THE POISONED OR OVERDOSED PATIENT

1. THE POISONED OR OVERDOSED PATIENT • Poisonings and drug overdoses can cause quick physical and mental changes in a person. • Bystanders usually are the ones who must initiate care and call a poison control center or emergency number. • Commonly observed poisonings or drug overdoses are caused by (but certainly not limited to) acetaminophen, amphetamines, benzodiazepines, carbon monoxide, cocaine, opiates, salicylates, and tricyclic antidepressants.

2. Poisoning • The most common routes of exposure in poisoning are inhalation, ingestion, and injection. • Toxic chemical reactions compromise cardiovascular, respiratory, central nervous, hepatic, gastrointestinal (GI), and renal systems. • Most exposures to toxic fumes أبخرة occur in the home. • Poisoning may result from the improper mixing of household cleaning products or malfunctioning household appliances that release carbon monoxide. • Burning wood, gas, oil, coal, or kerosene also produces carbon monoxide. • Carbon monoxide gas is colorless, odorless, tasteless, and nonirritating, which makes it especially dangerous.

3. The ingestion of poisons and toxins occurs in various settings and in different age groups. • Poisoning in the home usually occurs when children ingest household cleaners or medicines. • Improper storage of these items contributes to such accidents. • Plants, pesticides, and paint products are also potential household poisons. • Because of mental or visual impairment, illiteracy, or a language barrier, older adults may ingest incorrect amounts of medications. • In addition, poisoning may occur in the health care environment when medications are administered improperly.

4. Similarly, poisoning can also occur in the health care environment when a medication normally given only by the subcutaneous or intramuscular route is given intravenously, or when the incorrect medication is injected. • Poisoning by injection can also occur in the setting of substance abuse, as when a heroin addict inadvertently (without knowledge or intention) injects bleach (usually chlorine, used to whiten pulp) or too much heroin.

5. Substance Abuse and Overdose • Admission of most poisoned patients to a critical care unit is for an intentional or suspected suicidal overdose. • As part of their histories, these patients frequently have mental illness, substance abuse problems, or both. • Often, withdrawal symptoms and syndromes complicate the assessment of potential toxidromes. • A toxidrome is a group of signs and symptoms (syndrome) associated with overdose or exposure to a particular category of drugs and toxins.

6. Commonly abused substances are nicotine, alcohol, heroin, marijuana, narcotic analgesics, amphetamines, benzodiazepines, and cocaine. • Some children and adolescents turn to common household substances because they are readily available. • People who attempt to manage stress through substance abuse require a comprehensive treatment program to address their coping and adaptation problems.

7. ASSESSMENT • A health care facility’s systematic approach to the assessment of the poisoned or overdosed patient includes performing triage, obtaining the patient’s history, performing a physical examination, and conducting laboratory studies.

8. Triage (A process for sorting injured people into groups based on their need for or likely benefit from immediate medical treatment). • Although some type of triage usually is performed at the scene or by an emergency response team, triage is always the first step performed in the emergency department.

9. Two essential questions to be considered in the triage evaluation are: 1. Is the patient’s life in immediate danger? 2. Is the patient’s life in potential danger? • If the patient’s life is in immediate danger, the goals of immediate treatment are patient stabilization and evaluation and management of airway, breathing, and circulation (ABCs).

10. History • A history of the patient’s exposure provides a framework for managing the poisoning or overdose. • Key points include identifying the drug(s) or toxin(s), the time and duration of the exposure, first aid treatment given before arrival at the hospital, allergies, and any underlying disease processes or related injuries. • This information may be obtained from the patient, family members, friends, rescuers, or bystanders. • In some cases, family or police may need to search the patient’s home for clues. • Clothing and personal effects may supply additional information.

