How can we improve the blood flow to the brain during the construction of a bypass in the brain?

Patients receiving cerebral revascularization with a bypass are prone for cerebral hypoperfusion. Currently, blood pressure is often increased with vasopressors to prevent cerebral ischemia. However, this might cause vasoconstriction of the graft and cerebral vasculature. We hypothesized that cardiac output rather than blood pressure is essential for adequate cerebral perfusion and aimed to determine whether an increase in cardiac output results in higher graft perfusion (and thus cerebral perfusion) than an increase in blood pressure in patients undergoing cerebral bypass surgery. This randomized crossover monocenter study included 10 adult patients undergoing cerebral bypass surgery. Patients randomly and sequentially received dobutamine to increase the cardiac output (indexed for body surface area) and phenylephrine to increase the mean arterial blood pressure (MAP). An increase of >10% in cardiac index and >10% in MAP was targeted, respectively.

We hypothesize that cardiac output rather than blood pressure is essential for adequate cerebral perfusion during and after cerebral revascularization.

All interventions and measurements will be done during the hemostasis phase of extracranial-intracranial bypass surgery

Patients will receive, randomly and sequentially, dobutamine (2-15 µg/kg/min) to increase the cardiac output and phenylephrine (0.15-1 µg/kg/min) to increase the blood pressure.