Automated Intraoperative Lung Recruitment Maneuvers in Major Laparoscopic Surgery

Effect of Automated Intraoperative Lung Recruitment Maneuvers on Atelectasis in Patients Undergoing Major Laparoscopic Surgery: A Randomized Controlled Trial

Laparoscopic colorectal surgery is associated with an increased risk of intraoperative atelectasis due to pneumoperitoneum, Trendelenburg positioning, and prolonged anesthesia duration. Atelectasis developing during surgery may persist into the postoperative period and contribute to postoperative pulmonary complications. Automated lung recruitment maneuvers delivered by modern anesthesia ventilators may offer a standardized method to improve lung aeration and reduce atelectasis. This prospective, randomized, single-center controlled trial aims to evaluate the effect of automated intraoperative lung recruitment maneuvers on atelectasis detected by lung ultrasonography in patients undergoing elective major laparoscopic colorectal cancer surgery. Adult patients will be randomized to receive either automated lung recruitment maneuvers or standard mechanical ventilation without recruitment. Lung ultrasonography will be used to assess atelectasis at predefined perioperative time points. The primary outcome is the incidence of atelectasis detected by lung ultrasound, and secondary outcomes include postoperative pulmonary complications, length of intensive care unit stay, length of hospital stay, and perioperative hemodynamic instability.

Study Overview

• Status: Recruiting
• Conditions: Atelectasis; Postoperative Pulmonary Complications (PPCs)
• Intervention / Treatment: Procedure: Automated Intraoperative Lung Recruitment Maneuvers

Detailed Description

This study is a prospective, randomized, single-center controlled clinical trial designed to evaluate the effects of automated intraoperative lung recruitment maneuvers on perioperative atelectasis and postoperative pulmonary complications in patients undergoing major laparoscopic colorectal cancer surgery under general anesthesia.

Despite its minimally invasive nature, laparoscopic colorectal surgery is associated with significant perioperative respiratory challenges. Pneumoperitoneum, Trendelenburg positioning, and prolonged operative duration may reduce functional residual capacity, impair respiratory mechanics, and promote intraoperative atelectasis. Atelectasis developing during general anesthesia can persist into the postoperative period and is a major contributor to postoperative pulmonary complications.

Although lung recruitment maneuvers are frequently used to improve lung aeration, manual application lacks standardization and reproducibility. Automated lung recruitment maneuvers delivered by modern anesthesia ventilators may provide a standardized and controlled approach to lung recruitment. Lung ultrasonography is a reliable, bedside, radiation-free imaging modality that allows real-time assessment of lung aeration and detection of atelectasis without the need for patient transport.

After confirmation of eligibility and arrival in the operating room, participants will be randomized in a 1:1 ratio to either an automated lung recruitment maneuver group or a control group receiving standard mechanical ventilation without lung recruitment. Standard intraoperative monitoring will be applied to all patients.

Lung ultrasonography will be used to assess lung aeration and detect atelectasis at predefined perioperative time points, including preoperative baseline assessment, intraoperative evaluation, and postoperative follow-up. Lung ultrasound scores will be used to quantify the degree of aeration loss.

In the intervention group, automated lung recruitment maneuvers will be performed intraoperatively using the anesthesia ventilator according to a standardized protocol. An individualized optimal positive end-expiratory pressure will be determined based on dynamic lung compliance and maintained throughout the surgical procedure. A repeat recruitment maneuver will be applied at the end of surgery after cessation of pneumoperitoneum. The control group will receive standard mechanical ventilation according to institutional practice. Perioperative fluid management will be standardized in both groups using a goal-directed fluid therapy approach.

Postoperative follow-up will include systematic assessment for pulmonary complications. Surgical complications, length of intensive care unit stay, and total hospital length of stay will also be recorded.

The primary outcome of the study is the incidence of atelectasis detected by lung ultrasonography. Secondary outcomes include postoperative pulmonary complications, perioperative hemodynamic instability, length of intensive care unit stay, and length of hospital stay.

