Cardioplegia and MUF: Topic 4 Flashcards
What do we want in our cardioplegia system in pediatrics? (4)
Small Prime
Good heat exchange
Air handling capabilities
A versatile system
Cardioplegia Circuits may include: (6)
Blood shunt Crystalloid component Blood component Heat exchanger Bubble trap Air detectors
What two components of the cardioplegia circuit may be combined?
Heat exchanger
Bubble Trap
What is the most common heat exchanger in peds? How much prime does it use?
CSC 14
Actually uses 28 cc’s of prime
What are the two functional sizes for retrograde cardioplegia cannulas?
6Fr
10Fr
What is the standard size for the aortic root CP cannula? What kg weight range does it cover?
18 gauge
0-7 kg
What is the smallest size vent cannula you’ll see/
10 Fr
What is the ml/kg for antegrade delivery in peds?
30 mL/kg in pediatric patients.
What does line pressure depend on in antegrade cpg delivery in peds?What is the goal?
Pressure drop across the cpg system (goal is to maintain root pressure approx 70 mmHg)
*Look at your pre-op pressures
Flow in antegrade cpg delivery in peds is dependent on what?
Patient size
In retrograde cpg in peds, balloon is inflated and provides what two functions?
- Prevents backflow
2. Holds cannula in place
Retrograde cpg delivery in peds, flow should be titrated to maintain a coronary sinus pressure of what?
30-40 mmHg
** Do not exceed 40 mmHg on kidlets
What is used to halt the mechanical contractions of the heart and to allow intracardiac procedures to be performed in a motionless, bloodless field?
Myocardial-protection strategies (aka cpg)
Myocardial-protection strategy is designed to sufficiently reduce ________, so that myocardial function can resume at the end of the procedure with minimal dysfunction.
Myocardial oxygen consumption
Blood cpg solution in peds is usually what mixture?
4 parts blood and 1 part crystalloid
The addition of blood to the cardioplegic solution in peds enchances what?
Oxygen delivery, especially at the microcirculation level
What percent of cpg peditratic solutions are blood based?
86%
What percent of cpg pediatric solutions are cystalloid based?
14%
What are the 3 conclusions of the peditratic cpg solutions study?
- Myocardial protection techniques still remained highly variable among congenital heart surgeons
- Perception that del nido and custodial solutions can offer appropriate myocardial protection for longer intervals w/ decreased repeat dosing
- observational study should be considered
Whats the Del Nido Solution dose in peds to maintain arrest
20 mL/kg
Whats the Del Nido solution dose in peds for maintainance
10 mL/kg
What should you deliver Del Nido solution at?
90-180 mL/min
Never give custodial more than how long?
up to 2 hours
HTK
Histidine Tryptophan Ketoglutarate
The addition of _______ may provide a protective effect on the hypoxic- ischemic immature heart.
Magnesium
What effect does magnesium have?
Antiarrythmic, inhibited entry of calcium into the myocytes, and decreased uptake of sodium by myocytes during ischemia
Magnesium is exchanged for __________ during reperfusion.
Calcium
What development has significantly altered blood usage and post op care in pediatrics?
MUF
What is the purpose of MUF?
Allow recovery of the pump blood for the patient while allowing the patient to be in a hemodynamic state to accept the volume is the significant advance for pediatric perfusionists
MUF utilizes _______________ at a specific point post CPB.
a hemoconcentrator
Who developed MUF?
Mr. Martin Elliot (Great Ormand Street/Hospital for Sick Children London UK) in 1985
Why are MUF improvements not sustained 24 hours after the operation?
Pulmonary compliance is affected both by excess fluid form the hemodilutional effect of bypass, as well as the systemic inflammatory response
decreases total body water and removes inflammatory cytokines. Initiation of systemic inflammatory response most likely occurs during rewarming
Can’t overcome capillary leak caused by activated ongoing inflammatory response
MUF starts ________ (before/after) inflammatory cascade has been activated.
After
When is MUF performed?
after CPB is complete and allows filtration of both the patient and remaining contents of the CPB circuit, including the venous reservoir.
In MUF, where is the ultrafilter?
Interposed in the CPB circuit between the aortic arterial line and the venous.
After weaning from CPB, how is the blood removed?
From the patient via the aortic cannula and fed through the ultrafilter; outlet of the ultrafilter is fed to the RA of the patient
Blood flow through the ultrafilter approximates what?
20 mL/kg/min max
When suction is applied to the filter port of the ultrafilter, what is the ultrafiltration rate?
100 to 150 mL/min
What pressure is maintained constant in MUF to achieve continued hemodynamic stability in the patient?
Left atrial or right atrial pressure is maintained
When does ultrafiltration stop?
10-20 minutes OR HCT 40-50
But in reality, when the impatient surgeon makes you.
What are the beneficial effects of MUF?
Total body water is reduced as a direct result of removing the ultrafiltrate
Reduced edema
Reduced hospital stay
Reduced ventilation times
Reduced incidence of pleural and pericardial effusions
What are the arguments against MUF?
Possible air embolism
Circuit complexity and cost
Prolonged exposure to foreign surface
Patient can be concentrated before coming off CPB
Where does air enter in MUF?
Venous side
Endpoints of hemofiltration vary, but can be defined by? (3)
Time
Volume
Hematocrit
In the postoperative period, patients receiving MUF have __________ (smaller/larger) increases in total-body weight.
Smaller
In addition to decreasing edema, hemofiltration _________ (increases/decreases) HCT. What does this translate to?
Increases; translates to increased oxygen-carrying capacity
Removed fluids also contain what?
Inflammatory mediators and vasoactive substances
Clinical studies have demonstrated that MUF is associated with: (4)
Increased ventricular systolic function
Imrpoved cerebral blood flow, cerebral metabolic activity, cerebral oxygen delivery
Pulmonary function, decreased post op ventilation
Decreased postop bleeding, chest-tube drainage, pleural effusions
= Short hospital stays.
