35 Post surgery patient

Question 1

What are the effects of general anaesthesia and cardio-pulmonary bypass on LV function?

Answer 1

GA can cause vasodilatation which decreases SVR which decreases afterload, vasodilatation which causes hypotension and hypoperfusion, myocardial depression (global systolic and diastolic dysfunction), sympathetic block which can decrease the chronotropy (HR) and inotropy (contractility) which can decrease preload.

CPB can decrease SVR which decreases afterload, and cause stress and an inflammatory response which can decrease LV function.

Question 2

What are the common echo characteristics post-surgery?

Answer 2

Common TTE findings post-cardiac surgery include cardiac tamponade, RWMAs and valvular dysfunction.

Cardiac tamponade is common because the trauma, and the surgery, can cause inflammation causing a pericardial effusion and can cause a pericardial haemorrhage. RWMAs are common because surgery can cause ischemia and infarction, particularly in patients with CAD, and it can cause reperfusion injury. Valvular dysfunction is common if the surgery is unsuccessful.

Common TTE findings post-general surgery include emboli, MI and volume overload.

Emboli are common because surgery can introduce air or move fat. VTE are common because patients are immobile for a long time, surgery creates a hypercoagulable state, and central lines increase the risk of emboli. MI are common because surgery increases stress and affects blood volume and blood pressure which affects myocardial perfusion, particularly in patients with CAD. During surgery, the loss of blood and the maintenance of blood pressure is managed with fluids so, post-surgery, there is a risk of fluid overload.