12 - Poisonings

Editors: Susla, Gregory M.; Suffredini, Anthony F.; McAreavey, Dorothea; Solomon, Michael A.; Hoffman, William D.; Nyquist, Paul; Ognibene, Frederick P.; Shelhamer, James H.; Masur, Henry

Title: Handbook of Critical Care Drug Therapy, 3rd Edition

Copyright 2006 Lippincott Williams & Wilkins

> Table of Contents > Chapter 12 - Poisonings

Chapter 12

Poisonings

TABLE 12.1.General, Supportive, and Emergency Measures in Drug Overdose or Poisoning*

For poisoning emergency call 1-800-222-1222. The call is routed to the local poison control center serving the caller based on area code and exchange of the caller. The number is functional 24 hours/day in all 50 states, the District of Columbia, the U.S. Virgin Islands, and Puerto Rico.
Condition	Measures	Comments
Arrhythmias (see Tables 3.9 and 3.10)	Evaluate underlying causes (e.g., hypoxia, electrolytes, etc.)
	Ventricular arrhythmias: lidocaine phenytoin	May cause seizures with cocaine May increase risk of ventricular tachycardia with antidepressant overdose
	Tachyarrhythmias: -blockade	May lead to unopposed -adrenergic effects and coronary vasoconstriction in cocaine overdose May increase risk of ventricular tachycardia in cyclic antidepressant overdose Wide QRS tachycardia (if tricyclic antidepressant suspected or cocaine overdose): NaHCO3 50 100 mEq IV
Coma	Airway, ventilation, oxygenation, IV access Dextrose 50%, 50 100 mL IV Thiamine 100 mg IV (especially if history of alcoholism)
	Naloxone (IV/IM, or via endotracheal tube) 0.2 0.4 mg IV; in patients with suspected narcotic addiction 2 mg q 2 3 min until 10 mg total given	May precipitate withdrawal Synthetic opioids, such as fentanyl, may require larger doses
	Flumazenil 0.2 mg q 30 60 sec, total dose 3 5 mg IV if sedative-hypnotic overdose suspected	Contraindicated in patients with epilepsy receiving long-term benzodiazepine therapy and in severe mixed overdose with benzodiazepine and a proconvulsant drug (i.e., aminophylline, amitriptyline, or chloroquine)
Gastrointestinal decontamination	(See specific poisoning for indications)
	Ipecac syrup: 30 mL followed by 8 oz water, may repeat after 30 min; nausea and vomiting may delay the use of activated charcoal for up to 6 h	Contraindicated if drowsy, unconscious, convulsing, hydrocarbon ingestion, corrosive poisoning, or rapidly acting convulsants (strychnine, camphor, tricyclic antidepressants)
	Gastric lavage: stomach tube; 37 40F, usually most effective within first 4 h after overdose; lavage with 100 200 ml aliquots of 0.9% NaCl or water, usually 1 2 L sufficient to clear contents	Contraindicated in stuporous or comatose patient with absent gag unless intubated with endotracheal tube
	Activated charcoal: 1 2 g/kg oral aqueous slurry with sorbitol cathartic with first dose and then q 2nd or 3rd dose; repeat dose 20 30 g q2 4h; may hasten drug elimination but cathartics should not be used with each dose	Contraindicated in stuporous, omatose, or convulsing patient unless airway protected by endotracheal tube and gastric tube in place
	Catharsis: Magnesium sulfate 10%, 2 3 mL/kg PO or sorbitol 70%, 1 2 mL/kg PO	Contraindications: magnesium-based cathartics may accumulate in renal failure, oil-based cathartics carry risk of aspiration, sodium-based cathartics may exacerbate hypertension or heart failure
	Whole bowel irrigation: polyethylene glycol, electrolyte solution (COLYTE, GoLYTELY) 1 2 L/h via gastric tube until rectal effluent clear to push tablets through GI tract (especially iron ingestion, sustained release and enteric coated tablets)
	Pharmacobezoars may form from sustained-release products and result in continual drug absorption after gastrointestinal decontamination	May require endoscopic identification and removal or surgical removal if intestinal obstruction
Hypertension (see Tables 3.11 and 3.12)	Nitroprusside 0.25 10 g/kg/min or Phentolamine 2 5 mg IV; add -blocker as needed	-blockade may lead to unopposed -adrenergic effects and coronary vasoconstriction in cocaine overdose
Hyperthermia (>40 C)	Rapid cooling measures and benzodiazepines to decrease heat production if agitated or seizing
	If ineffective and extreme muscle rigidity present, then neuromuscular blockade (see Tables 2.4 and 2.5)
	If malignant hyperthermia, dantrolene 2.5 mg/kg IV (see Table 2.14)
	If neuroleptic malignant syndrome, bromocriptine 2.5 7.5 mg PO qd or dantrolene 2.5 mg/kg IV (maximum total dose 10 mg/kg)
Hypotension	Fluid resuscitation
	Vasopressor (e.g., dopamine)
	If suspected/documented overdose is:
	tricyclic antidepressant: NaHCO3 IV 1 2 mEq/kg
	-blocker: glucagon 5 10 mg IV
	calcium antagonist: calcium chloride 10% 10 15 ml IV
Renal excretion	Forced diuresis and urinary pH manipulation: limited utility of alkaline diuresis, 50 100 mEq of NaHCO3 in 1 L of 0.2% NaCl or D5W to urinary pH of 7 8 to prevent tubular reabsorption of acidic drugs, such as phenobarbital, salicylates, and isoniazid	Monitor for hypokalemia, metabolic alkalosis, hypernatremia
	Dialysis indicated if lethal amounts of dialyzable drug present	Hemodialysis: acetaminophen, arsenic, bromide, chloral hydrate, ethanol, ethylene glycol, lithium, mercuric chloride, methanol, salicylates Hemoperfusion cartridges with activated charcoal: amobarbital, butabarbital, carbamazepine, digitoxin, ethchlorvynol, methotrexate, paraquat, pentobarbital, phenobarbital, phenytoin, secobarbital, theophylline
Seizure (see Table 9.1)	Diazepam 2.5 10 mg IV Lorazepam 2 3 mg IV Midazolam 5 10 mg IV or IM Phenobarbital 10 20 mg/kg IV (over 30 min) Phenytoin 10 20 mg/kg (infusion should not exceed 50 mg/min)
GI, gastrointestinal; IM, intramuscular; IV, intravenous; PO, by mouth
*Fifty percent of all adult overdoses and 90% of all opioid overdoses are mixed ingestions. Most frequently abused: alcohol in combination with drugs, cocaine, heroin or morphine, acetaminophen, aspirin, marijuana, alprazolam, ibuprofen, diazepam, amitriptyline.

