The Effect of Remimazolam on Opioid Induced Hyperalgesia

The goal of this prospective, randomized, controlled study is to investigate the effect of remimazolam on opioid-induced hyperalgesia (OIH) in patients undergoing single port-laparoscopically assisted urologic surgery. The main question[s] it aims to answer are: [The mechanical hyperalgesia threshold] [Area of hyperalgesia around the surgical incision 24 h after surgery (cm^2)] In three groups: Group RHR (Remimazolam- High-dose Remifentanil), Group DHR (Desflurane-low-dose Remifentanil) or Group DLR (Control).

Ninety-three (n = 31 per group) American Society of Anesthesiologists I-II patients (age 20-65 years) will be scheduled for single port-laparoscopically assisted urologic surgery. Group RHR (Remimazolam-Remifentanil): Administer remimazolam at a dose of 6 mg/kg/h initially, followed by 1 mg/kg/h, and remifentanil at 0.3 µg/kg/min. Group DHR (Desflurane-Remifentanil): Administer desflurane at 1 minimum alveolar concentration (MAC), adjusting the dose by 1 vol% titration to maintain MAP and BIS levels, and remifentanil at 0.3 µg/kg/min. Group DLR (Control): Administer desflurane at 1 MAC, adjust the dose by 1 vol% titration to maintain mean arterial pressure (MAP) and bispectral index (BIS) levels, and remifentanil at 0.3 µg/kg/min. Mechanical hyperalgesia threshold, Time to first postoperative analgesic requirement (min), Injected PCA volume containing morphine for 12 h after surgery (ml), Pain intensity: VAS 1 h after surgery, VAS 6 h after surgery, VAS 12 h after surgery VAS 24 h after surgery. Area of hyperalgesia around the surgical incision 24 h after surgery (cm^2) will be checked.

Group RHR (Remimazolam- High doses of Remifentanil): Administer remimazolam at a dose of 6 mg/kg/h initially, followed by 1 mg/kg/h, and remifentanil at 0.3 µg/kg/min. Group DHR (Desflurane-High doses of Remifentanil): Administer desflurane at 1 MAC, adjusting the dose by 1 vol% titration to maintain MAP and BIS levels, and remifentanil at 0.3 µg/kg/min. Group DLR (Desflurane-Low-dose of Remifentanil): Administer desflurane at 1 MAC, adjust the dose by 1 vol% titration to maintain MAP and BIS levels, and remifentanil at 0.025 µg/kg/min.

A trained anesthesiologist not involved in general anesthesia assessed clinically relevant and mechanically evoked pain using the Von-Frey filaments and secondary outcomes after surgery.

Administer desflurane at 1 MAC, adjust the dose by 1 vol% titration to maintain MAP and BIS levels, and remifentanil at 0.025 µg/kg/min.

Administer desflurane at 1 MAC, adjusting the dose by 1 vol% titration to maintain MAP and BIS levels, and remifentanil at 0.3 µg/kg/min.

Administer remimazolam at a dose of 6 mg/kg/h initially, followed by 1 mg/kg/h, and remifentanil at 0.3 µg/kg/min.

The mechanical hyperalgesia threshold (g/mm^2) (preoperative) and 2 cm from the single port incision site (postoperative) at four points (horizontally and perpendicularly).

The Visual analogue scales (VAS)-100 is a line with words describing the extremes of pain from "no pain" to "worst imaginable pain".

The Visual analogue scales (VAS)-100 is a line with words describing the extremes of pain from "no pain" to "worst imaginable pain".

The Visual analogue scales (VAS)-100 is a line with words describing the extremes of pain from "no pain" to "worst imaginable pain".

The Visual analogue scales (VAS)-100 is a line with words describing the extremes of pain from "no pain" to "worst imaginable pain".

Inclusion criteria will include as follows; ASA(American Society of Anesthesiologists)physical status 1-2 patients, Age with 20-65 years, and Single port-laparoscopically assisted urologic surgery. Exclusion criteria will include as follows; a known allergy to remimazolam or remifentanil, a history of drug or alcohol abuse, psychiatric disorders, acute cardiovascular disorders, or unstable hypertension, and other respiratory or neuromuscular pathology, treated with opioid-containing any analgesic drug within 24 h before surgery and contraindications to the self-administration of opioids (i.e., were unable to understand the PCA device).