Perfusion (part 2) Flashcards
What are the two types of pump heads?
Roller and centrifugal pump
Which pump head is afterload independent?
Roller pump
Which pump head needs flowmeter?
Centrifugal pump
Which pump head has possibility of retrograde flow if pump stops?
Centrifugal pump
Which pump head is cheaper?
Roller pump
Which pump head is portable?
Centrifugal pump
Which pump head is short term use only?
Roller pump
Which pump head has circuit disruption from excessive line pressure?
Roller pump
Which pump head has greater risk of air embolism?
Roller pump
Which pump head has more priming volume?
Centrifugal pump
Which pump head is mostly used by CPB?
Roller pump
Why is the roller pump bulky?
Because it uses 2 rollers
Which pump head is more prone to heat generation?
roller pump
What is the purpose of the 2 rollers in pump head?
it rolls blood through tubing
The roller pump positively displace blood through _________________
peristaltic motion
TRUE OR FALSE:
Centrifugal pump is used because the roller pump can damage in blood components
TRUE
Roller pump produces ____________ while centrifugal pump produces _____________
flow, pressure
The centrifugal pump spins as a result of __________________
magnetic force
When the cone spins in centrifugal pump, it generates ____________
negative pressure = sucks blood creating vortex
What is the range of centrifugal force of centri pump?
2000-4000rpm
Which is more preferred pump head?
Centri pump
This pump head is reserved for more complex surgery of prolonged duration
Centri pump
Which pump head produces less hemolysis and platelet activation?
Centri pump
This component of the CPB acts as a CHAMBER FOR VENOUS BLOOD to drain into before it is pumped into the oxygenator and permits ready access for the addition of fluids and drugs
Reservoir
What are the other function of reservoir?
provides high efficiency filtration, defoaming, and responsible for removing foreign particles
To reduce the risk of perfusion accident, the reservoir needs _______________
to maintain a level of fluid
What are the two types of reservoir?
Hard shell and collapsible
Between the two types of reservoir, which is used for adult cardiac surgery?
Hard shell
This reservoir is comprised of polycarbonate housing, has polyester depth filter, and polyurethane defoamer
Hard shell
What is the function of oxygenator?
It provides an interface of high surface area between blood on one side and gas on the other
For the gas to travel across the interface, the oxygenator must be ____________
constructed with very thin material
What is the requirement for an oxygenator?
needs efficient oxygenation of desaturated hemoglobin and simultaneous removal of CO2
What is the most commonly used ooxygenator?
membrane oxygenator with microporous polypropylene hollow fiber structure
The internal diameter of membrane oxygenator is ________
100-200um
This is used to reduce the release of gaseous emboli due to alteration of temperature of saturated blood
Heat exchanger
The heat exchanger is placed _________________
proximal to oxygenator
This acts as the arterial capillary system of CPB machine
Oxygenator
What is the common constituent of all cardioplegia solutions?
High concentration of potassium
The common constituent of all cardioplegia solutions produces ____________________
diastolic cardiac arrest
This component of CPB is used to induce arrest of heart
Cardioplegia delivery system
This method is used to protect the heart or myocardial protection
Cardioplegia delivery system
The electromechanical arrest from the cardioplegia solution reduces ___________
oxygen consumption
The cardioplegia cannula is inserted _____________
proximally
This cannula is placed distal to plaque
aortic cannula
What does the aortic root vent does?
It separate pump that delivers cardioplegia antigrade to aortic root or retrograde to venous
What is the ratio of cardioplegia of oxygenated blood to crystalloid?
1:1 or 8:1
What is the most common cardioplegia?
Potassium
What are the other constituents of cardioplegia solution?
Bicarbonate, mannitol, magnesium, calcium, adenosine, procane, glucose, glutanone
What is the primary purpose of cardioplegia?
produce rapid diastolic cardiac arrest
This part of CPB contains semipermeable membranes that permit passage of water and electrolytes out of blood
Hemofilters
What are the other terms used for hemofilters?
ultrafilters or hemoconcentrators
What is the purpose of hemofilters?
it provides driving force of blood to device (allow blood to filter before returning blood to px)
What is the volume per min fluid removal?
30-50mL/min
What is the size of molecules na pwede maremove ng hemofilter?
up to 20,000 Daltons
When is the hemofilter utilized?
during and after CPB
Hemofiltration is mainly used ____________________
to manage hyperkalemia or acidosis
This device provides real time blood gas, acid-base, Hgb Hct, electrolyte analysis. It utilizes optical fluorescence and reflectance
Terumo CVI 500
This device is the real time saturation and hemog monitoring system. Non-invasive simultaneous arterial saturation monitors.