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FIGURE 12.1. Acetaminophen Overdose: N-acetylcysteine Dosing Nomogram Acetaminophen treatment protocol. (Adapted from Rumack BH, Peterson RC, Koch GG, et al. Acetaminophen overdose. 662 cases with evaluation or oral acetylcysteine treatment. Arch Intern Med 1981;141:382. Used with permission.)

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FIGURE 12.2. Salicylate Overdose Nomogram Nomogram relating serum salicylate level to severity of intoxication.

Mild toxicity: mild to moderate hyperpnea without acidosis, lethargy, and vomiting.

Moderate toxicity: severe hyperpnea with acidosis, marked lethargy or excitability but no coma or convulsions, and marked gastrointestinal distress.

Severe toxicity: severe hyperpnea, severe neurologic impairment that may include coma or convulsions and marked acidosis.

(Adapted from

Done AK. Aspirin overdose: incidence, diagnosis and management. Pediatrics 1978;62(suppl):895.

Reproduced with permission.)

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TABLE 12.2. Specific Therapy for Poisonings and Overdoses

Agent Ingested	Emergency/Supportive Care	Specific Therapy	Comments
Acetaminophen	Empty stomach (emesis or lavage) Activated charcoal	Acetylcysteine Oral solution; load 140 mg/kg then 70 mg/kg q4h 17 doses IV solution; load 150 mg/kg IV over 15 min, then 50 mg/kg infuse over 4 h, then 100 mg/kg infuse over 16 h	Refer to nomogram (Figure 12.1) to predict risk of toxicity Serum acetaminophen levels should be obtained (see Table 12.4). Levels 0 4 h after ingestion uninterpretable; NAC administration has priority over charcoal if levels are toxic Best if given within 8 10 h of overdose Narcotics and anticholinergics may interfere with oral absorption IV formulation may cause anaphylactoid reaction; interrupt infusion until allergic symptoms treated
Acid corrosives (pool, toilet bowl cleaners)	Do not induce emesis Dilute by drinking 8 oz milk or water Do not give bicarbonate Immediate lavage if possible	Surgical intervention for perforation, peritonitis, bleeding	UGI endoscopy to assess extent of tissue damage, do not pass beyond site of injury
Alkalis (lye, oven cleaners, Clinitest tablets, drain cleaners, disk batteries)	Do not induce emesis Dilute by drinking milk or water Immediate lavage if possible	Endoscopic removal of batteries Surgical intervention for perforation, peritonitis, bleeding	UGI endoscopy to assess extent of tissue damage, do not pass beyond site of injury
Amphetamines (dextroamphetamine, methylphenidate propylhexedrine, ephedrine, d-methamphetamine)	Airway, assisted ventilation Do not induce emesis (seizure risk) Gastric lavage Activated charcoal	Agitation or psychosis; diazepam 5 10 mg IV or midazolam 0.1 0.2 mg/kg IV/IM, lorazepam 1 2 mg IV Hypertension: labetalol 10 20 mg IV, or phentolamine 1 5 mg IV, or nifedipine 10 20 mg PO Tachyarrhythmias: esmolol 50 300 g/kg/min IV	-adrenergic blocker alone can worsen hypertension due to unopposed adrenergic effects
Antiarrhythmics (class IA: quinidine, procainamide, disopyramide; class IC: flecainide)	Activated charcoal and cathartic	Atrioventricular block, hypotension, QRS interval widening: sodium bicarbonate 50 100 mEq IV Torsade de pointes: magnesium sulfate 1 2 g IV or isoproterenol 1 5 g/min or overdrive pacing
Anticoagulants (warfarin, rodenticides)	Emesis or gastric lavage Activated charcoal	If prothrombin time elevated, give phytonadione (vitamin K) 5 10 mg IV If serious bleeding, give fresh frozen plasma to correct coagulopathy Recombinant activated factor VII (off label use) 15 30 g/kg IV q12h life threatening bleeding may use 90 120 g/kg IV bolus q2h
Antidepressants (tricyclic or tetracyclic, amitriptyline, maprotiline)	Airway, assisted ventilation Do not induce emesis (seizure risk) Gastric lavage Activated charcoal	Cardiotoxic effects: (supraventricular and ventricular tachycardias) sodium bicarbonate 50 100 mEq IV and specific therapy, alkalinize blood pH to 7.5 Seizures: diazepam 5 10 mg IV q1 2h prn Hyperthermia: sedate and paralyze Hypotension: volume resuscitation and then dopamine 5 20 g/kg/min or norepinephrine 5 100 g/min or epinephrine 1 20 g/min	QRS widening >0.10 correlates with increased risk of seizure, >0.16 increased risk of seizure and arrhythmias Class 1A (quinidine, disopyramide, procainamide), and class 1C (e.g., flecainide) contraindicated Phenytoin may worsen risk of ventricular tachycardia -blockade may worsen cardiac depression and hypotension Physostigmine, a cholinergic agonist, may cause seizures, ventricular fibrillation, and asystole Flumazenil contraindicated; may aggravate seizures and cardiotoxicity
nontricyclic (amoxapine)	Airway, assisted ventilation, supplemental oxygen, gastric lavage, activated charcoal	Seizures/status epilepticus: diazepam 5 10 mg IV q1 2h prn phenytoin 15 mg/kg IV load, infusion not to exceed 50 mg/min, then 100 mg IV q8h	Cardiovascular side effects less common than with tricyclic antidepressants
selective serotonin reuptake inhibitors (SSRI) (fluvoxamine, fluoxetine, paroxetine, sertraline)	Airway, assisted ventilation, supplemental oxygen, gastric lavage, activated charcoal	Agitation or mania, diazepam 2 5 mg IV or midazolam 3 5 mg IV	Low incidence of cardiac toxicity and seizures but if they occur are managed in same manner as tricyclic antidepressant overdose
Antihypertensives sympatholytics (clonidine, prazosin, methyldopa)	Airway, assisted ventilation Emesis or gastric lavage Activated charcoal Cathartic	Supportive therapy with fluids and vasopressor support (e.g., dopamine, Table 3.8)
Arsenic	Emesis or gastric lavage Activated charcoal Supportive care with IV fluids	Antidote for massive overdose; dimercaprol injection (BAL), 10% solution in oil, 2 3 mg/kg IM q4h 48 h, q6h 24, then q12h for 10 d, pretreat with diphenhydramine 25 50 mg PO Follow with dimercaptosuccinic acid (succimer) 10 mg/kg/dose PO q8h 5d, then q12h 14d
Atropine (anticholinergics)	No emesis if antidepressants with anticholinergic effects ingested, due to seizure risk, otherwise: Emesis or gastric lavage Activated charcoal	If pure atropine overdose, administer physostigmine salicylate 0.5 1 mg IV over 5 min, with ECG monitoring	Sedation and cooling measures (tepid baths, cooling blanket for increased temperature)
-adrenergic blockers	Airway, assisted ventilation Do not induce emesis (seizure risk) Empty stomach by gastric lavage Activated charcoal	Bradycardia or AVB: atropine 0.5 2 mg IV, isoproterenol 2 20 g/min IV, or pacemaker (transvenous or transcutaneous) If above fail, glucagon 5 mg IV followed by infusion 1 5 mg/h	Catecholamine infusion alone may lead to arrhythmias or hypotension. Use in conjunction with IV calcium chloride 1 gm of a 10% solution (10mL) via central line slow infusion, max 3 g and/or insulin 0.1 units/kg/h with glucose 1 gm/kg/h (continued next page) Monitor glucose levels q30 60 min for first 4 h
Benzodiazepines	See Sedative-hypnotics
Calcium channel blockers	Airway, assisted ventilation Do not induce emesis (seizure risk) Gastric lavage Activated charcoal	Bradycardia, AV block: atropine 0.5 2 mg IV, isoproterenol 2 20 g/min IV, or pacemaker (transvenous or transcutaneous) Negative inotropic effects: calcium chloride 10% 5 10 ml IV or calcium gluconate 10% 10 15 ml IV Epinephrine infusion 1 4 g/min Glucagon 5 mg IV followed by infusion 1 5 mg/h Insulin 0.1 unit/kg/h with glucose 1 gm/kg/h Monitor glucose levels q30 60 min for first 4 h
