Impact of Frailty on Nalbuphine Dose for Postoperative Analgesia in Elderly Patients Undergoing Laparoscopic GI Surgery

The median effective dose (ED50) of nalbuphine is defined as the dose at which 50% of patients report a resting Visual Analogue Scale (VAS) pain score of ≤3 within 24 hours postoperatively. The VAS is a 10-cm line scale ranging from 0 (no pain) to 10 (worst imaginable pain), evaluated at rest.

The 95% effective dose (ED95) of nalbuphine is defined as the dose at which 95% of patients report a resting pain score of ≤3 on the Visual Analogue Scale (VAS) within 24 hours after laparoscopic gastrointestinal surgery. The VAS is a 10-cm horizontal line scale from 0 (no pain) to 10 (worst pain imaginable), evaluated in a supine resting state

The VAS is assessed at rest and during moving (coughing or changing position from back to side in bed). The pain degree was assessed with a 10cm scale (0-10 points) : 0 was no pain; A score below 3 indicates mild pain, which the patient can tolerate; 4-6 patients pain and affect sleep, can still tolerate; 7-10 points patients have gradually intense pain, the pain is unbearable.

1 awake, patient anxious, restless or irritable; 2 points awake, patient cooperation, good orientation or quiet; At 3 points of wakefulness, the patient only responds to commands; 4 minutes sleep, patients respond quickly to tapping eyebrow or Johnson stimulation; 5 minutes sleep, the patient is slow to tap eyebrow or Johnson stimulation; 6 minutes of sleep, the person did not respond to tapping the eyebrow or Johnson stimulation.

0 is persistent pain; 1 is painless at rest, severe pain when breathing deeply or coughing; 2 are painless at rest, mild pain when breathing deeply or coughing; There was no pain during 3 minutes of quiet and deep breathing. 4 points: No pain when coughing.

Nausea is an uncomfortable feeling of wanting to vomit, but there is no contractive movement of the abdominal muscles, diaphragm muscles, etc. Vomiting refers to the contraction of the diaphragm, chest muscles and abdominal wall muscles, which may be accompanied by vomiting of stomach contents, including dry heaving. If the vomiting events are more than 1 minute apart, they are considered separate episodes. 0 degree indicates no nausea or vomiting. Grade I is nausea and no vomiting; Grade Ⅱ was nausea with mild vomiting; Degree III is severe vomiting requiring further treatment; Grade IV is vomiting that is difficult to control.

The effective number of PCIA compressions performed by the patient after surgery

The total number of postoperatively applied PCIA

rescue sufentanil doses in PACU

length of stay in PACU

Functional recovery is defined as the ability of the patient to (1) independently get out of bed, (2) walk at least 10 meters with or without assistance, (3) tolerate oral intake (clear fluids or diet), and (4) urinate spontaneously. Recovery is assessed using a standardized checklist by the attending physician or nurse prior to discharge.

Number of additional doses of rescue analgesics administered to the patient within the first 48 hours postoperatively, recorded by nursing staff

SBP will be measured using automated patient monitors at predefined time points. The values will be recorded and analyzed as a continuous variable.

Respiratory depression is defined as a respiratory rate <8 breaths per minute or an oxygen saturation (SpO₂) ≤90% on room air. The incidence will be recorded at each predefined time point by nursing staff using bedside monitors

Pruritus is defined as persistent itching that leads to administration of antipruritic medication (e.g., antihistamines or corticosteroids). The number of participants requiring such medications at each time point will be recorded by medical staff.

DBP will be measured using automated patient monitors at predefined time points. The values will be recorded and analyzed as a continuous variable.

MAP will be measured using automated patient monitors at each specified time point. MAP is calculated using the formula: (SBP + 2 × DBP) / 3.

Heart rate will be measured using automated patient monitors. The values will be recorded in beats per minute (bpm) and analyzed continuously over time.

SpO₂ will be recorded using pulse oximetry. Oxygen saturation (%) will be continuously monitored and recorded at predefined intervals.