test 10 Flashcards
Role of Perfusionist
- minimize the insult so that the internal regulatory systems can be maintained and reset once CPB is terminated.
- TEAM Player
Monitoring the patient
status
Cardiac Electrical Activity Cardiac Output Blood Pressure Filling Pressures Metabolic Status Temperature Renal Function Cerebral Electrical Activity Muscle Activity TEE (Trans-esophageal echocardiography)
Conduct of Cardiopulmonary
Bypass
Setup & Prime Manage patient coagulation status Initiate bypass Ensure adequacy of perfusion Manage patient blood volume Manage blood and body temperature Provide myocardial protection Terminate bypass Tear-down & clean-up
Setup: What are we doing?
Read the patient chart
Patient history, condition
Patient pathophysiology (Cardiac / other)
Planned conduct of operation by surgeon
Setup: Equipment Selection
Select equipment appropriate for surgery and
patient needs
Considerations:
Needed priming volume
Choice of cardioplegia solution and administration
technique
Need for hemoconcentrator / diuretics
Need for large venous reservoir / use separate cardiotomy reservoir
Optional monitoring equipment
Coagulation Management
Need to give heparin to avoid clot w/in circuit
Initial loading dose 3.0-4.0 mg/kg
Take an ACT after about 4-5 min
ACT to be 2x baseline before suckers turned on, and above 480sec prior to initiation of CPB
Maintenance will depend on pt response
Checklist – Initiation of
Bypass
Aortic and venous cannulae correctly connected
Cannulae de-aired – check for pulsations / patency
ACT adequately elevated (480sec +)
Necessary drugs are available and prepared (ie. BP)
Transducers zeroed and calibrated
Target blood flow calculated – correlated to pump rpm’s
Gas flow and FiO2 established per manufacturer’s specifications
Tubing clamps in proper positions
Alarm systems attached and ready to be activated
Final check of connections
Visually follow AV loop one last time
Going on Bypass
Surgeon instructs to “go on”
Repeat command “going on” then go on
Initiate forward flow (check line pressure)
Release venous line clamp as you come up on flow
Come up to full flow (turn on gas flow, timers, shunts, and anesthetic gas)
Once on, then what
Safety Checks of: Blood Flow Art Line Pressure Oxygenation Saturations Patient pressures Temperature Anesthetic gas Coagulation Safety Device Check
Adequacy of Perfusion perfusion parameters
Total systemic blood flow Input pressure waveform Systemic venous pressure Hematocrit Prime composition Arterial blood oxygen, carbon dioxide Perfusate & patient temperature
Adequacy of Patient perfusion parameters
Systemic vascular resistance Total body oxygen consumption Mixed venous blood oxygen levels Lactic acidemia / pH Regional / organ blood flow Organ function
Adequacy of Perfusion determinants
Maintain calculated flow rates Mean arterial pressure ~80-85 mmHg SVO2 > 70% Urinary output on bypass should be between 0.5 to 1 mls / kg / hr Level of anesthesia (fast tracking)
Hemodynamic Support
Normothermia range of 80-100 mmHg
Decreased perfusion pressures ~50-60 mmHg
cerebral injury / kidney function reduced
Increased perfusion pressures > 100 mmHg
increased intracranial pressures
excessive blood return to heart
fluid shifts create edema
increased SVR may decrease tissue perfusion
Adequacy of Perfusion dealing with age and size
Flow requirements are size (BSA) and Temperature
dependent
Newborns require about 2 times more oxygen/ body weight
Requirement peaks about 2mo old.
Exponential decline as age increases.
Distribution of Blood Flow
- as flow decreases, the flow through the brain and heart stays around the same
- as Q decreases, the rest of the organs drop dramatically
the volume low
- is HCT low?
- How low?
- is the patient old (young can handle low HCT)
- is the patient sick?
- how much longer is CPB?
- short: add crystalloid, albumin, reassess
Myocardial Protection
Administration temperature
Type of solution
Routes of Administration (antegrade, retrograde)
simplest form of cardioplegia delivery
-iv bag of straight crystalloid through roller head to aortic root
more complicated form of cardioplegia delivery
-using root vent, switch valve and with pressure bag on crystalloid, give straight crystalloid cardioplegia
most complicated form of cardioplegia delivery
Using ice bucket to keep CPG cold Has recirculation option bubble trap
Normal cardioplegia delivery
-use bigger ratios to avoid hemodilution
Checklist – Termination of Bypass
Patient temperature Blood gases Electrolytes & glucose Hematocrit Anticoagulation Ventilator on Pump vaporizer off Pressure monitors zeroed and calibrated Filling pressure available Normal sinus rhythm Cardiac contractility Pharmacologic agents available
Goal of Termination
Smooth transition from mechanical pump back to the heart as source of blood flow Optimize various cardiovascular variables Preload afterload heart rate conduction contractility oxygen supply/demand ratio
Termination of Bypass
- turn off shunts
- just past half bit on venous line (venous reservoir decreases)
- wait until PA diastolic about 6
- turn down flow to roughly 50% of original flow
- clamp at a 90 degree angle by the other clamp occluding the rest of the tubing by a half
- run down flow half of what it was previously
- always be watching pressure
