Protocol
Pain, pain
Premedication was not permitted for all participants. The prepared study drug was delivered to a clinical anesthesiologist (unrelated to this study) just before the start of anesthesia induction. On arrival in the operating room, standard monitors, including electrocardiograms, pulse oximetry, and noninvasive blood pressure (NIBP), were applied. A PI sensor (Radical-7®; Masimo Corporation, Irvine, CA, USA) was attached to the index finger and the finger was covered with a black opaque pouch to minimize light interference. The body temperature of all patients in our institute was maintained above 36.5 °C in the operating room using circulating-water blanket. The temperature of the operating room and PACU was maintained as 21 and 23 °C to prevent the influence of environmental temperature. In addition, to prevent the influence on blood flow, the NIBP was measured on the opposite side of the attachment site of the PI sensor.The degree of sedation was evaluated using the modified observer’s assessment of alertness/sedation (OAA/S) scale. To maintain OAA/S scale of 3–4, the study drugs were administered at the following doses: remifentanil 0.05–0.1 μg/kg/min and dexmedetomidine 0.2–0.7 μg/kg/h. The propofol infusion rate was adjusted to within the range of 25–75 μg/kg/min. If the patient or surgeon requested more sedation, 1–2 mg midazolam was additionally injected during the procedure. Before the surgical incision, all participants were administered 80 mg of 2% lidocaine as a local anesthetic on the skin. Depending on the surgical procedure, PI values, mean blood pressure (MBP), and heart rate (HR) were recorded at baseline, skin incision, dilator insertion, and skin suture. Intraoperative airway management was performed, including head tilting, chin lifting, jaw-thrust manipulation, and nasopharyngeal and laryngeal airway insertion. If airway management was required, the anesthetic dose was adjusted.After finishing the surgery, all anesthetics including the study drugs were discontinued in the operating room. Then, the patient was transferred to the post anesthesia care unit (PACU). PI values, pain severity, OAA/S scale, and additional analgesic requirements were recorded. Pain severity was investigated using numerical rating scale (NRS) scores on a 10-point scale and patient satisfaction was recorded using 5-point Likert scale [