Using Thoracic Paravertebral Block for Perioperative Lung Preservation During VATS Pulmonary Surgery

Background: Postoperative pulmonary complications (PPCs) may extend the length of stay of patients and even increase perioperative mortality after video-assisted thoracoscopic (VATS) pulmonary surgery. Thoracic paravertebral block (TPVB) can provide effective analgesia after VATS, however little is known about the effect of TPVB on PPCs. This study aims to determine whether TPVB combined with general anesthesia results in reducing PPCs and achieve perioperative lung protection in VATS pulmonary surgery compared with simple general anesthesia.

Methods: A total of 302 patients undergoing VATS lobectomy/segmentectomy will be randomly divided into two groups: Paravertebral block group (PV group) and Control group (C group). Patients of PV group will receive thoracic paravertebral block: 15 ml of 0.5% ropivacaine will be administered to the T4 and T7 thoracic paravertebral spaces respectively before general anesthesia. Patients of C group will not undergo intervention. Both groups of patients adopted protective ventilation strategy during operation. Perioperative protective mechanical ventilation and standard fluid management will be applied in both groups. Patient controlled intravenous analgesia was used for postoperative analgesia. The primary endpoint is the composite outcome of PPCs within 7 days after surgery. Secondary end points include blood gas analysis, postoperative lung ultrasound score, NRS score, QoR-15 score, hospitalization related indicators and long-term prognosis indicators.

Surgical resection is still the go-to treatment for lung cancer, which is the leading cause of cancer death As a minimally invasive operation, video-assisted thoracoscopic surgery (VATS) has significantly reduced surgical trauma and systemic inflammation, and has become the standard treatment method for lung cancer.

Postoperative pulmonary complications (PPCs) are one of the most common complications after thoracoscopic lung cancer surgery, with an incidence of 40.8%. PPCs increase hospitalization time, hospitalization cost, and perioperative mortality, and affect the treatment effect and utilization of medical resources. One of the most pressing clinical issues is how to lower the prevalence of PPCs. Previous research has shown that lung protective ventilation strategies, including low tidal volume, positive end expiratory pressure (PEEP), low inhalation oxygen concentration, etc., have a good prognosis in patients with lung injury, but they may not fully prevent acute lung injury caused by one-lung ventilation (OLV) during VATS.

The incidence of pain 24 hours after VATS was 38%, and the incidence of chronic pain 6 months after VATS was 25%. Poor postoperative analgesia will affect postoperative recovery, which may raise the risk of pulmonary complications due to insufficient respiratory function and weak sputum excretion. Thus, it is crucial to effectively control acute discomfort following VATS.

Ultrasound guided thoracic paravertebral block (TPVB) is a commonly used regional block technique in thoracic surgery. Local anesthetics can be injected into the paravertebral space to block the ipsilateral sympathetic and somatosensory nerves. TPVB combined with general anesthesia (GA) can reduce the pain after VATS, decreases the expression of matrix metalloproteinase-9, reduce the inflammatory reaction after thoracic surgery, improve the postoperative survival rate by blocking the unilateral sympathetic nerve, improve the postoperative rehabilitation of patients after VATS lung cancer radical surgery, and reduce the postoperative tumor recurrence. According to a recent retrospective propensity matching analysis, TPVB and GA together were linked to a decreased incidence of PPCs (29.8% vs. 34.2%). However, a prospective study on the effects of GA combined with GA alone vs GA coupled with TPVB on PPCs following VATS pulmonary surgery has not been retrieved.

The aim of this study is designed to explore whether general anesthesia combined with thoracic paravertebral block can reduce atelectasis, lung inflammation, and lung injury compared to general anesthesia during VATS pulmonary surgery, thereby reducing the incidence of postoperative pulmonary complications, achieving lung protection, and improving long-term prognosis of patients.

Eligibility Criteria:
Inclusion Criteria:

* Patients scheduled for elective VATS lobectomy/segmentectomy had an expected operation duration (from skin incision to suture) greater than 1h
* Age\>18
* American society of Anesthesiologists (ASA) physical status classification system: I - III

Exclusion Criteria:

* Patients with acute or chronic respiratory failure, chronic obstructive pulmonary disease (GOLD) grade ≥ Grade III, poorly controlled asthma or acute respiratory distress syndrome (ARDS, according to the new definition of ARDS at the 2011 Berlin Conference)
* Patients with severe cardiovascular complications (defined as New York Heart Association (NYHA) Grade IV, acute coronary syndrome, or persistent ventricular tachycardia)
* Patients who had a history of ipsilateral thoracotomy or had a history of mechanical ventilation within 4 weeks
* Patients with contraindications to TPVB (coagulation dysfunction, anticoagulation or antiplatelet therapy, skin ulcer infection, local anesthetic allergy, Spinal deformity, etc.)
* Patients with trachea malformation or tracheotomy
* Pregnant or lactating patients