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.
