T or F:

The goal of CPB is to provide a motionless heart in a bloodless field while the vital organs continue to be adequately oxygenated.

CPB produces significant physiologic and physical changes in the blood and flow dynamics, including heparinization, platelet dysfunction, coagulopathy, and fibrinolysis.  The change in the blood viscosity can trigger what type of all body response?

How much does the platelet count drop?  Hemodilution also decreases what other factors?

How is the flow different?

CPB induces an all body inflammatory response, causing symptoms similar to sepsis or trauma.

The platelet count may drop by 50% (usually remains > 100,000).

Coag factors are usually decreased.

Flow changes from pulsatile to nonpulsatile

1.  Oxygenator

2.  Venous reserve

3.  Arterial pump

4.  Cardioplegia circuit

5.  Ventilating circuit

6.  Monitoring and safety systems

7.  Various filters

Fill in the blanks.

Desaturated, venous blood exits via the ___1____ cannula and is diverted to the ________2______

by gravity siphon drainage through a large bore PVC tubing.  Since the venous drainage depends on _____3______, the patients  __________4_______, the position of the line, and the __________5_______ impacts the flow.  Table _____6_______ can affect the drainage to the pump!

1.  RA/IVC

2.  Venous reservoir

3.  gravity

4.  intravascular volume

5.  line resistance

6.  Height

When is cardioplegia given, and why?

What is the temperature, and how is it dosed?

Immediately following aortic cross clamping, to reduce myocardial ischemia and to quickly arrest the heart (electrical and mechanical).  It is usually given then every 15-30 minutes during aortic cross clamping.

It is cold, usually < 10 degrees, and is dosed based on pt weight or BSA.

What is the most common cardioplegia solution?

Why is antegrade and retrograde delivery usually used?

Hyperkalemic crystalloid mixed with blood (4:1 blood to crystalloid).

To reach areas of the myocardium beyond coronary blockage.  Retrograde does not always provide great protection to the right side of the heart, so both retrograde and antegrade may be used, as well as directly into the coronary ostia.

Adults usually have asanguineous priming, unless the patient requires an exchange transfusion prior to perfusion, such as in sickle cell or cardiac transplant.  Pediatrics usually used sanguinous, because the priming takes a lot of solution (2 liters), and the kids circulating volume is a lot less.

Asanguinous priming is used when the HCT is anticipated to be > 21% (some places 24%).  If the hct is expected to be less, they will add blood to the priming.  

The most commonly used solution to prime CPB is balanced solution with a pH and lyte profile similar to whole blood.  Why might the following additions be made?

1.  Heparin

2.  Bicarbonate

3.  Antifibrinolytics

4.  Mannitol

5.  Albumin or hespan

6.  Corticosteroids

1.  To reduce clot formation.  Although heparin is given prior to aortic cross clamp, once the pt goes on CPB, the level will be reduced.

2.  The circuit of the CPB contains acidic preservatives.

3.  Helps reduce blood loss during surgery.

4.  Helps preserve renal function

5.  Helps maintain colloid osmotic pressure and coat the artificial blood surfaces.

6.  Help with the inflammatory response

What are some benefits of hemodilution with CPB circuit priming?

How does hypothermia affect viscosity?

Decreases viscosity, RBC trauma, enhances tissue perfusion at a lower flow rate and reduces blood loss and need for banked blood.

Increases.

What happens with electrical failure while on CPB?

What if there is a run away arterial pump head?

What is the problem with pump creep (a roller that continues after it has been stopped)?

Has a battery backup that lasts 1 hour.  Use hand crank.

Pull the electrical plug, clamp the venous and arterial lines, move the tubing to a head that is functional.

Air may be entrained.

Lets talk about the risks of surgery...

What are 3 big risk factors associated with open heart surgery?

Who fairs better... chicks or dudes?

How does time on pump affect affect outcomes?

1.  Age

2.  Functional status

3.  Multiple surgical procedures

Operative mortality in women is twice as high as men.

Although it was thought to be a factor, mortality and cognitive impairment are the same whether on or off pump.

What medications should be taken up until surgery?

How do you feel about pre-medicating these fools?

When should you place lines?

All cardiac drugs except diuretics.  ACE inhibitors might cause hypotension on induction, but know that they're on it, and deal with it, bitches.

If they are unstable, I wouldn't give until they are hooked up to all their monitors...

I think this is going to go back to the "whatever-you-want-to-do-as-a-student-is-wrong" phenomenon... some place lines before induction, so they can see the hemodynamic response to induction, some do it after induction.  If it's an emergency, saving the life is priority, not swans...

Cath lab report, carotid dopplar studies, echo report (tells about valvular lesions), labs.  If pt has a UTI, better cancel.

You want to look for LV function (but don't be fooled by a normal EF!!), regurg vs stenosis, coexisting disease.

2 18g peripheral IVs

A-line (think about whether using radial graft, LIMA, RIMA, etc)

Central line--8.5 Fr for regular, 9 Fr for redo

PA catheter

Make sure the line work before the case starts!

Place in steep head-down position and be prepared to temporarily occlude carotid arteries.

Administer pressors to raise perfusion pressure

Ventilate lungs vigorously with 100% oxygen, administer steroids and mannitol.

Air for early patient arousal and assess for normal mentation.