Effect of Two Different Fluid Treatment Regimens on Ultrasonographic Upper Airway Measurements

The goal of this randomized controlled double blinded study is to compare the effect of the type of fluid theraphy on ultrasonographic upper airway measurements for spinal surgery in prone position longer than two hours. The main question it aims to answer is how do goal directed fluid theraphy and standard fluid theraphy effect ultrasonographic upper airway measurements. Participants will be American Society of Anesthesiology (ASA) physical status I and II, between 18- 65 ages. Resarchers will compare goal-directed fluid therapy with standard fluid theraphy to see if upper airway ultrasonography measurements differs between the groups.