Neurological dysfunction either transient or permanent is a major cause of morbidity and mortality after cardiopulmonary bypass, and cognitive dysfunction is more frequent in cardiac surgery than in non-cardiac procedures. Variations in cerebral blood flow and oxygen extraction are considered key contributing factors. Although pulsatile flow during bypass has shown benefits for renal function and recovery, its effects on postoperative neurological dysfunction and delirium remain unclear due to limited research. This study aims to evaluate the impact of pulsatile versus non-pulsatile cardiopulmonary bypass flow on POCD in adult CABG patients by measuring middle cerebral artery (MCA) flow using transcranial Doppler.
Patients aged 18-70
Patients scheduled for isolated elective cardiopulmonary bypass surgery
Patients with carotid stenosis ≥50%
Emergency patients or those with a history of reoperation
Patients with a history of cerebrovascular events
Patients who do not provide consent
Patients scheduled for isolated elective cardiopulmonary bypass surgery
Cohort
Prospective
Transcranial Doppler measurement of the middle cerebral artery
Procedure/SurgeryTranscranial Doppler examination was performed using a low-frequency (2-3.5 MHz) sector/cardiac probe through the transtemporal acoustic window. Middle cerebral artery (MCA) flow was identified in color Doppler mode at a depth of 3-7 cm with flow directed toward the probe. Pulsed-wave Doppler was applied, and peak systolic and end-diastolic velocities were recorded as the average of three measurements.
Middle cerebral artery mean flow velocity measured by transcranial Doppler
Perioperative transcranial Doppler will be used to measure middle cerebral artery mean flow velocity at predefined time points: before anesthesia induction, after anesthesia induction, at the 10th, 20th, and 30th minutes after aortic cross-clamping, and after removal of the aortic cross-clamp, end of the surgery.
Postoperative delirium incidence (yes/no)
Postoperative delirium will be assessed as present or absent based on delirium screening (CAM-ICU in ICU; 3D-CAM on the ward) performed twice daily during postoperative days 1-5. Delirium is defined as at least one positive screen.
Postoperative cognitive dysfunction (MMSE score change)
The outcome is the change in MMSE score from the preoperative baseline assessment to postoperative day 5.
Acute kidney injury stage (KDIGO)
Acute kidney injury will be defined and staged according to KDIGO criteria (stages 0-3) based on postoperative changes in serum creatinine and/or urine output
Duration of mechanical ventilation
The duration of ventilator support withdrawal in the postoperative intensive care unit
Length of stay in intensive care
The time the patient is transferred from intensive care to the ward
Length of hospital stay
The time the patient is discharged home
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