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Acute coronary syndrome (ACS) refers to a range of acute myocardial ischaemic states including:
- ST-elevation myocardial infarction (STEMI)
- Non-ST elevation myocardial infarction (NSTEMI)
- Unstable angina
Myocardial infarction (MI) can be classified as either type 1 or type 2. Type 1 MIs are caused by plaque rupture whilst type 2 MIs occur secondary to decreased supply (e.g. anaemia, hypoxaemia, hypotension) or increased demand (e.g. arrhythmias such as atrial fibrillation with rapid ventricular response).
ACS is life-threatening and must be recognised and treated in a timely manner. Remember: time is myocardium!
This guide provides an overview of the recognition and immediate management of ACS using an ABCDE approach.
The ABCDE approach can be used to perform a systematic assessment of a critically unwell patient. It involves working through the following steps:
- Airway
- Breathing
- Circulation
- Disability
- Exposure
Each stage of the ABCDE approach involves clinical assessment, investigations and interventions. Problems are addressed as they are identified and the patient is re-assessed regularly to monitor their response to treatment.
This guide has been created to assist students in preparing for emergency simulation sessions as part of their training, it is not intended to be relied upon for patient care.
Clinical features of ACS
Symptoms
Typical symptoms associated with ACS include:
- Chest pain
- Referred pain: chest pain can radiate to the epigastrium, arm, neck and jaw.
- Shortness of breath
- Palpitations
- Nausea and vomiting
- Sweating
- Syncope
Clinical signs
Typical clinical signs associated with ACS include:
- Tachycardia
- Tachypnoea
- Pallor
- Evidence of impaired myocardial function: hypotension, raised jugular venous pressure (JVP), coarse crackles on chest auscultation and additional heart sounds (e.g. pan-systolic murmur).
Tips before you begin
General tips for applying an ABCDE approach in an emergency setting include:
- Treat all problems as you discover them.
- Re-assess regularly and after every intervention to monitor a patient’s response to treatment.
- Make use of the team around you by delegating tasks where appropriate.
- All critically unwell patients should have continuous monitoring equipment attached for accurate observations.
- Clearly communicate how often would you like the patient’s observations relayed to you by other staff members.
- If you require senior input, call for help early using an appropriate SBARR handover structure.
- Review results as they become available (e.g. laboratory investigations).
- Make use of your local guidelines and algorithms in managing specific scenarios (e.g. acute asthma).
- Any medications or fluids will need to be prescribed at the time (in some cases you may be able to delegate this to another member of staff).
- Your assessment and management should be documented clearly in the notes, however, this should not delay initial clinical assessment, investigations and interventions.
Initial steps
Acute scenarios typically begin with a brief handover from a member of the nursing staff including the patient’s name, age, background and the reason the review has been requested.
Some reasons you may be asked to review a patient with ACS include chest pain and shortness of breath.
Introduction
Introduce yourself to whoever has requested a review of the patient and listen carefully to their handover.
Interaction
Introduce yourself to the patient including your name and role.
Ask how the patient is feeling as this may provide some useful information about their current symptoms.
Preparation
Make sure the patient’s notes, observation chart and prescription chart are easily accessible.
Ask for another clinical member of staff to assist you if possible.
If the patient is unconscious or unresponsive, start the basic life support (BLS) algorithm as per resuscitation guidelines.
Airway
Clinical assessment
Can the patient talk?
Yes: if the patient can talk, their airway is patent and you can move on to the assessment of breathing.
No:
- Look for signs of airway compromise: these include cyanosis, see-saw breathing, use of accessory muscles, diminished breath sounds and added sounds.
- Open the mouth and inspect: look for anything obstructing the airway such as secretions or a foreign object.
Interventions
Regardless of the underlying cause of airway obstruction, seek immediate expert support from an anaesthetist and the emergency medical team (often referred to as the ‘crash team’). In the meantime, you can perform some basic airway manoeuvres to help maintain the airway whilst awaiting senior input.
Head-tilt chin-lift manoeuvre
Open the patient’s airway using a head-tilt chin-lift manoeuvre:
1. Place one hand on the patient’s forehead and the other under the chin.
2. Tilt the forehead back whilst lifting the chin forwards to extend the neck.
3. Inspect the airway for obvious obstruction. If an obstruction is visible within the airway, use a finger sweep or suction to remove it.
