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.

• 15 quality of recovery assessments (QoR15) [Time frame: at 24, 48, and 72 hours after surgery]
• area under the NRS score curve (AUC) for exercise [Time frame: 48 hours after surgery]
• area under the NRS score curve (AUC) for resting and exercise [Time frame: 72 hours after surgery]
• area under the NRS score curve (AUC) for resting and exercise [Time frame: 96 hours after surgery]
• cumulative opioid consumption (morphine milligram equivalent, MME [Time frame: at 72 hours after surgery]