Topic 4 Flashcards
Pre-Bypass includes (6)
- Review the patient chart.
- Calculate/ determine the necessary blood flow
- Determine proper cannulas required for procedure
- Calculate drug doses
- Calculate predicted hematocrit
- Discuss with surgeon (predicted hct and plan for blood product usage)
Pre-Bypass Checklist=
Checklist that is completed prior to handing up the lines (most of it)
-Usually has a component to complete once lines are up at the field just prior to initiation of bypass
Pre-Bypass Checklist section-
Patient
Chart reviewed
Procedure verified
Pre-Bypass Checklist section-
Sterility
Checked for package integrity/ expiration date Heat exchanger(s) leak tested
Pre-Bypass Checklist section-
Pump
Speed controls operational
Roller heads smooth and quiet
Occlusions set
Flow meter in correct direction/ calibrated
Flow rate indicator correct for patient and tubing size
Holders secure
Pre-Bypass Checklist section-
Electrical
Power cords securely connected
Pre-Bypass Checklist section-
Gas Supply
Gas line securely connected
Blender functional
Hoses leak-free
Gas exhaust is unobstructed
Pre-Bypass Checklist section-
Lines/Pump Tubing
Connections secure Tubing direction traced and correct No kinks noted One way valve(s) in correct direction Debubbled/leak-free Patency of arterial line/ cannula verified
Pre-Bypass Checklist section-
Cardioplegia
Solution(s) checked
System debubbled/ leak-free
Pre-Bypass Checklist section-
Safety Mechanisms
Alarms operational and engaged
Arterial filter/ bubble trap debubbled
Cardiotomy reservoir vented
Pre-Bypass Checklist section-
Monitoring
Temperature probes in place and calibrated
Pump pressure monitors calibrated
In-line and/or online sensors calibrated
Oxygen analyzer calibrated
Pre-Bypass Checklist section-
Temperature control
Water source connected and functional
Pre-Bypass Checklist section-
Supplies
Tubing clamps available Drugs available and properly labeled Solutions available Blood available Sampling syringes/laboratory tubes available
Pre-Bypass Checklist section-
Anticoagulation
Heparin time and dose verified
Anticoagulation tested and reported
Pre-Bypass Checklist section-
Backup
Hand cranks available
Emergency lighting available
Duplicate circuit components available
Preparing to Initiate – Handing up lines=
- Prime was recirculating warm.
- Arterial AND Venous Lines clamped
- Lines handed up
- Someone will ask to divide the lines.
- They will remove the pre-bypass filter
Preparing to Initiate - Heparin=
Heparin is given
- Loading dose usually 300units/kg given via central line
- 3-5 minutes later draw an ACT
- Goal of 480 seconds for initiation of bypass
- Suckers may be turned on once ACT reaches 2x baseline
Once heparin is in, surgeon will put in
purse string sutures
Arterial Cannulation=
- De-air arterial cannula and clamp the cannula
- Bring up arterial line to the cannula
- Will ask to “come forward”/ “roll up”/ “trickle flow”…
- Turn on arterial pump SLOWLY!!
- Will make a wet-wet connection to the arterial cannula
- Check for air/bubbles
After arterial cannula is placed=
- Surgeon will remove clamp on arterial cannula
- Check for pulsations
- Make sure there is adequate line pressure, and adequate pulsations
- May be asked to do a test transfusion
- Make sure the cannula is in fact in the aorta and not in a false lumen/ misplaced.
After arterial cannula placement is secure=
- Venous cannula will be placed
- Retrograde cardioplegia cannula placed
- Now all lines should be placed, we should be ready to go on bypass.
- ACT should be complete by this time
Immediately pre-bypass=
- Double check you’re ready!!
- Everything’s clamped that should be clamped.
- Last chance to change anything and to check/tighten any and all connections
- FiO2 is preset
- CDI is ready to be turned on
- Timers are ready to be turned on
- Heater-cooler is set appropriately
Initiation of Bypass=
- Surgeon will instruct to “go on bypass”/ “let’s go on”
- Repeat command – LOUD!!! “Going on bypass”
- Then go on
- Start arterial pump first slowly
- Give a little preload
- Remove clamp from the venous line-Watch your level
Initiation of bypass once clamp is removed from venous line=
- Keep turning up arterial pump until you reach full flow
- Open shunts
- Turn on gas flow
- Start your timers
- Announce “On bypass at _______”
- Get to full flow
- Most places announce when full flow is obtained (“At full flow!”)
- Anesthesia stops ventilating
Just started bypass, what do you check/scan
- What are we flowing?
- Arterial Line Pressure?
- Oxygen started? Arterial sat coming up?
- SaO2 / SvO2 normal?
- Patient blood pressure normal?
- Temperature – time too cool?
