Effect of Daytime Variation on Postoperative Hyperalgesia Induced by Opioids

The Second Affiliated Hospital of Chongqing Medical University60 enrolled

Overview

To explore the effect of daytime variation on postoperative hyperalgesia induced by opioids. Patients receiving endoscopy surgery under general anesthesia during 08:00-12:00(morning group, n=30) and 14:00-18:00(afternoon group, n=30) using remifentanil for anesthesia maintenance were respectively included. Postoperative hyperalgesia at PACU and 24 hours after surgery were assessed through mechanical pain measurement. Comparative analysis of postoperative hyperalgesia levels, pain and analgesic requirements between morning group and afternoon group were performed.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Postoperative Hyperalgesia

Interventions

RemifentanilDRUG

Remifentanil was used for maintenance of anesthesia.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * American Society of Anesthesiologists classification I-II * Abdominal endoscopy surgery * Estimated surgery duration 1-2h * Right handedness * Voluntarily receive postoperative intravenous controlled analgesia Exclusion Criteria: * Heavy smoking or alcohol dependence * Puerpera or lactation women * History of chronic pain * Analgesic use within one month before surgery * Allergy to opioids * Can not follow with the study procedure

Outcomes

Primary Outcomes

Postoperative hyperalgesia when discharged from postanesthesia care unit

The ratio of pressure pain threshold when discharged from PACU compare to before surgery

Time frame: from the 30 minutes before the surgery until to the time when discharged from postanesthesia care unit, assessed up to about 2 hours

Secondary Outcomes

Postoperative hyperalgesia at 24 hours after surgery

The ratio of pressure pain threshold at 24 hours after surgery compare to before surgery

Time frame: from the 30 minutes before the surgery until to 24 hours after surgery

Postoperative pain intensity

Pain intensity was assessed by numerical rating scale (0-10, 0 represents painless; 10 represents intolerable pain)

Time frame: from the time when the surgery was completed until to 24 hours after surgery

Postoperative analgesic requirements

Analgesic requirements was assessed by recording the volume of patient controlled analgesia pump

Time frame: from the time when the surgery was completed until to 24 hours after surgery

Plasma concentration of remifentanil and sufentanil

Determined by Elisa test

Time frame: from 30 minutes before the surgery until to the time after stop infusion of remifentanil, assessed up to about 2 hours

Activity of plasma nonspecific esterase

Determined by laboratory detection

Time frame: from 30 minutes before the surgery until to the time after stop infusion of remifentanil, , assessed up to about 2 hours