Analgesic Effect of Preoperative Dexamethasone in Gynecological Laparotomies - a Dose-ranging Study

The objective of the study is to examine the effect of the addition of intravenous dexamethasone 1.5 hours prior to induction of anesthesia on the post-operative opioid consumption, pain scores, fatigue, and recovery in patients undergoing gynecological surgery with laparotomy under general anesthesia.

This is a dose finding study with two different doses (0.1 mg/kg vs. 0.2 mg/kg) of dexamethasone to find out the optimal efficacious dose of dexamethasone with minimal side effects.

Dexamethasone has anti-inflammatory, immunomodulatory, and analgesic effects; and is superior to placebo in providing post-operative pain control, lower analgesic consumption, prevention of postoperative nausea and vomiting, lesser post-operative fatigue, and better recovery profile. No dose response study has been done. The investigators hypothesize that a higher dose of dexamethasone may have an incremental beneficial effect.

Inclusion Criteria:

• Patients must be non-lactating
• 18-65 years of age
• ASA groups I-III for elective total abdominal hysterectomy (with or without salpingo-oophorectomy or minor bladder repair)or myomectomy through a lower transverse or low midline incision under general anesthesia. Incidental appendectomy and /or abdominal lipectomy were allowed as collateral surgical procedures if the same incision was used

Exclusion Criteria:

• Emergent procedures
• Diagnosed malignancy
• History of allergy to dexamethasone
• Allergy or contraindication to drugs used in study and anesthesia
• Patients with uncontrolled diabetes mellitus, recent history of gastrointestinal bleeding or ulceration within 30 days before the study)
• Patients who have taken drugs in the 12 hours preceding the surgery that could confound the analgesic response (specifically analgesics, neuroleptics, corticosteroids, NSAIDs)
• Patients who have been on long term oral steroid therapy
• Patients with BMI>40
• Serious organ disease/ dysfunction
• Chronic pain patients requiring >30mg morphine per day or equivalent
• Severe psychiatric disease
• Drug Addiction
• Pregnancy
• Language barrier
• Inability to cooperate with the use of the intravenous PCA morphine pump