Conduct of cardiopulmonary bypass

Chart of Tubing diameter for different patients weights

How do you calculate hemodilutional hematrocrit?

(Pt blood volume x wt x Hct) / Pt blood volume x wt + priming volume (mL)

What shoulds ACT be before initiating bypass?

>2.5 times baselines value

What should ACT be maintained during CPB?

400-600

When do you check ACT?

Every 20 minutes during normothermic and every 30 during hypothermic CPB

How to calculate blood flow rate in children

What clinical variables are monitored during bypass?

• Total systemic blood flow

• Central venous pressure (CVP), PA and LA pressures

• Urine output, temperature of perfusate and patient

• Depth of anesthesia

What laboratory variables are monitored during bypass?

• Hct, arterial blood gas (ABG), CO2

• ACT

• Mixed venous saturation to indicate adequate tissue perfusion

• ECF

• Neuromonitoring - NIRS, transcranial doppler

What circuit variables are monitored?

• Venous reservoir volume

• Induction and reversal of hypothermia

• Systemic line pressure

What should venous reservoir volume be equal to?

25% of systemic blood flow to allow for 15 second reaction time

What are desired values on pump?

How often do you perform ABG?

Every 10 minutes

What should you change if you have issues with blood gases?

How do you correct hypocalcemia?

Administer calcium chloride

What is the function of magenium in CPB?

Vasodilation of coronaries and prevent arrythmias

What are steps of termination of bypass?

1. Switch off gas flow

2. Switch off water circulation inside heat exchanger

3. Slowly reduce arterial pump flow and occlude the venous backflow

4. Clamp venous line

5. Clamp arterial line