Anaesthetic Considerations

Similar principles apply to the application of CPB in both cardiac and non-cardiac surgery. In practice, however, there are a number of important factors that must be considered. With the exception of thoracic aortic surgery, non-cardiac CPB procedures are performed rarely and frequently involve staff who have little or no regular experience of CPB. Moreover, non-cardiac surgeons do not routinely operate on fully anticoagulated patients. Published case series and experience gained in previous cases should form the basis of detailed protocols for future reference.

The use of femoro-femoral CPB, which avoids the need for sternotomy or thoracotomy, is often employed in procedures that do not routinely involve chest opening. In this situation, there is retrograde perfusion of the aorta. Although the size of the femoral arterial cannula has a minimal impact on CPB flow rates, a small femoral venous cannula may significantly reduce venous return. For this reason, the maximal achievable flow rate may be insufficient at normothermia. To circumvent this problem, partial or incomplete CPB is initiated and lung ventilation continued until the degree of hypothermia is compatible with CPB at reduced flow rates. It is essential that hypothermia-induced VF does not occur before reaching this level of hypothermia.

The risk of CPB-related adverse events is the same, regardless of the clinical application. The basic principles of adequate anticoagulation, avoidance of air embolism and maintenance of vital organ perfusion are no less important. Femoral cannulation may result in lower limb ischaemia or neurological injury (Chapter 29). In difficult cases, it should be borne in mind that femoro-femoral CPB can be established under local anaesthesia prior to the induction of general anaesthesia.

Thoracic Surgery

CPB for surgery on the ascending aorta and aortic arch is discussed in Chapter 13. Pulmonary embolectomy and (thrombo)endarterectomy, performed for acute and chronic pulmonary thromboembolic disease, respectively, typically requires CPB with or without deep hypothermic circulatory arrest (DHCA).

In the past, resection of tracheal and carinal tumours was routinely performed with CPB. Advances in endoluminal intervention (e.g. stents, cryotherapy, lasers, etc.) have limited the indications for CPB to:

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  Patients at high risk of airway obstruction following induction of anaesthesia

  
  
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  Repair of tracheal dehiscence following heart–lung transplantation

  
  
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  Resuscitation of patients suffering massive haemorrhage after pulmonary resection