4: Principles of Managing the Acutely Poisoned or Overdosed Patient

OVERVIEW

For over 5 decades, medical toxicologists and poison information specialists have used a clinical approach to poisoned or overdosed patients that emphasizes treating the patient rather than treating the poison.¹ Too often in the past, patients were initially all but neglected while attention was focused on the ingredients listed on the containers of the product(s) to which they presumably were exposed. Although the astute clinician must always be prepared to administer a specific antidote immediately in instances when nothing else will save a patient, such as cyanide poisoning, all poisoned or overdosed patients will benefit from an organized, rapid clinical management plan (Fig. 4–1).

Over the past 4 decades, some basic tenets and long-held beliefs regarding the initial therapeutic interventions in toxicologic management have been questioned and subjected to an “evidence-based” analysis. For example, in the mid-1970s, most medical toxicologists began to advocate a standardized approach to a comatose and possibly overdosed adult patient, typically calling for the intravenous (IV) administration of 50 mL of ­dextrose 50% in water (D₅₀W), 100 mg of thiamine, and 2 mg of naloxone along with 100% oxygen at high flow rates. The rationale for this approach was to compensate for the previously idiosyncratic style of overdose management encountered in different health care settings and for the unfortunate likelihood that omitting any one of these measures at the time that care was initiated in the emergency department (ED) would result in omitting it altogether. It was not unusual then to discover from a laboratory chemistry report more than one hour after a supposedly overdosed comatose patient had arrived in the ED that the initial blood glucose was 30 or 40 mg/dL—a critical delay in the management of unsuspected and consequently untreated hypoglycemic coma. Today, however, with the widespread availability of accurate rapid bedside testing for capillary glucose, pulse oximetry for ­oxygen saturation, and end-tidal CO₂ monitors coupled with a much greater appreciation by all physicians of what needs to be done for each suspected overdose patient, clinicians can safely provide a more rational, individualized approach to determine the need for, and in some instances more precise amounts of, dextrose, thiamine, naloxone, and oxygen.

A second major approach to providing more rational individualized early treatment for toxicologic emergencies involves a closer examination of the actual risks and benefits of various gastrointestinal (GI) emptying interventions. Appreciation of the potential for significant adverse effects associated ...