During a general anesthesia, people over 65 years old and hypertensive, have a modification of the vasoreactivity and their cerebral blood flow under vasoconstrictor such as norepinephrine or phenylephrine. We study the variation of the average velocity of the average cerebral artery under vasoconstrictor and during a modification of End Tidal CO2 (EtCO2) by transcranial Doppler.
General anesthesia induces a sympathetic block frequently leading to hypotension, especially in elderly and hypertensive patients. Currently, Phenylephrine (PE) and Norepinephrine (NE) are commonly used in clinical practice to address this arterial pressure drop. Their cardiovascular effects are not exactly the same, even though they both increase mean blood pressure. Maintenance of mean arterial pressure is not the only hemodynamic goal during general anesthesia in the elderly. Cognitive disorders have been demonstrated during post-anesthetic awakening. Cerebral hemodynamics is assessed by analyzing the speed of blood flow in the middle cerebral artery using transcranial Doppler (DTC). It measures the systolic and diastolic speed as well as the pulsatility index, which are predictive factors for lowering cerebral blood flow.
Study Type
OBSERVATIONAL
Evaluation of Vasoconstrictor Vasoreactivity with Transcranial Doppler
Variation of the velocity of the middle cerebral artery with vasoconstrictors and during a modification of EtCO2.
Measurements from transcranial doppler velocity of the middle cerebral artery
Time frame: 48 hours
Variation of cardiac output with vasoconstrictors and during modification of EtCO2.
Measurements from non invasive device (ClearSight System) of the cardiac output. The ClearSight system quickly connects to the patient by wrapping an inflatable cuff around the finger. Then the system presents cardiac output clearly and simply on the monitor.
Time frame: 48 hours
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