The purpose of this study, is to investigate the effectiveness of ultrasound-guided rhombic intercostal nerve block for postoperative pain control in thoracoscopic pulmonary resection with bupivacaine liposomes versus bupivacaine hydrochloride with dexamethasone to assess whether bupivacaine liposomes will produce analgesia superior to bupivacaine hydrochloride with dexamethasone in terms of analgesia effect and duration of analgesia. This study will also evaluate whether liposomal bupivacaine after nerve block improves the quality of postoperative recovery compared to bupivacaine hydrochloride combined with dexamethasone.

Approved by the Ethics Committee of Jiaxing No. 1 Hospital (approval number: 2024-KY-226). This study was enrolled prior to patient enrollment in the clinical trial. Written informed consent was obtained from all participants. The study is expected to be conducted from April 2024 through December 2025. This study enrolls 90 elective thoracoscopic lung resection surgery(including wedge resection, segmentectomy, or lobectomy) patients between the ages of 18-80 years, ASA Physical Status I and III, who had no allergic reaction to the study drug.

Basic monitoring such as electrocardiogram, pulse oximetry, and noninvasive blood pressure were arranged preoperatively. The bupivacaine liposome group was treated with bupivacaine liposome 93 mg combined with bupivacaine 25 mg, and the standard control group was treated with bupivacaine hydrochloride 105 mg combined with dexamethasone 5 mg, and both groups were perfused with saline 20 ml. ultrasound-guided rhombic intercostal muscle nerve block was performed for a total of 20 ml. postoperative analgesia was provided using patient-controlled intravenous analgesia (PCIA), and according to the patients weight and baseline condition. Upon arrival of postoperative patients to the ward, if the patient reports significant pain, defined as the numeric rating scale (NRS), score greater than 3, the first step is to administer one press of the analgesic pump. If the pain persists, the pain management protocol will be initiated. Cumulative PCIA consumption at different postoperative time intervals (including 0-24 hours, 24-48 hours, and 48-72 hours). Quality of Recovery Score (QoR-15) at 72 hours postoperatively, If NRS at 6 hours to 3 months, and patient satisfaction were recorded.Pain assessments were performed at the following time points: 0 hours postoperatively (upon tracheal extubation and patient awakening), 0.5 hours, 2 hours, 4 hours, 12 hours, 24 hours, 48 hours, and 72 hours. Pain score follow-up by telephone at the third month.

Inclusion Criteria:

ASA physical status I-III, aged between 18 and 80 years, scheduled for elective thoracoscopic lung resection surgery under general anesthesia with endotracheal intubation (including wedge resection, segmentectomy, or lobectomy) with one or three incisions, expected duration of surgery less than 4 hours, and body mass index (BMI) between 18 and 30 kg/m².

Exclusion Criteria:

1. trauma or emergency patients;
2. patients classified as New York Heart Association (NYHA) functional class 3-4;
3. unstable coronary artery disease patients;
4. patients with renal system diseases (estimated glomerular filtration rate <30 mL/min/1.73 m²);
5. patients with liver system diseases (alanine aminotransferase or aspartate aminotransferase levels exceeding twice the normal value);
6. patients with coagulation disorders, or those who have not discontinued warfarin or novel anticoagulants (such as rivaroxaban, dabigatran) prior to surgery;
7. individuals with a history of alcohol abuse or substance dependence within the past two months;
8. patients with uncontrolled anxiety, schizophrenia, or other psychiatric disorders;
9. pregnant or planning to become pregnant women;
10. individuals with a history of allergy to local anesthetics or investigational drugs. Additionally, patients who refuse to sign the informed consent form will also be excluded;
11. chronic pain syndromes (defined as reflex sympathetic dystrophy or complex regional pain syndrome);
12. chronic opioid use (longer than 3 months or daily morphine equivalents more than 5 mg/day for 1 month).

Blinding of medical staff and investigators: a study coordinator was developed to keep and distribute the randomisation numbers, an independent nurse anaesthetist prepared the medication for the study according to the randomisation result code, because bupivacaine liposomes are milky and bupivacaine is colourless, we set up an independent medication preparer and nerve block operator, and nerve block operators were not permitted to be associated with anaesthesia procedures and postoperative Patient assessment. The anaesthesiologist and the follow-up physician were unaware of the grouping.

Patients were blinded: all patients were anaesthetised and the nerve block was performed without the patients touching the drugs. The double blinding continued throughout the study period.