Ventilation Mode and Atelectasis After Prone-Position Surgery: A Lung Ultrasound Study

NCT07680881 | Completed

• 1 other identifier: CTH-PRONE-LUS-2024
• Study Type: observational
• Target: 90
• Locations: 1 country
• Sites: 1

Brief Summary

This prospective single-centre observational study compared two intraoperative mechanical ventilation modes, volume-controlled ventilation (VCV) and VCV with AutoFlow/AF, in adults undergoing elective surgery in the prone position. The ventilation mode was selected by the attending anaesthesiologist as part of routine clinical care; the investigators did not assign it. Perioperative atelectasis was assessed using a modified bilateral 12-zone lung ultrasound score obtained before induction of anaesthesia and after extubation, and oxygenation was assessed using the alveolar-arterial oxygen gradient calculated from an intraoperative arterial blood gas sample. The study also examined whether the effect of ventilation mode on atelectasis differed according to obesity.

Conditions

Pulmonary Atelectasis, Postoperative; Postoperative Pulmonary Complications

Keywords

Lung ultrasound; Atelectasis; Prone position; Mechanical ventilation; Alveolar-arterial oxygen gradient

Outcome Measures

Primary Outcomes (1)

• Postoperative modified lung ultrasound score

  Modified bilateral 12-zone lung ultrasound score assessed after surgery and compared between ventilation modes. Each hemithorax was divided into anterior, lateral and posterior regions, and each region was scored for loss of aeration, with a higher total score indicating greater atelectasis.

  At least 30 minutes after extubation

Secondary Outcomes (2)

• Alveolar-arterial oxygen gradient

  15 minutes after prone positioning

• Ventilation-mode by obesity interaction on postoperative lung ultrasound score

  At least 30 minutes after extubation

Study Arms (2)

VCV

Patients managed intraoperatively with volume-controlled ventilation, as chosen by the attending anaesthesiologist.

VCV-AF

Patients managed intraoperatively with Volume-Controlled Ventilation with AutoFlow ventilation, as chosen by the attending anaesthesiologist.

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Adults aged 18 to 65 years with American Society of Anesthesiologists physical status I or II and a body mass index below 35 kg/m2, scheduled for elective surgery in the prone position at a single tertiary care hospital. Patients were grouped according to the intraoperative ventilation mode selected by the attending anaesthesiologist (volume-controlled ventilation or volume-controlled ventilation with Autoflow).

You may qualify if:

• Consented adults aged 18 to 65 years American Society of Anesthesiologists (ASA) physical status I or II Body mass index below 35 kg/m2 Scheduled for elective surgery in the prone position Oriented and cooperative

You may not qualify if:

• No consent Pre-existing pulmonary disease Any perioperative lung pathology Inability to complete postoperative lung ultrasound assessment

Sponsors & Collaborators

• Prof. Dr. Cemil Tascıoglu Education and Research Hospital Organization: lead

Study Sites (1)

Cemil Tasciogu Research and Training Hospital

Istanbul, Sisli, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Pulmonary Atelectasis

Condition Hierarchy (Ancestors)

Lung Diseases; Respiratory Tract Diseases

Study Design

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

Study Record Dates

• First Submitted: June 26, 2026
• First Posted: July 2, 2026
• Study Start: March 1, 2024
• Primary Completion: October 30, 2024
• Study Completion: October 30, 2024
• Last Updated: July 29, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)