Comparison of Remifentanil-induced Postoperative Hyperalgesia Between Patients From Plain Area and Plateau Area

Comparison of Remifentanil-induced Postoperative Hyperalgesia After Gynecological Laparoscopic Surgery Between Patients From the Plain Area and the Plateau Area

Purpose:

1. To compare the incidence of postoperative hyperalgesia induced by remifentanil in patients undergoing gynecological laparoscopic surgery in plateau and plain areas
2. To compare the peri-operative analgesic requirements of patients in plain and plateau areas

Our research group has been committed to the research of remifentanil-induced hyperalgesia for a long time. In the previous study, it was found that intraoperative infusion of remifentanil (0.3ug/kg•min) >1h can lead to remifentanil-induced hyperalgesia and the incidence rate is relative high in the plain area. Due to the long-term low pressure and hypoxia of people living in plateau areas, a series of changes will occur in the respiratory and circulatory systems, and their anesthesia management needs to be adjusted accordingly. However, there is no relevant research on whether or not hyperalgesia occurs in people in plateau areas (altitude level >3000 meters). Therefore, this study hopes to compare the incidence and degree of remifentanil-induced hyperalgesia after gynecological laparoscopic surgery in plain areas and plateau areas.

Inclusion Criteria:

1. Subject is scheduled to undergo gynecological laparoscopic surgery under a short general anesthesia of less than 2 hours
2. Subject's American Society of Anesthesiologists physical status is I-II.
3. The subject's parent/legally authorized guardian has given written informed consent to participate.
4. Patients in plateau areas are long staying residents in above 3000 meters above sea level for enrollment, while patients in plain areas are long staying residents below 1000 meters above sea level.

Exclusion Criteria:

1. Subject has a diagnosis of renal or liver failure.
2. Subject has a diagnosis of Insulin dependent diabetes.
3. Subject is allergy and contraindication to any drugs used during general anesthesia.
4. Subject has a history of chronic pain, a history of alcohol or opioid abuse, pre-existing therapy with opioids, intake of any analgesic drug within 48 hours before surgery.
5. Subject has any contraindication for the use of patient-controlled analgesia (PCA).
6. Subject is pregnant or breast-feeding.
7. Subject is obese (body mass index >30kg/m2).