Question 15

Created on Fri, 05/29/2015 - 02:06
Last updated on Sat, 03/10/2018 - 21:28
Pass rate: 58%
Highest mark: ?

Topic

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You are phoned for advice by a doctor in a small and remote regional hospital emergency department who has just seen a 66 year old man.   He presents with central chest discomfort and dyspnoea which has been present for 60 minutes. The following ECG has arrived by fax.

a)          Please report the abnormalities on this ECG.

b)          Outline the management advice which you will give to the regional doctor.

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College Answer

ECG abnormalities
There is a right bundle branch block

Q waves in leads II, III and aVF - indicative of old inferior myocardial infarction.
>2mm ST segment elevation in leads V2 and V3 . There is also ST elevation leads V4 & V5. This is STEMI (ST elevated myocardial infarction) in a man with ECG evidence of previous myocardial infarction.

Management issues
1) This man should already have had aspirin, GTN, oxygen and morphine –this needs to be checked with the referring doctor.

2) Since he is <12 hrs from presentation and is in a remote hospital, then interhospital transfer to receive Percutaneous Coronary Intervention (PCI) should be considered, but would be impossible within the required 90 minutes from symptom onset. Therefore he needs urgent thrombolysis.

3) Can the hospital administer thrombolysis? What have they got, do they know how to administer it. Do they recognise the urgency of administration?
4) After administration he will need anti-thrombotic treatment (heparin infusion)  and needs urgent transfer to a centre able to perform PCI and/or surgery (particularly if he has evidence of cardiac failure). How he will be transferred and who will escort him must be considered. The receiving cardiologists need to be informed

Discussion

The management issue list in the answer is presented in a manner which most closely resembles a colloquial discussion of this matter over some beers.
Do they recognise the urgency of adminstration, we ponder.

Let us divide this into a structured model answer, based on the 2016 NHFACSANZ recommendations.

  • Immediate management:
    • A: keep nil-by-mouth, given the possibility of impending need for intubation
    • B: maintain normoxia (no need for supplemental oxygen unless he becomes hypoxic)
    • C: Continue ECG monitoring and insert 2 x widebore cannulae. 
    • D: Analgesia with morphine 
    • E: Check electrolytes (even if only by ABG); maintain K+ around 4.5 and Mg++ around 1.0 mmol/L.
    • F: Check renal function to predict risk from contrast; commence pre-hydration with 1-2ml/kg/hr if there is known renal dysfunction
  • Supportive pharmacotherapy:
    • Nitrates - sublingual and then infusion if pain is still poorly controlled
    • Dual anti-platelet therapy (aspirin + clopidogrel/prasugrel/ticagrelor): strictly speaking, one could limit oneself to aspirin alone if the risk stratification put this guy into a low risk category, but already the combination of ST elevation and ongoing chest pain places him into a high risk category which merits DAPT according to the NHF guidelines.
    • Heparin infusion (same reason, risk category for rebound ischaemia is high)
  • Definitive management
    • Thrombolysis (contraindications to thrombolysis are discussed in the chapter on pulmonary embolism)
    • Urgent transfer to cardiac cath lab in nearest hospital capable of percutaneous intervention
    • Hand-over to medical retrieval team and receiving cardiologist

In general, it seems in Australia about 26% of ACS patients fall into this category (i.e. they need transfer to definitive management). The hospital is described as "small and remote", which presumably means that the time to PCI would be more than 30 minutes. The NHF recommend immediate thrombolysis followed by transfer to the nearest cath lab within 24 hours. The logistics of the transfer itself would be unique to the geography of the scenario, and would depend on what facilities for retrieval and PCI are available to this regional doctor. There would be obvious implications if he were surrounded by farmland, in the middle of the outback, aboard an oil platform, or in the Antarctic.  

References

Chew, Derek P., et al. "Acute coronary syndrome care across Australia and New Zealand: the SNAPSHOT ACS study." Medical Journal of Australia 199.3 (2013): 185-191.

Sørensen, Jacob Thorsted, et al. "Urban and rural implementation of pre-hospital diagnosis and direct referral for primary percutaneous coronary intervention in patients with acute ST-elevation myocardial infarction." European heart journal 32.4 (2011): 430-436.

Chew, Derek P., et al. "National Heart Foundation of Australia & Cardiac Society of Australia and New Zealand: Australian clinical guidelines for the management of acute coronary syndromes 2016." Heart, Lung and Circulation 25.9 (2016): 895-951.

Hofmann, Robin, et al. "Oxygen therapy in suspected acute myocardial infarction." New England Journal of Medicine377.13 (2017): 1240-1249.