Carbon monoxide (CO)	Airway, assisted ventilation	100% O2 via tight fitting mask or endotracheal tube Hyperbaric O2 may be useful for patients with coma, seizure, pregnancy	Half life of CO is 4 5 h breathing room air but is reduced by high FiO2
Chlorinated insecticides (DDT, chlordane, lindane, toxaphene)	Do not induce emesis (seizure risk) Gastric lavage Activated charcoal	Diazepam 5 10 mg IV for seizures
Cocaine	Airway, supplemental oxygen	Anxiety, agitation, seizures: IV diazepam, or lorazepam Hyperthermia: rapid cooling, benzodiazepine Hypertension: benzodiazepine IV, nitroprusside or phentolamine Arrhythmias (QRS prolongation): NaHCO3 1 2 mEq/kg IV Myocardial ischemia: aspirin, nitroglycerin or calcium-channel blocker (see Table 3.1)	Excess sympathetic tone (centrally mediated) contributes to agitation, seizures, hypertension, tachyarrhythmias and is treated with benzodiazepines -blockade may lead to unopposed -adrenergic effects and worsen coronary vasoconstriction Associated with rhabdomyolysis
Cyanide	Airway and assisted ventilation For ingestion: emesis or gastric lavage and activated charcoal	Cyanide antidotes: (a) amyl nitrate inhalant 0.3 ml q3min 2 (b) sodium nitrite 6 mg/kg IV over 3 5 min (c) sodium thiosulfate 250 mg/kg IV (usually 50 ml or 12.5 g of a 25% solution) Decrease or discontinue nitroprusside infusion	Elevated venous oxygen saturation (>90%) Nitrites induce methemoglobinemia which binds free cyanide (may induce hypotension); thiosulfate promotes conversion of cyanide to thiocyanate (see Table 12.4)
Digitalis, cardiac glycosides	Airway and assisted ventilation Do not induce emesis (enhanced vagotonia) Gastric lavage Activated charcoal	Monitor potassium Ventricular arrhythmias: lidocaine (1 3 mg/kg IV) or phenytoin (10 15 mg/kg IV over 30 min) Bradycardia (atropine 0.5 2 mg IV), isoproterenol 2 20 g/min or pacemaker transvenous or transcutaneous)	Digoxin specific antibodies (see Table 12.3)
Ethanol	IV hydration	None	Identify and correct hypovolemia, hypoglycemia, respiratory monitoring and IV thiamine (100 mg) in patients at risk for Wernicke's encephalopathy Severe metabolic acidosis with increased anion gap may indicate cointoxication with other alcohols (methanol, ethylene glycol) Increased levels of ketones or acetones may indicate isopropyl alcohol ingestion
Ethylene glycol or methanol	Airway and assisted ventilation Emesis or gastric lavage Activated charcoal (limited effectiveness)	Fomepizole as soon as possible; loading dose 15 mg/kg IV in 100 mL D5W over 30 min, followed by 10 mg/kg IV q12h or 48 h, then 15 mg/kg q12h until ethylene glycol levels reduced (<20 mg/dL) or methanol levels reduced (<50 mg/dL), pH is normal, and patient is asymptomatic Dialysis should be considered in addition to fomepizole if renal failure present, worsening acidosis, or if elevated levels (>20 mg/dL ethylene glycol or >50 mg/dL methanol) Metabolic acidosis: sodium bicarbonate 50 100 mEg IV Ethanol: (alternative therapy if fomepizole unavailable) loading dose 750 mg/kg PO or IV (as 5% to 10% solution), maintenance 100 150 mg/kg/h (increase to 175 250 mg/kg/h during hemodialysis)	Fomepizole rapidly competitively inhibits alcohol dehydrogenase. It prolongs half-life of ethanol and simultaneous use not recommended Fomepizole is dialyzable and dose frequency should be increased to q4h during dialysis Adjunctive therapy for ethylene glycol poisoning; pyridoxine 50 mg IV/IM q6h and thiamine 100 mg IV/IM q6h and consideration of forced diuresis with fluids and mannitol to prevent oxalate crystal injury to renal tubules Methanol poisoning; folate 50 70 mg IV q4h 24 h Maintain serum ethanol concentration 100 130 mg/dl (See Table 12.4)
Hallucinogens
(LSD, mescaline, 3, 4 methylene- dioxymethamphetamine; ecstasy or MDMA, methylenedioxy-amphetamine or MDA		Hypersuggestible state managed with calm, supportive environment	Large doses of MDMA or MDA may produce amphetaminelike effects; hyperthermia, rhabdomyolysis, hyponatremia, cerebral infarction
Iron	Airway, assisted ventilation Emesis or lavage Activated charcoal not effective	Fluid resuscitation for vomiting, diarrhea, and corrosive effects on GI tract Endoscopy, surgery, or whole bowel irrigation for large tablet bolus visible on abdominal x-ray	Toxic serum iron level is 350 500 g/dl; toxicity associated with serum iron levels >1,000 g/dl severe
		Deferoxamine (if levels >500 g/dl) 10 15 mg/kg/h IV, or 40 50 mg/kg/h for massive overdose, continue until serum iron <350 g/dl	Do not exceed 6 g of deferoxamine in 24 h
Isoniazid	Airway, assisted ventilation Do not induce emesis (seizure risk) Gastric lavage and activated charcoal	Pyridoxine 5 g IV over 1 2 min for each isoniazid gram equivalent Seizures: diazepam 5 50 mg IV Hemodialysis or hemoperfusion may be considered, especially in patients with renal failure
Lead	Airway, ventilatory assistance Activated charcoal and cathartic for acute ingestion	Severe poisoning: dimercaprol 4 5 mg/kg IM q4h 5 d and edetate calcium disodium 50 mg/kg/d in 4 6 divided doses or continuous IV Less severe: edetate calcium disodium as above, or dimercaptosuccinic acid (succimer) 10 mg/kg/dose every 8 h 5d, then q12h for 14 d Lead-containing object may need to be removed by endoscopy, surgery, or whole bowel irrigation	Severe poisoning 70 100 g/dl
Lithium	Airway, assisted ventilation, gastric lavage	Whole bowel irrigation Hemodialysis for life-threatening toxicity	Serum levels >3.5 mmol/l are life-threatening Not absorbed by charcoal
Marine Toxins
Ciguatera	IV saline infusion	None	Toxins from dinoflagellates concentrate in tissue of fish Vomiting, diarrhea, abdominal cramp, bradycardia, heart block, hypotension
Scambroid	IV hydration	Antihistamines (H1 and H2), epinephrine or -agonists if bronchospasm or angioedema present	Bacterial overgrowth in improperly stored fish produce high levels of histamine result in IgE-like allergic reaction
Paralytic shellfish poisoning	Mechanical ventilation for severe neurologic sequelae	None	Toxins from dinoflagellates taken up by bivalve mollusks (mussels, clams, oysters) Mild to severe neurologic symptoms including paralysis and respiratory failure
Neurotoxic shellfish poisoning	IV hydration Supportive therapy	None	Toxins from dinoflagellates (hemolytic and neurotoxins) taken up by shellfish and aerosolized during algae blooms Results in either GI distress, neurologic symptoms or rhinorrhea with bronchospasm
Pufferfish poisoning (tetrodotoxin)	Supportive care and intestinal decontamination with gut lavage/charcoal	None	Neurotoxin associated with pufferfish upon ingestion results in paresthesias, nausea, loss of reflexes, or in severe cases hypotension and general paralysis
Mercury	Emesis or lavage Activated charcoal and cathartic	Dimercaprol 4 5 mg/kg IM q4h 5 d or penicillamine 100 mg/kg PO in divided doses or dimercaptosuccinic acid (succimer) 10 mg/kg PO q8h 5 d	No specific therapy for mercury vapor pneumonitis
Methanol	See Ethylene glycol above
