Intraoperative transcranial doppler ultrasonography monitoring of cerebral blood flow during coronary artery bypass grafting.

Perioperative neurologic events in heart surgery are the most devastating complications. Brain is the only organ not routinely monitored by any direct method during the administration of anesthesia. Brain monitoring with transcranial Doppler is of particular value when the brain is at risk of cerebral hyper- or hypoperfusion, gaseous or particulate embolization, or their combined effects. The main aim of this study was to assess cerebral blood flow differences and patterns during off-pump versus on-pump coronary artery bypass grafting (CABG). This prospective study was performed using transcranial Doppler ultrasonography (TCD) monitoring in 30 patients aged 39-81 undergoing elective coronary bypass surgery with or without cardiopulmonary bypass: 15 patients undergoing off-pump and on-pump CABG each. The two groups did not differ according to age, sex, risk factors, cerebrovascular disease, comorbid disease and NYHA class. Study results clearly demonstrated significant differences in blood flow velocity between off-pump and on-pump procedures (P=0.0001). The duration of hypoperfusion was longer in on-pump group, whereas shorter periods of more profound hypoperfusion were observed in off-pump group. Brain monitoring with TCD during CABG proved to be a useful tool to detect cerebral hypotension as it provided unique information on cerebral perfusion. Such monitoring may improve the safety of surgical procedures, allowing for hemodynamic interventions to perform rationally and without interruption of surgical procedure.