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Cardiac Anesthesia

Cardiac Anesthesia

1. Anesthetic Agents for Adult Cardiac Surgery

A. Narcotic Based: Fentanyl and Sufentanil (8 x more potent)
B. Hemodynamic stability without myocardial depression
C. Typical total dose during cardiac procedure
1) Fentanyl: 10-100 mcg/kd
2) Sufentanil: 8-15 mcg/kg
3) Remifentanil: 1-3 mcg/kg/min
D. Muscle Relaxation: Choice depends on desired heart rate response
E. Pavulon: Increases heart rate– may be useful in balancing the vagolytic effect of narcotics
F. Vercurium: No effect on heart rate of blood pressure-
1) Other new long-acting relaxants are similar to Vercurium

2. Induction and Maintenance of Anesthesia (Adult)

A. Induction
B. Narcotic
1) Remifentanil 1-2 mcg/kg
2) Fentanil 5-35 mcg/kg or Sufentanil 1-8 mcg/kg plus
3) Sedative-Hypnotic
4) Pentothal
5) Etomidate
6) Valium or Versed
7) Propofol
C. Maintenance
D. Narcotic PLUS
E. Propofol, Benzodiazepine, or low dose inhalation drug (Ethrane, Forane, Deslurane, Halothane, Sevoflurane)

3. Pediatric Anesthetic Agents

A. Induction is usually not intravenous
B. Induction
1) Ketamine 5 mg/kg intramuscular
2) Inhalation using Halothane or Sevoflurane
3) "Halothane sensitizes myocardium to arrhythmogenic influence of catacholamines"
C. IV established after induction
D. Maintenance
1) Narcotic PLUS
2) Hypnotic or Inhalation

4. Anesthetic Management of Ischemic Heart Disease

A. Goal: prevent myocardial damage
B. Optimum myocardial oxygen demand : supply ration
C. MVO2 is directly related to
1) Heart rate
2) Contractility
D. Oxygen supply is directly related to
1) Coronary blood flow
2) LV wall tension

5. Minimize Ischemia

A. Avoid tachycardia
1) Increased heart rates are correlated with post-operative MI
B. Maintain resting (ischemia-free) hemodynamics
1) Slow: maximize diastolic time
2) Small: minimize wall tension
3) Well Perfused: Adequate coronary pressure

6. Valvular Heart Disease

A. Aortic Stenosis
B. LVH
1) May have coronary artery disease
2) Requires high filling pressures
3) Anesthetic goals
4) Normal heart rate (avoid tachycardia)
5) Atrial "kick" crucial for adequate preloading of LV
C. Aortic Insufficiency
D. CHF common in acute AI
E. Anesthetic goals:
1) Decreased afterload
2) high-normal heart rate (avoid bradycardia)
F. Mitral Stenosis
G. High LA pressure and volume needed to fill LV
H. Anesthetic goals:
1) Adequate preload
2) Maintain diastolic filling time (avoid tachycardia)
I. Mitral Regurgitation
J. Volume overload leads to CHF and pulmonary hyptertension
K. Anesthetic goals:
1) Vasodilation improve forward flow
2) Normal to increased heart rate (avoid bradycardia)

7. Weaning from Bypass

A. Establish rhythm
1) Defrbrillate
2) AV pacing
3) Control rate
B. SVR (normal to low-normal)
1) SVR= (BP-CVP/CO) x 80
2) On pump: BP-CVP = mean BP; CO = Pump flow (L/min)
C. Normalize cardiac output
1) Visual
2) Blood pressure
3) Measured CO
D. Adjust preload
1) Post-bypass heart is stiff and volume dependent

8. Heparin Reversal

A. Use calculated dose of Protamine
B. Excess Protamine will cause a prolongation of A.C.T. and coagulopathy

9. One Lung Ventilation

A. To facilitate surgery on the lung or thoracic aorta
B. Absolute indications-
1) Lung abcess
2) HeartPort
C. Useful in-
1) Pulmonary hemorrhage
2) V.A.T.
D. Hypoxemia- commonly due to increased shunt
E. Minimize hypoxemia by-
1) 100% FiO2
2) Decrease volatile agents to < 1%
3) Increase ventilation to the dependent lung (non-operative)
4) PEEP the dependent lung
5) CPAP on the operative lung
6) Occlude the pulmonary artery of the operative lung

10. Pericardial Tamponade

A. Acute drop in BP on induction
1) Decreased venous return with controlled ventilation
2) Decreased sympathetic tone due to anesthetic state
B. Management
C. Prep awake with spontaneous ventilation
D. Ketamine induction
1) Sympathomimetic
2) Spontaneous ventilation possible

10. Anterior Mediastinal Mass

A. Sudden inability to ventilate
B. Obstruction of major airways with
1) Supine position
2) Controlled ventilation
3) Depressed ventilation
C. Management
D. Radiation therapy pre-op
E. Awake fiberoptic intubation (sitting)
1) Spontaneous ventilation
2) Standby cardiopulmonary bypass