Video-assisted Thoracis Surgery (VATS)

One-lung ventilation (OLV) is required for video-assisted thoracoscopic surgery (VATS) lung resection, but it exposes the dependent lung to atelectasis, high driving pressures, and oxidative stress, and is associated with postoperative pulmonary complications. Volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) are the conventional modes used during OLV. Flow-controlled ventilation (FCV) is a newer mode that delivers a constant gas flow during both inspiration and expiration through a narrow-bore endotracheal tube, and has been proposed to improve gas distribution and reduce mechanical stress on the lung. This prospective observational study evaluates oxygenation and respiratory mechanics in adult patients undergoing elective VATS lung resection under OLV. The ventilation mode used for each patient is determined by the attending anaesthesiologist as part of routine clinical care, independently of the study; investigators do not participate in any aspect of patient management and collect data through observation only. Patients are grouped according to the mode used in clinical practice (FCV, VCV, or PCV). The primary outcome is arterial oxygenation (PaO₂) at 30 minutes of OLV. Secondary outcomes include dynamic lung compliance, driving pressure, mechanical power, and haemodynamic parameters recorded at predefined intervals. A total of 120 patients (ASA I-III, GOLD stage 1-2) are planned for enrolment.

The goal of this clinical trial is to learn whether intravenous buprenorphine administered via a patient-controlled analgesia (PCA) system provides effective and safer postoperative pain control than intravenous oxycodone PCA in adults undergoing video-assisted thoracoscopic surgery (VATS). It will also evaluate the overall tolerability of buprenorphine in the early postoperative period and explore longer-term pain outcomes. The main questions it aims to answer are: Does buprenorphine PCA provide pain control that meets predefined targets during the first 48 hours after VATS (both at rest and during respiratory rehabilitation/mobilization), compared with oxycodone PCA? Does buprenorphine PCA reduce clinically relevant respiratory safety events (e.g., apnea or oxygen desaturation requiring intervention) and excessive sedation, compared with oxycodone PCA? What opioid-related adverse effects (e.g., nausea/vomiting, pruritus, constipation, hypotension) occur with buprenorphine PCA versus oxycodone PCA? Does buprenorphine PCA affect time to first patient-initiated analgesic demand and total opioid consumption within 48 hours? Does the choice of PCA opioid influence quality of recovery and the incidence of persistent postoperative pain at follow-up? Researchers will compare buprenorphine PCA to oxycodone PCA (both as part of standardized multimodal analgesia and perioperative care, including serratus anterior plane block) to determine whether buprenorphine provides non-inferior analgesia with a superior safety profile. Participants will: Be randomly assigned (double-blind) to receive buprenorphine PCA or oxycodone PCA for 48 hours after surgery, alongside standard multimodal analgesia Receive standardized general anesthesia for VATS with one-lung ventilation and an ultrasound-guided serratus anterior plane block at the end of surgery Have pain scores (NRS) recorded at multiple time points over 48 hours, at rest and during rehabilitation, and complete recovery questionnaires (QoR-15) early after surgery Be monitored regularly for vital signs, sedation level (RASS), respiratory events, and other adverse effects, with total opioid use recorded Provide satisfaction ratings at discharge and be followed after discharge to assess persistent postoperative pain/hyperalgesia at 1, 3, and 6 months