in children can be subtle. Look for age‐specific behaviors that range from irritability to anger to sleepiness to decreased interaction. As with adults, caregivers may use the mnemonic AEIOU TIPPS (Box 15.1) to assist in developing the differential diagnosis. The pediatric assessment triangle (PAT) is defined as appearance, work of breathing, and circulation and is a rapid method of determining abnormality in pediatric patients. To use the PAT effectively, EMS personnel must have a solid understanding of age‐appropriate vital signs [9].
Alcohol
One group that deserves special mention comprises those AMS patients who are diagnosed as being “just drunk.” EMS personnel, including field physicians, often focus on the presumption of alcohol intoxication without considering other potential conditions causing AMS in the patient who abuses alcohol. The alcoholic is also prone to myriad medical and traumatic problems, including liver disease, diabetes, hypoglycemia, electrolyte imbalances, and an increased propensity for intracranial hemorrhage (Box 15.2). The intoxicated patient should always have a rapid, but thorough, evaluation for trauma and other acute conditions.
Time‐critical causes
EMS clinicians should be sure to consider early the potential for causes of AMS that require time‐sensitive evaluation treatment at the hospital or a specialty center. For example, a patient who meets trauma criteria should have a short scene time and rapid transport to a trauma specialty center. Trauma, particularly of the head and neck, is always a possibility for patients with AMS. Although AMS (decreased GCS) is a criterion for specialty transport to a trauma center, a patient with AMS and otherwise minimal signs of trauma may have another competing or underlying etiology for his or her AMS [10]. In addition to trauma patients, those with ST‐segment elevated myocardial infarction (STEMI) and those who have positive stroke screens require rapid recognition and expeditious transport.
On‐scene treatments and dispositions
Some patients with specific, reversible causes of AMS may be definitively treated on‐scene and do not necessarily warrant rapid advanced life support transport to the emergency department. EMS clinicians should be cautious when attributing AMS to a single, “fixable” cause. Nonetheless, protocols may provide guidance for when patients with resolved AMS and no other acute problems may have an appropriate disposition other than a trip to the emergency department.
Box 15.2 Causes of altered mental status in alcoholics
Intoxication
Electrolyte abnormalities
Hypothermia
Hypoxia
Infection/sepsis
Liver diseaseHepatic encephalopathyCoagulation disordersHypoglycemia
Overdose/intoxication
Seizures
Trauma
Withdrawal
Glucose evaluation and administration
The measurement of serum glucose should be a universal step in the evaluation of an AMS patient. Hypoglycemia may be the sole and reversible cause of AMS in some EMS encounters. Although the defined level for hypoglycemia varies from system to system, many use a level of less than or equal to 70 mg/dL when accompanied by appropriate signs and symptoms of hypoglycemia. A method of testing then treating is generally preferable to the empiric administration of exogenous glucose to all patients with AMS. Only 25% of patients with AMS are hypoglycemic. The common assumption that an ampule of dextrose 50% in water “won’t hurt anyone” has been refuted [11], and it is well established that the blind administration of exogenous glucose may be harmful [12, 13]. After administration of dextrose to the known hypoglycemic patient, an improvement in mental status is usually seen within 5 minutes (see Chapter 20).
Opioid overdose
Another common and potentially reversible cause of AMS is toxic ingestion or drug overdose. Especially given the current opioid use crisis, in patients who may have an opioid toxidrome, consider administration of an opiate antagonist. Naloxone is the current opiate antagonist of choice in the acute care setting. Naloxone is generally safe, with very few serious side effects, the most common being precipitation of withdrawal. Low‐dose administration (0.4 mg initially, titrated to respiratory improvement) may reverse the life‐threatening respiratory depression of opiate overdose without precipitating a possibly agitated “emergence” from opioid sedation that occasionally accompanies full and rapid reversal. However, failure to give an adequate amount of an opioid antagonist is a potential pitfall. The synthetic and semi‐synthetic opioids, as well as heroin in a naive user, may require very large doses of naloxone for reversal. Thus, frequent titration with repeated small doses of naloxone and close monitoring are recommended.
Given the effectiveness of prehospital naloxone, early advanced airway management is contraindicated in the opioid overdose patient. Naloxone can be given by the IM, IN, IV, and IO routes, all of which have been shown to be similarly effective in the prehospital setting [14–16]. In all cases, the EMS clinician should observe and record any response by the patient to the administered medication, as this will facilitate management by subsequent medical personnel.
Refusal of care after resolution of AMS
EMS clinicians will “fix” many patients with AMS on the scene, especially those with relatively straightforward, isolated conditions such as hypoglycemia or opioid overdose. One of the greatest challenges with these patients is determining who has a single, self‐limited process that has been remedied and is unlikely to recur and therefore may be safe to not be transported to the ED or otherwise refuse care, and who requires further treatment or extended observation and therefore should be transported to the ED. Many hypoglycemic patients who have improvement in mental status with field treatment will refuse further medical care and transport. This practice has been shown to be generally safe if certain criteria are met [17, 18] (see Chapter 20).
In addition, individuals who recover after treatment with naloxone may feel well, wish to refuse transport to the emergency department, and have the capacity to do so. However, because of the relatively short half‐life of naloxone, there is concern that these patients may later develop recurrence of symptoms. Experience in EMS systems that have been fully reversing opioid overdose and allowing transport refusals suggests that the risk of clinically significant resedation is small and that adverse events due to rebound toxicity are rare [19–21]. Nonetheless, EMS encounters for opioid overdose patients do provide an opportunity to identify individuals at risk for dangerous substance use and subsequent opioid overdose [22].
Conclusion
The EMS physician, and all prehospital clinicians, must approach the prehospital management of the patient with AMS in a systematic fashion. A broad differential
