The Nociception Level During General Anesthesia

The following measurements will be collected during surgery for this research study. 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. 2. Analgesia Nociception Index (ANI) index The PhysioDoloris monitor attached to the IV pole will be connected with a cable to the anesthesia monitor. We will measure and record ANI 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 ANI index values that will only be collected for research purposes. The measurements will start 5 minutes prior to the administration of general anesthesia and will continue until 5 min. after initial surgical instruments insertion. 3. Blood Pressure and Heart Rate We will also collect blood pressure and heart rate measurements that are generated as part of the standard anesthesia monitoring from electronic anesthesia record at 30 second intervals. 4. Bispectral Index We will also collect Bispectral Index (BIS) measurements that are generated as part of the anesthesia monitoring from electronic anesthesia record at 30 second intervals. BIS is a monitor of the depth of anesthesia that uses a sensor placed on patient's forehead. BIS monitor calculates a dimensionless number estimating the patient's level of consciousness. The BIS values range from 0 (no brain activity) to 100 (fully awake) with the target range between 40 and 60 for general anesthesia. 5. Pain Medication Data: We will collect the amount of pain medications used during the surgery from electronic anesthesia record.