• Case Study #5: Antero-lateral STEMI

    by Alan Batt. Last modified: 08/03/14

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    Patient & Apparent Chief Complaint

    A 46 year old male presents to ambulance crew with central crushing chest pain, radiating to his shoulder blades.

    History

    This gentleman was packing golf clubs into his car with two friends present when he developed sudden, crushing pain in his chest, radiating to his shoulder blades. Pain 9/10 on scale. He had no previous medical history of significance, a non-smoker and non-drinker. Ambulance was called for by one of his friends. No first aid was administered.

    Initial Clinical Findings

    • Airway – clear
    • C Spine – not indicated (NOI: chest pain)
    • Breathing – adequate
    • Circulation – Pulse present, irregular; skin colour pale, cap refill normal
    • Disability – Patient alert and orientated, PEARRL

    Clinical Impression

    Cardiac chest pain, ? acute myocardial infarction

    AMPLE History

    • A NKDA
    • M No medications
    • P Nil medical history of significance
    • L Breakfast at 0930 (fruit)
    • E Packing car when pain occurred

    Observations

    • Pulse rate 100bpm
    • Pulse rhythm Irregular, weak and thready
    • ECG rate 108
    • ECG rhythm Sinus Tachycardia with ST elevation in antero-septal leads (V1-V4)

    anteroseptal

    • Resp rate 18
    • Resp quality Shallow and laboured in both lungs. No wheeze/crackles
    • SpO2% 99% on O2 @ 15lpm; 89% on room air
    • Cap Refill <2secs
    • BP 115/78
    • Pupils PEARRL, size 4
    • GCS 15/15 (E4, V5, M6)
    • BGL 5.8mmol/l
    • Temp 35.2C
    • Physical examination Nil of significance, nil pedal oedema. Patient diaphoretic and anxious.

    Pre-hospital care & management

    O2 @15lpm via NRB commenced by Paramedic crew. GTN 800mcg administered sublingually. Aspirin 300mg PO administered. Morphine 10mg IV administered in 2mg doses, 3 minutes apart. Clopidogrel 300mg PO administered.

    In-hospital care & management

    Patient triaged as Category 2 (Very Urgent; to be seen within 10 minutes) with central crushing chest pain, possibly cardiac.

    • Troponin I 22.93 (>0.10 is indicative of AMI)

    Clinical Findings

    Antero-septal STEMI

    ami1

    Patient candidate for thrombolysis therapy. Enoxaparin 30mg IV administered as per thrombolysis protocol. Tenectaplase 8000ú IV administered. Slow ST resolution evident on ECG. Pain reduced to 4/10. At 40 mins post lysis severe retrosternal pain re-occurred. – 10/10 on pain scale. Morphine 10mg IV administered. Worsening ST elevation evident on ECG. Patient sent for rescue PCI. LAD stented – severe 3 vessel disease.

    1 day post event – ST segment resolved, Q waves present in anterior and septal leads. Hypotensive (86/60). For Clopidogrel/Aspirin/Lipitor for life. Aggressive Cardiac Rehab to be commenced. Titrate ACE-Inhibitor & beta blocker as tolerated. Patient discharged home 4 days post event.

    Identification of all interventions initiated and rationale

    • Pulse oximetry – to monitor oxygen saturation levels in the blood
    • Supplemental oxygen – to re-oxygenate patient and increase potential oxygen supply to the myocardium
    • GTN – to reduce preload and in turn reduce myocardial oxygen demand.
    • Aspirin – to decrease the risk of further clots developing and causing further myocardial damage
    • Semi-recumbent position – comfortable for patients with chest pain, allows for relaxation of abdominal muscles, and allows for use of intercostals muscles of the back to aid breathing
    • 3 Lead ECG – to identify any life-threatening arrhythmias
    • 12 Lead ECG – to identify any life-threatening arrhythmias or ECG changes indicative of myocardial damage (secondary to hypoxia etc.)
    • Morphine – to relieve pain due to cardiac ischemia and to reduce anxiety
    • Clopidogrel – to further reduce the risk of clot formation
    • Thrombolysis – to dissolve any clot that may be present in the coronary arteries, causing myocardial ischemia
    • CXR – to identify pneumonia, pneumothorax, pleural effusion etc. that may increase morbidity
    • Blood tests – to identify any electrolyte imbalances, cardiac enzymes released due to myocardial damage, clotting factors present in blood etc.

    Learning Outcomes

    Pre-hospital intervention

    The ability of Paramedics to perform 12 Lead ECGs, and identify ST segment elevation/depression is a vital skill that can help to rapidly identify ST elevation MI’s. The facility to be able to transmit them to an emergency department or other facility for cardiology review is also another important aspect of pre-hospital cardiac care.

    This patient would also have been a candidate for pre-hospital thrombolysis in the event of a delay in transport for PCI. He was conscious, coherent and would have understood the therapy. He would have consented, was under 75 years of age, had symptoms for less than 6 hours and had ST elevation >1mm in 2 or more contiguous leads. He had no contraindications to thrombolysis. This would have reduced his time to receive thrombolysis therapy by 1½ hours.

    Manchester Triage Scale

    The Manchester Triage Scale is a method of categorising patients for medical attention based on their presentation, rather than their diagnosis. It is a system that triages patients into distinct categories, based on the severity of their presentation (Mackway-Jones, 2008). According to Cronin (2003) using a triage system “has many advantages for the emergency department including reference to a recognised decision-making structure and support in the form of a professionally accepted and validated system.”