This study aims to determine whether automated intraoperative lung recruitment maneuvers assessed using lung ultrasonography can reduce perioperative atelectasis and improve postoperative pulmonary outcomes in patients undergoing major laparoscopic colorectal surgery.

• Study Type: Interventional
• Enrollment (Estimated): 56
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Sena Gökçe Karataş; Phone Number: +90 212 414 71 71; Email: senagokce_96@outlook.com
• Study Contact Backup: Name: Evrim Kucur Tülübaş; Phone Number: +90 212 414 71 71; Email: kucurevrim@gmail.com

Study Locations

• Turkey (Türkiye)
  • Bakırkoy
    • Istanbul, Bakırkoy, Turkey (Türkiye), 34147
      • Recruiting
      • SBÜ Bakırköy Dr. Sadi Konuk Eğitim ve Araştırma Hastanesi
      • Contact: Phone Number: +90 212 414 71 71

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Age between 18 and 80 years
• Scheduled for elective laparoscopic colorectal cancer surgery
• American Society of Anesthesiologists (ASA) physical status I-III

Exclusion Criteria:

• ASA physical status IV or higher
• Pregnancy
• Body mass index (BMI) > 40 kg/m²
• Severe chronic obstructive pulmonary disease (COPD), GOLD stage III-IV
• Advanced heart failure with left ventricular ejection fraction <35%
• Previous thoracic surgery
• Preoperative requirement for supplemental oxygen therapy
• Refusal or inability to provide informed consent
• Intraoperative conversion to open surgery
• Development of significant hemodynamic instability during lung recruitment maneuvers

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Control Group; Participants assigned to the control group will receive standard intraoperative mechanical ventilation according to institutional practice during general anesthesia for laparoscopic colorectal surgery. No lung recruitment maneuvers will be performed. Perioperative monitoring, anesthetic management, and postoperative care will be standardized and identical to those of the intervention group, except for the application of automated lung recruitment maneuvers.
Experimental: Automated Recruitment Group; Participants in the intervention group will receive standard intraoperative mechanical ventilation plus automated lung recruitment maneuvers performed by the anesthesia ventilator. The automated recruitment protocol will be applied twice: once after induction of anesthesia and before the initiation of pneumoperitoneum, and once again after pneumoperitoneum is terminated. All other anesthetic management, monitoring, and postoperative care will be identical to the control group.	Procedure: Automated Intraoperative Lung Recruitment Maneuvers; Automated lung recruitment maneuvers will be performed intraoperatively using the anesthesia ventilator in pressure-controlled ventilation mode according to a standardized protocol.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Atelectasis detected by lung ultrasonography	The presence and severity of atelectasis will be assessed using lung ultrasonography performed with a standardized 12-zone scanning protocol. Lung ultrasound scores (LUS) will be calculated for each zone, and severe atelectasis will be defined as a lung ultrasound score of 2 or 3 in any lung region.Lung ultrasound score (LUS) will be assessed using a standardized 12-zone lung ultrasonography protocol. Each lung zone will be scored from 0 to 3 (0 = normal aeration, 1 = moderate loss of aeration, 2 = severe loss of aeration, 3 = consolidation), resulting in a total score ranging from 0 to 36. Higher LUS values indicate worse lung aeration.	Preoperative baseline (before anesthesia induction), intraoperative assessment (after induction and before pneumoperitoneum), early postoperative assessment (30 minutes after extubation), and postoperative day 1 (within 24 hours after surgery).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postoperative pulmonary complications	Postoperative pulmonary complications will be defined and classified according to the European Perioperative Clinical Outcome (EPCO) definitions. Complications will include respiratory infection, respiratory failure, pleural effusion, atelectasis, pneumothorax, bronchospasm, and aspiration pneumonia. Each complication will be diagnosed based on predefined EPCO criteria using clinical findings, imaging studies, laboratory results, and the need for respiratory support or therapeutic interventions.Postoperative pulmonary complications will be assessed daily during hospitalization.	From the end of surgery until hospital discharge (up to postoperative day 30).
Change in lung ultrasound score (LUS)	Changes in lung ultrasound score will be evaluated using a standardized 12-zone lung ultrasonography protocol. Lung ultrasound scores will be calculated at predefined perioperative time points, and changes in LUS from baseline to intraoperative and postoperative assessments will be analyzed.Lung ultrasound score (LUS) will be assessed using a standardized 12-zone lung ultrasonography protocol. Each lung zone will be scored from 0 to 3 (0 = normal aeration, 1 = moderate loss of aeration, 2 = severe loss of aeration, 3 = consolidation), resulting in a total score ranging from 0 to 36. Higher LUS values indicate worse lung aeration.	From preoperative baseline through postoperative day 1
Oxygenation parameters (PaO₂/FiO₂ ratio)	Arterial blood gas analyses will be used to assess oxygenation. The PaO₂/FiO₂ ratio will be calculated at predefined perioperative time points to evaluate changes in oxygenation status.	Intraoperatively,immediediately after the first recruitment maneuver(within 10 minutes after the maneuver) and during the early postoperative period (30 minutes after extubation).

