Off Pump coronary Artery Bypass Surgery

Question 1

Which vessels are commonly harvested for use in coronary artery bypass graft surgery

Answer 1

Saphenous Vein
Radial Artery
Internal Mammary Artery

Question 2

What are the theoretical advantages of off-pump coronary artery bypass grafting vs the on-bypass technique

Answer 2

Reduced platelet dysfunction
Reduced consumption of clotting factors
Reduced risk of inappropriate fibrinolysis
Reduced risk of blood transfusion due to coagulation defects
Reduced risk of renal dysfunction
Reduced risk of SIRS
Reduced risk of direct aortic damage
Reduced risk of air emboli
Reduced risk of neurological dysfunction
Reduced risk of fluid overload or fluid depletion
Reduced risk of electrolyte imbalance
Reduced risk of hypothermia and its consequences on wound healing and coagulation
Earlier extubation
Shorter or reduced ICU stay
Reduced cost
Overall, reduced mortality and morbidity

Question 3

What might cause haemodynamic instability during an off-pump coronary artery bypass grafting operation

Answer 3

Ischaemia due too vessel anastomosis (can be minimised using shunts)
Manipulation of the heart for access, e.g. lifting the heart out of its pericardial sac
Impaired filling due to the immobilisation device
Arrhythmias due to ischaemia, manipulation and reperfusion
Bleeding

Question 4

How can haemodynamic instability during an off pump coronary artery bypass be minimised

Answer 4

Minimise heart manipulation and stop manipulation if major instability

Minimise the periods of ischaemia through the use of shunts

Keeping the heart rate at a low or normal rate, and consequently minimise the oxygen requirement and reduce the effect of periods of ischaemia

Monitor and treat any electrolyte imbalances (keep K+ over 4.5 and give Mg2+ routinely)

Ensure the patient is adequately filled, this can be guided by cardiac output monitoring

Good communication between anaesthetist and surgeon

Question 5

What methods are there to minimise perioperative hypothermia during off pump coronary artery bypass grafting

Answer 5

Ensure the patients temperature is normal before the start of the case and keep checking intraoperatively (targeting a normal temperature)

Minimise the periods of leaving the patient uncovered

Warmed IV fluids

Forced Air Warming Blanket

Under body Resistive Heating Mat

Raised ambient temperature of the theatre brought up to a minimum of 21 degrees C

Foil Hat