after joining the study, you sign the informed consent form that explains the purpose of the trial and the procedures that will be performed.

the consent form also describes the possible risks and benefits, and confirms that participation is voluntary.

on the day before surgery, you perform spirometry tests using a portable electronic device to measure forced expiratory volume per second (fev1), peak expiratory flow (pef), and forced vital capacity (fvc).

you may also complete the quality of recovery questionnaire (qor‑15) to provide a baseline score.

during the operation, an intravenous (iv) medication is given according to the group to which you have been assigned.

if you are in the test group, you receive dexmedetomidine at a dose of 1.2 µg/kg, administered continuously through the iv line for the duration of the surgery.

if you are in a comparator group, you receive sufentanil at 1 µg/kg iv and remifentanil at 2 µg/kg iv, both given as continuous infusions throughout the procedure.

after surgery, you are taken to the recovery area where vital signs are monitored.

you complete the quality of recovery questionnaire (qor‑15) on postoperative day 0 (pod0).

pain is assessed using a numeric rating scale (nrs) from 0 (no pain) to 10 (worst pain) while at rest and during coughing.

if pain is reported, intravenous morphine may be administered as needed; the total amount given is recorded up to postoperative day 2 (pod2).

episodes of nausea or vomiting are noted, and medication is given if required.

on pod1 you complete the qor‑15 questionnaire again to evaluate recovery.

pain is reassessed with the nrs at rest and during coughing.

a cognitive assessment using the confusion assessment method (cam) is performed to detect any postoperative cognitive dysfunction.

spirometry measurements (fev1, pef, fvc) are repeated with the same portable device used preoperatively.

you are monitored for the return of bowel function, defined by the first passage of gas, and for any further episodes of nausea or vomiting.

oxygen therapy, if required, is recorded for up to 72 hours after surgery.

pain scores using the nrs are recorded again at rest and during coughing.

any additional morphine administered is added to the cumulative total recorded for the first two postoperative days.

nausea, vomiting, and bowel function are continue to be observed.

the date of first ambulation (walking) is noted, and the total length of hospital stay is recorded, with a maximum observation period of 28 days.

postoperative pulmonary complications are monitored according to the melbourne group scale for up to 28 days after surgery.

mortality is checked on postoperative day 28 (pod28).

by telephone, you are asked to answer a simplified dn4 questionnaire to evaluate the presence of chronic pain; a score of 3 or more positive answers out of 7 indicates chronic pain.

pain intensity is again rated with the nrs at rest and during coughing.

information on any analgesic medication taken, including opioids, is collected.