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Length of intensive care unit stay	The duration of intensive care unit stay will be recorded in days for patients requiring postoperative intensive care admission.	From postoperative intensive care unit admission until discharge from the intensive care unit (up to 30 days).
Length of hospital stay	Total length of hospital stay will be recorded in days from the day of surgery until hospital discharge.	From the day of surgery until hospital discharge(up to 30 days)

Collaborators and Investigators

• Sponsor: Bakirkoy Dr. Sadi Konuk Research and Training Hospital

Publications and helpful links

General Publications

• Shander A, Fleisher LA, Barie PS, Bigatello LM, Sladen RN, Watson CB. Clinical and economic burden of postoperative pulmonary complications: patient safety summit on definition, risk-reducing interventions, and preventive strategies. Crit Care Med. 2011 Sep;39(9):2163-72. doi: 10.1097/CCM.0b013e31821f0522.
• Jammer I, Wickboldt N, Sander M, Smith A, Schultz MJ, Pelosi P, Leva B, Rhodes A, Hoeft A, Walder B, Chew MS, Pearse RM; European Society of Anaesthesiology (ESA) and the European Society of Intensive Care Medicine (ESICM); European Society of Anaesthesiology; European Society of Intensive Care Medicine. Standards for definitions and use of outcome measures for clinical effectiveness research in perioperative medicine: European Perioperative Clinical Outcome (EPCO) definitions: a statement from the ESA-ESICM joint taskforce on perioperative outcome measures. Eur J Anaesthesiol. 2015 Feb;32(2):88-105. doi: 10.1097/EJA.0000000000000118.
• Miskovic A, Lumb AB. Postoperative pulmonary complications. Br J Anaesth. 2017 Mar 1;118(3):317-334. doi: 10.1093/bja/aex002.
• 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.
• Yu X, Zhai Z, Zhao Y, Zhu Z, Tong J, Yan J, Ouyang W. Performance of Lung Ultrasound in Detecting Peri-Operative Atelectasis after General Anesthesia. Ultrasound Med Biol. 2016 Dec;42(12):2775-2784. doi: 10.1016/j.ultrasmedbio.2016.06.010. Epub 2016 Sep 14.
• Nakahira J, Nakano S, Minami T. Evaluation of alveolar recruitment maneuver on respiratory resistance during general anesthesia: a prospective observational study. BMC Anesthesiol. 2020 Oct 17;20(1):264. doi: 10.1186/s12871-020-01182-9.

Study record dates

Study Major Dates

• Study Start (Actual): December 13, 2025
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: December 12, 2025
• First Submitted That Met QC Criteria: January 9, 2026
• First Posted (Actual): January 20, 2026

Study Record Updates

• Last Update Posted (Actual): January 21, 2026
• Last Update Submitted That Met QC Criteria: January 19, 2026
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: Lung Ultrasound Score (LUS); Automated Lung Recruitment Maneuvers; Laparoscopic Colorectal Surgery
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Pulmonary Atelectasis
• Other Study ID Numbers: BakirkoySadiKonukAnesthesia

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: No IPD will be shared due to privacy regulations and lack of ethics approval for external data sharing

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No