Extracorporeal Removal of Poisons and Toxins

Abstract

Extracorporeal therapies have been used to remove toxins from the body for over 50 years and have a greater role than ever before in the treatment of poisonings. Improvements in technology have resulted in increased efficacy of removing drugs and other toxins with hemodialysis, and newer extracorporeal therapy modalities have expanded the role of extracorporeal supportive care of poisoned patients. However, despite these changes, for at least the past three decades the most frequently dialyzed poisons remain salicylates, toxic alcohols, and lithium; in addition, the extracorporeal treatment of choice for therapeutic removal of nearly all poisonings remains intermittent hemodialysis. For the clinician, consideration of extracorporeal therapy in the treatment of a poisoning depends upon the characteristics of toxins amenable to extracorporeal removal (e.g., molecular mass, volume of distribution, protein binding), choice of extracorporeal treatment modality for a given poisoning, and when the benefit of the procedure justifies additive risk. Given the relative rarity of poisonings treated with extracorporeal therapies, the level of evidence for extracorporeal treatment of poisoning is not robust; however, extracorporeal treatment of a number of individual toxins have been systematically reviewed within the current decade by the Extracorporeal Treatment in Poisoning workgroup, which has published treatment recommendations with an improved evidence base. Some of these recommendations are discussed, as well as management of a small number of relevant poisonings where extracorporeal therapy use may be considered.

Keywords: toxicology; extracorporeal therapies; hemodialysis; poisoning; intoxication; acidosis; therapeutic plasma exchange; toxic alcohols; lithium; salicylates; Poisons; Toxins, Biological; hemoperfusion.

Figure 1.

Removal of toxins via HD decreases with greater degrees of protein binding. Comparison of removal of three uremic toxins (p-cresyl glucuronide, 13% protein-bound; indole 3-acetic acid, 73% protein-bound; and p-cresyl sulfate, 95% protein-bound) during a single HD session averaged over ten patients. Blood flow rates were 300 ml/min, dialysate flow rates were 700 ml/min, and dialyzer urea clearances varied. Modified from reference , with permission.

Figure 2.

Toxic alcohol metabolic pathways with mechanisms of toxicity of parent compounds and metabolites. Parent compounds and metabolites causing toxic effects (detailed at bottom of figure) are represented in red font. ADH, alcohol dehydrogenase; ALDH, aldehyde dehydrogenase; α2AR, α-2 adrenergic receptor; CNS, central nervous system; LDH, lactate dehydrogenase.