11. Physical Examination • A quick but thorough physical examination is essential. • Preliminary examination results lead to the in-depth evaluation and serial assessment of affected systems (actual or anticipated). • As noted previously, a toxidrome is a group of signs and symptoms associated with overdose or exposure to a particular category of drugs and toxins. • Recognizing the presence of a toxidrome may help identify the toxin(s) or drug(s) to which the patent was exposed, and the crucial body systems that may be involved.

12. Laboratory Studies • Relevant clinical laboratory data are vital to the assessment of the poisoned or overdosed patient. • Tests that provide clues to the agent(s) taken by the patient include electrolytes, hepatic function, urinalysis, electrocardiography, and serum osmolality tests. • A serum level measurement of acetaminophen is obtained in all patients who have overdosed because acetaminophen is a component of many prescription and over-the-counter preparations.

13. In the event of an acetaminophen overdose, the result of the level is plotted against the time since ingestion on the Rumack-Matthew nomogram. • Serum level measurements are also available for carbamazepine, iron, ethanol, lithium, aspirin, and valproic acid and may be obtained if these agents are suspected in an overdose.

14. MANAGEMENT • Management of the poisoned or overdosed patient seeks to prevent absorption of and further exposure to the agent. • After triage to determine the status of the patient’s airway, breathing, and circulation, the patient must be stabilized. • Treatment begins with first aid at the scene and continues in the emergency department and often the intensive care unit (ICU). • Advanced general management involves further steps to prevent absorption and enhance elimination of the agent. • For instance, antidotes, antivenins(the treatment of venomous bites or stings) or antitoxins may be administered.

15. The health care team must further support vital functions and monitor and treat multisystem effects. • Patient and family teaching to prevent future exposures is another part of the nurse’s management strategy.

16. Examples of Nursing Diagnoses • and Collaborative Problems for the Poisoned • or Overdosed Patient

17. Examples of Nursing Diagnosesand Collaborative Problems for the Poisonedor Overdosed Patient ■ Ineffective Role Performance ■ Acidosis/Alkalosis, Risk for ■ Atelectasis ■ Hypoxemia ■ Dysrhythmias ■ Hypovolemia ■ Electrolyte Imbalances • Poisoning • ■ Ineffective Breathing Pattern • ■ Impaired Gas Exchange • ■ Ineffective Tissue Perfusion • ■ Fluid Volume Imbalance, Risk for • ■ Impaired Thought Processes • ■ Violence, Risk for (to self or others) • ■ Self-Esteem Disturbance • ■ Ineffective Individual/Family Coping • ■ Injury, Risk for

18. Stabilization • Stabilization of patients includes performing the steps summarized in Box 56-2, which are also discussed in the • following list: ■ Airway: Nasotracheal or endotracheal intubation may be necessary to adequately maintain and protec the patient’s airway. ■ Breathing: Mechanical ventilation may be necessary to support the patient. Many drugs and toxins, such as heroin, depress the respiratory drive. Patients therefore may require ventilator assistance until the drugs or toxins are eliminated from the body.

19. Circulation: Complications range from shock caused by fluid loss to fluid overload, and are often related to the patient’s hydration status and the ability of the cardiovascular system to adjust to drug- or toxin-induced changes. • For example, rattlesnake envenomations often cause third-spacing of fluid into the area of the bite, leading to intravascular hypovolemia. • As a consequence, the patient develops hypotension, which usually responds to aggressive intravenous (IV) fluid therapy. • Some toxic drug ingestions impair myocardial contractility, and fluid overload may result because of the heart’s inability to pump effectively.