Methemoglobinemia inducing agents (dapsone, nitrites, nitric oxide, pyridium)	Airway, assisted ventilation Emesis or gastric lavage Activated charcoal	Methylene blue 1 2 mg/kg or 0.1 0.2 ml of 1% solution IV, may repeat 1 after 20 min	Severe poisoning methemoglobin fraction >40%, at 20% cyanotic appearance with normal pO2, inaccurate pulse oximetry Dapsone has long half-life requiring repeat doses of methylene blue
Monoamine oxidase inhibitors	Gastric lavage Activated charcoal and cathartic	Severe hypertension: nitroprusside, phentolamine, or labetalol (see Table 3.12) Hyperthermia: aggressive cooling Muscle rigidity, myoclonus, trismus, rhabdomyolysis: similar to neuroleptic malignant syndrome treated with dantrolene 2.5 mg/kg IV q5 10 min until improvement or 1 mg/kg maximum total dose	Hypertension may occur following tyramine-containing foods, sympathomimetic drug use Arrhythmias should not be treated with bretylium because of norepinephrine release Fatal hyperthermia associated with meperidine, fluoxetine, or serotonin-enhancing drugs
Mushrooms	Emesis (usually useless after symptoms occur) Activated charcoal and cathartic	Amatoxin-type cyclopeptides (Amanita): fluid resuscitation, supportive care for hepatic failure Gyromitrin type: pyridoxine 25 mg/kg IV Muscarinic type: atropine 0.01 mg/kg IV, repeat prn Anticholinergic type: physostigmine 0.5 1 mg IV Gastrointestinal irritant: hydration Disulfiram type: avoid alcohol Hallucinogenic type: diazepam 5 10 mg IV or haloperidol 1 2 mg IV q1 2h prn Cortinarius: hemodialysis for renal failure	Liver transplant for severely ill (amatoxin-type cyclopeptides)
Nerve gas poisoning (GA-tabun, GB-sarin, GD-soman, GF, VX) (see Table 12.6)	Protective gear for health workers Decontaminate skin with hypochlorite (bleach diluted 10:1) or soap and water; rinse eyes with plain water	Atropine for bronchoconstriction and secretions: 2 mg IM/IV for mild dyspnea to 6 mg for severe dyspnea or multisystem signs; may require repeat dose q5min (15 20 mg total within first 3 h) Pralidoxime chloride used with atropine: 1 g IV over 20 min, repeat q1h 1 2 Brain damage prophylaxis and seizures: diazepam 5 10 mg IV	Volatile liquids not gases, absorbed through skin or inhaled resulting in muscarinic-nicotinic hyperactivity, CNS stimulation-depression, paralysis Pralidoxime ineffective against GF and GD becomes refractory within minutes Pyridostigmine bromide used as pretreatment against GA or GD (30 mg PO q8h), enhances effectiveness of atropine or pralidoxime
Opioids (heroin, methadone, L-alpha-acetyl-methadol or LAAM, propoxyphene, meperidine, pentazocine, fentanyl, others)	Airway, assisted ventilation Emesis or gastric lavage for ingestion Activated charcoal	Naloxone 0.4 2 mg IV/IM, or endotracheal route, repeat as needed Large doses have been used (10 20 mg for fentanyl, codeine, or propoxyphene) Nalmefene 0.25 g/kg IV/IM/SC q2 5min, total dose 1 g/kg for postoperative respiratory depression. In nonopioid-dependent adult, initial dose of 0.5 mg/70 kg, followed by 1 mg/70 kg 2 5 min later; no added benefit of doses higher than 1.5 mg/70 kg; if opioid dependency suspected, a challenge dose of 0.1 mg/70 kg is recommended, followed by a 2 min wait for signs or symptoms of opioid withdrawal; if none appear, recommended doses may be given	Duration of naloxone effect 2 3 h (see Table 12.4), nalmefene effect ~11 h Naloxone or nalmefene may precipitate withdrawal in opioid-dependent patients and may be more prolonged with nalmefene Acute opioid withdrawal: anxiety, piloerection, yawning, sneezing, rhinorrhea, nausea, vomiting, diarrhea, abdominal or muscle cramps Usually not life-threatening Symptoms lessened with clonidine
Paraquat	Immediate emesis Gastric lavage Activated charcoal or clay (bentonite or Fuller's earth) repeat q2h 3 4	Charcoal hemoperfusion reported anecdotally to be lifesaving	Lethal levels: 2 mg/L at 6 h, 0.2 mg/L at 24 h
Pesticides, cholinesterase inhibitors (organophosphates)	Emesis or gastric lavage Activated charcoal	Atropine 2 mg IV (reverses muscarinic stimulation) Pralidoxime (2-PAM) specific antidote for reversing organophosphate binding to cholinesterase enzyme 1 2 g IV q3 4h prn or a continuous IV infusion 200 400 mg/h	Serum and red cell cholinesterase activity <50% below baseline in severe intoxications
Petroleum distillates (kerosene, gasoline, paint thinner)	Emesis or lavage controversial, usually only if agent has known systemic toxicity If lavaged, intubate to prevent aspiration		Risk of systemic toxicity high with camphor, phenol, chlorinated insecticides, benzene, toluene, or other aromatic hydrocarbons; variable risk with turpentine or pine oil
Phencyclidine	Maintain in quiet atmosphere If awake, activated charcoal Obtunded: gastric lavage with protected airway	Agitated patient: diazepam 5 10 mg IV or midazolam 0.1 mg/kg IM/IV or haloperidol 0.1 mg/kg IM (titrated small aliquots of IV anxiolytics may be used) Hyperthermia: cooling measures Muscle rigidity: paralysis with neuromuscular blockade or dantrolene 2.5 mg/kg IV q5 10min as needed
Salicylates	Airway or assisted ventilation Emesis or gastric lavage Activated charcoal	Hemodialysis may be lifesaving in severe poisoning Urine alkalinization: 100 mEq NaHCO3 in 1 L D5/0.20% NaCl at 200 ml/h with 20 mEq KCL	Acute severe poisoning: >100 mg/dl Chronic poisoning: 60 70 mg/dl Associated hypoglycemia, water, and electrolyte losses (see Figure 12.2)
Sedative/hypnotic agents (ethanol, barbiturates, benzodiazepines)	Airway, assisted ventilation Emesis or gastric lavage Activated charcoal	Flumazenil (benzodiazepine antagonist) 0.2 mg IV over 30 s up to total dose 3 5 mg Hemoperfusion for severe phenobarbital intoxication	Coma usually with ethanol levels >300 mg/dl or 65 mmol/L, phenobarbital >80 100 mg/L (see Table 12.4) Flumazenil contraindicated in patients with epilepsy receiving long-term benzodiazepines, and in severe mixed overdose with a benzodiazepine and a proconvulsant drug, such as aminophylline or amitriptyline; may also predispose to catecholamine surge upon awakening resulting in hypertension or, rarely, arrhythmias
Theophylline	Airway, assisted ventilation Emesis or gastric lavage Activated charcoal with catharsis	Hemoperfusion is effective for severe overdose (e.g., status epilepticus) Hypertension and tachycardia: -blockers (e.g., esmolol 50 300 g/kg/min IV or propranolol 0.5 1 mg IV)	Acute severe poisoning: >80 90 mg/L Chronic poisoning: >60 mg/L Hypokalemia common
Tranquilizers, phenothiazines	Emesis or gastric lavage Activated charcoal and cathartic	Hypotension and arrhythmias: sodium bicarbonate (50 100 mEq IV, maintain pH 7.4 7.5) Extrapyramidal signs: diphenhydramine 0.5 1 mg/kg IV or benztropine mesylate 1 2 mg IM Neuroleptic malignant syndrome: bromocriptine 2.5 7.5 mg PO qd	Monitor QT interval
Tricyclic antidepressants	See Antidepressants above
Volatile inhalants (nitrous oxide, gasoline, propane, freons, trichlorethylene, perchloroethylene, toluene)	Airway, assisted ventilation, supplemental oxygen	Supportive therapy	Sudden death presumably due to cardiac arrhythmias Arrhythmogenic drugs such as sympathomimetics should be avoided if possible
Warfarin	See Anticoagulants above
AVB, atrio-ventricular block; CNS, central nervous system; ECG, electrocardiogram; IM, intramuscular; IV, intravenous; UGI, upper gastrointestinal

