The Prediction for Postoperative Pain

Study Overview
=================
Brief Summary
-----------------
If the individual patient's pain is assessed and the amount of analgesic needed after surgery is predicted, appropriate injection of pain control and excessive injection of narcotic analgesic can be prevented. Therefore, investigators try to evaluate the degree of pain during surgery and the amount of analgesic use for management of postoperative pain.

Detailed Description
-----------------
Post-operative pain not only alleviates patient discomfort, but also delays recovery and thus prolongs the hospital stay. There are many ways to control postoperative pain, but analgesic infusion through venous route, patient controlled analgesia (PCA), especially narcotic analgesics, is often used to control the infusion when needed. However, because PCA is based on only age, weight, and underlying diseases, there are limitations in effective analgesia, and excessive sedation due to excessive infusion. Therefore, if the individual patient's pain is assessed and the amount of analgesic needed after surgery is predicted, appropriate injection of pain control and excessive injection of narcotic analgesic can be prevented. The noxious stimuli during surgery may have a negative effect on the healing process and surgical outcome of the wound due to stress reaction and catabolism, secretion of pituitary hormone, activation of the sympathetic nervous system, and immunological changes. Therefore, proper analgesia is needed during general anesthesia. A non-invasive, non-invasive analgesic device is currently available for Surgical pleth index (SPI) to assess the status of intraoperative analgesia. SPI = 100- (0.3 * heart beat interval + 0.7 * photoplethysmographic pulse wave amplitude) is automatically and continuously calculated from the waveform of peripheral oxygen saturation. In the postoperative pain prediction study with SPI, the SPI value at the end of the operation was found to be proportional to the pain in the recovery room. However, only the pain score immediately after the operation was confirmed in these studies. Therefore, investigators try to evaluate the degree of pain during surgery and the amount of analgesic use for management of postoperative pain.

Official Title
-----------------
Can we Predict Postoperative Analgesic Requirement by Intraoperative Nociception?

Conditions
-----------------
Pain, Postoperative, Nociceptive Pain, Analgesia, Patient-Controlled, Analgesics

Intervention / Treatment
-----------------
* Device: surgical pleth index


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: undergoing liver resection (laparoscopic or laparotomy) Exclusion Criteria: patients who refused to participate patients who have cardiac arrythmia patients who have allergic history for remifentanil

Ages Eligible for Study
-----------------
Minimum Age: 20 Years
Maximum Age: 80 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: SPI Group<br>All patients who received the liver resection surgery will receive surgical pleth index | Device: surgical pleth index<br>* All patients applied surgical pleth index after recovery of spontaneous breathing at the time of peritoneum and skin closure under Bispectral index score <=60.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The correlation of requirement of postoperative analgesics for postoperative 24 hours and intraoperative nociception score | The consumption of patient controlled analgesia and intraoperative surgical pleth index score | intraoperative nociception score: 3 minutes during closure peritoneum and skin; requirement of postoperative analgesics: the first 24 hour in postoperative phase | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The correlation of requirement of postoperative analgesics for postoperative 6 hours and intraoperative nociception score | The consumption of patient controlled analgesia and intraoperative surgical pleth index score | intraoperative nociception score: 3 minutes during closure peritoneum and skin; requirement of postoperative analgesics: the first 6 hour in postoperative phase | 
| The correlation of requirement of postoperative analgesics for postoperative 48 hours and intraoperative nociception score | The consumption of patient controlled analgesia and intraoperative surgical pleth index score | intraoperative nociception score: 3 minutes during closure peritoneum and skin; requirement of postoperative analgesics: the first 48 hour in postoperative phase | 
| The correlation of postoperative pain score and intraoperative nociception score | The postoperative pain score (numeric rating pain score, no pain=0  worst pain=10)and intraoperative surgical pleth index score | awaken after general anesthesia in post-anesthesia care unit , postoperative 6, 24, 48 hours | 
| The side effects of analgesics | nausea/vomiting, sedation, itching, respiratory depression | awaken after general anesthesia in post-anesthesia care unit , postoperative 6, 24, 48 hours |