A thorough understanding of what occurred intraoperatively is critical to postoperative management after cardiac surgery.

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  Cardiac Anesthesia:

  
  
  
  
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    Induction technique and maintenance of anesthesia depend on the underlying anatomic defect, cardiac function, and degree/duration of sedation required. The goal is to minimize hemodynamic instability, particularly in patients with low cardiac reserve.

    
    
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    Premedication: Often utilizes a benzodiazepine or barbiturate orally.

    
    
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    Airway management: Skillful manipulation of the airway and management of ventilation are critical to minimize unfavorable cardiopulmonary interactions.

    
    
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    Induction and maintenance of anesthesia: Wide variety of agents administered alone or in combination. Neuromuscular blockade typically utilizes a nondepolarizing muscle relaxant.

  
  
  
  
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  Cardiopulmonary Bypass (CPB): Cardiothoracic surgery may be performed with or without cardiopulmonary bypass.

  
  
  
  
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    Considerations include pump prime strategy and dilutional effect on blood volume, use of hypothermia, use of regional low-flow perfusion or circulatory arrest, use of modified ultrafiltration (MUF), acid–base strategy, use of intraoperative steroids.

    
    
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    Sequelae of CPB include renal dysfunction, capillary leak, systemic inflammation, abnormal glucose regulation, hemodilution, and neurologic injury.

  
  
  
  
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  Hemostasis: Bleeding is often a problem after CPB due to a combination of systemic anticoagulation, platelet dysfunction, and systemic inflammation. Intraoperative concern about bleeding, last activated clotting time (ACT), and blood product administration should be quantified. Assess need and timing for postoperative anticoagulation (ex: aspirin for shunt).

  
  
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  Hemodynamics: Mean arterial pressure maintained with combination of CPB and vasoactive medications. Any intraoperative hemodynamic instability should be discussed at handoff. Invasive monitoring devices (arterial lines, intracardiac lines, central venous access, Foley catheter, chest tubes, pacing wires, etc.) placed during surgery should be identified.

  
  
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  Anatomic Considerations: Technical aspects of the surgical repair and postoperative cardiac function often assessed by transesophageal echocardiography intraoperatively.

Postoperative status should be monitored both invasively and noninvasively.

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  Noninvasive Monitoring:

  
  
  
  
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    Vital signs: Heart rate, blood pressure, respiratory rate, near-infrared spectroscopy (NIRS), end-tidal CO₂, chest radiograph, electrocardiogram, echocardiogram

    
    
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    Physical exam: Pulses, perfusion, capillary refill, mental status (if applicable), urine output, chest tube output

  
  
  
  
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  Invasive Monitoring: Peripheral or central arterial line, central venous pressure, intracardiac lines, Swan-Ganz pulmonary artery catheter

  
  
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  Laboratory Monitoring: Blood counts, coagulation profile, electrolytes, renal and hepatic function, blood gas analysis (including mixed venous saturation), lactate

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  Pain Control/Sedation: Depends on degree of postoperative clinical instability. Awake, extubated patients can be managed with an intermittent opioid regimen. Patients moving towards extubation may benefit from adjunctive dexmedetomidine to minimize respiratory depression. Ketorolac and other nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce narcotic burden, but should be used cautiously in setting of renal dysfunction and/or bleeding concerns.

  
  
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  Fluid and Nutrition Management:

  
  
  
  
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    CPB results in release of circulating hormones that promote sodium and fluid accumulation. At the same time, capillary leak may result in intravascular volume depletion. Frequent clinical reassessments are required to manage dynamic changes in volume status.

    
    
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    Diuretics are typically started 12 to 24 hours post-CPB, once hemodynamics have stabilized.

    
    
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    Enteral nutrition should be withheld until acidosis is improved and postoperative hemodynamics have stabilized.

    
    
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    For patients requiring nutritional support, a restrictive fluid strategy should be used initially with careful monitoring of electrolytes (K > 3.5–4 mmol/L, Mg > 2 mg/dL, iCa > 1mmol/L). Total parenteral nutrition (TPN) is usually deferred for the first 24 hours.

    
    
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    Existing data does not support a strategy of tight glycemic control in the postoperative pediatric cardiac surgery population. Dextrose composition is 10% in neonates, 5% for infants and children.

  
  
  
  
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  Inotropic Support: See Chapter 14 and Chapter 30.

  
  
  
  
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    Milrinone (phosphodiesterase inhibitor) is commonly used in the postoperative period to provide inotropy, lusitropy, and afterload reduction. It can be associated with excessive vasodilation and hypotension, particularly in patients with abnormal renal clearance.

    
    
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    Catecholaminergic agents (epinephrine, dopamine) are commonly used in the postoperative setting to provide inotropy. They can also increase vascular tone and augment blood pressure at higher doses. They can both be associated with arrhythmias.

    
    
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    Vasoconstrictive agents (vasopressin, norepinephrine) may be required to augment vascular tone in hypotensive patients, but should be used cautiously in patients with depressed ventricular function, as they will increase afterload on the systemic ventricle.

  
  
  
  
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  Mechanical Circulatory Support: In some circumstances, particularly in the setting of complex congenital lesions, patients may be unable to separate from mechanical circulatory support and may require transition to extracorporeal membrane oxygenation (ECMO) postoperatively (see Chapter 25).

  
  
  
  
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    Clinical Tip: Postoperative ECMO is required in approximately 10% of patients undergoing stage 1 Norwood palliation for hypoplastic left heart syndrome.

  
  
  
  
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  Mechanical Ventilation: Early postoperative extubation has been utilized in appropriate patients at many centers and decreases resource utilization and length of stay.

  
  
  
  
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    Positive pressure ventilation will decrease left ventricular afterload, but may increase pulmonary vascular resistance (PVR) and decrease preload, particularly after Glenn/Fontan procedure.

    
    
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    Extubation readiness: Appropriate mental status, stable hemodynamics, adequate oxygenation and ventilation on minimal support, control of bleeding, sternum closed, appropriate volume status, adequate pain control.