Liposomal and Standard Bupivacaine in Thoracic Paravertebral Block for Post-Thoracoscopic Pain

Standard monitoring, including electrocardiography (ECG), heart rate (HR), noninvasive blood pressure (NIBP), pulse oxygen saturation (SpO2), end-tidal carbon dioxide (ETCo2), and bispectral index (BIS) was initiated on arrival in the operating room. A neuromuscular monitor (JS-100, Beijing SLGO Medical Technology Co., Ltd., China) was used to confirm neuromuscular block (NMB).

Intravenous anesthesia was induced with 0.04 mg/kg midazolam, 0.3-0.5 μg/kg sufentanil, 1.5-2.5 mg/kg propofol, and 0.6 mg/kg rocuronium. Hemodynamics were supported with vasoactive agents (atropine, norepinephrine, dopamine, esmolol) as needed. After the train of four count (TOFC) ratio reached zero, a double-lumen tube or a single-lumen tube with a bronchial blocker was inserted, with correct positioning confirmed by fiberoptic bronchoscopy. Under real-time ultrasound visualization, a senior anesthesiologist performed thoracic paravertebral blocks at the T4-5, T6-7, and T8-9 levels in patients placed in the lateral decubitus position, injecting 6 mL, 8 mL, and 6 mL of local anesthetic at the respective levels.

Group B : Patients in the intervention group received a mixture of 10 mL of 1.33% liposomal bupivacaine (133 mg) and 10 mL of 0.5% bupivacaine hydrochloride,.

Group A: whereas those in the control group received 20 mL of 0.5% bupivacaine hydrochloride (total dose, 100 mg).

All patients received total intravenous anesthesia during surgery. Propofol was administered at a rate of 2-4 mg/kg/h, and remifentanil was administered at a rate of 0.05-0.3 μg/kg/min to maintain a BIS value range from 40 to 60. Rocuronium will be administered and adjusted to achieve deep NMB (defined as a TOFC=0 and a post-tetanic count =1-2). Standard ventilation parameters included a respiratory rate of 10-12 breaths·min-¹ and a positive end-expiratory pressure (PEEP) of 5cmH₂O. During double-lung ventilation, a tidal volume of 8 mL/kg was used, with ETCo2 maintained between 35-45 mmHg and peak airway pressure kept below 20cmH₂O. During single-lung ventilation, the tidal volume was reduced to 6 mL/kg, with ETCo2 maintained below 60 mmHg and peak airway pressure kept below 30cmH₂O. Intravenous sufentanil (0.15 μg/kg) and ondansetron hydrochloride (8mg) were administered prior to the end of surgery. After surgery, patients were transferred to the post-anesthesia care unit (PACU) for further monitoring. Additionally, 2-4 mg/kg of sugammadex was given to reverse the residual effect of rocuronium.

In the PACU, an intravenous bolus of 0.1 μg/kg sufentanil was administered when the numeric rating scale (NRS; 0, no pain; 1-3, mild pain; 4-6, moderate pain; and 7-10, severe pain) score was ≥4. The drugs used for postoperative patient-controlled intravenous analgesia (PCIA) were sufentanil (2 μg/kg), which were diluted in 0.9% normal saline to a final volume of 100mL. The analgesia pump settings were as follows: background dose, 0 mL/h; self-controlled additional dose, 1 mL/time; and lockout time, 10 min. The patients were sent to the ward upon meeting the following criteria for at least 30 minutes: NRS score <4, an Adrelete score ≥9 and absence of other adverse reactions. The number of PCA attempts and the total drug delivery were automatically recorded by the postoperative analgesia system.

Inclusion criteria

• 1) Age ≥18 years old;

• Patients undergoing unilateral initial thoracoscopic lobectomy under general anesthesia (TV or robot-assisted);

• American Society of Anesthesiologists (ASA) Grade I - III;

• Voluntarily participate in the study and sign the informed consent.

Exclusion criteria

• 1) Pregnant or lactating women;

• Pulmonary wedge-shaped resection;

• ≥2 thoracic drainage tubes;

• Abnormal liver function: ALT and/or AST>2×ULN, or

TBIL≥1.5×ULN;

• Renal function impairment (serum creatinine >176μmol/L), or received dialysis treatment within 28 days before surgery;

• Participate in another research trial involving an investigational drug within 6 months;

• A history of drug or alcohol abuse;

• Long-term use of opioids (more than 3 months or more than 5 mg daily morphine equivalent per day for 1 month);

• History of allergy to local anesthetics or one of the investigational drugs;

• Uncontrolled mental or neurological symptoms.