After bypass is started and you completed your checks/scans and are stable, what do you do next
- Turn on Anesthetic Gas (Vaporizer)
- Get ready for AoXC placement
- Make sure CPG line is filled / clear of bubbles to the table
- Cool to desired systemic temperature
- When you’re settled, draw ACT- Never get caught behind with heparinization
Cross Clamp Placement=
- Once you’re cool enough, and surgeon is ready, they will instruct “Flow Down”. Repeat command-Do the action- Confirm the action
- AoXC on- Listen for the clicks of the clamp
- The surgeon will tell you “Cross clamp on, come back up on flow”. Repeat command- Come up on flow gradually
- Watch line pressures
Cardioplegia=
After the AoXC is on, Cardioplegia will be given.
- Surgeon will instruct, “Start Cardioplegia”- Repeat command- Start cardioplegia
- Watch delivery pressures
- Notify surgeon of flow and pressures
- Give antegrade and retrograde doses
What do you manage while running the case?
- Manage Volume/ Fluid Balance (Blood products and Hemoconcentration)
- Manage Anticoagulation
- Manage Hypothermia
- Manage Blood Gases (Acid/Base Balance)
- Management of Myocardial Protection
Cardiopulmonary Bypass-
Used to provide _____ and ______ for the patient while the heart is stopped
blood flow
respiration
Cardiopulmonary Bypass is a pathophysiological
insult on the body
Role of Perfusionist=
minimize the insult so that the internal regulatory systems can be maintained and reset once CPB is terminated
Adequacy of Perfusion=
- Keep the patient safe!!!!! DO NO HARM
- Supply the metabolic need of each tissue according to its need
- Respiratory support / status
- Hemodynamic support / status
- Acid-base status
- Anesthetic support / status
- Cerebral / myocardial protection
Goal of perfusion is to
supply the metabolic need of each tissue according to its demand.
Important factors to the adequacy of perfusion include
- Pressure
- Flow
- Perfusate (hemodilution)
- Temperature (hypothermia)
- Oxygen consumption
Adequacy of Perfusion Determinants
- Maintain calculated flow rates
- Mean arterial pressure ~80-85 mmHg
- SVO2 > 70%
- Urinary output between 0.5 to 1 mls / kg / hr
- Acid-Base status does not indicate metabolic acidosis
- Level of anesthesia-Paralyzed, proper level sedation
Normothermia range necessary for proper organ function
80-100 mmHg
Decreased perfusion pressures of ______ result in cerebral injury / kidney function reduced
~50-60 mmHg
Increased perfusion pressures > 100 mmHg result in
- increased intracranial pressures
- excessive blood return to heart
- fluid shifts create edema
- increased SVR may decrease tissue perfusion
Flow Rates can be calculated two ways
body wt. (mls / min / kg) cardiac index (L / min / m2)
Average flow at normothermia for adults
60 to 70 (mls / min / kg)
2.2 to 2.6 (L / min / m2)
Average flow at normothermia for pediatric
80 to 100 (mls / min / kg)
2.4 to 2.8 (L / min / m2)
Average flow at normothermia for neonate
120 to 150 (mls / min / kg)
3.0 to 3.4 (L / min / m2)
Preparation for Termination=
- Surgical correction is complete
- Should be in the process of rewarming
- Some cross clamp drugs should be given (lidocaine, mannitol and magnesium sulfate)
- Surgeon will instruct “Flow down”-Repeat command-Confirm action
- Surgeon will remove the AoXC
Preparation for Termination after AoXc is removed=
- Surgeon will let you know “Cross clamp is off”
- May or may not instruct “Flow back up”
- Confirm: “Cross clamp off at _____. Coming back up on flow”- Come back up on flow gradually
- . Watch pressures
- Temporary pacemaker is placed- Usually
Final Checks before termination=
- Should do an ABG close to AoXC removal
- EKG is acceptable
- Hct is acceptable
- Potassium is acceptable- Will drop about 1.0mEq/L in the immediate post CPB period
- Check vents to see if any are still on
- Anesthesia is ventillating the patient
- PA Catheter is in the proper postion
- Bed is level and the transducers zeroed
Termination of bypass=
- Partially clamp the venous line
- Watch filling pressures (CVP/PA)
- Watch level
- Have a hand on the arterial pump head knob
- When filling pressures reach the target number, turn the pump down and maintain that filling pressure
Termination of bypass after target filling pressure has been reached=
- Maintain that volume in the reservoir
- When instructed, take a bigger bite of tubing on the venous line
- Maintain the filling pressures
- Turn down the pump again
- Maintain
- Continue to fill the patient
- Come down on flow until you are off bypass
- Off bypass!
Once off bypass=
- Turn off shunts (purge line, mannifold(s))
- Clamp your arterial line
- Gas flow off
- Vaporizer off
- Timers stopped
- CDI off
- Announce “OFF BYPASS @ ________”
- Be prepared to transfuse residual pump blood via arterial cannula if needed or chase the circuit
chase the circuit=
transfuse most of the pump blood in the reservoir. Add crystalloid to the reservoir. This crystalloid will keep the circuit primed while displacing all the good pump blood back to the patient
Post Bypass=
- Protamine given-PUMP SUCKERS OFF!!!
- Surgeon will decannulate
- Process pump blood (Cell saver, Hemobag/ hemoconcentrator)
- Restock
- Post CPB ABG/ACT
- Clean up
- Take lines from the table
- Dispose of pump
