From the Guidelines
Pre-hospital aspirin (acetylsalicylic acid) should be administered to all patients with suspected acute coronary syndrome (ACS) who do not have contraindications to aspirin, with a recommended dose of 162-325 mg chewed or crushed as soon as ACS is suspected. This recommendation is based on the most recent and highest quality study available, which emphasizes the importance of early aspirin administration in reducing mortality in ACS patients 1. The evidence suggests that prehospital EMS providers should administer aspirin to chest pain patients suspected of having ACS unless contraindicated or already taken by the patient 1.
Key Considerations
- The recommended dose is 162-325 mg chewed or crushed (not swallowed whole) as soon as ACS is suspected.
- Contraindications include known aspirin allergy, active bleeding, or recent major surgery.
- Patients with chest pain, pressure, or discomfort suggestive of myocardial ischemia, along with associated symptoms like shortness of breath, nausea, diaphoresis, or radiation of pain to the jaw, neck, or arm, should receive aspirin.
- Emergency medical services personnel should administer aspirin in the field unless contraindicated, and if not already given, it should be administered immediately upon hospital arrival.
Rationale
The rationale for early aspirin administration is that it irreversibly inhibits platelet aggregation by blocking thromboxane A2 production, which helps prevent further clot formation in the coronary arteries. This simple intervention has been shown to significantly reduce mortality in ACS patients when given early 1.
Additional Guidance
While other studies provide additional guidance on the use of aspirin in various clinical scenarios, the key takeaway is that pre-hospital aspirin administration is a critical component of early ACS management, and its benefits in reducing morbidity and mortality outweigh the risks in most patients 1.
From the Research
Pre-Hospital Aspirin Administration
Patients who receive pre-hospital aspirin for acute coronary syndromes include:
- Those with suspected acute coronary syndrome (ACS) unless contraindicated 2
- Individuals with chest pain or anginal equivalent symptoms, where aspirin is recommended as a class I guideline medical treatment 3
- Patients with ST-segment elevation myocardial infarction (STEMI) or non-ST-segment elevation ACS (NSTE-ACS), where aspirin is part of the initial management 4
Patient Selection
The following patients may benefit from pre-hospital aspirin administration:
- Those with chest pressure, shoulder pain, palpitations, lightheadedness, and chest pain, who are significantly younger than those without these symptoms 5
- Individuals reporting sweating, chest discomfort, and unusual fatigue, which are predictive of ACS diagnosis 5
- Patients experiencing shortness of breath, which is associated with increased odds of adverse events 5
Considerations
When administering pre-hospital aspirin, consider the following:
- Aspirin should be given as soon as possible, ideally within the pre-hospital period, to reduce total ischemic time and improve patient outcomes 3, 5
- The benefits of aspirin in patients with coronary ischemia should be weighed against the potential harm, including a slightly elevated bleeding risk in patients with chest pain of another origin than myocardial infarction 3