Enhancing the elimination of a xenobiotic from a poisoned patient is a logical step after techniques to inhibit absorption such as orogastric lavage, activated charcoal, or whole-bowel irrigation have been considered. Table 9–1 lists methods that might be used to enhance elimination. Some of these techniques are described in more detail in chapters that deal with specific xenobiotics. In this chapter, hemodialysis, hemoperfusion, and hemofiltration are considered extracorporeal therapies because xenobiotic removal occurs in a blood circuit outside the body. Currently these methods are used infrequently as intensive supportive care because most poisonings are not amenable to removal by these methods. Because these elimination techniques have associated adverse effects and complications, they are indicated in only a relatively small proportion of patients.
Table 9–1. Potential Methods of Enhancing Elimination of Xenobiotics |Favorite Table|Download (.pdf)
Table 9–1. Potential Methods of Enhancing Elimination of Xenobiotics
|Cerebrospinal fluid drainage and replacement|
|Sodium polystyrene sulfonate (Kayexalate)|
|Manipulation of urinary pH|
|Multiple-dose activated charcoal|
|Sorbent hemoperfusion (charcoal, others)|
|Xenobiotic-specific antibody fragments|
Although undoubtedly an underestimate of true use, enhancement of elimination was used relatively infrequently in a cohort of more than 2.4 million patients reported by the American Association of Poison Control Centers (AAPCC) National Poison Data System (NPDS) in 2007 (Chap. 135)31. Alkalinization of the urine was reportedly used 9430 times, MDAC 3114 times, hemodialysis 2106 times, hemoperfusion 16 times, and "other extracorporeal procedures" (most likely continuous venovenous hemofiltration [CVVH]) 24 times. As in the past, there continue to be many instances of the use of extracorporeal therapies that are considered inappropriate, such as in the treatment of overdoses of cyclic antidepressants (CAs) or acetaminophen.31
Although data reporting remains important in comparing the most recent data with past reports (Table 9–2), there is a continued increase in the reported use of hemodialysis, paralleling a decline in reports of charcoal hemoperfusion (Chap. 135). Lithium and ethylene glycol were the most common xenobiotics for which hemodialysis was used between 1985 and 2005.
Table 9–2. Changes in Use of Extracorporeal Therapiesa |Favorite Table|Download (.pdf)
Table 9–2. Changes in Use of Extracorporeal Therapiesa
|Other extracorporeal: CVVH, CVVHD, etc||26||33||24|
Possible reasons for the decline in use of charcoal hemoperfusion are described in the Charcoal Hemoperfusion section below. Various resins and other sorbents once used for hemoperfusion are not currently available in the United States. Peritoneal dialysis (PD), a slower modality that should have little ...