IMMEDIATE MANAGEMENT OF LIFE-THREATENING PROBLEMS
Approach to the unconscious patient.
Coma is defined as the total absence of arousal and awareness lasting at least 1 hour associated with injury or functional disruption of the ascending reticular activating system in the brain stem or bilateral cortical structures. Comatose patients demonstrate no eye opening, speech, or spontaneous movements, and motor activity elicited by painful stimuli (if present) is abnormal or reflexive rather than purposeful. Coma must be differentiated from other pathologic changes in consciousness such as brain death, vegetative state, and delirium, although it may be difficult to do so in the emergency department.
Initial management of the comatose patient involves the same steps needed to manage any critically ill patient presenting to the emergency department. Immediate assessment and support of airway, breathing, and circulation should be performed before efforts to diagnose or address specific causes of coma are undertaken, with the caveat that consideration may be given to postponing intubation until administration of empiric therapy for coma. Empiric therapy, often abbreviated by the acronym “NGT,” for the selective use of each component as necessary, consisting of Narcan, glucose, and thiamine has replaced the “DON’T” protocol. Narcan (naloxone) rapidly reverses coma and respiratory depression secondary to narcotic overdose, but because of short half-life, multiple doses may be required. Glucose (Dextrose) reverses coma secondary to hypoglycemia and is indicated if rapid testing of blood glucose is unavailable. Thiamine is given for the treatment of Wernicke encephalopathy. Flumazenil specifically antagonizes benzodiazepines, but is not routinely given empirically as it may precipitate seizures that are then refractory to benzodiazepines. It may be indicated in iatrogenic coma secondary to excess benzodiazepine administration.
If coma persists following the administration of naloxone, glucose, and thiamine, definitive management of airway and breathing should be considered. Intravenous (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 hypo- or hyperthermia and hypoxia. A focused physical examination should be performed to evaluate for potential precipitating factors (evidence of drug use, systemic trauma, etc). Obtaining additional history from friends, relatives, bystanders, and emergency medical service (EMS) personnel is essential.
Neurologic assessment in comatose patients is of paramount importance, and a structured evaluation should be conducted as soon as possible once immediate threats to life have been addressed. Level of consciousness, cranial nerve examination, and motor examination should be performed. Lateralizing deficits and a rostrocaudal progression of brainstem dysfunction are seen with structural lesions, while involuntary movements are suggestive of a metabolic cause of coma. Although originally developed ...