What is ASA?​

• Paramedics administer ASA to patients experiencing signs and symptoms of cardiac ischemia ​
• ASA works by inhibiting cyclooxygenase enzymes (mainly COX-1 and COX-2)​
  • COX-1 produces Thromboxane A-2 which causes platelet aggregation (clotting)​
    • Therefore ASA inhibits platelet aggregation​
• With ASA circulating throughout the bloodstream the chances of a new clot forming or an old clot growing is decreased.

What if the patient has already had ASA administered?

• According to the ISIS-2 trial (Lancet, 1988), ASA decreased the mortality in patients experiencing ACS by 23%​
• Due to the benefits of ASA in patients experiencing symptoms of cardiac ischemia, your patient may still benefit from ASA administration, even if it was administered prior to your arrival​
• This may include patient or family self-administration, or healthcare clinic or office administration

Rationale for more ASA​

• Ensures the patient gets the appropriate dose of ASA​
  • Was the dose taken expired?​
  • Was it truly ASA?​
• No harm in getting an extra dose​
  • Therapeutic dosing may be up to 1500mg (that is 18 tablets of 80-81mg ASA). From OBHG Companion Document:

Summary​

• ASA has been found to decrease mortality and is therefore a helpful treatment in suspected cardiac ischemia ​
• Paramedics are encouraged to provide ASA even if the patient has already had this medication administered​
  • Rationale: ​
    • You ensure the patient gets the dose and medication we know helps save lives in cardiac ischemia​
    • The therapeutic range (1500mg) is far above what an additional dose (or two!) would be​
  • This includes patient self-administration as well as healthcare provider administered ASA

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