acute opioid tolerance
Conditions
Interventions
1:After induction of anesthesia, remifentanil is continuous infused at rate of 0.1ug/kg/min, sevoflurane are adjusted according to hemodynamic parameters narcotrend, each time in 1% increments or decr
2:end-tidal sevoflurane concentration is maintained at 0.8 minimum alveolar concentration, adjust to age. Remifentanil is started infusing at rate of 0.25ug/kg/min and subsequently increased stepwise
3:end-tidal sevoflurane concentration is maintained at 0.8 minimum alveolar concentration, adjust to age. Remifentanil is started infusing at rate of 0.25ug/kg/min and subsequently increased stepwise
Sponsors
The First Affiliated Hospital of Sun Yat-sen University
Eligibility
Sex/Gender
All
Inclusion criteria
Inclusion criteria: 1. Male and female aged 18 to 65 years old; 2. Able and willing to provide signed informed consent; 3. Schedule for open colorectal surgery lasting at least 120 min; 4. American Society of Anesthesiologist physical status I-III; 5. Apply for postoperative analgesia.
Exclusion criteria
Exclusion criteria: 1) their Body Mass Index are less than 19 or greater than 31; 2) they have a history of chronic pain; 3) they have a history of drug or alcohol abuse; 4) they take analgesic or opioids 12 h before surgery; 5) they have status of contraindications to the drugs we use in our study; 6) immediate extubation is not planned after surgery; 7) they cannot understand and make use of the PCA device; 8) there is existence of pregnancy, lactation, liver and kidney failure or respiratory failure.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| the visual analog scale scores and mophine consump;the total and effective times of press at 6, 12, 2;?T=T2-T1(T1=extubation time, T2=time of first use;the verbal response scores and mophine consumption;the visual analog scale scores and mophine consump; | — |
Secondary
| Measure | Time frame |
|---|---|
| the visual analog scale scores and mophine consumption at 6, 12, 24, 48 and 72 h after the surgery.; | — |
Contacts
Public ContactXiongqing Huang
Outcome results
None listed