Off Pump CABG & Mechanical Circulatory Devices - Quiz 7 Flashcards by Donny Le

What are the different approaches for doing a CABG?

Thoracotomy - minimally invasive

Full Sternotomy

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Other than the Surgeon & Anesthetist, who else is also required to be in the room for a CABG?

Perfusionist w/ a CPB machine ready

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An Off-Pump CABG usually takes _____ time than a traditional CPB CABG

An Off-Pump CABG usually takes MORE time than a traditional CPB CABG

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What makes a pt. a good candidate for an Off-Pump CABG?

Good LV Function

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How does Fluid Management differ from an On-Pump CABG vs an Off-Pump CABG?

Harder to give large amt of fluid Off-Pump unlike the CPB Machine that can give large amounts extremely quickly

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Normothermia is absolutely necessary during a CABG. What are ways to maintain normothermia?

Monitor Core Temp

Water Thermoregulation Mattress

Heat Preserving Bouffant

↑Room Temp

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What can happen if a pt does not maintain normothermia of 36^o C during a CABG?

Will be unable to Extubate

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Which Antifibrinolytic is normally given for an On-Pump CABG, but NOT given for an Off-Pump CABG?

Aminocaproic Acid (Amicar) - inhibits Plasminogen binding to Fibrin converting it to Plasmin

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What is the dose of Heparin given for an Off-Pump CABG?

Less than it would be for On-Pump CABG

100-200 units/kg w/ a goal ACT > 300

(sometimes full heparin @ 300-400 units/kg)

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What is the reversal for Heparin?

Protamine

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How is the heart visualized during an Off-Pump CABG?

Surgeon uses Footplate Stabilizers & Retractors that Suction & Lift the Heart

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How is the Blood Pressure managed during Verticalization of the Apex to visualize the PDA & Circumflex?

Keep MAP Elevated & Give Volume to counter Extreme Hemodynamic Compromise & Ischemia

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At what point during an Off-Pump CABG does the MAP need to be lowered to 60 mmHg?

During the Proximal Graft Aortic Anastomosis

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What are the Advantages of an Off-Pump CABG?

Less Bleeding

Less Heparin

Normothermia Maintained –> Potential Extubation

No Aortic Cross-Clamp

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Why are Intra-Aortic Ballloon Pumps (IABP) used?

↑Cardiac Perfusion w/ Sync’d Counterpulsation

↑Coronary Blood Flow on Diastole

↓Afterload on Systole

Stabilizes PreOP CABG Pts post MI

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What is used as a supplement for an Off-Pump CABG or for patients who have difficulty coming off the CPB machine?

Intra-Aortic Balloon Pump (IABP)

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What are contraindications for placing a pt on a IABP?

Sepsis

Descending Aortic Disease

Severe PVD

Severe Aortic Regurg.

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What site is the IABP inserted?

Via Femoral Artery

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For an Intra-Aortic Balloon Pump, where does the Tip of the Balloon lie?

At the Junction of Aortic Arch & Descending Aorta

2 cm distal to the origin of Left Subclavian Artery

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How does the Timing of an IABP work?

Timed w/ Dicrotic Notch & Inflates on Diastole when AV Closes to seal and increase pressure, sending blood to the coronary arteries

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When does the IABP deflate?

Study These Flashcards

Deflates right before Systole at the beginning of the R-Wave

What does IABP Deflation do?

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Vacuum Effect

↓Aortic Pressure & ↓Afterload

Facilitates Ventricular Ejection

↓O₂ Demand

What is happening here?

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Premature Deflation during Diastole

Suboptimal Perfusion

Backflow

Angina

↑O₂ Demand

What is happening here?

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Deflation in Late Diastole as AV Begins to Open

No Afterload Change or ↑Afterload

↑O2 Demand

Prolonged Isovolumetric Contraction

What is happening here?

**Inflation before AV Closure** ↑LVEDV, ↑LVEDP, & ↑PCWP ↑LV Wall Stress ↑O2 Demand Aortic Regurg.

What is happening here?

**Inflation way after AV Closure** Suboptimal Pefusion

When would it be safe for a pt to be weaned off a IABP?

When pt does ok w/ a 1:4 Ratio on the IABP

What are complications associated w/ an IABP?

Vascular Injury/Ischemia - most common Thrombus Infection Thrombocytopenia

What is Extracorporeal Membrane Oxygenation (ECMO)?

Closed circuit device that allows heart/lungs to recover while maintaing oxygenation & perfusion

When is ECMO indicated?

Cardiogenic Shock Failure to Wean off CPB Rt. Heart Failure Heart Failure unresponsive to VAD Post CPR ARDS

What is the preferred ECMO method for pts. w/ Respiratory Failure & Intact Cardiac Function?

Venovenous ECMO

What are the common cannulation sites for Venovenous ECMO?

Femoral & IJ Veins

How does Venovenous ECMO work?

Blood is drained from SVC & IVC via IJ/Femoral Vein then Oxygenated then Returned to the Right Atrium (can be separate drain & return cannulae or Single double lumen cannula)

Which type of pt is Venoarterial ECMO used on?

Pts who need LV & Pulmonary Support

How is Venoarterial ECMO different from Venovenous ECMO?

Venoarterial ECMO skips the Pulmonary Circulation for Higher Arterial Oxygenation

How does Venoarterial ECMO work?

Centrally placed cannulas drain blood from Right Atrium & Returned to Ascending Aorta

How would Venoarterial ECMO work if there is Peripheral Cannulation?

Blood is drained from Right IJ / Femoral & Returned to Femoral Artery

For Venoarterial ECMO, what happens to the blood once it is drained and before it is returned?

Goes to a roller pump that circulates @ 3-6 L/min thru a Membrane Oxygenator, which removes CO₂, Adds O₂, then Rewarmed

What are complications of ECMO?

Bleeding Stroke Infection Limb Ischemia Multiorgan Dysfunction

What are indications for a Ventricular Assist Device?

Cardiogenic Shock post MI Viral Cardiomyopathies Post CPB

What are contraindications to a Ventricular Assist Device?

Active Infection Irreversible Renal/Hepatic Dysfunction Severe Pulm. HTN Metastatic Cancer Major Coagulopathy

How does an LVAD work?

Collects Oxygenated Blood from LA via Inflow Cannula & Pumps blood to the Aorta via the Outflow Cannula

How do various Ventricular Assist Devices differ?

Continuous vs. Pulsatile Short Term vs Longterm Pneumatic vs Electric Location: Intra-, Extra-, Para-Corporeal

What is an Impella?

Small VAD placed percutaneously thru the Femoral Artery that pumps blood from LV to the Aorta @ 2.5 L/min

Why do pts w/ an LVAD have a higher risk for bleeding?

These pts may have Hepatic Congestion from Right HF

What are the Anesthetic Cardiovascular goals for pts w/ an LVAD?

Prevent Bradycardia & Maintain Sympathetic Tone

What is the leading cause of death in LVAD patients?

Sepsis - maintain strict sterile technique

Why is Intra-Op TEE used for pts w/ LVAD?

30% of these pts develop RV Dysfunction - use TEE to avoid RV Overfilling

What meds can be given to treat RV Dysfunction?

Epinephrine & Milrinone - ↓RV Afterload Nitric Oxide - Dilates Pulmonary Vessels

LVAD Flow is highly dependent on Volume. What is the Volume of Choice?

Blood & Blood Products

Off Pump CABG & Mechanical Circulatory Devices - Quiz 7 Flashcards

(50 cards)