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TABLE 12.3. Digoxin Fab Antibody Therapy

Digibind (Ovine digoxin immune Fab antibody fragments)
Each vial of digibind contains 38 mg of purified digoxin-specific Fab fragments which will bind approximately 0.5 mg of digoxin or digitoxin.
Dosage calculation:
(1) From a known digoxin ingestion:
Dose (# of vials) = Body load (mg) 0.5 (mg/vial)
Number of Digoxin Tablets or Capsules Ingested*	Digibind Dose
	mg	Number of Vials
25	340				10
50	680				20
75	1,000				30
100	1,360				40
150	2,000				60
200	2,680				80
*0.25 mg tablets with 80% bioavailability, or 0.2 mg Lanoxicaps.
(2) From a measured serum digoxin concentration:
Dose (# of vials) = serum digoxin concentration (ng/ml) body weight (kg) 100
		Serum digoxin concentration (ng/ml)
		1	2	4	8	12	16	20
Patient	40	0.5	1	2	3	5	7	8
Weight	60	0.5	1	3	5	7	10	12
(kg)	70	1	2	3	6	9	11	14
	80	1	2	3	7	10	13	16
	100	1	2	4	8	12	16	20
(3) From a measured serum digitoxin concentration:
Dose (# of vials) = serum digitoxin concentration (ng/ml) body weight (kg) 1000
Administration:
Digibind is administered IV through a 0.22 mm filter over 30 minutes. If cardiac arrest is imminent, a bolus dose can be administered. If, after several hours, overdose has not been reversed adequately or appears to recur, readministration of digibind at a dose guided by clinical judgement may be required. If neither a serum digoxin concentration nor an estimate of amount ingested is available, 20 vials (680 mg) of digibind should be administered.
Monitoring:
Patients should have close monitoring of temperature, blood pressure, and ECG during and after administration of digibind. Potassium concentrations should be monitored carefully. Severe digitalis intoxication can cause life-threatening elevation in potassium concentration, which can lead to increased renal excretion of potassium. After administration of digibind, patients should be monitored for hypokalemia as the effect of digitalis on potassium is neutralized. Digibind is not removed from the systemic circulation by hemodialysis or continuous arteriovenous hemofiltration. Patients with normal renal function rapidly eliminate Fab and digoxin bound to Fab. Patients with end-stage renal disease eliminate Fab and digoxin very slowly (half-life of total digoxin 46 330 hours). They will need free digoxin level monitored if digoxin therapy is going to be reinitiated soon after giving the Fab.
Interference with laboratory tests:
Total serum digoxin concentrations may rise precipitously after the administration of digibind. Immunoassays will not give an accurate measure of the serum digoxin concentration after the administration of digibind and should not be used as a measure of therapeutic success. Digibind will interfere with immunoassay measurements until the digibind/digoxin complex is eliminated from the body, which may take a week or longer, depending on renal function. Free digoxin concentration may be a useful monitoring tool, and levels correlate with recurrences of digoxin toxicity, the need for supplemental Fab doses, and the efficacy of digoxin therapy initiated during Fab therapy.

