Hypotension on Bypass

Abstract

Cardiopulmonary bypass is performed so commonly that it is easy to take many of the nuances for granted. At a high level it is a simple task: to take the deoxygenated blood off of the venous side, pass it though the gas exchanger for CO₂ removal and oxygenation, and pump it back on the arterial side. But the number of variations and combinations of arrangements of the cardiopulmonary bypass tubing including shunts is remarkable. It is equally remarkable that no single optimal circuit has been defined, with each perfusion team and sometimes each perfusionist within a single institution having their own preferred arrangements. Surgeons who find themselves operating at different hospitals may find themselves doing cases with unfamiliar perfusion teams and unfamiliar bypass pumps. This case demonstrates exactly that problem. It also demonstrates the value of checklists as applied to cardiac surgery. Checklists are particularly useful for addressing the human:machine interface, which is exactly what occurs with the heart–lung machine. In this instance, application of a checklist prior to instituting bypass would ensure that all of the humans in the room are correctly interfacing with the heart–lung machine. Similarly, checklists are of particular value prior to weaning from bypass as the machine critical to the survival of the patient transitions from the heart–lung machine to the anesthesia machine and ventilator. Checklists are not the solution to all problems, but when judiciously applied to appropriate situations, they can be lifesaving.