Dexmedetomidine Reduces Sevoflurane MAC-BAR During Pneumoperitoneum

Laparoscopic (minimally invasive) surgery has several advantages over open surgery, including less tissue damage, faster recovery, and fewer complications. This has led to widespread use of laparoscopic techniques. However, the inflated carbon dioxide gas used to create the surgical space during laparoscopic surgery causes significant changes in the body's normal blood pressure and heart function.

The anesthetic drug sevoflurane is commonly used during these procedures, but higher doses are needed to adequately block the body's stress response to the inflated gas. The minimum alveolar concentration blunting the adrenergic response (MAC-BAR) measures the minimum anesthetic depth required to suppress the sympathetic/stress response in 50% of patients. Doctors use MAC-BAR values to help determine the appropriate anesthetic dose to maintain hemodynamic stability. Unfortunately, using higher sevoflurane doses to reach the necessary MAC-BAR increases the risk of low blood pressure, reduced heart function, and confusion after surgery.

The drug dexmedetomidine has properties that can help manage the body's stress response during surgery. Researchers wanted to see if dexmedetomidine could allow the use of lower, more stable doses of sevoflurane during laparoscopic procedures by reducing the body's reaction to the inflated gas.

The goal of this study was to evaluate how dexmedetomidine affects the MAC-BAR of sevoflurane needed to block the sympathetic/stress response to the inflated gas used in laparoscopic surgery.

Inclusion criteria

• 1. Aged 18-45 years.
• 2. American Society of Anesthesiologists (ASA) grade I - II.
• 3. Patients undergoing elective laparoscopic cholecystectomy.

Exclusion criteria

• 1. Inability to provide informed consent;
• 2. History of chronic pain or substance abuse;
• 3. Pregnancy;
• 4. Body mass index (BMI) ≥ 30 kg/m2;
• 5. Known allergies to the study medications;
• 6. Intake of medications within the last 72 hours that potential interfere with the determination of the MAC-BAR;
• 7. Any other condition deemed exclusionary by the investigators.