Supine vs Prone Position and Atelectasis Assessed by Lung Ultrasound

NCT07320092 | Recruiting

• 2 other identifiers: E-74555795-050.04-12317522025/24
• Study Type: observational
• Target: 80
• Locations: 1 country
• Sites: 1

Brief Summary

Atelectasis frequently develops during and after general anesthesia due to factors such as anesthesia-induced diaphragmatic dysfunction, reduced functional residual capacity, altered ventilation-perfusion matching, and surgical positioning. The development of atelectasis has been associated with postoperative hypoxemia and other pulmonary complications. Lung ultrasound (LUS) has emerged as a reliable, radiation-free bedside imaging modality for the detection and monitoring of atelectasis. LUS allows assessment of lung aeration through standardized ultrasound patterns and scoring systems, enabling dynamic evaluation in the perioperative period. This is a prospective, observational cohort study designed to compare the incidence and severity of atelectasis in patients undergoing surgery in the supine position versus the prone position under general anesthesia. Adult patients undergoing elective surgical procedures will be enrolled. No experimental intervention will be applied, and all anesthetic and surgical management will follow routine clinical practice. Lung ultrasound examinations will be performed at predefined time points after induction of anesthesia and before extubation. A standardized lung ultrasound protocol and scoring system will be used to assess lung aeration loss and detect the presence of atelectasis. The primary outcome of the study is the difference in atelectasis detected by lung ultrasound between supine and prone surgical positions. The secondary outcome is the change in lung ultrasound scores over time. This study aims to clarify the effects of supine and prone positions on perioperative atelectasis and to support the clinical use of lung ultrasound as a noninvasive monitoring tool in perioperative and anesthetic practice..

Conditions

Postoperative Atelectasis

Keywords

Lung Ultrasound; Atelectasis; Supine Position; Prone Position; General Anesthesia; Perioperative Care

Outcome Measures

Primary Outcomes (1)

• Difference in lung ultrasound-detected atelectasis between supine and prone surgical positions

  Lung aeration will be evaluated using the Lung Ultrasound Score (LUS), a semiquantitative scoring system assessing aeration loss in 12 lung regions. In the supine position, lung ultrasound assessment will be performed along: the parasternal line (intercostal spaces 1-4 and 4-8), the anterior axillary line (intercostal spaces 1-6 and 6-12), and the posterior axillary line (intercostal spaces 1-6 and 6-12). In the prone position, lung ultrasound assessment will be performed along: the paravertebral line (intercostal spaces 1-6 and 6-12), the posterior axillary line (intercostal spaces 1-6 and 6-12), and the anterior axillary line (intercostal spaces 1-6 and 6-12). Each lung region will be scored from 0 to 3, resulting in a total LUS ranging from 0 to 36, where higher scores indicate greater loss of aeration and more severe atelectasis. Assessments will be performed after induction of general anesthesia and before extubation.

  Perioperative (After induction of general anesthesia and before extubation)

Study Arms (2)

Supine Position

Patients undergoing surgery in the supine position under general anesthesia.

Prone Position

Patients undergoing surgery in the prone position under general anesthesia.

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

The study population consists of adult patients aged 18 years and older who are scheduled to undergo elective surgical procedures under general anesthesia. Patients will be evaluated according to surgical positioning (supine or prone) during routine perioperative care.

You may qualify if:

• Adult patients aged 18 years or older.
• Patients scheduled for elective surgery under general anesthesia.
• Patients undergoing surgery in the supine or prone position.
• Patients able to provide informed consent.

You may not qualify if:

• Emergency surgical procedures.
• Pre-existing severe pulmonary disease affecting lung ultrasound assessment.
• Hemodynamic instability requiring urgent intervention.
• Contraindications to lung ultrasound examination.

Sponsors & Collaborators

• Istanbul University - Cerrahpasa: lead

Study Sites (1)

Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine

Istanbul, Istanbul, 34320, Turkey (Türkiye)

RECRUITING

Related Publications (5)

• Bouhemad B, Brisson H, Le-Guen M, Arbelot C, Lu Q, Rouby JJ. Bedside ultrasound assessment of positive end-expiratory pressure-induced lung recruitment. Am J Respir Crit Care Med. 2011 Feb 1;183(3):341-7. doi: 10.1164/rccm.201003-0369OC. Epub 2010 Sep 17.

  PMID: 20851923 BACKGROUND

• Tusman G, Böhm SH, Warner DO, Sprung J. Atelectasis and perioperative pulmonary complications in general anesthesia. Br J Anaesth. 2012;108(2):229-240. PMID: 22156255.

  BACKGROUND

• Acosta CM, Maidana GA, Jacovitti D, Belaunzaran A, Cereceda S, Rae E, Molina A, Gonorazky S, Bohm SH, Tusman G. Accuracy of transthoracic lung ultrasound for diagnosing anesthesia-induced atelectasis in children. Anesthesiology. 2014 Jun;120(6):1370-9. doi: 10.1097/ALN.0000000000000231.

  PMID: 24662376 BACKGROUND

• Monastesse A, Girard F, Massicotte N, Chartrand-Lefebvre C, Girard M. Lung Ultrasonography for the Assessment of Perioperative Atelectasis: A Pilot Feasibility Study. Anesth Analg. 2017 Feb;124(2):494-504. doi: 10.1213/ANE.0000000000001603.

  PMID: 27669555 BACKGROUND

• Lichtenstein DA. Lung ultrasound in the critically ill. Ann Intensive Care. 2014 Jan 9;4(1):1. doi: 10.1186/2110-5820-4-1.

  PMID: 24401163 BACKGROUND

MeSH Terms

Conditions

Pulmonary Atelectasis; Deception

Condition Hierarchy (Ancestors)

Lung Diseases; Respiratory Tract Diseases; Social Behavior; Behavior

Study Officials

• ÖZLEM KORKMAZ DİLMEN, PROFESSOR

  Istanbul University - Cerrahpasa

  PRINCIPAL INVESTIGATOR

Central Study Contacts

CHINARA NAMAZOVA, MD, Research Assistant

CONTACT

+90 554 174 87 91; chinara.namazova@iuc.edu.tr

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Research Assistant

Study Record Dates

• First Submitted: December 22, 2025
• First Posted: January 6, 2026
• Study Start: September 15, 2025
• Primary Completion: March 30, 2026
• Study Completion: April 15, 2026
• Last Updated: March 24, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)