Dexmedetomidine Versus Magnesium Sulfate as Adjuvants to Intraperitoneal Bupivacaine for Postoperative Analgesia After Elective Laparoscopic Cholecystectomy

Pain after laparoscopy is less intense than after laparotomy, but laparoscopy is not pain free and analgesia after this type of surgery is inadequately studied. Intraperitoneal (IP) instillation/nebulization of local anesthetics has been used as a method for reducing postoperative pain and opioid use following laparoscopy through acting on visceral nociceptors of the peritoneum.

Bupivacaine is indicated for local infiltration, peripheral nerve block, sympathetic nerve block, and epidural and caudal blocks. It is available mixed with a small amount of epinephrine to increase the duration of its action. It typically begins working within 15 minutes and lasts for 2 to 8 hours.

Dexmedetomidine is a selective alpha-2 (α2) adrenergic agonist known to have analgesic and sedative characteristics that can augment the duration of action of local anesthetics.

Magnesium is an N-methyl-D-aspartate receptor antagonist in addition to its effects on calcium influx. The anti-inflammatory and opioid-sparing effects make it a popular component of opioid free anaesthesia. It is extensively used for perioperative analgesia in a dose of 30- to 50-mg/kg intravascular bolus followed by a 10- to 15-mg/kg/h infusion.

Inclusion criteria

• Age from 21 to 65 years.
• Both sexes.
• American Society of Anesthesiologists (ASA) class I-III.
• Scheduled to undergo elective laparoscopic cholecystectomy.

Exclusion criteria

• Patient refusal.
• Body mass index ≥40.
• Allergy to the study drugs.
• Advanced cardiac, renal and hepatic diseases.
• Patients with peritoneal drain or peritoneal wash after surgery.
• Uncooperative patients.
• Chronic pain medications.
• Hypomagnesaemia or hypermagnesaemia.