Does Midazolam Affect Postoperative Pain?

Study Overview
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Brief Summary
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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 open inguinal hernia repair. The investigators hypothesize that patients being administered higher midazolam doses will refer more pain.

Detailed Description
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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 prospective cohort study will be conducted in four Portuguese ambulatory surgery units. A convenience sample with consecutive design will include patients admitted for open inguinal hernia repair. After anxiety and pain evaluation, a tailored dose of midazolam will be administered as premedication according to the anesthetist's best judgement within each unit's protocol (routine care; this dose may be null). Subsequent anesthesia and analgesia will be standardized. Postoperative pain will be blindly assessed by telephone interviews at 24h, 7 days, and 3 months. Statistical analysis will be performed separately for each gender, centre and type of anesthesia, adjusting for preoperative anxiety and other confounding variables with multivariate analysis. The investigators intend to clarify the relation between anxiety, preoperative midazolam and postoperative pain.

Official Title
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Does Preoperative Midazolam Dose Affect Postoperative Pain? - a Multicentric Observational Study in Open Inguinal Hernia Repair

Conditions
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Pain, Postoperative

Intervention / Treatment
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* Drug: Midazolam injection


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - adults proposed for open inguinal hernia repair in Portuguese ambulatory surgery units Exclusion Criteria: psychiatric disorders alcoholism illiteracy or poor understanding of the Portuguese language history of chronic pain under opioids recurrent surgery

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Drug: Midazolam injection|The dose of preoperative midazolam is the predictor variable and will be registered as a continuous variable in a single cohort.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative pain | Pain numeric rating scale (NRS) 0-10 | 24h after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative pain | Pain NRS | 7 days after surgery | 
| Postoperative pain | Pain NRS | 3 months after surgery | 
| Patient satisfaction | NRS | 7 days after surgery | 
| Patient satisfaction | NRS | 3 months after surgery | 
| Analgesic consumption | Total analgesic drugs taken in a time period | 24h after surgery | 
| Analgesic consumption | Total analgesic drugs taken in a time period | 7 days after surgery | 
| Adverse events | Number of patients with adverse events like bleeding, nausea, uncontrolled pain | 7 days after surgery | 
| Global surgery recovery index | Global surgery recovery index | 3 months after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Midazolam, Inguinal hernia