Anaesthesia for off-pump coronary artery bypass grafting surgery

Abstract 

Coronary artery bypass grafting (CABG) surgery may be undertaken with or without cardiopulmonary bypass (CPB) that is on- or off-pump. Although mortality and the incidences of coronary artery graft occlusion, myocardial infarction and stroke are equivalent, off-pump is associated with less blood loss, transfusion, requirement for inotropes, atrial fibrillation and chest infection compared with on-pump CABG surgery. Traditional high-dose opioid techniques of general anaesthesia should be avoided and either inhalation or total intravenous (IV) anaesthesia may be used. Meticulous monitoring, including electrocardiograph (ECG) and invasive arterial pressure measurement, is required. During grafting, good communication between anaesthetist and surgeon is essential. Maintenance of diastolic arterial pressure (DAP) is the key to preventing myocardial ischaemia and cardiovascular collapse. Surgical positioning for grafting to minimize hypotension is paramount and during grafting, IV fluid loading or vasoconstrictors and inotropes are effective treatments. Correction of bradycardia with atropine 0.3 mg IV or epicardial pacing also helps to maintain DAP. Persisting hypotension may require intra-aortic balloon pumping or conversion to on-pump CABG surgery. As there is less blood loss, there is a minimal requirement for cardiovascular support and early recovery of consciousness associated with off-pump compared with on-pump CABG surgery; patients in some institutions may be managed in a recovery room then transferred to a high-dependency unit, thus bypassing ICU.

Keywords: cardiopulmonary bypass, coronary artery bypass, coronary disease, epidural analgesia, general anaesthesia, hypotension, intraoperative monitoring, vasoconstrictor agents