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TABLE 12.4. Poisonings Antidotes

Indication	Antidote	Initial Dosage	Maintenance Dosage
Benzodiazepines
Reversal of conscious sedation	Flumazenil	0.2 mg IV over 15 sec	After waiting an additional 45 s, 0.2 mg q1min up to 4 additional times, to a maximum of 1 mg
Reversal of recurrent sedation			Repeat doses at 20-min intervals as needed No more than 1 mg (given as 0.2 mg/min) should be administered at any one time, and no more than 3 mg in any 1 h
Benzodiazepine Overdose
Initial	Flumazenil	0.2 mg IV over 30 s	After waiting an additional 30 s, 0.3 mg IV over 30 s Repeat doses of 0.5 mg can be administered over 30 s at 1 min intervals up to a cumulative dose of 3 mg
Partial response			With a partial response after 3 mg, additional doses up to a total dose of 5 mg may be administered
Repeat treatment			No more than 1 mg (given as 0.2 mg/min) should be administered at any one time, and no more than 3 mg in any 1 h
Continuous infusion		0.1 0.5 mg/h	Useful for reversal of long- acting benzodiazepines or massive overdoses
Narcotics
Postoperative narcotic depression	Naloxone	Bolus: 0.1 0.2 mg IV at 2 3 min intervals	Repeat doses may be indicated within 1 2 h depending on amount, type, and time interval since administration of narcotic
	Nalmefene	0.25 g/kg IV, IM/SC q 2 5 min, total dose 1 g/kg	Duration of effect ~11 h
Narcotic overdose	Naloxone	Bolus: 0.4 2 mg IV/IM or endotracheal route, repeat as needed	0.4 2 mg may be repeated at 2 3 min intervals If no response is obtained after 10 mg have been administered, the diagnosis of narcotic toxicity or overdose should be questioned Naloxone is preferred for emergency department treatment of opioid overdose because it produces a less prolonged period of withdrawal in opioid-dependent patients than nalmefene
		Infusion: 0.4 mg/h or 0.002 mg/kg/h	Dilute 2 mg in 500 ml of compatible fluid; final concentration of 0.004 mg/ml
	Nalmefene	Nonopioid dependent adult initial dose of 0.5 mg/70 kg, followed by 1 mg/70 kg 2 5 min later; no added benefit of dose greater than 1.5 mg/70 kg; if opioid dependency suspected, a challenge dose of 0.1 mg/70 kg is recommended, followed by a 2 min wait for signs or symptoms of opioid withdrawal; if none appear, then recommended doses may be given
Narcotic-induced pruritus	Naloxone	Infusion: 5 g/kg/hr	Useful in patients experiencing pruritis while receiving epidural narcotic infusions
Acetaminophen	N-acetylcysteine	PO: 140 mg/kg diluted 1:3 in cola, juice, soda, or plain water	Additional 17 doses 70 mg/kg PO q4h; refer to nomogram to predict risk of toxicity (Figure 12.1) Administration of activated charcoal is not recommended because it may interfere with the absorption of N-acetylcysteine If administered within 8 16 h of ingestion, N-acetylcysteine minimizes hepatotoxicity, but treatment is still indicated as late as 24 h
		IV solution load 150 mg over 15 min, then infuse 50 mg/kg over 4 h, then 100 mg/kg infused over 16 h	IV formulation may cause anaphylactoid reaction Interrupt infusion until allergic symptoms treated
Methanol and ethylene glycol	Ethanol	Fomepizole as soon as possible; loading dose 15 mg/kg IV in 100 mL D5W over 30 min, followed by 10 mg/kg IV q12h or 48 h, then 15 mg/kg q12h until ethylene glycol levels reduced (<20 mg/dL) or methanol levels reduced (<50 mg/dL) pH is normal and patient is asymptomatic Dialysis should be considered in addition to fomepizole if renal failure present, worsening acidosis or if elevated levels (>20 mg/dL ethylene glycol or >50 mg/dL methanal) Metabolic acidosis: sodium bicarbonate 50 100 mEg IV	Fomepizole rapidly competitively inhibits alcohol dehydrogenase; it prolongs half-life of ethanol and simultaneous use not recommended Fomepizole is dialyzable and dose frequency should be increased to q4h during dialysis Adjunctive therapy for ethylene glycol poisoning; pyridoxine 50 mg IV/IM q6h and thiamine 100 mg IV/IM q6h and consideration of forced diuresis with fluids and mannitol to prevent oxalate crystal injury to renal tubules Methanol poisoning; folate 50 70 mg IV q4h 24 h
		Ethanol: (alternative therapy if fomepizole unavailable) loading dose 750 mg/kg PO or IV (as 5% to 10% solution), maintenance 100 150 mg/kg/h (increase to 175 250 mg/kg/h during hemodialysis) 0.75 g/kg (approximately 1 ml/kg) of 10% solution infused over 15 min	Maintain serum ethanol concentration 100 130 mg/dl (see Table 12.4) 130 mg/kg/h (approximately 0.16 ml/kg/h) of a 10% solution titrated to maintain an ethanol level between 100 150 mg/dl Infusion should continue for 2 3 d
Cyanide	Sodium nitrate	10 ml of a 3% solution IV over 3 5 min	If signs of poisoning persist, readminister both sodium nitrate and sodium thiosulfate
	Sodium thiosulfate	50 ml of a 25% solution IV	Note: amyl nitrate may be crushed and inhaled q15 30s until IV access is established
ECG, electrocardiogram; IM, intramuscular; IV, intravenous, PO, by mouth

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TABLE 12.5. Antivenin for Snake and Spider Bites

