Clinical Research Directory

Peak Airway Pressure and Respiratory Mechanics During PRVC Ventilation in Laparoscopic Surgery

This study aims to evaluate peak airway pressure and respiratory mechanics during pressure-regulated volume control (PRVC) ventilation in patients undergoing elective laparoscopic abdominal surgery. Pneumoperitoneum and patient positioning during laparoscopic procedures can significantly affect respiratory mechanics, including airway pressures and lung compliance. The study will assess changes in peak airway pressure, dynamic compliance, and other ventilatory parameters during different intraoperative phases. The findings are expected to provide insights into optimizing ventilatory strategies to improve patient safety and minimize ventilator-associated complications during laparoscopic surgery.

Intra-Abdominal Pressure, Respiratory Mechanics, and Ventilator Liberation After Emergency Major Laparotomy

This prospective observational cohort study aims to investigate the relationship between intra-abdominal pressure (IAP), respiratory system mechanics, and successful liberation from invasive mechanical ventilation in adult patients admitted to the intensive care unit (ICU) following emergency major laparotomy. Increased intra-abdominal pressure may impair respiratory mechanics by reducing chest wall compliance, increasing airway pressures, and limiting diaphragmatic movement. These physiological changes may contribute to prolonged mechanical ventilation and difficulties in ventilator liberation. The study will enroll 100 adult patients who undergo non-traumatic emergency major laparotomy with primary fascial closure and require invasive mechanical ventilation upon postoperative ICU admission. Intra-abdominal pressure will be measured using a standardized intravesical technique through an existing urinary catheter. Serial measurements will be performed during the first 48 hours after ICU admission, alongside simultaneous assessments of respiratory system mechanics, including static respiratory system compliance and driving pressure. The primary objectives are to evaluate the longitudinal association between IAP and static respiratory system compliance and to investigate whether early IAP trajectories are associated with time to successful liberation from invasive mechanical ventilation within 28 days. Secondary outcomes include driving pressure, mechanical ventilation status on day 7, extubation failure, ventilator-free days through day 28, and mortality. All clinical management decisions, including ventilator settings, sedation, spontaneous breathing trials, extubation, and tracheostomy, will remain under the responsibility of the treating ICU team. No study-directed therapeutic interventions will be performed.

Effects of Trendelenburg Position and Pneumoperitoneum on Mechanical Power and Respiratory Mechanics During V-NOTES Surgery

The purpose of this observational study is to evaluate the effects of Trendelenburg positioning and pneumoperitoneum on mechanical power and respiratory mechanics in adult women undergoing vaginal natural orifice transluminal endoscopic surgery (vNOTES) for bilateral tubal ligation. The main questions this study aims to answer are: * Does Trendelenburg positioning and pneumoperitoneum increase mechanical power during vNOTES surgery? * How do Trendelenburg positioning and pneumoperitoneum affect respiratory mechanics, including driving pressure, lung compliance, and airway pressures? Participants who are already scheduled to undergo vNOTES bilateral tubal ligation as part of their routine medical care will receive standard general anesthesia and mechanical ventilation. Researchers will record mechanical power and respiratory parameters at six predefined time points during surgery, before and after the application of pneumoperitoneum and Trendelenburg positioning. A total of 14 adult women will be included. No additional experimental treatment or intervention will be performed as part of the study.

Bedside Assessment of Right Ventricular Output Lying in Prone Or Supine

Right ventricular failure (RVF) is a common complication to cardiac surgery, which is associated to mortality, kidney failure, stroke, prolonged mechanical ventilation and ICU stay. The right ventricle is particularly vulnerable to an increased afterload. By increasing pulmonary vascular resistance (PVR), atelectasis might mitigate a negative effect on the right ventricle. Recruitment maneuvers have been shown to resolve atelectasis and improve hemodynamics by increasing cardiac output and lowering PVR. However these maneuvers transiently raise airway pressures, which in turn increases right ventricular afterload, a situation often poorly tolerated by patients with RVF. Prone position is used in patients with respiratory failure and has been shown to decrease mortality in patients with ARDS. Prone position decreases atelectasis and moves ventilation dorsally. In ARDS it also seems to mediate beneficial hemodynamic effects such as an increase in cardiac output and a decrease in PVR. The investigators hypothesis is that prone position early after cardiac surgery will increase cardiac output by recruitment of atelectasis and thereby decrease PVR.