    There are 5 categories in the Manchester Triage Scale

    • Category 1 is life threatening and should be seen and assessed immediately.
    • Category 2 is very urgent and patients in this category should be seen within 10 minutes.
    • The lower categories (3, 4 and 5) have target assessment times of 60, 120 and 240 minutes respectively.

    All patients have an initial set of vital signs performed on them in the Triage room, which are then available for the nursing and medical staff in the ED. Triage is a dynamic process, and patients may be re-evaluated and re-categorised if their condition improves or deteriorates.

    (Ganley & Gloster, 2011)

    Diagnosing an AMI in the ED

    1. Typical history:
      1. central, retrosternal chest pain, may be described as crushing, squeezing, tightness or pressure on the chest lasting > 30mins, unrelieved by nitrates.
      2. May be associated with nausea, vomiting, sweating, dyspnoea
    2. ECG changes:
      1. ST segment elevation > 2mm in 2 or more of the precordial leads, or >1mm in the limb leads.
      2. ST segment depression in leads V1-V3 (strongly suspicious of posterior MI) along with dominant R waves and upright tall T waves
      3. Right sided ECG will show ST elevation in lead V4 – observing for right ventricular involvement.
    3. Cardiac Enzyme elevation:
      1. CK (Creatnine Kinase) greater than 180U/L from 6 hours of onset of chest pain
      2. Troponin I greater than 2.5ng/ml after 8 hours of commencement of chest pain

    Immediate management of AMI in the ED

    1. Soluble Aspirin 300mg PO
    2. 12 lead ECG, bloods, large bore IV access obtained in case of arrest
    3. Analgesia (e.g. Cyclimorph 10mg IV, divided into doses of 2.5mg)
    4. Possible administration of antiemetic (e.g. Metoclopramide 10mg IV)
    5. Thrombolysis if suitable candidate; Primary PCI may be considered with some individuals
    6. Oxygen, dosage based on individual basis
    7. Beta-blocker

    Morphine (Opioid)

    • Presentation: Ampoule (10mg/1ml)
    • Administration: Slow IV push
    • Dosage: 2mg IV at not <2min intervals
    • Effects: Reduces pain & anxiety, vasodilation, respiratory depression, reduces pre-load to myocardium
    • Side-effects: Respiratory depression, drowsiness, nausea & vomiting
    • Additional Info: Cyclizine IV given to counteract nausea & vomiting.

    Cardiac Rehabilitation

    Cardiac rehabilitation is a programme which patients post MI or post any type of acute coronary event such as angina are encouraged to undergo (Davies et al., 2010), which aims to address many issues such as reduce their anxiety about their condition (Whalley et al., 2011); educate them with regards to health, diet and lifestyle changes; promote changes in exercise and diet regimes; promote independence and return to normal activities of daily living and more (Taylor et al., 2010).

    It addresses medical, physical, psychological, social and societal issues, and aims to reduce the morbidity of coronary events, and thus further reduce the burden on the health services (Heran et al., 2011; Brown et al., 2011). It consists of a medical director, nursing staff, dieticians, physiotherapists, social workers, occupational therapists, pharmacists, community care practitioners and more.

    References (non-PubMed)

    Mackway-Jones K. (2008) The Manchester Triage System. Presentation to Utrecht University School of Public Health 8th February 2008. Utrecht Public Health.

    References

     
    1.

    Ganley L1, Gloster AS. An overview of triage in the emergency department. Nurs Stand. 2011 Nov 23-29;26(12):49-56; quiz 58. PMID: 22216667.

     
    2.

    Cronin JG. The introduction of the Manchester triage scale to an emergency department in the Republic of Ireland. Accid Emerg Nurs. 2003 Apr;11(2):121-5. PMID: 12633631.

     
    3.

    Heran BS1, Chen JM, Ebrahim S, Moxham T, Oldridge N, Rees K, Thompson DR, Taylor RS. Exercise-based cardiac rehabilitation for coronary heart disease. Cochrane Database Syst Rev. 2011 Jul 6;(7):CD001800. PMID: 21735386.

     
    4.

    Brown JP1, Clark AM, Dalal H, Welch K, Taylor RS. Patient education in the management of coronary heart disease. Cochrane Database Syst Rev. 2011 Dec 7;(12):CD008895. PMID: 22161440.

     
    5.

    Taylor RS1, Dalal H, Jolly K, Moxham T, Zawada A. Home-based versus centre-based cardiac rehabilitation. Cochrane Database Syst Rev. 2010 Jan 20;(1):CD007130. PMID: 20091618.

     
    6.

    Davies P1, Taylor F, Beswick A, Wise F, Moxham T, Rees K, Ebrahim S. Promoting patient uptake and adherence in cardiac rehabilitation. Cochrane Database Syst Rev. 2010 Jul 7;(7):CD007131. PMID: 20614453.

     
    7.

    Whalley B1, Rees K, Davies P, Bennett P, Ebrahim S, Liu Z, West R, Moxham T, Thompson DR, Taylor RS. Psychological interventions for coronary heart disease. Cochrane Database Syst Rev. 2011 Aug 10;(8):CD002902. PMID: 21833943.

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    Alan Batt

    Alan Batt

    Paramedic, educator, researcher
    Alan is a critical care paramedic, paramedic educator and prehospital researcher, currently working around the world as an educator and researcher. He has previously worked and studied across Europe, North America and the Middle East. He holds a Graduate Certificate in Intensive Care Paramedic Studies, and an MSc in Critical Care. His main interests are in care of the elderly, end-of-life care, patient safety, professionalism (including role and identity), and paramedic education.

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