Agent	Indications	Dose	Comments
Antivenin (Crotalidae) Polyvalent (Equine)	Neutralizes absorbed venom of North and South American crotalids or pit vipers (e.g., rattlesnake, copperhead, cottonmouth or water moccasin, tropical moccasins, fer-de-lance, bushmaster, tropical and Asiatic crotalids); prevents or minimizes the effects of poison	Minimal envenomation: 20 40 ml (2 4 vials) Moderate envenomation: 50 90 ml (5 9 vials) Severe envenomation: 100 150 ml (10 15 vials) or more	IV preferred to IM, especially if severe envenomation or shock present The initial 5 10 ml of diluted antivenima should be infused over 3 5 min observing for systemic anaphylaxis reaction; if no signs, then infusion continued at maximal rate Equine deriveda; entire initial dose should be given ASAP, ideally within 4 h of bite; less effective beyond 12 h but should be given even if 24 h have elapsed Additional doses based on clinical response if swelling progresses, signs or symptoms of envenomation increase, hypotension or a decrease in hematocrit then an additional 10 50 ml (1 5 vials) should be given IV Immobilize bitten extremity Contact Poison Control Center Not for use with coral snake bites
Antivenin (Crotalidae) polyvalent immune Fab (Ovine)	Neutralizes absorbed venom of North and South American crotalidae or pit vipers (e.g. rattlesnake, copperhead, cottonmouth or water moccasins, tropical moccasins, fer-de-lance, bushmaster)	Initial dose; 4 6 vials infused within 6 h after snake bite, infuse over 60 min (20 50 mL/h) for first 10 min, if no allergic reaction seen increase rate to 250 mL/h Repeat (4 6 vials) if control not achieved with initial dose (i.e., local signs of injury continue or if systemic signs and coagulation tests not improved) Maintenance infusion 2 vials q6h 3 additional doses	Immunoglobin fragments from sheep Side effects include rash, urticaria, pruritus, and rare serum sickness Drug availability 1-800-231-0206
Antivenin (Micrurus fulvius)	Neutralizes venom of North American coral snake	IV, 30 50 ml (3 5 vials) 50 60 ml (5 6 vials) if pain or neurologic symptoms 80 100 ml (8 10 vials) if bulbar signs present	Equine deriveda Infuse ASAP even if signs of envenomation are not yet present Additional doses based on clinical response, usually 10 50 ml (1 5 vials)
Antivenin (Latrodectus mactans)	Neutralizes venom of black widow spider or related species	2.5 ml (1 vial) IM or slow IV infusion after skin or conjunctival sensitivity testingb	IV infusion preferred for severe cases May be repeated Equine deriveda Contact Poison Control Center Adjunctive case includes warm baths, 10 ml of 10% calcium gluconate IV to control muscle pain; therapy with antivenin can be deferred and treatment with a skeletal muscle relaxant considered
IM, intramuscular; IV, intravenous aRisk of immediate sensitivity reactions (shock, anaphylaxis in patients with atopic sensitivity to horses) occurs within 30 minutes of administration. Prior to initiating therapy, intradermal sensitivity test should be performed using 0.02 0.03 ml of a 1:10 dilution of normal equine serum or antivenin in 0.9% NaCl. After 5 30 minutes, positive test = urticarial wheal and erythema. Desensitization consists of 0.1, 0.2, and 0.5 ml 1:100 SC injection at 15-minute intervals, then 1:10 dilution, and then undiluted serum. Alternatives to desensitization in critically ill patients include slow IV diluted antivenin with IV antihistamine (e.g., 50 100 mg of diphenhydramine HCl) or IV epinephrine. Serum sickness may occur 5 24 days after administration. bPrior to initializing therapy, 0.02 ml of 1:10 dilution of normal equine serum in 0.9% NaCl is administered intradermally. A positive skin test consists of an urticarial wheal surrounded by erythema. If skin test is negative, the antivenin can be administered. If skin test is positive, a conjunctival test made by placing 1 drop of 1:10 diluted normal equine serum on the conjunctiva and noting results after 10 minutes. A positive conjunctival test reaction consists of vessel congestion, lacrimation, and itching. If both the skin and conjunctival tests are positive, then the antivenin should be avoided. If life-threatening situation, then desensitization should be attempted as in previous footnote.

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TABLE 12.6. Chemical Terrorism

Protection of Health Care Workers
First responders to chemical agent exposure must be equipped with appropriate protective clothing and equipment (boots, gloves, coveralls, masks, and breathing apparatus). Reactive skin decontamination lotion (RSDL): Neutralizes toxicity of nerve and blister agents (especially nerve agent VX, mustard, lewisite). Apply within 3 minutes of contamination, wash away residue at later time. Decontamination of patient and health care workers: Removal of clothing avoiding contact of skin to residues. Copious water showers. Key agencies: Emergency Federal hotline (U.S. Government Response Center) 1-800-424-8802 Centers for Disease Control (www.bt.cdc.gov) 1-404-639-3311 Food and Drug Administrative Counter-Terrorism Office 1-301-827-7777
Category/Example	Action/Syndromes	Medical Management
Biotoxins
Ricin	Inhibition of protein synthesis Clinical manifestations depend on route of exposure: Ingestion profuse vomiting, diarrhea, multiorgan failure, and death 36 72 h Inhalation respiratory distress, fever, cough, pulmonary edema, hypotension, and death within 36 72 h	Supportive care with fluids, mechanical ventilation, oxygen No specific antidote exists
Blister Agents/Vesicants
Sulfur mustard gas	DNA synthesis inhibition	No specific therapy for mustard gas effects on skin, eyes, and lungs
Nitrogen mustard	Eye injury and skin burns with vesicle formation
Lewisite	Respiratory irritation (wheezing, laryngeal edema, acute lung injury) Garlic smell/onions Radiomimetic effects including leukopenia, pulmonary and GI mucosal damage	Supportive treatment, respiratory support, pain relief RSDL neutralizes toxicity of blister agents applied topically Dimercaprol (topical antidote for lewisite)
Toxic Asphyxiants
Cyanide (hydrocyanic acid) Arsine (arsenic trihydride)	Mitochondrial cytochrome oxidase inhibition, inhibit cell respiration, lactic acidosis, cytotoxic hypoxia in cardiovascular and central nervous system Colorless liquid or gas Almond smell (cyanide), garlic smell (arsine) Therapy based on administration of nitrites that form methemoglobin, which combines with cyanide to form cyanomethemoglobin and frees cytochrome oxidase to resume aerobic metabolism	Cyanide poisoning: 100% O2 Sodium nitrite 300 mg IV infused over 5 15 min, may repeat after 30 min with 150 mg IV Amyl nitrite ampules (0.3 mL) if IV route unavailable; inhale vapors for 30 sec/min 3 per ampule; repeat up to 5 ampules Sodium thiosulfate to form thiocyanate complex; after nitrite treatment, 12.5 g IV slow push (50 mL); may repeat in 30 min at one-half the dose Hydroxocobalamin 10 mL of 40% solution (4g) IV over 20 min No specific antidote for arsine Supportive treatment for hemolysis (exchange transfusion) and renal failure diuresis with mannitol, alkaline diuresis
Caustics
Hydrofluoric acid/hydrogen fluoride	Found in refrigerants, herbicides, high-octane gasoline, etching glass/metal Rapidly absorbed through skin into tissues Skin contact severe burns with ulceration, inhalation; lung injury with pulmonary edema, irritation of eyes and nose Splashes of hydrogen fluoride on skin can be fatal; swallowing small amounts of hydrogen fluoride may be fatal	Remove clothing, wash from skin with large amounts of water, dispose of clothes If hydrogen fluoride is swallowed do not induce vomiting, do not give activated charcoal Calcium or magnesium containing antacids with 1 2 glasses of water if alert Calcium gluconate gel applied to skin to prevent absorption
Pulmonary Irritants
Chlorine Phosgene Ammonia	Burn and irritate skin and eyes Direct lung tissue injury, pulmonary edema Smell of new-mown hay (phosgene) Pungent smell (chlorine) Cleaning agent (ammonia)	No antidote exists for any of the pulmonary irritants Remove clothing, rapidly wash body with soap and water Supportive care for acute respiratory distress;    Bronchodilators    Corticosteroids    Mechanical ventilation    Oxygen therapy    Mydriatic for eyes and topical antibiotic
Nerve Agents
GX, sarin, tabun, VX	Cholinesterase inhibitors, acetylcholine excess syndrome, severe secretions, smooth muscle stimulation, skeletal muscle neural inhibition, respiratory failure	Atropine IV or IM 2 4 mg then 2 mg IV/IM q5 10min until muscarine symptoms resolve; doses of 200 mg may be required every 24 h Pralidoxime 1 2 g IV with 5 min of presentation, repeat in 20 60 min if weakness unchanged; alternative IM route; 600 mg in large muscle Maintain airway, ventilator assistance, supplementary oxygen Avoid succinylcholine to prevent excess acetylcholine release Seizure diazepam 5 10 mg IV/IM, repeat after 10 20 min (max 30 mg q8) RSDL applied topically neutralizes nerve agent VX
Riot Control Gas
Tear gas Mace	Irritation of eyes, skin, upper respiratory tract, lower respiratory tract	No specific antidote exists for riot control agents
Chloroacetophenone (CN) Chlorobenzylidene-malononitrile (CS) Chloropicrin (PS) Bromobenzylcyanide (CA)	Excessive tearing, blurred vision, runny nose, difficulty swallowing, chest tightens, burns or skin rash, nausea, and vomiting	Remove clothing and wash off agent from skin with soap and water. Rinse eyes Supportive care:    Bronchodilators    Oxygen therapy    Corticosteroids
Dibenzoxazepine (CR)	Long-lasting exposure (closed setting) may lead to blindness, immediate death due to chemical burns to throat and lungs, respiratory failure
GI, gastrointestinal; IM, intramuscular; IV, intravenous; RSDL, reactive skin decontamination lotion

