Middle Cerebral Artery Velocity and Oxygen Saturation of the Brain During Carotid Endarterectomy

Investigation of Blood Flow Velocity in the MCA and Oxygen Saturation of the Brain During Carotid Endarterectomy in Local Anesthesia in Patients With and Without Neurological Symptoms Using Transcranial Doppler (TCD) and INVOS Monitor

The primary endpoint of our study is to determine whether neurological symptoms (aphasia, paresis, loss of consciousness, numbness) occur after clamping the internal carotid artery, and if so, changes showed by transcranial Doppler or INVOS monitor is more sensitive regarding the symptoms? Secondary endpoint: the degree of change in the measured parameters after the internal carotid artery is clamped, and if there is any difference between the operated and non-operated sides?

Investigation of blood flow velocity in the middle cerebral artery and oxygen saturation of the brain bilaterally during carotid endarterectomy carried out in local anesthesia in patients with and without neurological symptoms using transcranial Doppler (TCD) and INVOS monitor.

Zoltán Gyöngyösi Study protocol

The primary endpoint of our study is to determine whether neurological symptoms (aphasia, paresis, loss of consciousness, numbness) occur after clamping the internal carotid artery, and if so, changes showed by transcranial Doppler or INVOS monitor is more sensitive regarding the symptoms? Secondary endpoint: the degree of change in the measured parameters after the internal carotid artery is clamped, and if there is any difference between the operated and non-operated sides?

Patients and Methods

Outpatient examination, preparation and anesthesia of the patients:

• ECG test
• Echocardiography, if it is necessary due to the cardial status of the patient.
• Indication of surgical intervention provided by the cerebrovascular outpatient clinic, with attached carotid ultrasound and angiography results.

Surgical anesthesia:

• Superficial and deep cervical block with 3.75% ropivacaine (50ml ropivacaine 3.75%) (incase of allergy bupivacaine should be used)
• Securing venous catheter, infusion of Lactated-Ringer or Voluven solution.
• In case of pain topical administration of Lidocaine by the surgeon, intravenous administration of 25-50ug Fentanyl or 1 vial of Algopyrin.

Intraoperative measurements:

• Bilateral transcranial Doppler measurements of the blood flow velocity within the middle cerebral arteries: 1. before local anesthesia, 2. after the onset of local anesthetic, but before skin incision, 3. intraoperatively before clamping the internal carotid artery, 4. one minute after clamping the internal carotid artery, 5. five minutes after clamping the internal carotid artery, 6. fifteen minutes after clamping the internal carotid artery, 7. directly after the restoration of blood flow in the internal carotid artery, 8. postoperatively, 4-6 hours after the intervention.
• Recording mean arterial pressure with each TCD measurement.
• Recording cerebral saturation (INVOS) with each TCD measurement.
• Recording any anti-hypertensive therapy in the postoperative phase.
• Recording heart rate.
• Recording arterial oxygen saturation.
• Recording the patients' neurological status with each TCD measurement and continuous neurological monitoring while the internal carotid artery is clamped.

Inclusion Criteria:

• 100 patients awaiting carotid artery endarterectomy carried out in regional anesthesia.
• Age: patients over 18 years.
• Gender: both female and male patients are included in the study.
• Medical equipment: venous catheter, arterial catheter for invasive blood pressure monitoring.
• Bilateral continuous measurement of the middle cerebral arteries with Transcranial Doppler.
• Bilateral continuous measurement of the cerebral saturation with INVOS monitor.

Exclusion Criteria:

• Allergy to ropivacaine, bupivacaine.
• Patients who does not consent to the awake surgery or does not sign the informed consent of the study.
• If the patient is either psychologically or neurologically unsuitable for the awake surgery.