End-expiratory Pressure During Laparoscopic Surgery in the Trendelenburg Position by Electrical Impedance Tomography (CP-EIT)

Positive End-expiratory Pressure Titration During Laparoscopic Gynecological Surgery in the Trendelenburg Position Based on Ventilation and Perfusion Measured by Electrical Impedance Tomography: the CP-EIT Observational Study

Pneumoperitoneum (PNP) and the position of the patient required for laparoscopic surgery lead to pathophysiological changes that complicate anesthesia. PNP is characterized by an increased intra-abdominal pressure (IAP), the cranial displacement of the diaphragm that can lead to the formation of intraoperative atelectasis and decrease end-expiratory lung volume (EELV). At the same time, PNP can reduce respiratory system compliance by 30-50% in healthy patients. During elective abdominal surgery under general anesthesia, atelectasis forms in almost 90% of patients and can become a focus of postoperative pneumonia. The negative effect of PNP is more prominent in Trendelenburg position. And one of the methods to avoid the effects of PNP and Trendelenburg position on lung tissue is to apply positive end-expiratory pressure (PEEP). PEEP is acknowledged as a component of lung protective ventilation (LPV) along with low tidal volume (TV) 6-8 ml/kg. On the other hand, excessive PEEP can lead to the overdistension of lung tissue and cause volutrauma and hemodynamic instability. It is necessary to use sufficient PEEP to minimize atelectasis, improve respiratory biomechanics and maintain oxygenation.

Electrical impedance tomography shows changes in ventilation and perfusion during mechanical ventilation with the different PEEP levels.

The study aimed to select optimum PEEP level based on optimum ventilation-to-perfusion match based on electrical impedance tomography measurements.

Study Overview

• Status: Completed
• Conditions: Laparoscopic Surgery; Pneumoperitoneum; Trendelenburg Position
• Intervention / Treatment: Device: electrical impedance tomography

Detailed Description

Electrical impedance tomography shows changes in ventilation and perfusion during mechanical ventilation with the different PEEP levels. The investigators will measure the following variables: resistivity of low and high pass band and end-expiratory lung index in 4 regions of interest and globally, global inhomogeneity index, global lung-heart index, global regional ventilation delay, compliance win, compliance loss, plateau pressure, and driving pressure.

The investigators will measure abovementioned variables in the following conditions:

• PEEP 5 mbar with the patient in a horizontal supine position (initial measurement, Baseline),
• PEEP 5 mbar in Trendelenburg position in carboxyperitoneum conditions (after reaching the set abdominal pressure of 12-14 mbar) (reference measurement, Ref),
• PEEP 8 mbar in Trendelenburg position under carboxyperitoneum conditions (abdominal pressure 12-14 mbar),
• PEEP 10 mbar in Trendelenburg position in carboxyperitoneum conditions (abdominal pressure 12-14 mbar),
• PEEP 12 mbar in Trendelenburg position in carboxyperitoneum conditions (abdominal pressure 12-14 mbar),
• PEEP 14 mbar in Trendelenburg position in carboxyperitoneum conditions (abdominal pressure 12-14 mbar),
• PEEP 16 mbar in Trendelenburg position in carboxyperitoneum conditions (abdominal pressure 12-14 mbar)
• PEEP 5 mbar with the patient in a horizontal supine position after deflation of the carboxyperitoneum.

After 5 minutes of carboxyperitoneum in Trendelenburg position the investigators will assess ventilation, perfusion and their relationship by the "Analysis" tab in comparison with the initial one in the intubated patient in the supine position (Baseline): improvement of ventilation (CW - compliance win, in %) and deterioration of ventilation (CL - compliance loss, in %), global homogeneity of ventilation (GI - homogeneity index, in %), regional ventilation delays (RVD, in %), ventilation compliance index and perfusion (LHI - lung heart index, in %).

After all stages have been completed, a comparative analysis of the influence of different levels of PEEP on ventilation, perfusion and their ratio will be carried out by using the "Analysis" tab at each stage in comparison with the reference (Ref): CW and CL, GI, RVD, LHI.

• Study Type: Observational
• Enrollment (Actual): 50

Contacts and Locations

Study Locations

• Russian Federation
  • Moscow, Russian Federation, 119048
    • Clinical Hospital 4, Sechenov University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients who underwent elective gynecological operations in conditions of carboxyperitoneum with Trendelenburg position

Description

Inclusion Criteria:

• Patients who undergo gynecological surgery under conditions of carboxyperitoneum in the Trendelenburg position.

