Review assessment and management of unconscious pt, focus on overdose situations. What are the priorities
in management and what principles underlie the treatment of overdose?
Assessment revise
Neurologic assessment in unconscious patients is of paramount importance,
and a structured evaluation should be conducted as soon as possible once
immediate threats to life have been addressed. Although originally
developed for traumatic brain injury, the Glasgow Coma Scale has been
shown to have predictive value in many different types of coma. Both total
and component (eye, verbal, motor) scores should be documented:
Cranial nerve examination (especially papillary response) is an essential
part of the neurologic examination and may assist in determining the level
of brainstem dysfunction. Symmetrically reactive pupils that are unusually
large or small are commonly secondary to drug ingestions.
Initial Management
Initial management of the comatose patient involves the same steps needed
to manage any critically ill patient presenting to the emergency department.
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Immediate assessment and support of airway, breathing, and
circulation should be performed before efforts to diagnose or
address specific causes of coma are undertaken But consideration
postponing intubation until administration of empiric therapy for
coma.
Empiric therapy, often referred to as the "coma cocktail, " consists of IV dextrose, thiamine, naloxone.
o Naloxone (0.4–2.0 mg IV) rapidly reverses coma and respiratory depression secondary to narcotic overdose but has a short halflife and multiple doses may be required.
o Dextrose (50 mL of 50% solution in adults) reverses coma secondary to hypoglycemia and is indicated if rapid testing of blood
glucose is unavailable.
o Thiamine (100 mg IV) is commonly given along with dextrose to avoid precipitating Wernicke encephalopathy in predisposed
patients.
o Flumazenil (0.2 mg/min IV) specifically antagonizes benzodiazepines but is not routinely given empirically as it may precipitate
seizures that are then refractory to benzodiazepines.
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If coma persists definitive management of airway and breathing should be considered.
IV access with two large-bore IVs should be obtained and blood pressure (especially hypotension) managed aggressively.
A complete set of vital signs, including temperature and pulse oximetry, is essential to avoid missing coma complicated by severe hypoor hyperthermia and hypoxia.
Cervical spine immobilization should be maintained if there is any suspicion of trauma.
A focused physical examination should be performed to evaluate for potential precipitating factors (evidence of drug use, systemic
trauma, etc.).
History should be obtained from whatever sources are available, including friends, bystanders, police, and EMS personnel. Accurate and
early identification of poison(s), time of ingestion, vomiting history etc can critically assist in management.
Crucial points include the following:
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recent head trauma, even seemingly trivial
drug use (including alcohol), recent or past
past medical history, including a history of seizures, diabetes, cirrhosis, or other neurologic disease
precomatose activity and behaviour (headache, confusion, vomiting)
sudden versus gradual onset of coma
other individuals with similar symptoms (indicates food poisoning, carbon monoxide poisoning, bioterrorism etc..)
scenario- location/environment, suicide note, pills/bottles etc. present
Laboratory Evaluation
o Electrolytes, LFTs, CBC, UA, urine/serum toxicology screens, thyroid function studies, BUN/Cr, and ABG should be obtained early in
the evaluation of coma.
o Lumbar puncture and CSF analysis should be performed if not contraindicated (e.g., mass lesions or other evidence of increased ICP) in
patients for whom the cause of coma is unclear or in whom an infectious cause is suspected.
o ECG should be obtained and cardiac monitoring instituted to eliminate cardiac arrhythmias as a contributing factor.
o An EEG should be obtained when possible, especially in intubated patients receiving paralytics and in those for whom nonconvulsive
status epilepticus is a consideration.
Imaging – Not indicated when unconsciousness is obviously related to hypoglycaemia, overdose or other metabolic causes, but a noncontrast
head CT is an integral part of the workup for coma and should be strongly considered in any patient who remains comatose after dextrose and
naloxone
Principle and Priorities in Drug Overdose management and treatment
Drug overdose is one of the most common causes of coma in patients presenting to the emergency department. Many drugs may be implicated,
including sedative–hypnotics, opiates, tricyclic antidepressants, and antiepileptics.
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Keep Airways Open
Obtain Arterial Blood Gas and pH measurements
Gain Intravenous Access- draw blood for complete blood count, serum electrolyte and blood glucose measurements, and tests of renal
and hepatic function.
Treat Coma Promptly- see Coma Cocktail above, or with antedote if applicable/known eg. N-acetylcysteine for paracetamol
Maintain circulation and treat shock by restoring intravascular volume with intravenous infusion of crystalloid solutions
Treat Seizures- diazepam, 0.1–0.2 mg/kg, or lorazepam, 0.05 mg/kg, intravenously
Start Electrocardiographic Monitoring
Perform Gastric Decontamination- The administration of activated charcoal is contraindicated in those patients unable to protect their
airway. Activated charcoal may be administered by nasogastric or orogastric tube following intubation for patients who do not have an
intact airway. The effectiveness of activated charcoal decreases with time, and it will be ineffective for most substances if given more
than 1 or 2 hours after the ingestion. Charcoal has great adsorptive properties and can bind most poisons (exceptions include caustics,
hydrocarbons, alcohols, iron, lithium, lead, and potassium). If the ingested dose of poison is known, give at least 10 times that weight of
charcoal, in divided doses if necessary.
Search for Associated Illness
Obtain Brief History- but do not be misled by the history. What the patient or friends say was ingested may differ from what was actually
swallowed, especially in suicide attempts.
References Reference: C. Keith Stone, Roger L. Humphries. Chapter 15: Comas; Chapter 45: Poisoning. CURRENT Diagnosis &
Treatment: Emergency Medicine, 6e. Accessed: http://www.accessmedicine.com.
Summary- Approach to the unconscious patient