Persistent postoperative pain occurs up to 25 to 60 % after mastectomy. This occurs at a higher frequency than the rate of invasive surgery.Therefore, many ways have been tried to study risk factors. A study was conducted to predict postoperative pain for items (preoperative pain, sensitivity, pain prediction). As a result, it was reported that the scope of surgery, pre-operative pain, young age, and depression were associated with persistent pain.

This study try to find out whether persistent pain after mastectomy is affected anesthetic factors appropriate anesthesia depth and opioid using standardized monitoring devices limited to similar surgical ranges.

Persistent postoperative pain occurs up to 25 to 60 % after mastectomy. This occurs at a higher frequency than the rate of invasive surgery.Therefore, many ways have been tried to study risk factors. A study was conducted to predict postoperative pain for items (preoperative pain, sensitivity, pain prediction). As a result, it was reported that the scope of surgery, pre-operative pain, young age, and depression were associated with persistent pain.

There were reports of no association with anesthesia in the area of anesthesia to the high pain control requirement in the postoperative recovery room, 24 hours of high pain medication, use of inhalation agent, and a high dosage of remifentanil. However, an anesthesia-related study was either a retrospective study or anesthetic was injected with more than a clinical dose in order to make the difference following methods.

In this study, bispectral index is used to maintain anesthesia depth. In addition, the commercially available noninvasive pain depth equipment (Surgical Pleth Index) is used to assess the nociception-antinociception balance. Displays the automatically calculated values of SPI=100-(0.3*heartbeat interval + 0.7*photoplethysmographic pulse wave ampule) using a waveform with peripheral oxygen saturation. Through this process, patients want to objectify the amount of anesthetic agent used during surgery. And all patients are inserted the laryngeal mask airway.

This study would try find out whether persistent pain after mastectomy is affected anesthetic factors appropriate anesthesia depth and opioid using standardized monitoring devices limited to similar surgical ranges.

The investigators hypothesize that patients who suffered severe acute postoperative pain, regardless of their anesthesia method, have a higher incidence of persistent post-mastectomy pain.

Inclusion Criteria:

-undergoing breast conserving surgery + sentinel lymph node dissection

Exclusion Criteria:

• cardiac arrythmia
• allergic history for drugs
• renal failure (Cr> 1.5 mg/dl)
• performing axillary lymph node dissection or Total mastectomy
• difficult airway and failed to place laryngeal mask airway properly

the 20-70 year old patients who undergoing breast conserving surgery + sentinel lymph node dissection at samsung medical center