Chapter 47. Poisoning

Victims of Poisoning with Coma, Seizures, or Marked Obtundation

Keep Airway Open

Establish and maintain an adequate airway and ventilation. Begin supplemental oxygen, 12 L/min, by nonrebreathing mask. If the patient has no gag reflex, intubate for airway protection, to facilitate oxygenation and to remove airway secretions. Continuously monitor oxygen saturation.

Obtain Arterial Blood Gas and pH Measurements

Obtain arterial blood for blood gas and pH measurements to determine adequacy of ventilation and perfusion.

Gain Intravenous Access

Insert a large-bore (≥18-gauge) peripheral or central intravenous catheter, and draw blood for complete blood count, serum electrolyte and blood glucose measurements, and tests of renal and hepatic function.

Treat Coma Promptly

Give glucose, 50 mL of a 50% solution (25 g of glucose) intravenously over 3–4 minutes, if a normal blood glucose cannot be determined immediately. If the patient's response is weak or if narcotic overdose is suspected, as indicated by pinpoint pupils and shallow respirations, give repeated doses of naloxone 2 mg every 1–2 minutes up to a total dosage of 10–20 mg. Note: The duration of action of naloxone (2–3 hours) is shorter than that of many of the narcotics it reverses. Patients responding to naloxone must be observed for at least 3 hours after the last dose.

If alcoholism or malnutrition is suspected, give thiamine, 100 mg intramuscularly or in intravenous solution with or prior to glucose administration.

Maintain Circulation

Maintain circulation, and treat shock by restoring intravascular volume with intravenous infusion of crystal-loid solutions. Caution: Fluid overload and pulmonary edema may occur with overly vigorous hydration. Some medications (salicylates) put patients at higher risk for pulmonary edema. If administration of more than 20–30 mL/kg of crystalloid solution and usual doses of dopamine (ie, 5–15 μg/kg/min intravenously) fail to restore blood pressure, insert a central venous catheter and arterial pressure catheter to obtain pressure readings and help guide further therapy with fluids or pressor agents.

Treat Seizures

If the patient is experiencing seizures, give diazepam, 0.1–0.2 mg/kg, or lorazepam, 0.05 mg/kg, intravenously. If this is not effective, within a few minutes, repeat the dose. If the seizures continue, administer phenobarbital, 20 mg/kg, intravenously over 20 minutes. Phenytoin is ineffective for stopping seizures caused by most poisonings.

Start Electrocardiographic Monitoring

Start cardiac monitoring. Obtain a 12-lead electrocardiogram (ECG) and note especially the rate; rhythm; presence of arrhythmias; and PR, QRS, and QT intervals. If overdose of tricyclic antidepressants is suspected, obtain serial ECGs.

Perform Gastric Decontamination

Place a nasogastric or orogastric tube for the administration of activated charcoal. Activated charcoal may be premixed with a 70% ...