Jaw thrust
If the patient is suspected to have suffered significant trauma with potential spinal involvement, perform a jaw-thrust rather than a head-tilt chin-lift manoeuvre:
1. Identify the angle of the mandible.
2. With your index and other fingers placed behind the angle of the mandible, apply steady upwards and forward pressure to lift the mandible.
3. Using your thumbs, slightly open the mouth by downward displacement of the chin.
Oropharyngeal airway (Guedel)
Airway adjuncts are often helpful and in some cases essential to maintain a patient’s airway. They should be used in conjunction with the maneuvres mentioned above as the position of the head and neck need to be maintained to keep the airway aligned.
An oropharyngeal airway is a curved plastic tube with a flange on one end that sits between the tongue and hard palate to relieve soft palate obstruction. It should only be inserted in unconscious patients as it is otherwise poorly tolerated and may induce gagging and aspiration.
To insert an oropharyngeal airway:
1. Open the patient’s mouth to ensure there is no foreign material that may be pushed into the larynx. If foreign material is present, attempt removal using suction.
2. Insert the oropharyngeal airway in the upside-down position until you reach the junction of the hard and soft palate, at which point you should rotate it 180°. The reason for inserting the airway upside down initially is to reduce the risk of pushing the tongue backwards and worsening airway obstruction.
3. Advance the airway until it lies within the pharynx.
4. Maintain head-tilt chin-lift or jaw thrust and assess the patency of the patient’s airway by looking, listening and feeling for signs of breathing.
Nasopharyngeal airway (NPA)
A nasopharyngeal airway is a soft plastic tube with a bevel at one end and a flange at the other. NPAs are typically better tolerated in patients who are partly or fully conscious compared to oropharyngeal airways. NPAs should not be used in patients who may have sustained a skull base fracture, due to the small but life-threatening risk of entering the cranial vault with the NPA.
To insert an oropharyngeal airway:
1. Check the patency of the patient’s right nostril and if required (depending on the model of NPA) insert a safety pin through the flange of the NPA.
2. Lubricate the NPA.
3. Insert the airway bevel-end first, vertically along the floor of the nose with a slight twisting action.
4. If any obstruction is encountered, remove the tube and try the left nostril.
Other interventions
If the patient has clinical signs of anaphylaxis (e.g. angioedema, rash) commence appropriate treatment as discussed in our anaphylaxis guide.
CPR
If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.
Re-assessment
Make sure to re-assess the patient after any intervention.
Breathing
Clinical assessment
Observations
Review the patient’s respiratory rate:
- A normal respiratory rate is between 12-20 breaths per minute.
- Patients with ACS may be tachypneic in an attempt to increase myocardial tissue oxygenation.
Review the patient’s oxygen saturation (SpO2):
- A normal SpO2 range is 94-98% in healthy individuals and 88-92% in patients with COPD who are at high-risk of CO2 retention.
- Hypoxaemia may occur due to cardiac failure and secondary pulmonary oedema.
Auscultation
Auscultate both lungs:
- Reduced air entry bilaterally suggests significant airway compromise and the need for critical care input.
- Crackles or crepitations on auscultation may represent pulmonary oedema due to impaired cardiac function.
Percussion
Percuss the chest to assess for dullness associated with pleural effusion (e.g. secondary to cardiac failure).
Investigations and procedures
Arterial blood gas
Take an ABG if indicated (e.g. low SpO2) to quantify the degree of hypoxia.
An ABG should not delay the management of ACS.
Chest X-ray
A chest X-ray may be indicated if abnormalities are noted on auscultation (e.g. reduced air entry, coarse crackles) to screen for evidence of pulmonary oedema. A chest X-ray should not delay the emergency management of ACS.
See our CXR interpretation guide for more details.
Interventions
Oxygen
Administer oxygen if the patient has a low SpO2. This typically involves the use of a non-rebreathe mask with an oxygen flow rate of 15L. If the patient has COPD and a history of CO2 retention you should switch to a venturi mask as soon as possible and titrate oxygen appropriately.
If the patient is conscious, sit them upright as this can also help with oxygenation.
