Emergency Medical Services. Группа авторов
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.
Box 18.1 Mimics of stroke
Bell palsy
Complex migraine
Conversion disorders
Encephalopathy
Hypoglycemia
Labyrinthitis
Ménière disease
Postictal (Todd) paralysis
Ramsay–Hunt syndrome
Box 18.2 Inclusion and exclusion criteria for intravenous tPA
Inclusion criteria
Ischemic stroke onset within 4.5 h of drug administration