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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2 2 Douglas VS, Josephson SA. Altered mental status. Continuum Lifelong Learning Neurol. 2011; 17:967–83.
3 3 Menegazzi JJ, Davis EA, Sucov AN, Paris PM. Reliability of the Glasgow Coma Scale when used by emergency physicians and paramedics. J Trauma. 1993; 34:46–8.
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5 5 Kidwell CS, Starkman S, Eckstein M, Weems K, Saver JL. Identifying stroke in the field. Prospective validation of the Los Angeles Prehospital Stroke Screen (LAPSS). Stroke. 2000; 31:71–6.
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11 11 Browning RG, Olson DW, Stueven HA, Mateer JR. 50% dextrose: antidote or toxin? Ann Emerg Med. 1990; 19:683–7.
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15 15 Ashton H, Hassan Z. Best evidence topic report. Intranasal naloxone in suspected opioid overdose. Emerg Med J. 2006; 23:221–3.
16 16 Barton ED, Colwell CB, Wolfe T, et al. Efficacy of intranasal naloxone as a needleless alternative for treatment of opioid overdose in the prehospital setting. J Emerg Med. 2005; 29:265–71.
17 17 Anderson S, Hogskilde PD, Wetterslev J, Bredgaard M, Moller JT, Dahl JB. Appropriateness of leaving emergency medical service treated hypoglycemic patients at home: a retrospective study. Acta Anaesthesiol Scand. 2002; 46:464–8.
18 18 Thompson R, Wolford R. Development and evaluation of criteria allowing paramedics to treat and release patients presenting with hypoglycemia: a retrospective study. Prehosp Disast Med. 1991; 6:309–13.
19 19 Vilke GM, Sloane C, Smith AM, Chan TC. Assessment for deaths in out‐of‐hospital heroin overdose patients treated with naloxone who refuse transport. Acad Emerg Med. 2003; 10:893–6.
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21 21 Greene JA, Deveau BJ, Dol JS, Butler MB. Incidence of mortality due to rebound toxicity after 'treat and release' practices in prehospital opioid overdose care: a systematic review. Emerg Med J. 2019; 36:219–24.
22 22 Barefoot EH, Cyr JM, Brice JH, et al. Opportunities for emergency medical services intervention to prevent opioid overdose mortality. Prehosp Emerg Care. 2020. Published online ahead of print. DOI:10.1080/10903127.2020.1740363
CHAPTER 16 Syncope
David J. Schoenwetter
Introduction
Syncope is defined as a “loss of consciousness and postural tone caused by diminished cerebral blood flow” [1]. Also, by definition the condition must be self‐corrected as to cause a return to normal state of consciousness. Syncope is a common complaint in both the emergency department (ED) and in prehospital medicine and is the sixth leading cause of hospital admission in people over the age of 65 [2, 3]. Of course, estimates are limited by the accuracy of determining true syncope versus other transient causes of loss of consciousness. Transient loss of consciousness has a cumulative lifetime incidence of approximately 35% to 41%, with recurrent syncope occurring in 13.5% of patients [4, 5].
Pathophysiology
Before discussing the assessment and management of syncope, it is important to understand the multiple etiologies that lead to the final pathway of a transient loss of consciousness. Any process that results in a loss of consciousness must affect both cerebral hemispheres simultaneously or involve the reticular activating system in the brainstem. In the case of syncope, the pathologic process is transient, resulting from a loss of needed substrate to the brain (be it oxygen or other nutrients) that corrects without external therapeutic intervention (such as the administration of IV dextrose). Typically, the impairment of substrate delivery is caused in part by upright posture. Thus, assuming a supine position after consciousness is lost improves substrate delivery and typically leads to spontaneous recovery.
As with any disease process, classification of etiology aids in diagnosis, treatment, and prognosis for patients. Understanding the patient’s prognosis aids