Continuous positive airway pressure
Continuous positive airway pressure (CPAP) should be considered for patients who do not improve after supplemental oxygen and intravenous diuretics (see below). Commencing CPAP is a skill beyond the scope of most junior doctors and should always involve more senior doctors.
CPR
If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.
Re-assessment
Make sure to re-assess the patient after any intervention.
Circulation
Clinical assessment
Pulse
Assess the patient’s pulse:
- Tachycardia is a common feature of ACS.
- Bradycardia is a late sign and often precedes cardiac arrest.
Blood pressure
Assess the patient’s blood pressure:
- Patients may be hypertensive due to increased sympathetic activity and pain.
- Hypotension is a late sign and represents cardiac failure.
Inspection
Inspect the patient from the end of the bed: they may appear in pain and clammy/pale.
Fluid balance assessment
Calculate the patient’s fluid balance:
- Calculate the patient’s current fluid balance using their fluid balance chart (e.g. oral fluids, intravenous fluids, urine output, drain output, stool output, vomiting) to inform resuscitation efforts.
- Reduced urine output (oliguria) is typically defined as less than 0.5ml/kg/hour in an adult.
Investigations and procedures
Intravenous cannulation
Insert at least one wide-bore intravenous cannula (14G or 16G) and take blood tests as discussed below.
See our intravenous cannulation guide for more details.
Blood tests
Collect blood tests after cannulating the patient including:
- Troponin: to help confirm the diagnosis of myocardial infarction.
- FBC: to screen for anaemia and signs of infection.
- U&Es: to assess renal function and electrolyte levels.
- CRP: to screen for evidence of infection.
- Serum glucose: to identify hyperglycaemia which should then be treated to improve outcomes.
- LFTs: to assess liver function (e.g. ischaemic hepatitis secondary to cardiac failure).
- Coagulation screen: to assess for coagulopathy.
Record an ECG
In the context of ACS, an ECG can provide valuable information as to the sub-type of ACS. Typical findings in each of the subtypes of ACS include:
- STEMI: ST elevation and/or new left bundle branch block (LBBB)
- NSTEMI: T wave inversion and/or ST depression
- Unstable angina: often there are no specific ECG abnormalities
Interventions
Morphine
Morphine has a dual purpose in ACS treatment, both as a coronary artery vasodilator and as an analgaesic.
Nitrates
Nitrates, such as glyceryl trinitrate spray, cause coronary artery vasodilation and improve cardiac perfusion.
If the patient is hypotensive, nitrates are contraindicated due to their vasodilatory effects.
Aspirin and clopidogrel
Aspirin (300mg) and clopidogrel (300mg) are administered to try and improve blood flow through the coronary vessels by inhibiting platelet aggregation.
Diuretics
If clinical signs of pulmonary oedema are present (e.g. shortness of breath, coarse bibasal crackles) consider administration of an intravenous diuretic (e.g. furosemide):
- Furosemide increases diuresis and aids the clearance of pulmonary oedema.
- If a patient is hypotensive, diuretics should not be administered in a ward setting and urgent critical care input should be sought.
Fluid resuscitation
Hypovolaemic patients require fluid resuscitation:
- Administer a 500ml bolus of Hartmann’s solution or 0.9% sodium chloride (warmed if available) over 15 mins.
- Administer 250ml boluses in patients at increased risk of fluid overload (e.g. heart failure).
After each fluid bolus, reassess for clinical evidence of fluid overload (e.g. auscultation of the lungs, assessment of JVP).
Repeat administration of fluid boluses up to four times (e.g. 2000ml or 1000ml in patients at increased risk of fluid overload), reassessing the patient each time.
Seek senior input if the patient has a negative response (e.g. increased chest crackles) or if the patient isn’t responding adequately to repeated boluses (i.e. persistent hypotension).
See our fluid prescribing guide for more details on resuscitation fluids.
Percutaneous coronary intervention (PCI)
Patients with clinical evidence of STEMI require urgent PCI and should be discussed with the on call interventional cardiologist as soon as possible.
CPR
If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.
Re-assessment
Make sure to re-assess the patient after any intervention.
Disability
Clinical assessment
Consciousness
In the context of ACS with hypotension, a patient’s consciousness level may be reduced.
Assess the patient’s level of consciousness using the AVPU scale:
- Alert: the patient is fully alert, although not necessarily orientated.
