter
• requires anticoagulation (may need high doses of heparin due to adsorption)
• cartridge is primed (usually 2-3L saline or dextrose solution depending on the model)
• The hemoperfusion cartridge usually gets saturated and requires replacement after 3-4 h

OTHER INFORMATION

• Molecular weight, protein binding and lipid solubility do not significantly influence hemoperfusion
• selective sorbents have been developed (e.g. using ligands specific for agents such as endotoxin)

COMPLICATIONS

Venous access complications

• see central line / vascath

Complications due to exposure to charcoal filter (bioactivation and mechanical effects)

• Thrombocytopenia (30%)
• Leucopenia (10%)
• Hemolysis
• Hypocalcemia
• Hypoglycemia
• Coagulopathy (e.g. low fibrinogen)
• Hypothermia
• sorbent embolisation (major issue with early uncoated cartridges)

Complications of anticoagulation

References and Links

LITFL

• CCC — Enhanced Elimination
• CCC — Activated charcoal

FOAM and web resources

• DerangedPhysiology.com
  —  Indications for hemoperfusion
  —  Complications of hemoperfusion
  —  Hemoperfusion: The hemoperfusion circuit
  —  Selectivity of sorbents and efficiency of adsorption