The proposed study is designed to further demonstrate the performance of the Nociception Level (NoL) Index - in surgical patient under general anesthesia, by evaluating its response to controlled changes in the levels of noxious stimuli/analgesia and to correlate early outcome predictors to the NoL values throughout the surgical procedure, thus provide the medical caregiver general recommendations on how to interpret the NoL Index in terms of magnitude and direction, and how to utilize it during the surgical procedure.

The proposed study is designed to further demonstrate the performance of the NoL Index in surgical patient under general anesthesia, by evaluating its response to controlled changes in the levels of noxious stimuli/analgesia mentioned characteristics and to correlate early outcome predictors to the NoL values throughout the surgical procedure, thus provide the medical caregiver general recommendations on how to interpret the NoL Index in terms of magnitude and direction, and how to utilize it during the surgical procedure.

In this study the investigators plan to demonstrate that the NoL Index is a continuous index. It is anticipated that a higher level of nociception will correspond to a higher NoL index. On the other hand, it is anticipated that higher levels of analgesic agent for the same noxious stimulus will lead to a lower NoL index. This will be achieved by measuring the NoL response to various types of noxious stimuli, varying in their intensities, under different levels of analgesic agents.

The noxious stimuli that will be used in this pivotal study are:

1. - Intubation
2. - Incision and/or trocar insertion
3. - Internal handling during the surgical procedure
4. - Extubation
5. - Other specific pain event related to the surgical procedure (e.g. bone related treatment in orthopedic, muscle tension or cut etc.).

The study population includes subjects requiring a surgical procedure under general anesthesia. During the surgical procedure the subject is anesthetized (by various anesthetic agents) and paralyzed (by muscle relaxant agents). Thus, the response to noxious stimuli under those conditions will be related to the underlying physiological response. The participants will be monitored, as in a typical surgery and according to the local guidelines, by various types of monitoring devices, such as: vital signs, pulse oximeter, Bispectral Index (BIS), Electroencephalography (EEG) etc. Therefore, patients suffering from fluctuations in their vital signs and hemodynamic parameters during the surgical procedure, can be detected by the various monitors. However, assessment of the level of nociception is still complex, subjective and mainly depends on the physician's experience and knowledge.

Development of a nociception monitor that may present an index to assess the level of nociception will allow the anesthesiologist better patient management during the surgical procedure.

Inclusion Criteria:

• The subject age is > 18 years old
• The subject requires surgery under general anesthesia.
• A blood pressure measurement (via arterial line or cuff) will be available during the surgical procedure.
• The subject signed an Informed Consent Form (ICF)

Exclusion Criteria:

• History of severe cardiac arrhythmias within the last 12 months
• Pregnancy or lactation
• Chronic pain conditions or analgesic usage (> 1 month of large doses of opioids: more than 30mg PO equivalent of morphine)

The study population includes subjects requiring a surgical procedure under general anesthesia.