- Verbal: the patient makes some kind of response when you talk to them (e.g. words, grunt).
- Pain: the patient responds to a painful stimulus (e.g. supraorbital pressure).
- Unresponsive: the patient does not show evidence of any eye, voice or motor responses to pain.
If a more detailed assessment of the patient’s level of consciousness is required, use the Glasgow Coma Scale (GCS).
Pupils
Assess the patient’s pupils:
- Inspect the size and symmetry of the patient’s pupils
- Assess direct and consensual pupillary responses
Drug chart review
Review the patient’s drug chart for medications which may cause a reduced level of consciousness (e.g. opioids, sedatives, anxiolytics, insulin, oral hypoglycaemic medications).
Investigations and procedures
Blood glucose and ketones
Measure the patient’s capillary blood glucose level to screen for causes of a reduced level of consciousness (e.g. hypoglycaemia or hyperglycaemia).
A blood glucose level may already be available from earlier investigations (e.g. ABG, venepuncture).
The normal reference range for fasting plasma glucose is 4.0 – 5.8 mmol/l.
Hypoglycaemia is defined as a plasma glucose of less than 3.0 mmol/l. In hospitalised patients, a blood glucose ≤4.0 mmol/L should be treated if the patient is symptomatic.1
See our blood glucose measurement guide for more details.
Imaging
Request a CT head if intracranial pathology is suspected after discussion with a senior.
See our guide on interpreting a CT head for more details.
Interventions
Maintain the airway
Alert a senior immediately if you have any concerns about the consciousness level of a patient. A GCS of 8 or below warrants urgent expert help from an anaesthetist. In the meantime, you should re-assess and maintain the patient’s airway as explained in the airway section of this guide.
CPR
If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.
Re-assessment
Make sure to re-assess the patient after any intervention.
Exposure
It may be necessary to expose the patient during your assessment: remember to prioritise patient dignity and conservation of body heat.
Clinical assessment
Inspection
Inspect for relevant clues and clinical signs which may indicate increased cardiovascular risk (e.g. cigarettes, xanthelasma, corneal arcus).
Look for any sources of bleeding which may have precipitated a myocardial infarction (e.g. rectal bleeding).
Urine output
Review the patient’s urine output as part of a fluid balance assessment to inform ongoing fluid management.
Temperature
Measure the patient’s temperature:
- If fever is present, make sure to consider co-existing infection.
- Patients with ACS may develop a fever as part of a catecholamine response.
Interventions
Catheterisation
Catheterise the patient to closely monitor urine output to guide fluid resuscitation and need for escalation.
CPR
If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.
Re-assessment
Make sure to re-assess the patient after any intervention.
Reassess ABCDE
Re-assess the patient using the ABCDE approach to identify any changes in their clinical condition and assess the effectiveness of your previous interventions.
Deterioration should be recognised quickly and acted upon immediately.
Seek senior help if the patient shows no signs of improvement or if you have any concerns.
Support
You should have another member of the clinical team aiding you in your ABCDE assessment, such a nurse, who can perform observations, take samples to the lab and catheterise if appropriate.
You may need further help or advice from a senior staff member and you should not delay seeking help if you have concerns about your patient.
Use an effective SBARR handover to communicate the key information effectively to other medical staff.
Next steps
Well done, you’ve now stabilised the patient and they’re doing much better. There are just a few more things to do…
Take a history
Revisit history taking to explore relevant medical history. If the patient is confused you might be able to get a collateral history from staff or family members as appropriate.
See our history taking guides for more details.
Review
Review the patient’s notes, charts and recent investigation results.
Review the patient’s current medications and check any regular medications are prescribed appropriately.
Document
Clearly document your ABCDE assessment, including history, examination, observations, investigations, interventions, and the patient’s response.
See our documentation guides for more details.
Discuss
Discuss the patient’s current clinical condition with a senior clinician using an SBARR style handover.
Questions which may need to be considered include:
- Are any further assessments or interventions required?
- Does the patient need a referral to HDU/ICU?
- Does the patient need reviewing by a specialist?
- Should any changes be made to the current management of their underlying condition(s)?
Handover
The next team of doctors on shift should be made aware of any patient in their department who has recently deteriorated.
