1. Nociception Level (NoL) index The PMD-100 monitor includes a small probe similar to the pulse oximeter that will be placed on the subjects finger, which will be connected to the laptop placed next to the anesthesia machine. We will measure and record NoL index values at the following painful events: placement of breathing tube, skin incision, initial surgical instruments insertion and muscle relaxation assessment with a twitch monitor (60mA, 100Hz, 30sec). The anesthesiologist will be blinded to NoL index values that will only be collected for research purposes. We will compare the NoL index to ANI index, BP and HR. The measurements will start 5 minutes prior to the administration of general anesthesia and will continue until 5 min. after initial surgical instruments insertion.