In an overdose, treat the patient, not the poison
When you treat an overdose patient, focus on symptoms instead of substances, recommends Steve Weinman, RN, BSN, CEN, emergency department instructor at New York Weill Cornell Medical Center at New York (City) Presbyterian Hospital.
Treating the patient instead of the poison is one of the most basic rules of toxicology, but it’s often overlooked, notes Weinman.
"The small percentage of drug overdoses that do display symptoms of toxicity are often treated based on the symptoms they display," he stresses. "Basic treatment typically is geared toward measures that decreased drug absorption." (See protocol for management plan for poisoned patients, pp. 81-84.)
There are very few poisonings/overdoses that have antidotes, says Diana Meyer, RN, MSN, CCNS, CCRN, CEN, clinical nurse specialist for emergency services at Presbyterian Intercommunity Hospital in Whittier, CA.
"The care is supportive and specific to the symptoms," Meyer explains. "There are literally thousands of products that can poison us, and only about 20 of those appear on a routine toxicology screen."
Here are some recent updates for management of overdose patients:
• Protect yourself from exposure.
When the poison suspected is an organophosphate, cyanide, or carbamate insecticide, take precautions to protect yourself from exposure while caring for the patient, Meyer cautions.
• Know which patients should be admitted.
Overdose patients should be admitted when airway, breathing, circulation and disability continue to be problems, when antidote treatment will take several hours (such as in Tylenol overdose), or when sequelae may be expected because of the type of poison, says Meyer.
Typically, most overdose patients are observed in the ED for four to six hours, says Weinman.
"The vast majority of overdose patients will display some degree of symptomatology within this time frame," he says.
Patients who have ingested a toxic or lethal dose of a drug, display moderate to severe symptomatology, or are judged to be a threat to themselves or others should be admitted, says Weinman. "This is typically a minority of the patients."
• Use toxidromes.
Toxidromes are groups of symptoms that help narrow the choices of agent to a class of poisons, such as opiates, stimulants, cholinergics, and anticholinergics, says Meyer. "Using these can help you fine-tune your treatment of patients."
For example, symptoms of the anticholinergic toxidrome include tachycardia, hyperthermia, psychosis, flushed dry skin, mydriasis, and decreased bowel sounds, says Linda Courtemanche, RN, CSPI, director of the New Hampshire Poison Information Center in Lebanon.
• Read up on current literature.
Nurses should keep abreast of the current toxicology research on modalities of treatment, drugs, and treatment modalities that have not proven to benefit the patient and might even be deleterious, Weinman advises. (See Recommended Reading, p. 85.)
Herbals have side effects
• Ask about herbal supplements.
When taking the history of an overdose patient, don’t forget to ask about herbs or supplements the patient is taking, Courtemanche advises. "Drug interactions can occur, and certain herbal drugs are known to have certain side effects or adverse reactions."
• Know what your hospital lab includes in a toxicology screen.
"If they are not looking for amphetamines, they will not show up as positive in the screen," Courtemanche notes.
• Evaluate the patient’s suicide risk.
Statistically, 7%-10% of overdoses are suicidal gestures, but this is believed to be under-reported, says Weinman.1
These patients need to be medically evaluated for stability, treated as indicated, then referred for psychiatric evaluation prior to discharge from the ED, he advises. Suicidal patients need to be monitored closely, and often they are placed on one-to-one observation to ensure they do not elope until medically cleared and evaluated by a psychiatrist or other appropriate mental health professional, Weinman adds.
Obtain an acetaminophen concentration on all suicidal patients, regardless of other substances involved, notes Courtemanche. "Draw a level when the patient arrives."
Sustained release requires two levels: One at four hours after ingestion and again at eight hours, Courtemanche says. "If either is toxic according to the nomogram, the patient should be treated accordingly."
Over half of suicidal patients’ histories are incorrect, notes Courtemanche. Take what the patient says as "stated history" and try to prove the facts, she advises. Determine: When was the prescription filled? How many pills were used? How many are left? "Realize that even then, the patient may have gone to two pharmacies, and you still may not have the facts."
Reference
1. Litovitz TL, Smilkstein M, Felberg L, et al. 1996 Annual report of the American Association of Poison Control Centers toxic exposure surveillance system. Am J Emerg Med 1997; 15:447-500.
For more information about approaches to overdose patients, contact:
• Steve Weinman, RN, BSN, CEN, Emergency Department, New York Weill Cornell Medical Center, New York Presbyterian Hospital, 525 E. 68th St., Box 174, New York, NY 10021. Telephone: (212) 746-2914. Fax: (212) 746-1490. E-mail: [email protected].
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