Gastroesophageal Reflux and Respiratory Function in Patients Undergoing Abdominoplasty

The objective of this observational study is to compare parameters of diaphragmatic mechanics, respiratory muscle function, and thoracoabdominal kinematics among women with gastroesophageal reflux disease (GERD) and a history of abdominoplasty, women with a history of abdominoplasty alone, and women with GERD alone, seeking to understand whether the association between these conditions is linked to greater impairment of respiratory function and thoracoabdominal dynamics. The main question the study aims to answer is: Do women with GERD and a history of abdominoplasty exhibit greater impairment of diaphragmatic mechanics compared to those with a history of abdominoplasty alone and those with GERD alone? Researchers will compare three groups of participants: women with GERD and a history of abdominoplasty, women with a history of abdominoplasty alone, and women with GERD alone to determine whether the coexistence of GERD and abdominoplasty is associated with greater alterations in diaphragmatic mobility and thickness, respiratory muscle strength and endurance, thoracoabdominal kinematics, abdominal core and sternocleidomastoid muscle thickness, and body composition, as well as worse GERD-related symptoms and quality of life. Participants will undergo an initial clinical assessment, including medical history, anthropometric measurements, and body composition analysis via bioimpedance. They will also complete questionnaires regarding GERD symptoms, quality of life, and physical activity levels. Subsequently, assessments will be performed, including ultrasound of the diaphragm, abdominal muscles, and sternocleidomastoid muscle; spirometry; evaluation of thoracoabdominal kinematics; measurement of respiratory muscle strength via manovacuometry; and a respiratory muscle endurance test. When necessary for the diagnostic confirmation of GERD, 24-hour ambulatory esophageal impedance-pH monitoring will be performed. Upon completion of the assessments, the results obtained will be compared across the three groups to identify potential differences related to the association between GERD and abdominoplasty.

Pulmonary Mechanics and Cerebral Oxygenation During Prone Lumbar Disc Surgery

This prospective observational study aims to evaluate the relationship between changes in respiratory mechanics and cerebral oxygenation in adult patients undergoing elective lumbar disc surgery in the prone position under general anesthesia. Cerebral regional oxygen saturation will be monitored using bilateral frontal near-infrared spectroscopy (NIRS), while respiratory parameters including tidal volume, respiratory rate, peak airway pressure, plateau pressure, positive end-expiratory pressure, and dynamic compliance will be recorded from the anesthesia ventilator. Measurements will be obtained at predefined time points before and after positioning the patient prone and after returning to the supine position at the end of surgery. No changes will be made to anesthesia, ventilation, medication doses, or surgical management for research purposes. All clinical care will be provided according to routine practice by the responsible anesthesia team. The study will investigate whether changes in respiratory mechanics during prone positioning are associated with changes in cerebral regional oxygen saturation.

Dynamic Non-invasive Monitoring of Inspiratory Effort

This prospective, observational cohort study aims to evaluate whether the dynamic monitoring of a patient's breathing effort can predict successful liberation from invasive mechanical ventilation. The study will include 120 patients who have undergone 36 hours or more of controlled mechanical ventilation and deep sedation. Patient monitoring will commence immediately upon their transition to an assisted spontaneous breathing mode with pressure support. Starting from this clinical milestone, the researchers will track the patients' longitudinal inspiratory effort daily through four specific variables: maximum occlusion pressure, muscle pressure index, flow index via visual waveform inspection, and diaphragmatic thickening fraction via ultrasound. Concurrently, ventilator safety parameters (plateau pressure, driving pressure, transpulmonary pressure, and compliance) will be recorded. The primary outcome is the time from PSV initiation to successful weaning (defined as 72 hours without ventilator support). Clinical events such as death or return to a controlled mode due to PSV failure will be statistically treated as competing risks. Secondary outcomes include the incidence of pneumonia, ICU-acquired weakness, delirium, mortality, and PSV failure. Data will be analyzed using multivariate joint modeling within a Bayesian framework.

