Читать книгу Emergency Medical Services - Группа авторов - Страница 243

Acute aortic dissection classically causes sudden pain in the chest, sometimes radiating to the back. The dissection is caused by a tear in the intimal lining of the aorta with entry of high‐pressure blood into the wall of the aorta. The dissection propagates distally and sometimes proximally. If the dissection extends around the origin of a peripheral artery, then that vessel can be partially or completely occluded, creating a >15‐ to 20‐mmHg difference in blood pressures between patient arms. If the origin of a carotid or vertebral artery is occluded, then the patient may develop neurologic signs suggesting a stroke. Occlusion of a spinal artery from the aorta can cause acute paralysis of both legs. Most patients with dissection have long‐standing hypertension, but the problem can occur in younger patients with other conditions such as Marfan syndrome.

In the majority of cases of aortic dissection, the12‐lead ECG will be abnormal, but will not show ST‐segment elevation unless the origin of a coronary artery is occluded by the dissection [74]. Without imaging capability that exists in the hospital, EMS clinicians may suspect, but cannot identify, aortic dissection definitively [75, 76]. If aortic dissection is suspected, morphine can be used for pain control but aspirin should be avoided, since patients with acute aortic syndrome who receive antithrombotic agents such as aspirin or fibrinolytics are more likely to bleed [77].