As a Hospital Corpsman, you may encounter patients as the result of poisoning, drug overdose, or exposure to hazardous materials. Such patients may initially present with no symptoms or with varying degrees of overt intoxication. The asymptomatic patient may have been exposed to or ingested a lethal dose of a substance but not exhibit any manifestations of toxicity. A patient with mild symptoms may deteriorate rapidly, so observe them closely. Potentially significant exposures should be observed in an acute care facility whenever possible. Remember, though: We are not always in a hospital environment, and we must be prepared to deal with each situation when and wherever it should present itself.

In this chapter, we will discuss the assessment and treatment for ingested, inhaled, absorbed, and injected poisons. Drug abuse assessment and treatment procedures, patient handling techniques, and the recognition of hazardous material (HAZMAT) personal safety guidelines and information sources will also be covered. The last part of the chapter will cover rescue, patient care, and decontamination procedures for patients exposed to HAZMAT.

NOTE: Prior to deployments and operational commitments, commands are strongly recommended to contact the area
Environmental Preventive Medicine Unit
(EPMU) for current, specific, medical intelligence, and surveillance data. With this information at hand, the local preventive medicine authority can identify, prevent, and treat conditions not common to the homeport area. The cognizant EPMU will provide data through MEDIC, (Medical, Environmental, Diagnosis, Intelligence and Counter- measure). Formally called a Disease Risk Assessment Profile (DISRAP), MEDIC is a comprehensive, constantly updated management tool. MEDIC is an invaluable aid for identifying at-risk communicable diseases, immunization requirements, and- as applies especially to this chapter-local pests and environmental dangers.

POISONING
LEARNING OBJECTIVE: Recall assessment and treatment procedures for ingested, inhaled, absorbed, and injected poisons

Apoison is a substance that, when introduced into the body, produces a harmful effect on normal body structures or functions. Poisons come in solid, liquid, and gaseous forms, and they may be ingested, inhaled, absorbed, or injected into the system.

Every chemical in a sufficient dose can cause toxic effects in a human-or in any organism. The amount or concentration of a chemical and the duration of exposure to it are what determine the chemical's dose and toxicity. A16 th century quotation from Paracelsus states, "Dose alone makes a poison. . . .All substances are poisons, there is none which is not a poison. The right dose differentiates a poison and a remedy. "

A poisoning is defined as the presence of signs or symptoms associated with exposure or contact with a substance. If there are no clinical manifestations or toxic effects, the incident is simply an "exposure" or a contact with a potentially poisonous substance. Just being exposed to a chemical does not mean that a poisoning has or will occur. It is a matter of dose and a few other variables (e.g., age, sex, individual resistance, or state of health) that determine if, or what, toxic effects will occur.

ASSESSMENT AND TREATMENT OF PATIENT

In most cases, ASSESSMENT AND TREATMENT OF THE PATIENT IS MORE IMPORTANT THAN EFFORT TO IDENTIFY AND TREAT A SPECIFIC POISON. Supportive therapy-managing the ABCs (Airway, Breathing, and Circulation) of basic life support and treating the signs and symptoms-is safe and effective in the vast majority of poisonings. Extraordinary means to enhance elimination of the poison (hemodialysis and hemoperfusion) are seldom needed. Except for agents with a delayed onset of toxicity (such as acetaminophen), most ingested poisons produce signs and symptoms in less than 4 hours, and most efforts to decontaminate the gut (remove an ingested poison) have little value more than 1 hour after ingestion.

In acute poisonings, prompt treatment is indicated. After the patient has been evaluated and stabilized, general poison management can be initiated. There are six steps in the initial evaluation and follow-on poison management:

1. Stabilization, which consists of a brief evaluation and assessment directed toward identifying the measures required to maintain life and prevent further deterioration of the patient.

Observe the ABC+ D & E(Drug-induced central nervous system (CNS) depression, and undressing/uncovering to Expose the patient for disabilities (injuries) to ensure areas of contact or exposure to a chemical can be seen.)

Check the pupils for size and reactivity to light, and do a basic neurologic exam.

Administer oxygen as needed, IV line for fluids.
Watch for signs and symptoms of anaphylaxis. 2. Evaluation, which must be performed once the patient is stabilized.

Include a full history, physical exam, and ordering of appropriate tests (i.e., labs, EKG, x-rays) directed toward identification of toxic agent, evaluating the severity of toxic effects, and searching for trauma and complications.

Periodically reassess the patient. Look for changes. Monitor vital signs, urine output, and cardiac rhythm.
Record your findings (including time), and respond to important changes appropriately.

3. Prevention or limitation of absorption, through skin decontamination, flushing of eyes, ventilation, stomach emptying, administration of charcoal and cathartics, and whole bowel irrigation.

4. Elimination enhancement, through serially administered activated charcoal, ion-trapping (pH adjustment of the urine to promote excretion of certain poisons), hemodialysis, and hemoperfusion (similar to hemodialysis, but used for larger size molecules).

5. Administration of specific antidotes. Less than 5 percent of poisons have specific antidotes. All patients who present should receive glucose, thiamine, and naloxone. Consider supplemental oxygen.

6. Continuing care and disposition, including a period of observation and education (i.e., poison prevention) or psychiatric counseling. Establish follow-up.