The Impact of Ultrasound-Guided Superficial and Deep Paravertebral Nerve Blocks at the Superior Costotransverse Ligament on Hemodynamics During the Induction Phase of Thoracoscopic Lung Lobectomy: A Multicenter, Double-Blind, Randomized Controlled Trial

This study aims to determine whether performing a paravertebral nerve block at the superficial surface of the superior costotransverse ligament (SCTL) (without needle penetration of the SCTL) is more effective in maintaining hemodynamic stability during the induction phase of thoracoscopic lung lobectomy compared to the deep surface of the SCTL (with needle penetration of the SCTL). This is a multicenter, double-blind, randomized controlled trial enrolling a total of 168 participants across five hospitals. To investigate the effects of different nerve block methods on hemodynamics during induction, participants will be allocated to either the deep plane SCTL block group (T group) or the superficial plane SCTL block group (S group) using a stratified randomization scheme. The stratification accounts for a 40% proportion of hypertensive patients within each treatment group at each center. Thirty minutes before surgery, patients will receive either an ultrasound-guided deep SCTL block (needle penetrating the SCTL) or a superficial SCTL block (needle not penetrating the SCTL) in the pre-anesthesia room. The target vertebral levels for the block are T4 and T6, and 20 mL of 0.375% ropivacaine hydrochloride solution will be injected slowly at each site. Researchers will document whether subpleural compression is observed on ultrasound imaging and monitor for complications such as hemothorax, pneumothorax, local hematoma, local anesthetic toxicity, epidural anesthesia, or total spinal anesthesia during the procedure. Another investigator, blinded to the group allocation, will evaluate patients after the nerve block procedure, recording any occurrences of hemothorax, pneumothorax, local hematoma, local anesthetic toxicity, epidural block, or total spinal anesthesia. Cold sensitivity tests using the temperature method will be conducted at the midaxillary line within the corresponding blocked regions at 5, 10, 20, and 30 minutes post-block, and the sensory blockade level will be recorded. Thirty minutes after the block, anesthesia induction will be performed using target-controlled infusion (TCI) of propofol and remifentanil, along with rocuronium (0.6 mg/kg). Heart rate (HR), mean arterial pressure (MAP), stroke volume (SV), cardiac index (CI), and stroke volume index (SVI) will be measured every minute from induction until 5 minutes after intubation. Hypotension is defined as a MAP decrease of 20% or an absolute MAP \< 65 mmHg, while severe hypotension is defined as a MAP decrease of 30% or an absolute MAP \< 55 mmHg. Hemodynamic stability will be maintained using vasoactive medications as needed. The study will record intraoperative consumption of propofol and remifentanil, anesthesia duration, intraoperative intravenous fluid volume, urine output, blood loss, and extubation time. Postoperative assessments will include resting and movement-evoked (coughing) VAS scores at 4 and 24 hours, opioid consumption within 24 hours (oxycodone usage, first demand time, number of effective and actual demands), and additional analgesic requirements. The QOR-15 score at 24 hours and puncture-related complications within 72 hours postoperatively will be documented, along with a patient satisfaction survey at 72 hours. For the imaging study evaluating drug diffusion following each block method using CT (3D) imaging, 40 patients will be recruited at Nanjing First Hospital. Patients requiring preoperative CT-guided localization and puncture will receive an ultrasound-guided deep SCTL block (T group) or superficial SCTL block (S group) 30 minutes before the procedure, with 10 patients in each group. The block sites will be at the surgical side T4 and T6 levels, using 20 mL of a nerve block solution containing 0.375% ropivacaine mixed with 2 mL of iohexol (total 20 mL). Following the nerve block, patients will be placed in the supine position, and after 30 minutes, a blinded investigator will assess sensory loss using cold stimulation at the anterior chest wall (midclavicular line), lateral chest wall (posterior axillary line), and posterior chest wall (paravertebral region). Subsequently, patients will undergo routine CT-guided lesion localization and 3D imaging technology will be used to evaluate drug diffusion patterns for the two block techniques. Any adverse events occurring during the trial will be managed according to the study protocol and recorded accordingly.