Coronary artery bypass graft

Coronary artery bypass graft

Anesthesia type	GA
Airway	ETT
Lines and access	PIV x2 Arterial line Central line [often 2] Introducer ± PA catheter
Monitors	Standard 5-lead ECG Temperature ABP CVP TEE NIRS ± PAP
Primary anesthetic considerations
Preoperative	beta-blocker discussion with surgeon regarding any regional anesthesia adjuncts
Intraoperative	Heparinization for graft harvest Full heparinization prior to coming on CPB Hemodyamics and cardiac function coming off CPB Reversal of heparin with protamine Discussion with surgeon regarding extubation in OR
Postoperative	transfusion and vasopressor requirements inotropic support
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Coronary Artery Bypass Graft, also known as CABG, is a common cardiac surgery procedure in which vein or artery is used as a conduit and is either grafted from the aorta (or if using left internal mammary artery, used in situ) to a coronary artery beyond a blockage in the vessel, with goal of improving blood flow to the heart, i.e. surgical coronary re-vascularization. The left internal mammary artery (LIMA) is considered first choice of graft due to high patency rate of > 90% at 10 years, though saphenous vein grafts are often used as well. It is most often indicated for individuals with significant multi-vessel Coronary Artery Disease, in particular those with Diabetes Mellitus or left main coronary vessel disease; it can also be used on a more emergent basis for those with Acute Coronary Syndrome and ST-Elevation Myocardial Infarction cases that are refractory to PCI or maximal medical management. It can be described by the number of vessels to be bypassed (single, double, triple, quadruple) as well as the technique (traditional on-pump, off-pump or minimally invasive direct).

Preoperative management

Patient evaluation

System	Considerations
Neurologic	cognitive function Identify any atherosclerotic lesions along carotid vessels
Cardiovascular	Identify diseased vessels & any associated collaterals Evaluate LVEF, wall thickness and valve functionality All antianginal medications should be given day of surgery
Pulmonary
Gastrointestinal	Evaluate for dysphagia, difficulties swallowing and hx of esophageal/gastric surgery (TEE carries a risk of esophageal rupture)
Hematologic	Confirm T+S and at least 4 units pRBCs are on hold, as well as FFP Anticoagulation is common in these patients
Renal	Evaluate for any pre-operative renal insufficiency
Endocrine	Evaluate HgbA1c and if Insulin-dependent diabetic, note current insulin regimen
Other	Redo sternotomies have a greater risk of significant bleeding and complication

Labs and studies

• CBC, CMP
• PT, PTT
• CXR: to evaluate for abnormalities (cardiomegaly, pleural effusions)
• EKG: check for LBBB. If a PA catheter is planned, occasionally patients with LBBB may develop a third degree block as a consequence of PA catheter placement

Operating room setup

• Have at least 5-8 channels for infusions
  • Epi, norepi, carrier, insulin (some institutions use phenylephrine in place of norepi)
  • Consider ketamine, precedex, ancef
• Drugs:
  • Emergency medications (bolus):
    • Epi, atropine
    • Other bolus vasopressors (e.g. vaso, phenylephrine, NE)
    • +/- Esmolol, nicardinpine, and nitroprusside
  • Heparin, protamine, calcium
  • +/- Magnesium
• Perfusion technician should be available along with cell saver
• Fluid warmer
• Triple transducers primed and zeroed
• Internal defibrillator/pacer available in room
• TEE machine with appropriately sized probe

Patient preparation and premedication

• All cardiac medications should be continued on day of surgery except ACE inhibitors which should be stopped 24h prior to surgery

Regional and neuraxial techniques

• Pre-Op: Erector Spinae Plane Block -- check departmental policy as institutions vary on candidacy for pre-op block based on vessel pathology
• Intra-op: Parasternal Intercostal Block - after sternal wound closure and prior to emergence

Intraoperative management

Monitoring and access

• 2 large bore PIVs
• Arterial line - often these are placed awake, especially if there are athersclerotic lesions along Left Main artery or concern for Right ventricle failure
• CVP
• Cordis
• +/- Pulmonary artery catheter

Induction and airway management

• Cardio-protective induction with etomidate vs standard induction with propofol depending on patient's cardiac function and pathology

Positioning

• Supine position

Maintenance and surgical considerations

• Redo sternotomies have higher risk of significant bleeding
  • type and cross with anticipation of early blood loss
  • consider having a cooler of blood in the room
• Patients that have been on heparin leading up to the procedure may have developed resistance to heparin via ATIII depletion. If the max dosage of heparin has been given and ACT is still below goal at time of full heparinization, you may need to give ATIII concentrate
• If procedure uses bypass, have a plan for what drips to use coming off of pump.
  • Tailor medications based on hemodynamic needs. (e.g. if there is need for inc afterload, inotropy, both, ect.)
  • Have other agents readily available such as - Milrinone, dobutamine, Vasopressin, angiotensin II

Emergence

• Consider parasternal intercostal blocks pre-emergence/prior to transport to CVICU
• Patients will usually remain intubated and sedated through transit to cardiac ICU, though in certain cases & institutions, emergence and extubation may be considered
  • Sedation during ICU transfer with gtt - use what is safest for the patient while providing amnesia
  • Consider utilizing gtt that will be used by ICU staff after handoff

Postoperative management

Disposition

• Cardiac ICU

Pain management

• Can consider regional anesthesia with parasternal intercostal plane blocks [completed pre-emergence] , or Erector Spinae block (pre-induction)

Potential complications

• MI 6%
• CVA 5%
• Mild neuropsychatric effects 90%
• Death 1-3% (preop-risk dependent)
• Transfusion 40-90%
• Delirium 8%-15%
• Atrial fibrillation Up to 35%
• Renal failure 1%
• Mediastinitis 1-2%

Procedure variants

	Variant 1	Variant 2
Unique considerations
Position
Surgical time
EBL
Postoperative disposition
Pain management
Potential complications