Myocardial Infarction Treatment & Management: Approach ...

All patients being transported for chest pain should be managed as if the pain is ischemic in origin, unless clear evidence to the contrary is established. If available, an advanced cardiac life support (ACLS)–trained unit should transport patients with hemodynamic instability or respiratory difficulty.

Prehospital notification by emergency medical services (EMS) personnel should alert ED staff to the possibility of a patient with MI. EMS personnel should receive online medical advice for a patient with high-risk features; this allows for early and prompt delivery of medical treatment and, most importantly, facilitates the transportation of patients to facilities with the appropriate level of care.

Immediate transport to a PCI-capable hospital is recommended in those with suspected STEMI for primary PCI, with a system goal of 90 minutes or less of first medical contact to first device time, as well as in those with cardiac arrest and STEMI who have been resuscitated. [1] Prehospital integration of ECG interpretation has been shown to decrease "door-to-balloon time” and to expedite care by allowing an ED physician to activate the catheterization laboratory before the patient's arrival.

Specific prehospital care includes the following:

• Intravenous access, supplemental oxygen if the oxygen saturation (SaO2) is less than 90%, pulse oximetry
• Immediate administration of nonenteric-coated chewable aspirin en route
• Nitroglycerin for active chest pain, given sublingually or by spray
• Telemetry and prehospital electrocardiography (ECG), if available

Most deaths caused by MI occur early and are attributable to primary ventricular fibrillation (VF). Therefore, initial objectives are immediate ECG monitoring; electric cardioversion in cases of VF; and rapid transfer of the patient to facilitate prompt coronary assessment.

Additional objectives of prehospital care by paramedical and emergency personnel include adequate analgesia (generally achieved with morphine); pharmacologic reduction of excessive sympathoadrenal and vagal stimulation; treatment of hemodynamically significant or symptomatic ventricular arrhythmias (generally with amiodarone and lidocaine); and support of cardiac output, systemic blood pressure, and respiration.

Prehospital fibrinolytic therapy by the administration of tissue-type plasminogen activator (t-PA), aspirin, and heparin may be given to patients with bona fide MI by paramedics, as guided by ECG findings, within 90 minutes of the onset of symptoms. This treatment improves outcomes, as compared with thrombolysis begun after the patient arrives at the hospital. Prehospital fibrinolytic therapy is not used widely in the United States due to the lack of resources to train EMS personnel or the lack of funding for necessary equipment. However, it is more widespread in some regions in Europe and the United Kingdom.