Ensuring patient safety in surgeries upon the head and neck is a complex task in anesthesiology. These patients present a myriad of concerns that need to be considered to create a safe and thorough anesthetic plan that include potentially difficult airways, varied patient positioning, and the intricate involvement of anesthetic drugs upon the quality of the surgical field. During common procedures such as sinus endoscopy, patients undergo endotracheal intubation and mechanical ventilation for airway protection and a strategy of deliberate hypotension is implemented with the goal of creating a clean surgical field that minimizes avoidable bleeding. The objective of this strategy is to allow the surgeons to complete their procedure more quickly and with less hypothetical risk of injury due to poor visualization of structures. However, this strategy of deliberate hypotension carries with it the potential risk of cerebral hypoperfusion as the lower limits of cerebral autoregulation are not known on an individual patient basis. Furthermore, mechanical ventilation- particularly with hyperventilation- can further decrease cerebral blood flow and potentially compromise cerebral perfusion. The current standard of care to monitor the hemodynamics of patients undergoing these procedures are standard American Society of Anesthesiologists monitors, which includes non-invasive blood pressure measurements. The investigators propose the use of a non-invasive monitor of cerebral oxygenation with cerebral oximeter probes in a prospective, observational study of a series of patients undergoing routine head and neck surgery.