CABG (on-pump, elective)
Patient phenotype
Typically male 55–75, multi-vessel CAD, often diabetic, ex-smoker, on dual antiplatelet + statin + β-blocker. May have preserved or reduced EF. Last meal NPO since midnight.
Procedure
Median sternotomy, harvest LIMA + saphenous vein, cannulate aorta + RA, go on cardiopulmonary bypass, cross-clamp aorta, distal then proximal anastomoses, wean off bypass, decannulate.
Anesthetic plan
GETA with high-dose opioid + low-dose volatile, balanced for hemodynamic stability. Goal: smooth induction without tachycardia, low-normal BP throughout. TEE intraop.
Setup
- ·5-lead ECG with ST analysis
- ·A-line pre-induction (radial, sometimes femoral backup)
- ·Multi-lumen central line (RIJ usually)
- ·PA catheter or TEE — institutional preference
- ·Two large-bore PIVs
- ·Cell saver
- ·Heparin + protamine drawn + checked
- ·ACT machine
Biggest concerns by phase
Anti-platelet + DOAC + heparin bridge — when to stop?
Aspirin: continue (cardioprotective). Plavix: stop 5–7 days. Brilinta: stop 5 days. Warfarin: stop 5 days, bridge with heparin if mechanical valve. DOACs: stop 24–48 h normal renal, longer if CrCl reduced. Confirm with surgical team + cards.
Smooth induction — avoid tachycardia, hypotension
Tachycardia + hypotension → ischemia in CAD. Goal: maintain MAP ≥ 65, HR < 70. Etomidate 0.2 mg/kg or fentanyl-heavy + propofol 1 mg/kg. Pretreat with fentanyl 5 mcg/kg + lidocaine 1 mg/kg to blunt laryngoscopy. Have phenylephrine ready.
Heparinization for bypass + ACT monitoring
Heparin 300–400 U/kg pre-cannulation. Goal ACT ≥ 480 sec before bypass. Recheck q30 min on pump. If ACT inadequate after redose, suspect AT-III deficiency — give AT-III concentrate or FFP.
Coming off bypass — TEE-guided wean
Perfusion warms to 36 °C, restart ventilation at low TV, restart inotropes if indicated (epi, milrinone, dobutamine), clamp off, decannulate venous then arterial. TEE assesses RV function, valve function, residual air, regional wall motion.
Protamine reactions
Protamine reverses heparin 1 mg per 100 U heparin. Risks: hypotension (most common, slow push helps), pulmonary HTN + RV failure (catastrophic), anaphylaxis (especially NPH-insulin diabetics, prior protamine exposure, fish allergy). Have epi + vasopressin + iNO ready.
Bleeding, tamponade, low CO syndrome — to ICU intubated
Standard transport intubated to CVICU. Watch for sudden chest tube output > 200 mL/hr, drop in CVP/wedge with rising HR (tamponade), refractory hypotension despite filling (low cardiac output syndrome — may need IABP or VAD).
Mock-defense scenarios
Practice answering these out loud. The probes show what an examiner is listening for.
Your CABG patient is on bypass, surgeon is doing the LIMA-to-LAD anastomosis. ACT is 510. Suddenly pump pressures rise, the perfusionist says the venous return is dropping. What's happening and what do you do?
What an examiner probes for
- ▹Differentiates: caval cannula migration, intracardiac air, bleeding, dissection, aortic cannula problem
- ▹Communication with surgeon + perfusionist — team coordination
- ▹Considers TEE for aortic dissection or air
- ▹Action: surgeon adjusts cannula vs. emergency circuit changes
After protamine your patient becomes profoundly hypotensive, BP 60/30, PA pressures rise to 65/40 (was 35/20), CVP 18, and you can't ventilate against rising airway pressures. What's happening and what do you do?
What an examiner probes for
- ▹Recognizes type III protamine reaction (pulmonary vasoconstriction)
- ▹Stop protamine, IV fluids, vasopressin, iNO, milrinone
- ▹May need to go back on bypass + restart heparin
- ▹Anticipates: CXR for pulmonary edema, ABG for hypoxemia
Sources
- Kaplan Cardiac Anesthesia 8e
- STS guidelines
- ASA Practice Advisory: TEE
Anatomy reference
Sourced reference images. 4 matches for "heart coronary cardiac chambers".
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