One-lung Ventilation (OLV)

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.

This prospective, single-center, randomized controlled trial aims to evaluate the efficacy of an intraoperative "Individualized Open Lung Ventilation" strategy compared to a standard lung-protective ventilation strategy in patients undergoing thoracic surgery. One-lung ventilation (OLV) is essential for thoracic surgery but can cause lung injury. While standard care often uses fixed ventilation parameters, this study investigates whether personalizing Positive End-Expiratory Pressure (PEEP) to achieve the lowest driving pressure can reduce the incidence of postoperative pulmonary complications (PPCs) within 7 days after surgery.

One-lung ventilation (OLV) is commonly used during thoracic surgery but may negatively affect lung mechanics and gas exchange. Different ventilation strategies are used during OLV, and their effects on respiratory parameters remain an important clinical concern. Flow-controlled ventilation (FCV) is a newer ventilation mode that allows precise control of inspiratory and expiratory flow, potentially improving lung mechanics and gas exchange. Volume-controlled ventilation (VCV) is a widely used conventional ventilation strategy during thoracic anesthesia. The FCVOLVent study is a multicenter, prospective observational study designed to compare the effects of FCV and VCV during one-lung ventilation in adult patients undergoing thoracic surgery. Patients will be ventilated with either FCV or VCV as part of routine clinical practice. The study aims to evaluate respiratory mechanics and oxygenation parameters, including the PaO₂/FiO₂ ratio, airway pressures, lung compliance, and mechanical power during surgery. Data will be collected at predefined time points during one-lung ventilation. The results of this study are expected to provide real-world clinical evidence on the potential advantages and limitations of flow-controlled ventilation compared with volume-controlled ventilation during one-lung ventilation.

One-lung ventilation is commonly used during thoracic surgery but is frequently associated with impaired oxygenation and altered respiratory mechanics. Traditional oxygenation indices require arterial blood gas analysis and do not fully reflect the mechanical stress applied to the lungs. This prospective observational study aims to evaluate the correlation between oxygenation indices and oxygen saturation indices during one-lung ventilation in adult patients undergoing elective thoracic surgery. Modified indices incorporating driving pressure and mechanical power will also be assessed. No intervention beyond standard clinical care will be applied. The findings of this study may help clarify the clinical utility of non-invasive oxygenation indices for intraoperative monitoring during one-lung ventilation.

In most clinical scenarios, left DLT is preferred for one-lung ventilation because of its anatomical ease of placement; these tubes allow separate ventilation of both lungs. If the DLT is not placed in the proper size and depth, it may result in repeated intubation attempts, airway and dental trauma, failed lung isolation, tube dislodgement, and various unwanted events such as hypoxemia. The first and most common method for correct placement of a DLT is the conventional technique, blindly advanced into the left main bronchus, and then confirmed with fiberoptic bronchoscopy (FOB). In this method, the depth at which the tube should be left before performing FOB is left to the clinician's experience. Generally, the DLT is advanced in the trachea until a slight resistance is felt. This may lead to excessive advancement of the DLT into the left main bronchus or premature resistance due to the tube tip touching the carina, causing the clinician to stop before entering the left main bronchus. Therefore, just as selecting the correct size of the DLT is crucial, correctly estimating the appropriate depth is also of great importance. For this reason, different formulas have been proposed in the literature, and new formulas are still being investigated. The patient's gender and height are determinant in selecting the appropriate size of the DLT. However, studies in the literature indicate that the accuracy of these formulas may be limited in Asian populations. Therefore, it is important to evaluate the applicability of these formulas in different populations and, if necessary, develop new formulas. In the Turkish population as well, verifying the accuracy of these formulas for determining the proper size and depth of DLT-and if needed, developing new recommendations and formulas-holds clinical importance. In this study, conducted at Ankara Atatürk Sanatorium Training and Research Hospital, the aim is to evaluate the accuracy of six different formulas available in the literature for predicting DLT depth in patients undergoing thoracic surgery. Additionally, the correlations between DLT depth and demographic parameters as well as external airway measurements (mouth opening, sternomental distance, thyromental distance, distance between the mentum and manubrio-sternal angle, distance between tragus and manubrio-sternal angle, distance between sternal angle and xiphoid process) will be analyzed. Furthermore, challenges during DLT application, malposition rates and types, and complications will be assessed. The primary objective of this study is to evaluate, in patients undergoing thoracic surgery at Ankara Atatürk Sanatorium Training and Research Hospital, how accurate and applicable six different formulas defined in the literature are for predicting the placement depth of the DLT. If the existing formulas are insufficient, the aim is to develop a new formula.