vNOTES vs Laparoscopy: Respiratory Mechanics and Hemodynamics

Comparison of the Effects of vNOTES and Laparoscopic Gynecological Surgery on Intraoperative Respiratory Mechanics and Hemodynamics: A Prospective Observational Cohort Study

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.

This study aims to compare vNOTES (Vaginal Natural Orifice Transluminal Endoscopic Surgery) and laparoscopic gynecological surgery in terms of intraoperative respiratory mechanics and hemodynamics in patients scheduled for elective gynecological surgery.

The findings of this study will contribute to more effective planning of ventilation and hemodynamic management by anesthesiologists in vNOTES cases, the development of lung-protective ventilation protocols, and the improvement of perioperative anesthesia quality.

This study is designed as a prospective, observational, single-center, parallel-group cohort study. Patients scheduled for elective gynecological surgery will be divided into two groups according to the surgical technique: Group 1 (vNOTES, n=15) and Group 2 (Laparoscopic surgery, n=15). No randomization will be performed; the surgical technique, insufflation pressure, and Trendelenburg angle will be left to the clinician's discretion.

Measurements will be performed at four time points: T0 (10th minute after intubation, before insufflation), T1 (15th minute after pneumoperitoneum and Trendelenburg positioning), T2 (45th minute after pneumoperitoneum; or the last 5 minutes before desufflation in cases where the 45th minute is not reached), and T3 (15th minute after desufflation). At each time point, respiratory mechanics parameters (Ppeak, Pplateau, DP, MPtot, MPdyn, Crs), hemodynamic parameters (MAP, HR, vasopressor requirement), and intraoperative opioid consumption will be recorded. Insufflation pressure, Trendelenburg angle, and surgical duration will be recorded as confounding variables.

Inclusion Criteria:

• Female patients aged 18 to 75 years
• Patients scheduled for elective gynecological surgery
• Patients undergoing mechanical ventilation under general anesthesia
• ASA physical status I-III
• Patients providing written informed consent

Exclusion Criteria:

• Severe or uncontrolled chronic obstructive pulmonary disease, asthma, or other chronic pulmonary diseases
• Cardiac arrhythmia
• ASA physical status IV or above
• Patients developing intraoperative hemodynamic instability
• Patients receiving spinal or epidural anesthesia
• Cases requiring conversion to laparoscopy or laparotomy
• Patients refusing to participate