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TABLE 12.7. Radiation Exposure Emergencies^a

General Principles		Medical Management Principles
Exposure to radiation source (x-rays, gamma rays, neutrons, protons high dose over short period minutes) can cause tissue injury. Patients do not become radioactive. External contamination: loose particles of radioactive material are deposited on surfaces, skin, clothing Internal contamination: radioactive material is inhaled, ingested, or lodged within wound. Contaminated patients should be decontaminated as soon as possible		Establish triage area for contamination containment and decontamination Remove contaminated outer garments of patients and staff and double bag using radioactive waste guidelines Body survey staff and patient with radiation meter Wash wounds and skin with saline/soap and water Resurvey and repeat washing until radiation level no more than twice background or unchanged
Additional Resources
Armed Forces Radiobiology Research Institute Medical Radiobiology Team 1-301-295-0530 www.afrri.usuhs.mil Centers for Disease Control and Prevention 1-800-CDC-INFO www.bt.cdc.gov/radiation		Radiation Emergency Assistance Center/ Training Site (REAC/TS) 1-865-576-3131 (M F day) 1-865-576-1005 (After hours) www.orau.gov/reacts
Acute Radiation Syndromes	Dose Exposure	Signs, Symptoms, Outcome
Bone marrow syndrome	<0.7 Gyb (70 rads) mild symptoms with 0.3 Gya (30 rads)	Anorexia, nausea, vomiting May have latent period of appearing well Primary cause of death is infection and hemorrhage
Gastrointestinal syndrome	<100 Gyb (1,000 rads) same symptoms with 6 Gy (600 rads)	Anorexia, nausea, vomiting, cramps, diarrhea May have latent period of appearing well Death due to infection, dehydration, electrolyte abnormalities 100% lethality 10 Gy
Cardiovascular/central nervous system syndrome	<50 Gyb (5,000 rads), some symptoms with 20 Gy (2,000 rads)	Nervousness, confusion, nausea, vomiting, diarrhea, loss of consciousness, burning sensation of skin May have partial return of function for hours Death within 3 days of this level of exposure
If Radiation Exposure Suspected:
Triage	Diagnosis of acute radiation syndrome	Initial treatment and diagnostic evaluation
Airway, ventilatory, and circulatory support Physiologic monitoring Treat major trauma, burns, and respiratory injury	Diagnosis is difficult and depending on dose, signs and symptoms may occur within hours or days or be in a latent stage	Treat vomiting Record clinical symptoms including nausea, vomiting, diarrhea, and itching, reddening, or blistering of skin with time of onset (see Table 12.8)
Obtain blood samples for complete blood count with differential (attention to lymphocytes) and HLA typing prior to transfusion	If exposure occurred within 8 12 h, repeat complete blood count with attention to lymphocyte count q2 3h for first 8 12 hrs after exposure and then q4 6h for the following 2 3 d (see Andrews nomogram Table 12.8)	Consider tissue, blood typing, and initiating viral prophylaxis Consultation with radiotherapy and hematology experts regarding dosimetry, prognosis, and treatment options Prophylaxis and treatment of infections Use of hematopoietic growth factors and/or stem cell transfusions Chromosome aberration cytogenic bioassay best method of dose assessment
aAdapted from www.bt.cdc.gov/radiation. bExposure of entire body to high dose (>0.7 Gray (Gy) or >70 rads) radiation (i.e., x-rays, gamma rays, neutrons) for short periods of time (usually minutes) resulting in immediate tissue injury and depletion of immature parenchymal stem cells. Symptoms can be immediate or delayed, mild, or severe, depending on radiation dose. Nausea and vomiting may occur minutes to days after the exposure. The time of onset of vomiting is a major sign to assist in diagnosis and dose exposure estimation (Table 12.8).

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TABLE 12.8. Estimation of External Radiation Dose Related to Onset of Vomiting and Changes in Absolute Lymphocyte Counts

Vomiting Post Incident	Estimated Dosea	Degree of ARSb
<10 min	>8 Gy	Lethal
10 30 min	6 8 Gy	Very severe
<1 h	4 6 Gy	Severe
1 2 h	2 4 Gy	Moderate
>2 h after	<2 Gy	Mild
aFor acute external exposures only. Gray (Gy) is the SI unit of measurement for radiation absorbed dose. bARS, acute radiation syndrome. (Adapted from: Berger ME, Leonard RB, Ricks RC, Wiley AL, Lowry PC. Hospital triage in the first 24 hours after a nuclear or radiological disaster, REAC/TS [Radiation Emergency Assistance Center/Training Site]; http://www.orau.gov/reacts:2004.)

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FIGURE 12.3. Andrews Lymphocyte Nomogram From Andrews GA, Auxier JA, Lushbaugh CC. The importance of dosimetry to the medical management of persons exposed to high levels of radiation. In Personal dosimetry for radiation accidents. Vienna: International Atomic Energy Agency;1965.

Source: http://www.bt.cdc.gov/radiation/arsphysiciantactsheet.asp. Accessed March 21, 2006.