What is the treatment protocol for an acute ST-Elevation Myocardial Infarction (STEMI) in the prehospital setting?

From the Guidelines

The prehospital treatment protocol for an acute ST-elevation myocardial infarction (STEMI) should prioritize rapid recognition, stabilization, and preparation for definitive reperfusion therapy, with immediate administration of aspirin 325 mg chewed and consideration of P2Y12 inhibitors like ticagrelor 180 mg loading dose, as recommended by the most recent guidelines 1.

Key Components of Prehospital STEMI Management

• Administer aspirin 325 mg chewed (or 4 baby aspirins) to inhibit platelet aggregation and reduce thrombus formation, as supported by the American College of Cardiology and American Heart Association guidelines 1.
• Give supplemental oxygen if oxygen saturation is below 94%, targeting 94-98%, to ensure adequate oxygenation of the myocardium.
• Establish IV access and administer nitroglycerin 0.4 mg sublingually every 5 minutes for up to 3 doses if systolic blood pressure exceeds 90 mmHg to reduce cardiac preload and relieve chest pain, as recommended by the European Society of Cardiology guidelines 1.
• Consider P2Y12 inhibitors like ticagrelor 180 mg loading dose if hospital protocols permit, as supported by the Acute Cardiovascular Care Association of the European Society of Cardiology 1.
• Perform a 12-lead ECG within 10 minutes of first medical contact and transmit to receiving facility if possible, to facilitate rapid diagnosis and treatment.
• Alert the receiving hospital of a "STEMI activation" to prepare the cardiac catheterization laboratory, minimizing door-to-balloon time, as recommended by the American Heart Association guidelines 1.

Transportation to a PCI-Capable Facility

• Minimize scene time with rapid transport to a PCI-capable facility, as timely reperfusion significantly improves survival and reduces myocardial damage, as supported by the European Heart Journal 1.
• The goal is to achieve first medical contact to device time under 90 minutes, as recommended by the American College of Cardiology and American Heart Association guidelines 1.

Monitoring and Preparation for CPR

• Monitor vital signs continuously and be prepared to perform CPR if needed, as cardiac arrest can occur at any time during the prehospital phase.
• Ensure that all necessary equipment and medications are available and easily accessible during transport, to facilitate rapid response to any changes in the patient's condition.

From the Research

Treatment Protocol for Acute ST-Elevation Myocardial Infarction (STEMI) in the Prehospital Setting

• The primary goal in the prehospital setting is to quickly identify patients with STEMI and initiate rapid reperfusion with primary percutaneous coronary intervention (PCI) within 120 minutes 2, 3.
• If PCI within 120 minutes is not possible, fibrinolytic therapy with alteplase, reteplase, or tenecteplase at full dose should be administered for patients younger than 75 years without contraindications and at half dose for patients 75 years or older 2.
• Prehospital diagnosis of STEMI is crucial, and a 12-lead ECG should be performed as soon as possible after first medical contact to identify patients with STEMI 3, 4.
• Antithrombotic therapy, including aspirin, heparin, and ticagrelor, should be administered at first medical contact (FMC) to improve outcomes in STEMI patients undergoing primary PCI 5, 6.
• The administration of dual antiplatelet therapy as early as possible is recommended, with ticagrelor being the preferred choice due to the largest amount of evidence available 6.

Prehospital Management

• A 12-lead ECG should be documented in all patients with suspected acute coronary syndrome (ACS) to identify those with STEMI 4.
• Patients with STEMI should be transferred to a cardiac catheterization laboratory as quickly as possible, with a goal of PCI within 120 minutes 2, 3.
• Antithrombotic therapy should be initiated in the prehospital setting, with the choice of medication depending on the patient's risk factors and medical history 5, 6.
• Prehospital care times may be longer for patients with non-STEMI (NSTEMI) compared to those with STEMI, highlighting the need for efficient prehospital management 4.