Ultrasonographic Abdominal Fat Thickness and Driving Pressure During Prone Spinal Surgery

This prospective observational study aims to evaluate the association between preoperative abdominal subcutaneous fat thickness measured by ultrasonography and intraoperative driving pressure in adult patients undergoing elective spinal surgery in the prone position under general anesthesia. Anthropometric measurements including body mass index, waist circumference, waist-to-height ratio, and neck circumference will also be evaluated for their association with respiratory mechanics. No additional intervention beyond routine clinical care will be performed.

vNOTES vs Laparoscopy: Respiratory Mechanics and Hemodynamics

Pneumoperitoneum and Trendelenburg position are unavoidable in laparoscopic surgery and are known to have adverse effects on intraoperative respiratory mechanics and hemodynamics. These conditions increase the risk of ventilator-induced lung injury (VILI) and highlight the importance of lung-protective ventilation strategies. vNOTES (Vaginal Natural Orifice Transluminal Endoscopic Surgery) is a minimally invasive technique that requires less Trendelenburg tilt and lower insufflation pressures compared to conventional laparoscopic surgery, and may therefore offer a more favorable intraoperative profile. This prospective, observational, single-center, parallel-group cohort study aims to compare respiratory mechanics parameters (Ppeak, Pplateau, DP, MPtot, MPdyn, Crs) and hemodynamic parameters (MAP, HR, vasopressor requirement) between vNOTES (n=15) and laparoscopic gynecological surgery (n=15) groups at four intraoperative time points.

Low-flow Versus Minimal-flow Sevoflurane Anesthesia During Robot-assisted Laparoscopic Radical Prostatectomy

Study Synopsis This protocol is formatted for ClinicalTrials.gov-style registration and manuscript-facing documentation. It is based on the uploaded Turkish ethics protocol and keeps the original core design: comparison of low-flow and minimal-flow sevoflurane anesthesia in robot-assisted laparoscopic radical prostatectomy. Background and Rationale Robot-assisted laparoscopic radical prostatectomy (RALRP) is increasingly preferred for localized prostate cancer because of lower blood loss, reduced transfusion requirements, shorter hospitalization, and lower complication rates compared with open surgery. However, RALRP requires carbon dioxide pneumoperitoneum and steep Trendelenburg positioning, both of which may adversely affect respiratory mechanics, gas exchange, and hemodynamic stability. Low-flow and minimal-flow anesthesia may improve humidification and warming of inspired gases, reduce inhalational agent consumption, decrease environmental waste, and potentially lower overall cost. Despite these theoretical and practical advantages, evidence remains limited regarding the physiologic safety and performance of minimal-flow sevoflurane anesthesia during long robotic pelvic surgery performed under pneumoperitoneum and steep Trendelenburg positioning. Accordingly, this randomized prospective trial will compare low-flow (1 L/min) and minimal-flow (0.5 L/min) sevoflurane anesthesia during RALRP with respect to respiratory parameters, arterial blood gas values, intraoperative oxygenation variables, anesthetic consumption, and selected postoperative biochemical markers.

Comparison of FCV and VCV in One-Lung Ventilation

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.

Effects of Sevoflurane Versus Desflurane Anesthesia Under Protective Mechanical Ventilation for Robotic Assisted Surgery

Inhalational anesthetics, when used in abdominal surgery, offer advantages of lung protection and reduced alveolar inflammation. There is little literature, however, in the comparative use of sevoflurane versus desflurane anesthesia in patients undergoing abdominal robotic-assisted surgery and their effects on lung mechanics.