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Haemodialysis to increase elimination has been greatly overused in poisoning and recommended by some authors on the basis that some drug was removed by this process or that the patient survived (ridiculous for all but universally fatal conditions and particularly so for poisoning, which has an in-hospital mortality of less than 1% and an ICU mortality of less than 5%). Renal failure developing as a consequence of poisoning is usually treated as acute renal failure in a conventional manner and will not be discussed.
Poisons must have the following characteristics for there to be any possible significant increase in clearance from haemodialysis:
- Low molecular weight (< 500 Daltons)
- Highly water soluble
- Low volume of distribution (< 1 L/kg)
- Low protein binding
In addition, the toxic effects of the poisons should be serious, related to the plasma concentration, and not treatable easily by less invasive means.
These restrictions mean that the number of poisons where haemodialysis is indicated are few and generally limited to only selected patient with these poisonings. These poisons (linked to their indications) are listed below:
Serious adverse effects directly due to haemodialysis are unusual if performed by staff familiar with the procedure. The most frequent significant adverse effect is hypotension and extra care should be taken with monitoring volume depletion as the fluid requirements of these patients are liable to change far more rapidly than those of the usual patient with renal failure. Simultaneous monitoring of central venous pressure is advisable in some circumstances.