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As always, initial attention should be directed to airway, breathing, and circulation issues to ensure a stable patient, notwithstanding the new neurologic deficit. EMS personnel should be intimately familiar with the signs and symptoms of stroke, and with regional therapeutic protocols. Scenario and simulation‐based education leads to significant improvement in EMS clinician knowledge of stroke patient care.

A stroke scale should be completed, as it will help to add a degree of objectivity to the description of exam findings that can be conveyed to medical personnel later in the sequence of care. There are several prehospital stroke assessment tools available to assist with stroke identification. The Cincinnati Prehospital Stroke Scale (CPSS) and the Los Angeles Prehospital Stroke Scale (LAPSS) are both validated instruments that can increase the sensitivity for identification of stroke [9–11]. (See Tables 18.1 and 18.2.)

Prehospital stroke scales are valuable tools. However, EMS clinicians should also consider stroke mimics (Box 18.1). Not all of these conditions will be easily differentiated in the field. However, hypoglycemia is capable of manifesting with focal neurologic findings. Thus, all potential stroke patients should have point‐of‐care glucose testing, and hypoglycemia should be treated. Additional historical features may help to determine the nature of some problems that subsequently appear similar to strokes. For example, preceding seizure activity might indicate Todd’s paralysis or increase the probability of ICH. Accompanying symptoms of migraine might indicate a complex migraine. In any case, expediency is important, but taking the time to obtain an accurate history is of vital importance to an appropriate stroke patient evaluation and potential interventions.

There are some immediately relevant points with regard to the medical history of a possible stroke patient, including any recent trauma, recent surgery, and the current use of anticoagulation or antiplatelet agents. Because family and other witnesses frequently do not arrive at the hospital with the patient, attempting to determine the inclusion and exclusion criteria for thrombolytic therapy before hospital arrival can be very helpful and has the potential to influence the opportunity for therapeutic interventions (Box 18.2). However, obtaining an accurate and detailed history should not delay transport, with the exception of confirming when the patient was last at his or her baseline neurologic function.

If possible, an intravenous (IV) cannula may be inserted to facilitate the future administration of necessary medications and the possible acquisition of blood for subsequent laboratory tests. In general, dextrose‐containing solutions should be avoided unless treating hypoglycemia. Hyperglycemia is associated with delays in recanalization of the occluded vessel [12]. Hypoxia should be treated to decrease further insult to the already ischemic brain. However, indiscriminant administration of high‐flow oxygen has not proven to be of any benefit. The current evidence indicates that maintaining normal oxygen saturation levels (i.e., treating hypoxia) is the best recommendation [13]. Supplemental oxygen should only be used to achieve oxygen saturations of 94% [9].

Table 18.1 The Cincinnati Prehospital Stroke Scale

Source: Modified from Kothari RU, Pancioli A, Liu T, et al. Cincinnati prehospital stroke scale: reproducibility and validity. Ann Emerg Med. 1999; 33: 373–7.

Evaluate the following	Result
Facial droop (ask the patient to smile showing teeth)	Normal: No asymmetry
Abnormal: One side of the face droops
Arm drift (with eyes closed, have the patient hold arms in front of body, palms up, for 10 seconds)	Normal: Able to hold arms out at 90°; both arms stay up or fall together
Abnormal: One arm drifts downward
Abnormal speech (ask the patient to say a simple sentence, for example, “It is sunny today.”)	Normal: No slurring
Abnormal: Slurs words or uses words that make no sense

Table 18.2 Los Angeles Prehospital Stroke Scale

Criteria	Results
Over age 45	Yes	Unknown
No history of seizures	Yes	Unknown
Symptoms less than 24 hours	Yes	Unknown
Patient’s baseline function is not bedridden or confined to a wheelchair	Yes	Unknown
Blood glucose between 60 and 400	Yes	No
Examination for asymmetry
Facial droop	Normal	Right	Left
Grip strength	Normal	Weak/none
Arm strength (by downward drift)	Normal	Drifts down	Falls rapidly
Examination finding unilateral?	Yes	No

If exam findings are positive and answers are “yes,” then LAPSS screening criteria are met and stroke is suspected. Source: Modified from Kidwell C, Starkman S, Eckstein M, et al. Identifying stroke in the field – prospective validation of the Los Angeles prehospital stroke screen (LAPSS). Stroke 2000; 31: 71–6. Reproduced with permission of Wolters Kluwer Health.

Stroke patients are at risk for dysrhythmias due to increased catecholamines. Therefore, continuous cardiac monitoring is recommended [13, 14]. Most stroke patients will not experience dysrhythmias that require treatment unless they have a concomitant illness, but this is always a consideration (see Chapter 10). Acute myocardial infarction and stroke may also present simultaneously. It is important to consider concomitant disorders and prioritize care accordingly.

Blood pressure control among stroke patients is an area of controversy and active investigation. Perfusion to the ischemic brain following a stroke is dependent on arterial blood pressure to maintain cerebral perfusion. Thus, hypotension or a relatively low blood pressure for a patient with chronic hypertension could theoretically adversely affect needed cerebral perfusion to at‐risk areas (e.g., penumbra). In fact, many patients experience hypertension immediately after a stroke, and studies have indicated that hypertension usually resolves spontaneously within a few hours. Yet, systolic blood pressure greater than 185 mmHg has been associated with increased risk of ICH among patients who subsequently receive fibrinolytic therapy. Blood pressure control is also postulated to be helpful in reducing hematoma expansion among ICH patients. In general, blood pressure management is best deferred until the patient is in a more controlled environment, such as an ED, where invasive monitoring is possible. If there are compelling reasons to lower a patient’s blood pressure in the field, such as coexisting pulmonary edema, for example, great care must be taken not to over‐correct. A suitable initial target is a 10% reduction of systolic blood pressure, but not lower than 150 mmHg.