The first principle in the management of the poisoned patient is to treat the patient, not the poison. Airway, breathing, and circulation are assessed and addressed initially, along with any other immediately life-threatening toxic effect (for example, profound increases or decreases in blood pressure, heart rate, breathing, or body temperature, or any dangerous dysrhythmias).
Acid/base and electrolyte disturbances, along with an acetaminophen and salicylate blood level, can be further assessed as laboratory results are obtained. After administering oxygen, obtaining intravenous access, and placing the patient on a cardiac monitor, the poisoned patient with altered mental status should be considered for administration of the “coma cocktail” as possibly diagnostic and therapeutic.
The “coma cocktail” consists of intravenous dextrose to treat hypoglycemia, a possible toxicological cause of altered mental status, along with naloxone to treat possible opioid or clonidine toxicity, and thiamine for ethanol-induced Wernicke encephalopathy. [Note: Hypoglycemia may be caused by oral hypoglycemics, insulin, ackee plant, and ethanol.]
Once the patient is stabilized, the assessment for decontamination can occur. This may include flushing of the eyes with saline or tepid water to a neutral pH for ocular exposures, rinsing of the skin for dermal exposures, as well as administration of gastrointestinal (GI) decontamination with gastric lavage, activated charcoal, or whole bowel irrigation (utilizing a polyethylene glycol electrolyte balanced solution) for selected ingestions. Several substances do not adsorb to activated charcoal (for example, lead and other heavy metals, iron, lithium, potassium, and alcohols), limiting the use of activated charcoal unless there are co-ingested products.
The elimination of some medications/toxins may be enhanced by hemodialysis if certain properties are met: low protein binding, small volume of distribution, small molecular weight, and water solubility of the toxin. Some examples of medications or substances that can be removed with hemodialysis include methanol, ethylene glycol, salicylates, theophylline, phenobarbital, and lithium.
Alkalinization of the urine enhances the elimination of salicylates or phenobarbital. Increasing the urine pH with intravenous sodium bicarbonate transforms the drug into an ionized form that prevents reabsorption, thereby trapping it in the urine to be eliminated by the kidney. The goal urine pH is within the range of 7.5 to 8, while ensuring that the serum pH does not exceed 7.55.
Multiple-dose activated charcoal
Multiple-dose activated charcoal therapy enhances the elimination of certain drugs (for example, theophylline, phenobarbital, digoxin, carbamazepine, valproic acid) by creating a gradient across the lumen of the gut. Medications traverse from areas of high concentration to low concentration, promoting medication already absorbed to cross back into the gut to be adsorbed by the activated charcoal present.
In addition, activated charcoal blocks the reabsorption of medications that undergo entero hepatic recirculation (such as phenytoin), by adsorbing the substance to the activated charcoal. Bowel sounds must be present prior to each activated charcoal dose to ensure movement of the GI tract and prevent obstruction.