Cardiac output and cerebral blood flow during carotid surgery in regional versus general anesthesia: a prospective randomized controlled study.

Abstract Objectives Endarterectomy of the carotid artery (CEA) is a preventive procedure aimed at decreasing the subsequent risk of fatal or disabling stroke in patients with significant carotid stenosis. It is well known that carotid surgery under ultrasound-guided regional anesthesia (US-RA) causes a significant increase in blood pressure, heart rate and stress hormone levels due to increased sympathetic activity. However, little is known about the effects on cardiac output (CO), cardiac index (CI) and cerebral blood flow (CBF) under US-RA as compared to general anesthesia (GA). Methods Patients scheduled for CEA were prospectively randomized to receive US-RA (n=37) or GA (n=41). The primary endpoint was the change in CI after induction of anesthesia and the change from baseline over time at four different times during the entire procedure in the respective randomized US-RA and GA groups. In addition to systolic blood pressure (SBP) and heart rate, we also recorded peak systolic velocity (PSV), end diastolic velocity (EDV) and minimum diastolic velocity (MDV) as seen from transcranial Doppler ultrasonography (TCD), as well as regional cerebral oxygenation (rSO2) as seen from near-infrared refracted spectroscopy (NIRS) in order to evaluate CBF. Results In the US-RA group CI increased after induction of anesthesia (3.7 ± 0.8 L/min/m2) and remained constant until the end of the procedure. In the GA group CI was significantly lower (2.4 ± 0.6 L/min/m 2 , P Conclusion CI was maintained near baseline values throughout the procedure during US-RA, while a significant decrease in CI values was observed during CEA under GA. NIRS values, reflecting blood flow in small vessels, were higher in US-RA patients than in those with GA. These differences did not influence clinical outcome.