Pain, Postoperative
Conditions
Keywords
midazolam, ambulatory surgery
Brief summary
To investigate whether midazolam has any effect on postoperative pain in outpatient surgery, the investigators will assess the impact of different midazolam doses on pain scores 24h, 7 days and 3 months after ambulatory surgery. The investigators hypothesize that patients being administered higher midazolam doses will refer more pain.
Detailed description
Systemic midazolam prescribed perioperatively might have impact on pain, with studies suggesting antinociceptive and hyperalgesic effects. Anxiety might be a confounder in this association. In order to investigate the effect of midazolam on postoperative pain, a clinical trial will be conducted in Portuguese ambulatory surgery units. A convenience sample with consecutive design will include patients admitted for open inguinal hernia repair, varicose vein stripping, knee arthroscopy or hallux valgus surgery under spinal anesthesia. Patients will be randomized into 3 premedication groups, and this randomization will be stratified for each centre and each type of surgery. Postoperative pain will be blindly assessed by telephone interviews at 24h, 7 days, and 3 months. The investigators will use multiple regression models to explore the interaction of midazolam dose with preoperative anxiety, gender and chronic benzodiazepine use, as they hypothesize there might be a differential effect of midazolam on postoperative pain amongst these subgroups.
Interventions
intravenous
OTHERNormal saline
intravenous
PROCEDURESpinal anesthesia
8mg of heavy bupivacaine 0.5% injected in the subarachnoid space, during lateral decubitus
PROCEDURESurgery
Open inguinal hernia repair, varicose vein stripping, knee arthroscopy or hallux valgus surgery
DRUGPostoperative analgesia
IV acetaminophen 1g + IV ketorolac 30mg
DRUGRescue analgesia
Tramadol 2mg/Kg IV in 100mL of normal saline, if pain NRS\>3.
DRUGWound infiltration
Wound infiltration with 10mL of ropivacaine 0.75%, in open inguinal hernia repair
DRUGAnalgesia at home
Oral acetaminophen 1g 6/6h + ibuprofen 400mg 8/8h (+ rescue analgesia with tramadol 50mg 6/6h)
Sponsors
Centro Hospitalar de Entre o Douro e Vouga
Centro Hospitalar de Vila Nova de Gaia/Espinho
Universidade do Porto
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* adult patients submitted to open inguinal hernia repair, varicose vein stripping, knee arthroscopy or hallux valgus surgery in Portuguese ambulatory surgery units
Exclusion criteria
* psychiatric disorders * alcoholism * illiteracy or poor understanding of Portuguese language * history of chronic pain under opioids * recurrent surgery * contraindication for midazolam or deep sedation * contraindication for spinal anesthesia
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Postoperative pain | Day 1 after surgery | Assessed by the Brief Pain Inventory severity score (24h recall time): mean of 4 items assessing pain at the moment of the interview, on average, at its least and at its worst during the last 24h |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Pain interference in daily life | Day 1 after surgery | Assessed by the Brief Pain Inventory interference score (24h recall time): interference of pain in general activity, mood, walking ability, normal work, relations with other people, sleep and enjoyment of life. |
| Analgesic consumption | Day 1 after surgery | Total analgesic drugs taken in a time period (first day after surgery) |
| Postoperative pain | Day 7 after surgery | Assessed by the Brief Pain Inventory severity score (24h recall time): mean of 4 items assessing pain at the moment of the interview, on average, at its least and at its worst during the last 24h. Features of neuropathic pain as assessed by DN4 patient-reported symptoms |
| Adverse events | Day 7 after surgery | Number of patients with adverse events like bleeding, nausea, uncontrolled pain |
| Global surgery recovery index | Month 3 after surgery | Global surgery recovery index (0-100%) |
| Patient satisfaction | Day 7 after surgery | NRS 0-10 |
Countries
Portugal
Contacts
Primary ContactCaroline Dahlem, MD
Outcome results
None listed