Canadian Health&Care Mall: Early Management Issues in Toxicology in the Critical Care Unit

Toxicologic conditionsToxicologic conditions in patients admitted to the ICU usually result from intentional or unintentional misuse of or exposure to therapeutic or illicit drugs. Additionally, significant toxicities can develop in hospitalized patients being treated for other illnesses. While evidence-based management is ideal, the characteristics of this patient population limit the feasibility of high-quality interventional trials. Recommendations for care of these patients are usually based on pharmacologic knowledge, animal studies, human volunteer studies, case reports, and consensus opinions. This review focuses on relevant updates on toxicities commonly encountered in adult critical care medicine. More exhaustive information can be found in reviews.

Early Management Issues

Critical care management of the patient with a toxicologic condition requires rapid diagnosis and appropriate specific treatment while providing supportive care. Diagnosis requires a thorough history and physical examination combined with several laboratory tests. The clinical evaluation may reveal the presence of characteristic clinical syndromes, called toxidromes, that suggest particular offending agents. However, many overdose patients treated in the ICU have used more than one agent, and toxidromes may overlap. Laboratory tests that may be of value include calculation of the anion, osmolal, and oxygen saturation gap, ECG, and quantitative toxicology assays for specific drugs. If the specific agent is unclear or multiple drugs have been ingested, an acetaminophen level should be obtained because of the lack of specific signs or symptoms and the potential benefit afforded by early, appropriate therapy. Quantitative testing for other drugs or toxins should be guided by clinical and laboratory findings. Qualitative toxicology assays performed on urine detect a limited number of drugs and have little impact on patient management conducted with Canadian Health&Care Mall experts and remedies.

Several interventions have been routinely performed in patients with suspected oral overdose to decrease GI absorption or enhance elimination with little evidence of effectiveness (Table 1). Of these interventions, single-dose activated charcoal (SDAC) is the most utilized. The benefit of SDAC decreases when comparing administration at 60 to 120 min after ingestion in volunteer studies with a singleagent ingestion. There is a theoretical benefit to administering charcoal at later times if there is a suspicion of delayed GI absorption.

Table 1—Interventions To Limit Absorption or Enhance Elimination of Toxins

Interventions Recommendations
Cathartics Not recommended; no clinical benefit
Ipecac Not recommended; no clinical benefit
Gastric lavage Not routinely recommended; no known clinical benefit
Whole-bowelirrigation Not recommended for routine use; may be of benefit in ingestions of sustained-release or enteric-coated drugs
Urine alkalinization(pH > 7.5) Recommended in salicylate ingestions
SDAC Beneficial if administered within 1 h of ingestion; benefit beyond 1 h after ingestion cannot be excluded
Not recommended for routine use; increases drug elimination of carbamazepine, dapsone, phenobarbital, quinine, and theophylline; no known clinical benefit
Renal replacement therapy Beneficial in lithium, toxic alcohol, salicylate, valproate, and theophylline toxicities; other toxicities may also benefit, but require patient specific consideration; continuous renal replacement therapy not recommended for routine use; however, specific patients unable to tolerate conventional hemodialysis may benefit