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 diagnosis must be considered and maintained throughout the patient encounter. Ongoing evaluation must occur even while treatment steps are accomplished. Attention must be given to supporting the patient’s vital functions and to reversing those disorders that can be treated in the field.
Basic life support protocols for patients with AMS should focus on the evaluation and treatment of airway and breathing problems while assessing vital signs for further clues as to the etiology of the AMS. BLS personnel also have the ability to identify and treat opioid overdose with naloxone and to treat hypoglycemia with oral glucose in many jurisdictions.
Advanced life support clinicians may provide fluid resuscitation, IV dextrose to patients with hypoglycemia, other possible antidotes for suspected overdose, and many other medications to treat the suspected underlying cause of AMS. The advanced clinician’s greatest tool, however, is his or her education and ability to maintain a high degree of suspicion for multiple possible contributors to a patient’s AMS. The appropriate EMS protocol for AMS is one that prioritizes rapid and thorough assessment and management of vital signs, allows for the correction of conditions that are reversible in the field, and branches to consider other protocols based on the likely underlying causes of AMS.
References
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