Exclusion Criteria:

• Pregnancy,
• Hypoxemia before surgery (SpO2 < 94%),
• body mass index more than 35 kg/m2,
• Unstable hemodynamics and/or life-threatening arrhythmia,
• Primary or secondary lung diseases (COPD, interstitial lung diseases, metastatic lung disease)
• Presence of an implantable pacemaker and/or defibrillator
• Chronic diseases in the stage of decompensation with the development of extrapulmonary organ dysfunction (liver cirrhosis, progression of cancer, chronic heart failure).

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Optimum positive end-expiratory pressure level by compliance win	Positive end-expiratory pressure level selected by maximal compliance win measured by electrical impedance tomography	40 minutes
Optimum positive end-expiratory pressure level by heart-lung index	Positive end-expiratory pressure level selected by maximal heart-lung index measured by electrical impedance tomography	40 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Compliance win	Increase in compliance measured by electrical impedance tomography in percent	3 minutes
Compliance loss	Decrease in compliance measured by electrical impedance tomography in percent	3 minutes
Global inhomogeneity index	Global inhomogeneity index measured by electrical impedance tomography in percent	3 minutes
Regional ventilation delay	Regional ventilation delay measured by electrical impedance tomography in percent	3 minutes
Lung-heart index	Lung-heart index measured by electrical impedance tomography in percent	3 minutes
Resistivity of Low Pass Band	Low pass band resistivity measured by electrical impedance tomography in Ohms*m	3 minutes
Resistivity of High Pass Band	High pass band resistivity measured by electrical impedance tomography in Ohms*m	3 minutes
End-expiratory volume index change	End-expiratory volume index change measured by electrical impedance tomography	3 minutes
Plateau pressure	Pressure measured in circuit during the inspiratory pause in mbar	3 minutes
Driving pressure	Difference between plateau pressure and positive end-expiratory pressure in mbar	3 minutes

Collaborators and Investigators

• Sponsor: I.M. Sechenov First Moscow State Medical University
• Investigators: Principal Investigator: Andrey I Yaroshetskiy, MD, PhD, ScD, Sechenov University

Publications and helpful links

General Publications

• Fahy BG, Barnas GM, Nagle SE, Flowers JL, Njoku MJ, Agarwal M. Changes in lung and chest wall properties with abdominal insufflation of carbon dioxide are immediately reversible. Anesth Analg. 1996 Mar;82(3):501-5. doi: 10.1097/00000539-199603000-00013.
• Andersson LE, Baath M, Thorne A, Aspelin P, Odeberg-Wernerman S. Effect of carbon dioxide pneumoperitoneum on development of atelectasis during anesthesia, examined by spiral computed tomography. Anesthesiology. 2005 Feb;102(2):293-9. doi: 10.1097/00000542-200502000-00009.
• Loring SH, Behazin N, Novero A, Novack V, Jones SB, O'Donnell CR, Talmor DS. Respiratory mechanical effects of surgical pneumoperitoneum in humans. J Appl Physiol (1985). 2014 Nov 1;117(9):1074-9. doi: 10.1152/japplphysiol.00552.2014. Epub 2014 Sep 11.
• Barbosa FT, Castro AA, de Sousa-Rodrigues CF. Positive end-expiratory pressure (PEEP) during anaesthesia for prevention of mortality and postoperative pulmonary complications. Cochrane Database Syst Rev. 2014 Jun 12;2014(6):CD007922. doi: 10.1002/14651858.CD007922.pub3.
• Slutsky AS, Ranieri VM. Ventilator-induced lung injury. N Engl J Med. 2013 Nov 28;369(22):2126-36. doi: 10.1056/NEJMra1208707. No abstract available.

Study record dates

Study Major Dates

• Study Start (Actual): June 24, 2024
• Primary Completion (Actual): December 1, 2024
• Study Completion (Actual): December 31, 2024

Study Registration Dates

• First Submitted: June 18, 2024
• First Submitted That Met QC Criteria: June 25, 2024
• First Posted (Actual): July 1, 2024

Study Record Updates

• Last Update Posted (Actual): May 2, 2025
• Last Update Submitted That Met QC Criteria: April 29, 2025
• Last Verified: June 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Digestive System Diseases; Peritoneal Diseases; Pneumoperitoneum
• Other Study ID Numbers: CP-EIT

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No