Intraoperative Myocardial Ischaemia

Emergency Quick Reference Guide

V. 1.02

01 – 2013

1

Intraoperative Myocardial Ischaemia

Sign: ECG: ST-Segment depression/elevation, new T-wave inversion, new dysrhythmias
Goal: Reduction in myocardial oxygen consumption & increase in myocardial oxygen delivery
Oxygenation

• 
  Increase F_iO₂ 100% (SpO₂ > 94%)
  
• 
  Correct anaemia.
  

Check Hb and consider transfusion (aim Hb 7 – 9 g/dl)
Stress Response

• 
  Check depth of anaesthesia (avoid stimulation if possible)
  
• 
  Sufficient analgesia
  

Myocardial Perfusion Pressure

• 
  Increase perfusion pressure
  

Consider Noradrenalin 5 – 10 mcg i.v. if HR > 90/min

Consider Ephedrin 5 mg i.v. if HR < 90/min
Heart Rate

• 
  Titrate to desired heart rate while avoiding Hypotension
  
• 
  Goal 60 – 80 beats/min
  

Consider Esmolol 0.25 - 0.5 mg/kg i.v. (± 50 – 200 mcg/kg/min)

Consider Metoprolol 2.5 mg i.v.
Contractility

• 
  Increase contractility
  

Consider Dobutamin 2 – 4 mcg/kg/min
Preload

• 
  Decrease preload
  

Consider sublingual Nitroglycerine (NTG) initially or

NTG infusion 0.5 - 1 mcg/kg/min

Monitor carefully
Volume status

• 
  Avoid hypovolaemia
  

Consider volume load 20 ml/kg

Consider further actions

• 
  Anticoagulation (Heparin and/or Aspirin)
  
• 
  HDU/ICU admission
  

Multi-lead ECG monitoring, invasive monitoring, TEE, 12-lead ECG asap, repeated lab chek for troponin, CK, CK-Mb etc.

• 
  Coronary intervention
  
• 
  Intra-aortal balloon pump (IABP)