Chronic pain
Conditions
Interventions
Two groups:Nitrous oxide versus 30%oxygen in air
Sponsors
The Chinese University of Hong Kong
Eligibility
Sex/Gender
All
Age
18 Years to 80 Years
Inclusion criteria
Inclusion criteria: (1) men or women aged =18 years; (2) American Society of Anesthesiologists physical status class 1-3; (3) major elective (open or laparoscopic) abdominal surgery, with an abdominal incision of at least 10 cm.
Exclusion criteria
Exclusion criteria: (1) acute bowel obstruction (contraindicated for N2O administration); (2) marked impairment of gaseous exchange (usually due to severe chronic obstructive pulmonary disease, requiring inspired O2 concentration >40%); (3) patients who plan to have a regional block for perioperative analgesia; (4) patients who are taking daily doses of opioids, tramadol, ketamine, gabanoids, tricyclic antidepressants, neuroleptics, serotonin reuptake inhibitors, COX2 inhibitors or other non-steroidal anti-inflammatory drugs 7 days before surgery; (5) atients who are not expected to be available for, or to cooperate with, interviews and those who refuse consent or who previously enrolled in the study.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Severe pain over the surgical site; | — |
Secondary
| Measure | Time frame |
|---|---|
| Any pain over the surgical site lasting for 6 months after surgery.; Interference of chronic postsurgical pain with daily activities;Impact of chronic postsurgical pain on general health status recorded by EQ-5D.; | — |
Countries
China
Contacts
Public ContactMatthew Chan
The Chinese University of Hong Kong
Outcome results
None listed