Chapter 10 Mark R. Quale and Jefferson G. Williams The patient presenting with altered mental status (AMS), also referred to as altered level of consciousness or ALOC, in the prehospital setting is one of the most common encounters in EMS. Many etiologies of AMS have the potential to cause significant morbidity and mortality. It is essential that proper care be initiated in the field, along with the early consideration of a broad differential diagnosis. Often, treatment must begin before the etiology of AMS is established. In most instances, this treatment should be instituted in conjunction with attempts to determine the underlying cause. The main challenge of a prehospital patient with undifferentiated AMS is to rapidly identify and treat potentially reversible problems in the field in order to prevent added morbidity from the complications of a prolonged condition. The differential diagnosis for AMS is extensive and complex. Although the definitive treatment for many of these causes may fall outside the scope of practice of the EMS provider or the duration of the prehospital contact, he/she and the EMS physician should focus on identifying and managing conditions that may be effectively treated in the field. A brief on-scene interval and expeditious transport are required for time-critical causes of AMS (e.g. stroke, trauma) if these are identified. A simple and frequently used mnemonic for the potential causes of AMS is AEIOU TIPPS (Box 10.1). Once scene safety is assured, EMS personnel of all levels should assess the ABCs, check vital signs, and immediately address life-threatening conditions. Once the ABCs are adequately addressed, additional history, physical examination, and field findings may prove useful in developing an appropriate treatment plan. As the situation permits, EMS personnel should systematically obtain as much information about the patient as possible from the scene. Because the patient often cannot provide an adequate history, field personnel should seek additional information from alternative sources, such as bystanders, family, and physical surroundings. Important questions include the patient’s baseline health and past medical history, the rapidity of the onset of the symptoms, and any complaints voiced or signs exhibited by the patient. One particularly useful question is whether or not the patient ever had a complete loss of consciousness or seizure-like activity. Emergency medical services personnel should search common locations such as bathrooms, medicine cabinets, bedrooms, nightstands, and kitchens for clues about underlying illnesses or possible ingestion. A medical alert bracelet or necklace should be sought. Other household members with similar signs and symptoms, or the presence of multiple patients with altered mental status, or the presence of sick or deceased pets may point to a toxic environmental exposure such as carbon monoxide (CO) poisoning. If a drug overdose or poisoning is suspected, EMS personnel should gather further pertinent information, including the route of exposure, the type of substance involved, and the time and amount of exposure. In the majority of cases, overdoses will occur by ingestion. If the exact amount of exposure or ingestion is not known, personnel should try to establish the maximum possible quantity. They should also note any actions taken by the patient or bystanders, including the administration of any “antidotes.” Empty pill containers, liquor bottles, syringes, and other drug paraphernalia can greatly facilitate later treatment decisions. One important route of ingestion that is not always considered is “huffing” or the use of chemical vapor to achieve AMS. Data from the 2012 Monitoring the Future Study [1] show that, while inhalant abuse has declined as prescription drug abuse has climbed, inhalants are still easy “legal” drugs to obtain for young teens, with inhalant use declining as age increases. With any inhalant there is a risk of sudden sniffing death caused by an irregular heart rhythm leading to heart failure. Suffocation, asphyxiation, and aspiration are also risks inherent to this form of substance abuse. Regarding the physical examination, the first task is to determine the degree of the AMS. Unfortunately, a variety of inexact terms are commonly used to describe AMS. Descriptive terms such as stuporous, comatose, semi-comatose, obtunded, confused, and delirious are poorly defined and may lead to different interpretations by bystanders, EMS providers, and hospital-based physicians. In general, it is best for the level of consciousness to be described on the basis of the response that the patient makes to a given stimulus. Field providers can use the simple mnemonic AVPU. Emergency medical services personnel may also use the Glasgow Coma Scale (GCS) (see Volume 1, Chapter 30). A study done with paramedics scoring videotaped patients with AMS confirmed that paramedics can determine GCS scores that correlate well with those of emergency physicians [2]. The directed and focused physical exam and secondary survey can aid in determining the cause of AMS. The head should be examined for any obvious signs of trauma, such as scalp and facial lacerations, abrasions, and contusions. The pupils should be observed for symmetry and light reactivity. If they demonstrate bilateral mydriasis this may indicate cerebral hypoxia or a toxicological etiology (anticholinergics, sympathomimetics, selective serotonin reuptake inhibitors, etc.). Miosis is often due to opioid overdose. However, clonidine, antipsychotics, organophosphates, sedative-hypnotics, and pontine stroke may also cause miosis. Unequal pupils may be found as a normal variant, but they could also indicate impending herniation from trauma or a spontaneous intracranial hemorrhage. Any odor on the patient’s breath (acetone, bitter almonds, ethanol, or volatile agent) should be noted. The tongue should be checked for bleeding, which may indicate seizure activity. Any upper airway stridor should be documented, and plans to care for a partially or soon-to-be obstructed airway must take precedence. Should signs of possible acute trauma be found in a patient with AMS, the cervical spine should be evaluated and EMS personnel should maintain cervical spine precautions in keeping with protocols. The respiratory rate, pattern, and depth should be noted. Again, any outward signs of trauma should be identified. A patient with AMS who presents with a rigid, distended, or tender abdomen may be having an intraabdominal catastrophe. Pregnancy and its complications (eclampsia, HELLP syndrome, ectopic pregnancy) should be considered in females of child-bearing age, especially if the patient appears gravid. In these situations, EMS protocols or direct medical oversight should provide the option for the patient to be transported to a medical facility capable of caring for acute surgical patients or pregnancy-related complications. In addition to pupillary findings, any focal neurological signs suggesting stroke or increased intracranial pressure, such as extremity flaccidity or Cushing’s triad, should be noted and recorded as a baseline for possible progression. Altered speech patterns may also be elicited with the aid of bystanders. EMS personnel should screen for stroke using an established stroke scale, such as the Cincinnati Prehospital Stroke Scale, Los Angeles Prehospital Stroke Screen, or the Melbourne Ambulance Stroke Screen [3–5]. The skin may be used to determine temperature, which may be increased in infection or heat illness and decreased in cold exposure, dehydration, or alcohol or barbiturate overdose. Rashes potentially indicating infection or allergic reaction should be noted. Track marks consistent with needle injections and narcotic overdose should be checked for. Signs of a previous suicide attempt, such as healed wrist scars, may be apparent. The undifferentiated patient should be log-rolled and examined head to toe for occult puncture wounds or other subtle findings. The focus of a care protocol for the patient with AMS is to secure the ABCs and rapidly identify and treat reversible conditions. Appropriate basic life support measures, such as basic airway management and spinal precautions, should be instituted before any attempt is made to gather a complete history or perform a detailed physical examination. For the majority of AMS patients, the first priority is to establish and maintain an adequate airway. If the patient is apneic or hypoventilating, respirations should be assisted by bag-valve-mask (BVM). Advanced airway placement may be considered if BVM ventilation is not effective, but the majority of patients can be managed with airway adjuncts, enough hands, and basic maneuvers. For the patient with adequate respirations, a nasal or oropharyngeal airway with oxygen via a non-rebreather mask may be appropriate. Continuous positive airway pressure (CPAP) may be of great assistance in the patient with adequate respiratory drive but shallow or ineffective ventilation, who may be hypercapneic. End-tidal CO2 monitoring can assist the prehospital provider in both diagnosing and managing the patient with elevated pCO2
Altered mental status
Introduction
Evaluation
Head
Neck
Chest
Abdomen
Neurological
Skin
Management
Airway
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