Spectrum Medical
The monitoring device is placed in circuit for blood gas analysis using ____________
electrochemical electrodes and cuvettes
The monitoring device is placed in external tubing for blood gas analysis using ____________
Light absorbance or reflectance
What does the primary perfusionist does in pre-bypass checklist?
check mismong nakalagay sa checklist
What does the secondary perfusionist does in pre-bypass checklist?
goes through list and check if nacheck lahat
This is where the minimum requirements for cardiopulmonary bypass procedures is stated
pre-bypass checklist
What should be checked prior to CPB?
review patient for allergies, significant comorbidities or conditions like diabetes, anemia, thrombocytopenia, hyperkalemia
blood availability in dk
note height and weight for heparin dosage (300mg/kg) and select appropriate size of venous and arterial cannula for flow rate
What should be the activated clotting time?
more than 400secs
To reduce the risk of perfusion accident, ____________________
dapat di mawawalan ng laman ang reservoir
This is the deairing of CPB circuit consisting of a mixture of crystalloids and colloids
Priming solutions
Priming causes _______________________
hemodilutions which improves flows during hypothermia
What are the commonly used additives?
Heparin, bicarbonate, mannitol, calcium, and steroids
What is the measurement of prime to ensure adequate anticoagulation?
1000-2500 U/L
How many heparin is added to prime?
3-4units/mL
What is the target Hct in bypass?
21-24% (adults) and 28-30% (children)
How to assess target Hct?
Compute for TCV (Total circulating volume)
How to compute for TCV?
Px’s blood volume + priming volume
How to compute for target Hct?
Px’s blood volume + Hct/TCV
How to compute for the blood required on prime?
(Target Hct x TCV) - Px’s Hct x PBV ) / Hct of donor
What is the cardiac index for a 70kg adult w/ normal metabolism at 37 deg C?
2.2-2.4L/m2/min
How much prime of bicarbonate is used as buffer when unbalanced priming solutions are used?
25mmol/L
The mannitol additive is a __________________
osmotic diuretic and free radical scavenger
Calcium as additive is ____________________
needed if citrated blood is added to the prime to prevent chelation of calcium
Steroids is used as additive to ____________________
attenuate systemic inflammatory response to CPB (evidence weak)
TRUE OR FALSE:
Clotting in CPB may cause death
TRUE
Need to always check for ACT every 30-40mins during bypass
What is a normal ACT?
80-120 secs
What does ACT assess?
the adequacy of heparinization, affected by hemodilution and hypothermia
This is the standard anticoagulant for CPB
Unfractionated heparin (UFH)
What are the characteristics of UFH?
Relatively safe easy to use fast onset of action measurable, titratable reversible cost-effective
Aside from UFH, the other anticoagulant used are: ________________________________
Low molecular weight heparin (Danaparoid)
FIbrinolytics (Ancrod = viprinex)
DTI (direct thrombin inhibitors = lepirudin, argatroban, bivalirudin)
How would you say that a patient has heparin resistance?
Failure to achieve target ACT even with high dose of heparin (80-1000U/kg)
Heparin resistance can be observed among ______________________
geriatric recent heparin exposure nitroglycerin infusion thrombocytosis antithrombin III deficiency
How to treat heparin resistance?
administer antithrombin III (1000 units) or FFP (2-4units)
This is the main method of cerebral protection
Hypothermia
TRUE OR FALSE:
Hypothermia has presumed organ protective effects
TRUE
In perfusion, maintenance of higher perfusion pressure despite hemodilution, as blood viscosity increases ________________
theres hypothermia
What are the 4 types of hypothermia?
Tepid
Mild
Moderate
Deep
What is the use and temperature of Tepid hypothermia?
33-35deg C
good for short operations, healthy Px w/ high HCT
What is the use and temperature of Mild hypothermia?
31-32 deg C
Protection of beating heart and neurological systems
What is the use and temperature of moderate hypothermia?
25-30 deg C
Protection of non-beating heart and neurological systems
What is the use and temperature of deep hypothermia?
15-20 deg C
DHCA (deep hypothermic circulatory arrest) for typically 40-50 minutes
To prevent cerebral injury, it is important to observe the ____________
rate of rewarming and cerebral hyperthermia
What are the core monitoring sites of tempearture?
rectum
urinary bladder
esophagus
pulmonary artery
This gives an estimate of cerebral temperature
Nasopharyngeal temperature
In acid base management of perfusion, with cooling, CO2 becomes __________
more soluble = DEC partial pressure causing alkalosis
This is used in CPB to ensure small enough para makapasok sa semipermeable fiber of hemofilters
exogenous sodium bicarbonate (NaHCO3)
Weaning is ____________________
process of transition from CPB to normal, physiological circulation
Weaning requires ______________
excellent communication and teamwork between perfusionist, surgeon, and anesthetist
What is the first step of weaning?
re-warming of core temperature above 36 deg C
Hgb concentration should be ______________ prior to termination of CPB
> 7.5g/dL
Prior to weaning, you must _____________
assess cardiac function (rate, rhythm, contractility)
What are the complications in perfusion?
selective cerebral perfusion plaque dislodgement and dissection massive air embolism qualitative and quantitative platelet dysfunction inflammatory response hypotension acute kidney injury (AKI) acute respiratory distress syndrome anesthesia-induced atelectasis