Surgical Management of CAD (Powerpoint1) Flashcards
Why is the Left Main artery not grafted directly?
It is inaccessible without dividing the pulmonary artery and the aorta.
Which artery supplies 50% of the blood flow to the left ventricle?
The LAD (Left anterior descending.)
Which artery supplies blood flow to the left atrium?
The circumflex (Cx)
The ramus supplies blood flow to which area of the heart?
The LV (but this artery is not present in everyone.)
What is the reason for inducing hypothermia during cardioplegia?
Hypothermia reduces myocardial oxygen demand.
During CPB, where is the arterial cannula placed?
Into the aorta.
During CBP, hwere is the venous cannula placed?
Into the RA.
Why is aortic sclerosis a contraindication for CABG?
Aortic sclerosis prevents safe cross clamping of the aorta and has increased risk of stroke.
Activation of mast cells during CBP, causes histamine release. What is the effect on the vascular system?
- Capillaries become leaky
- Smooth Muscle contracts
- Vasodilation
Why do platelets lower after CBP?
Platelets adhere to the synthetic substances of the pump.
Why are platelets less effective after CBP?
Hypothermia causes platelet dysfunction.
What effect does the CBP have on red blood cells?
The suction of the machine can cause hemolysis.
Which catecholemines are increased during CBP?
- Epinephrine (10x increase in production
- Norephinephrine (4x increase in production)
- Vasopression (20x increase in production)
What happens to cortisole production during CBP?
Cortisol production increases (Raising serum blood sugar.)
Why is there less insulin after/during CBP?
Hypothermia of the pancreas impairs insulin production.
Also, insulin binds to the oxygenator tubing.
Activation of what system during CBP causes increased vasopressin production (ADH)?
R-A-A-S Renin-Angiotension-Aldosterone System
What happens to sodium? To potassium? During CBP
Sodium retention is promoted
Potassium is excreted
How fast does ECF (Extracellular fluid) build up during CBP?
800 mL/hour of bypass.
Protamine reaction will manifest in what symptoms?
Low SVR, flushing, hypotension
Why is the IMA the first choice for conduits?
It has 90% patency at 10 years after surgery.
The radial artery is the second choice for conduit but has what complication?
Vasospasm - treat with nitrates or calcium channel blockers after surgery
Normal CVP
2-6
Normal PAOP
6-12
