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Aspirin administration

Why is this important?

The Australian Resuscitation Council (ARC) guideline for Acute Coronary Syndromes (ACS) states that the early administration of aspirin in an antiplatelet dose of 300 mg is recommended in patients with suspected ACS where contraindications such as true anaphylaxis or bleeding disorder have been excluded[1]. The ARC cited a randomised trial of antiplatelet therapy where it was found that 'Aspirin is protective in most types of patient at increased risk of occlusive vascular events, including those with an acute myocardial infarction (AMI) or ischaemic stroke, unstable or stable angina,previous myocardial infarction, stroke or cerebral ischaemia, peripheral arterial disease, or atrial fibrillation' [2]. Other studies have reported that giving aspirin in the first 24 hours after AMI can increase the chance of survival, and reduce morbidity and mortality [3- 6 ]. A study in USA [7] on review of trends in treatment and survival from myocardial infarction concluded that "The greatest effect of any given therapy was that of aspirin, which accounted for 34%of the decrease in mortality, followed by thrombolytics (17%)".

Given the large benefit, good safety profile, and low cost, in many countries aspirin has become part of the guidelines for the management of cardiac patients [8]. In this section we have presented pre-hospital administration of aspirin to AMI patients to whom an ambulance was called in New South Wales (NSW).


[1] Australian Resuscitation Council Guideline 14.2, Acute Coronary Syndromes: Initial Medical Therapy, July 2012:1-9
[2] Antithrombotic Trialists' Collaboration. Collaborative meta­analysis of randomised trials of antiplatelet therapy for prevention of death, myocardial infarction, and stroke in high risk patients. BMJ 2002; 324:71-86.
[3] Antiplatelet Trialists' Collaboration. Collaborative overview of randomised controlled trials of antiplatelet therapy - prevention of death, myocardial infarction and stroke by prolonged antiplatelet therapy in various categories of patients. BMJ 1994; 308:81-106.
[4] Woollard M, Smith A, Elwood P. Pre-hospital aspirin for suspected myocardial infarction and acute coronary syndromes: A headache for paramedics? Emerg Med J 2001; 18:478-481
[5] Wright et al. 20112011 ACCF/AHA Focused Update of the Guidelines for the Management of Patients With Unstable Angina/Non-ST-Elevation Myocardial Infarction (Updating the 2007 Guideline) A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines Developed in Collaboration With the American College of Emergency Physicians, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. J Am Coll Cardiol. 2011; 57(19):1920-1959.
[6] Zijlstra et al. Influence of prehospital administration of aspirin and heparin on initial patency of the infarct-related artery in patients with acute st elevation myocardial infarction. J Am Coll Cardiol. 2002; 39(11):1733-1737.
[7] Second International Study of Infarct Survival Group. Randomised trial of intravenous streptokinase, oral aspirin, both or neither among 17,187 cases of suspected acute myocardial infarction: ISIS-2. Lancet 1988;ii:349-60.
[8] Heidenreich PA, McClellan M. Trends in treatment and outcomes for acute myocardial infarction: 1975-1995. AmJ Med 2001; 110:165-74.


The proportion of adult patients with suspected AMI receiving pre-hospital aspirin has increased from 85.1 per cent in 2011-12 to 97.3 per cent in 2013-14 and a similar trend was observed across all ambulance sector and divisions (Chart AM01). The rate was slightly lower in regional operational sectors as compared to metropolitan operational sectors.


NSW Ambulance has significantly improved performance against this KPI over the past 3 years. It can now be confirmed that 97 per cent of patients suspected of having a myocardial infarction (attended to by an Ambulance Service of NSW Paramedic) will receive optimal cardiac care in relation to aspirin.

Non-compliance with this KPI is routinely analysed by the Clinical Support Managers by way of In-field clinical audit tool (ICAT). Anecdotal evidence from the ICAT indicates that non-compliance is usually due to Paramedic documentation error. For example, for cases where Aspirin had already been administered prior to Paramedic arrival the event is incorrectly being recorded in free text of the Electronic Medical Record (eMR) rather than being documented as being administered 'by other' in the management section.

What we don't know

It is presumed that in the regional areas, compliance levels are lower because they have a higher proportion of cases where Aspirin is administered prior to Paramedic arrival. The reasons why regional patients are more likely to have received Aspirin prior to Paramedic arrival could be attributed to longer response times, greater attendance by Community First Responders (CFRs), and more single paramedic responses.

AM01 (Cardiac): Per cent out of hospital patients

Per cent out of hospital patients with suspected myocardial infarction having received aspirin by Ambulance zone in NSW July 2011 to January 2014

Source: NSW Ambulance.

End Matter

Drafted by: NSW Ambulance and eChartbook team, CEC eChartbook team

Data analysis by: CEC eChartbook team
Reviewed by: NSW Ambulance
Edited by: CEC eChartbook team

Suggested citation
Clinical Excellence Commission [access year]. eChartbook Portal: Safety and Quality of Healthcare in New South Wales. Sydney: Clinical Excellence Commission. Available at: Accessed [insert date of access].

© Clinical Excellence Commission 2013
This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced without prior written permission from the Clinical Excellence Commission (CEC). Requests and enquiries concerning reproduction and rights should be directed to the Director, Corporate Services, Locked Bag 8, Haymarket NSW 1240.


Chart: AM01

Admin Status: Current

Indicator Name: Aspirin administration to cardiac patients

Description: Per cent out of hospital ambulance patients with suspected myocardial infarction who are reported as having received aspirin by Ambulance Zone in NSW July 2011 to January 2014

Dimension: Patient safety: Pre-hospital care (Ambulance patients)

Clinical Area: Initiatives in safety and quality health care: Pre-hospital care (Ambulance patients)

Data Inclusions: All transported patients to hospital with myocardial infarction age 16 years and older by Ambulance sectors

Data Exclusions: Excluded patients those who have aspirin allergy

Numerator: Total number of patients received aspirin administered ambulance paramedic

Denominator: Total number of ambulance patients with suspected MI

Standardisation: None (crude rate per 100 was calculated)

Data Source: NSW Ambulance