The authors note ten keypoints:
1. Evidence shows that maintaining mean arterial blood pressures in the range of 70-80 mmHg and increasing hypotension durations below the recommended range can increase mortality and endorgan dysfunction postoperatively.
2. Maintaining perfusion and oxygenation, especially to the brain and kidneys, during cardiopulmonary bypass (CPB) requires an understanding of capillary perfusion. Adequate oxygenation is
typically assessed using a combination of pulse oximetry, cerebral oximetry, and arterial blood oxygen pressure. Hypotension during CPB has many possible causes, and evaluation and treatment
need to be a joint process involving the surgeon, anesthetist, and perfusionist. Vasoplegia while on CPB is due to interaction between the patient’s blood and the CPB circuit and can be difficult
to treat.
3. Many different vasopressors can improve perfusion pressure while on CPB, with different mechanisms of action, indications, and physiologic effects. Epinephrine and norepinephrine are the
most commonly used, and function to increase systemic vascular resistance significantly.
4. Anesthesia while on CPB may be maintained with inhalation or intravenous agents, both of which have advantages and disadvantages. No outcome differences could be demonstrated between those techniques.
5. Malignant hyperthermia is an anesthetic emergency that may present while on CPB and requires expertise to diagnose and treat.
6. Anticoagulation while on CPB is typically maintained with heparin, though resistance may occur and can be treated with fresh frozen plasma or antithrombin III. Heparin is reversed with protamine
sulfate, which has its own risks and potential side effects.
7. Anemia and coagulopathy are a constant concern during cardiac surgery, especially for patients on CPB, due to the loss of normal coagulation from interactions between platelets and the CPB circuit. Treating these conditions is necessary to decrease complications, but administration of non-autologous blood products can lead to transfusion reactions and other complications.
8. While most normal metabolic functions are maintained on CPB, non-pulsatile blood flow, as well as periods of hypotension and hypoxia, can lead to metabolic derangements that may require artificial correction by the perfusionist or anesthetist via renal replacement therapy.
9. Air embolism is a potentially catastrophic complication of CPB, and the anesthetist, perfusionist, and surgeon must all be vigilant to diagnose and treat this dreaded event.
10. Transesophageal echocardiography, an excellent modality used to diagnose, monitor, and direct therapy towards the patient undergoing cardiac surgery, plays a large role in patient management.
Extracorporeal Circulation
Anesthesia Considerations for Cardiopulmonary Bypass
Rudolf J. Tschaut, Molly Dreher, Tami Rosenthal & Ashley Walczak
2020, 731 pages, hardcover
Print: ISBN 978-3-95853-545-9
eBook: ISBN 978-3-95853-546-6