20. In these cases, fluid balance needs to be carefully controlled. • Invasive monitoring (e.g., central venous pressure, pulmonary artery catheter, Foley catheter with urometer) and drug therapy may be necessary to prevent or minimize complications such as pulmonary edema

21. Cardiac function: Many drugs and toxins cause cardiac conduction delays and arrhythmias. • The history of the drug(s) or toxin(s) involved may not be reliable or even known, especially when patients are found unconscious or have attempted suicide

22. In these cases, continuous cardiac monitoring and 12-lead electrocardiograms help detect cardiotoxic effects. • ■ Acid–base balance and electrolyte homeostasis: Electrolyte abnormalities and metabolic acidosis frequently occur and may require serial measurements of electrolytes and arterial blood gases (ABGs), and other specific laboratory tests. • For example, serial measurements of electrolytes, ABGs, and salicylate levels are the means of evaluating aspirin toxicity. • Aspirin, in large ingestions, may form a solid mass in the gastrointestinal (GI) tract, called a concretion, instead of breaking apart and dissolving.

23. As a result, absorption is delayed, and the development of toxic effects, such as hypokalemia, metabolic acidosis, and respiratory alkalosis, may not be observed for several hours.

24. Mentation: Many factors can affect the patient’s mental status. • Hypoglycemia and hypoxemia are two that can be life-threatening but easily addressed by administering oxygen and IV dextrose until laboratory results are available. • Patients with chronic alcoholism also have a special risk called Wernicke-Korsakoff syndrome, which is characterized by ataxia and altered mentation.

25. Early IV or intramuscular administrationn of thiamine (vitamin B1) may prevent exacerbation of the syndrome. • Naloxone (Narcan) is a narcotic antagonist that reverses narcotic-induced central nervous system (CNS) and respiratory depression. • It is often initially given to comatose patients. • It must be given cautiously, however, because it can precipitate withdrawal in narcotic-dependent individuals, which may present as violent, agitated behavior, thus placing nurses and other health care providers in danger. • In the critical care unit it may be necessary to continue to administer boluses of naloxone to a patient because of its short duration of action compared with the duration of action of most opioids.

26. In such circumstances it may be necessary to give naloxone by continuous infusion. • Because it is often unclear why a patient is comatose, emergency response personnel may administer what is commonly referred to as a “coma cocktail,” consisting of D50, vitamin B1, and naloxone, at the scene. • These agents are well tolerated and have minimal toxicities. • Proceeding with this therapy at the scene addresses all three easily correctable possibilities (hypoglycemic, alcoholic, or narcotic coma) without wasting time waiting for laboratory results to become available.

27. Injuries associated with toxic exposure and underlying • disease processes: • Any injuries associated with toxic exposure and other underlying disease processe identified during the initial physical examination are treated or monitored, or both. • For example, the street drug phencyclidine (PCP) may provoke violent, agitated, bizarre behavior, leading to trauma during the acute toxic phase. • For instance, the patient with pre-existing ischemic heart disease may not be able to tolerate the hypoxemia associated with carbon monoxide poisoning as well as a young, healthy patient.

28. Vital signs and temperature: • The critical or potentially critical patient’s vital signs and temperature are measured frequently to track changes indicating additional problems.

29. Initial Decontamination • First aid may be given by a bystander, health care provider, or emergency response team, or in the emergency department. • The physicochemical properties of the agent and the amount, route, and exposure time help determine the type and extent of management required. • Decontamination methods for ocular, dermal, inhalation, and ingestion exposures follow.

30. OCULAR EXPOSURE • Many substances can accidentally splash into the eyes. • When this happens, the eyes must be flushed to remove the agent. • Immediate irrigation with lukewarm water or normal saline is recommended. • Continuous flooding of the eyes with a large glass of water or low-pressure shower should be done for 15 minutes. • The patient should blink the eyes open and closed during the irrigation. • If necessary, the pH of the eyes can be tested. If the pH is abnormal, irrigation should continue until the pH normalizes. • An ophthalmologic examination is needed when ocular irritation or visual disturbance persists after irrigation.

31. DERMAL EXPOSURE • When dermal exposure occurs, the patient should flood the skin with lukewarm water for 15 to 30 minutes. • Most companies that produce or use chemical agents have showers for this purpose. • The patient should remove any clothing that may have been contaminated. • After standing under running water for the allotted time الوقت المخصص, the patient should then wash the area gently with soap and water and rinse thoroughly.

