Chapter 19

### GENERAL CONSIDERATIONS

Coma is defined as the total absence of arousal, and awareness of the self and surroundings that last at least 1 hour. Coma is characterized by the absence of sleep-wake cycles and unarousable unresponsiveness, which are associated with injury or functional disruption of the ascending reticular activating system in the brainstem or bilateral cortical structures. Comatose patients demonstrate no eye opening, age-appropriate speech/vocalizations, or normal spontaneous movements. Movement elicited by painful stimuli (if present) is abnormal or reflexive rather than purposeful. Although definitive discrimination of coma from other pathological states associated with decreased consciousness such as delirium, vegetative state, and brain death should be attempted, but it may be difficult in the emergency setting. Terms such as obtundation, stupor, and lethargy are imprecise and there is variability among physicians in their use. A specific description of the patient’s level of consciousness or the stimuli to which the patient arouses is preferable.

### INITIAL MANAGEMENT

The initial management of the comatose patient presenting to the emergency department should proceed similar to that for any critically ill patient. Patients who do not respond to empiric therapy for coma should have immediate assessment and support of airway, breathing, and circulation (ABC) before efforts to diagnose or address specific causes of coma are undertaken. Empiric therapy, referred to as the “coma cocktail,” consists of intravenous (IV) naloxone and dextrose (Table 19–1). Naloxone (IV 0.1 mg/kg in neonates and children < 5 yr; 2 mg in children > 5 yr) rapidly reverses coma and respiratory depression secondary to narcotic overdose but has a short half-life and multiple doses or continuous infusion may be required. Dextrose (0.5 g/kg) reverses coma secondary to hypoglycemia and is indicated if rapid testing of blood glucose is unavailable. Agents, such as flumazenil, are rarely given empirically as they may precipitate seizures that are then refractory to benzodiazepines. Flumazenil may be indicated in iatrogenic coma secondary to excess benzodiazepine administration, such as following procedural sedation.

Coma that persists following the administration of naloxone and dextrose should prompt consideration of definitive management of airway and breathing. Intravenous access should be obtained and blood pressure (especially hypotension) managed aggressively. Focused physical examination, including a complete set of vital signs, should be obtained to evaluate for potential precipitating exposures such as trauma or evidence of drug use as well as to avoid missing complicating factors such as hypo- or hyperthermia and hypoxia. Maintain cervical spine immobilization if there is suspicion or evidence of trauma. Additional history obtained from friends, relatives, teachers, or emergency medical services (EMS) personnel is imperative.

### NEUROLOGICAL ASSESSMENT

After immediate threats to life have been addressed, a structured neurological assessment including level of consciousness, cranial nerve examination, and sensorimotor examination should be conducted as soon as possible. Structural lesions are more likely to produce lateralizing deficits and a rostrocaudal progression of brainstem dysfunction, ...

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