Cardiopulmonary Bypass - Complications

Complications

CPB is not benign and there are a number of associated problems:

• Postperfusion syndrome (also known as Pumphead)
• Hemolysis
• Capillary leak syndrome
• Clotting of blood in the circuit – can block the circuit (particularly the oxygenator) or send a clot into the patient.
• Air embolism
• Leakage – a patient can rapidly exsanguinate (lose blood perfusion of tissues) if a line becomes disconnected.
• 1.5% of patients that undergo CPB are at risk of developing Acute Respiratory Distress Syndrome.

As a consequence, CPB is only used during the several hours a cardiac surgery may take. Most oxygenators come with a manufacturer's recommendation that they are only used for a maximum of 6 hours, although they are sometimes used for up to 10 hours, with care being taken to ensure they do not clot off and stop working. For longer periods than this, an ECMO (extra-corporeal membrane oxygenation) or VAD (ventricular assist device) circuit is used, which can be in operation for up to 31 days – such as in this Taiwanese case, for 16 days, after which the patient received a heart transplant.

CPB may contribute to immediate cognitive decline. The heart-lung blood circulation system and the connection surgery itself release a variety of debris into the bloodstream, including bits of blood cells, tubing, and plaque. For example, when surgeons clamp and connect the aorta to tubing, resulting emboli may block blood flow and cause mini strokes. Other heart surgery factors related to mental damage may be events of hypoxia, high or low body temperature, abnormal blood pressure, irregular heart rhythms, and fever after surgery.