32. Some toxins may require further decontamination. For example, three separate soap and water washings or showers are recommended to decontaminate organophosphate pesticides (e.g., Malathion or Diazinon). • Protective clothing should be worn to reduce the risk for toxicity while handling contaminated clothing or assisting with skin decontamination.

33. Although it may seem logical to apply an acid to neutralize a base exposure and a base to neutralize an acid exposure, this can be quite dangerous. • Neutralization is the reaction between an acid and a base, in which the H+ of the acid and the OH− of the base react to produce H2O (water) and heat. • The heat produced by this reaction is significant enough to cause burns. • Therefore, neutralizing the skin after a dermal exposure is not recommended.

34. INHALATION EXPOSURE • A victim of an inhalation exposure should be moved to fresh air as quickly as possible. • The responder must also protect himself or herself from the airborne toxin. • Further evaluation is needed if the patient experiences respiratory irritation or shortness of breath. • Large-scale exposures or those that occur at the workplace may require consultation with a HAZMAT team, a group of individuals specially trained to manage exposures to hazardous materials.

35. INGESTION EXPOSURE • Milk or water dilutes ingested irritants such as bleach or caustics such as drain cleaner. • After such an ingestion, adults should drink 8 oz of milk or water and children should drink 2 to 8 oz (based on their size). • Further evaluation is necessary after dilution if there is mucosal irritation or burns. • Because of the risk of aspiration, ingestions should not be diluted when they are accompanied by seizures, depressed mental status, or loss of the gag reflex. • Again, neutralization is not used because of the risk of thermal burn.

36. Gastrointestinal Decontamination • Gastric lavage, adsorbents *is the adhesion of molecules of gas, liquid, or dissolved solids to a surface.( الممتزات, cathartics, and whole-bowel irrigation are used to prevent absorption of, and forestall إحباط toxicity from, almost all drugs and a variety of toxins. • The American Academy of Pediatrics no longer recommends the use of emetics (such as syrup of ipecac) for GI decontamination.

37. GASTRIC LAVAGE • Gastric lavage is a method of GI decontamination. • Fluid (usually normal saline) is introduced into the stomach through a large-bore orogastric tube and then drained in an attempt to reclaim part of the ingested agent before it is absorbed. • A small-bore nasogastric tube is ineffective for lavage because particulate matter such as tablets or capsules are too large to pass through the tube. • If airway protection is necessary, the patient should be intubated before lavage begins.

38. As noted, a large-bore orogastric tube (a 36 to 40 French in adults and a 16 to 28 French in children) is used to evacuate particulate matter, including whole tablets and capsules. • For the lavage, the patient is positioned in the left lateral decubitus position, with the head lower than the feet. • Before beginning, the tube should be coated with a jelly lubricant such as hydroxyethylcellulose. • The position of the tube must be confirmed after passing, either by aspirating and checking the pH of the aspirate, or by insufflation of air, while listening over the stomach.

39. The lavage is accomplished by attaching a funnel or syringe to the end of the tube and instilling aliquots of 150 to 200 mL (50 to100 mL in children) of 100°F (38°C) saline into the stomach. • Placing the funnel and tube below the patient allows the fluid to return by gravity. • This procedure is repeated until clear fluid returns or 2 L of fluid has been used. • The contents of the stomach can then be collected for drug or toxin identification.

40. Complications of gastric lavage include esophageal perforation, pulmonary aspiration, electrolyte imbalance, tension pneumothorax, and hypothermia (when cold lavage solutions are used). • Lavage is contraindicated in cases of ingestion of caustics or hydrocarbons with a high aspiration potential. • Because of the associated risks and the lack of clear evidence supporting its use, gastric lavage should be used only if the patient has ingested a life-threatening amount of a substance and the procedure is undertaken within an hour of the ingestion.

41. ADSORBENTS • An adsorbent is a solid substance that has the ability to attract and hold another substance to its surface (“to adsorb”). • Activated charcoal is an effective nonspecific adsorbent of many drugs and toxins. • Activated charcoal adsorbs, or traps الفخاخ, the drug or toxin to its large surface area and prevents absorption from the GI tract.

42. ■ Acetaminophen ■ Amphetamines ■ Antihistamines ■ Aspirin ■ Barbiturates ■ Benzodiazepines ■ Beta blockers ■ Calcium channel blockers ■ Cocaine ■ Opioids ■ Phenytoin ■ Theophylline ■ Valproic acid Drugs and Toxins Not Well Adsorbed by Activated Charcoal ■ Acids ■ Alkalis ■ Alcohols ■ Iron ■ Lithium ■ Metals Drugs and Toxins Well Adsorbedby Activated Charcoal

43. ADSORBENTS • Activated charcoal is a fine, black powder that is given as a slurry الطين with water, either orally or by nasogastric or orogastric tube, as soon as possible after the ingestion. • Commercially available activated charcoal products may be mixed with 70% sorbitol to decrease grittiness (composed of or covered with relatively large particles, increase palatability (Acceptable to the taste) , and serve as a cathartic. • The usual dose that is given is one 50-g bottle.

44. ADSORBENTS • Administration of more than one dose is controversial, and usually limited to overdoses of large quantities of aspirin, and theophylline. • Activated charcoal is used cautiously in patients with diminished bowel sounds and is contraindicated in patients with bowel obstruction.

45. CATHARTICS • A cathartic is a substance that causes or promotes bowel movements. • The use of cathartics alone in the management of poisoning is not an acceptable means of G decontamination. • In theory, cathartics decrease the absorption of drugs and toxins by speeding their passage through the GI tract, thereby limiting their contact with mucosal surfaces.

46. CATHARTICS • Magnesium citrate or 70% sorbitol often is used. • Currently, however, there is no clinical evidence that shows that a cathartic can reduce the bioavailability of drugs or improve the outcome of poisoned patients. • Data regarding the effectiveness of mixing cathartics with activated charcoal are not yet available. Clearly, more research needs to be done in this area of clinical practice.

47. WHOLE-BOWEL IRRIGATION • The goal of whole-bowel irrigation is to give large volumes of a balanced electrolyte solution rapidly (1 to 2 L/hour) to flush the patient’s bowel mechanically without creating electrolyte disturbances. • Used as a bowel preparation for colonoscopy, it is also used as a GI decontamination procedure for patients who have ingested bags or vials of narcotics to avoid arrest, for drug smugglers who pack their GI tracts with narcotics (either orally or rectally), and for patients who have overdosed on modified-release pharmaceuticals.

48. Commercial products used in whole-bowel irrigation include GoLYTELY and Colyte. • Both products are dispensed (To prepare and give out ) as powders and are given after adding water. • Whole-bowel irrigation is contraindicated in the patient with bowel obstruction or perforation.

49. Enhanced Eliminationof the Drug or Toxin • The pharmacological and kinetic characteristics of a drug or toxin greatly influence the severity and length of the clinical course in the acutely poisoned or overdosed patient. • The absorption rate, body distribution, metabolism, and elimination must be considered when choosing methods to eliminate the drug or toxin from the body. There are six methods of enhanced elimination: 1. Multiple-dose activated charcoal 2. Alteration of urine pH 3. Hemodialysis 4. Hemoperfusion 5. Chelation 6. Hyperbaric oxygenation (HBO) therapy

50. MULTIPLE-DOSE ACTIVATED CHARCOAL • Administering multiple doses of activated charcoal can result in greater adsorption of certain drugs such as aspirin, valproic acid, and theophylline. • Multiple-dose activated charcoal is given orally, by nasogastric tube, or by orogastric tube every 2 to 6 hours. • Complications of multipledose activated charcoal include aspiration and bowel obstruction.