HFNC for Postoperative Atelectasis After Laparoscopic Surgery

June 27, 2026 updated by: Selvinaz Yüksel Tanrıverdi, Bursa Yuksek Ihtisas Training and Research Hospital

The Role of High-Flow Nasal Cannula in Monitoring Postoperative Atelectasis With Lung Ultrasonography After Laparoscopic Surgery: A Prospective Observational Study

Pneumoperitoneum and Trendelenburg positioning during laparoscopic surgery promote atelectasis development, which has been reported in up to 90% of patients under general anesthesia and increases the risk of postoperative pulmonary complications. High-flow nasal cannula (HFNC) oxygen therapy may reduce post-extubation atelectasis through alveolar recruitment. This prospective observational cohort study aims to evaluate the role of HFNC in postoperative atelectasis monitored by lung ultrasonography (LUS) in patients undergoing elective laparoscopic surgery.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

General anesthesia with laparoscopic surgery causes cephalad diaphragm displacement and reduction in functional residual capacity due to pneumoperitoneum and Trendelenburg positioning, predisposing patients to atelectasis development. Perioperative atelectasis has been reported in up to 90% of patients under general anesthesia, increasing the risk of hypoxemia, prolonged oxygen therapy, and postoperative pulmonary complications (PPCs).

High-flow nasal cannula (HFNC) oxygen therapy supports alveolar recruitment, enhances mucociliary clearance, and may reduce post-extubation atelectasis through heated and humidified gas delivery and generation of low-level positive end-expiratory pressure (PEEP). Randomized controlled trials have demonstrated that HFNC significantly reduces the incidence and severity of atelectasis assessed by LUS in robot-assisted laparoscopic rectal cancer surgery. Lung ultrasonography (LUS) has emerged as a reliable, rapid, and radiation-free method for diagnosis and monitoring of perioperative atelectasis with 87.7% sensitivity and 92.1% specificity.

This study is designed as a prospective, observational, single-center, parallel-group cohort study. No intervention or randomization will be performed. HFNC application will be left entirely to the clinician's discretion; the investigator will not be involved in the treatment process.

Patients in whom HFNC is initiated by the clinician in the post-extubation period will be defined as Group 1 (HFNC group), and patients receiving conventional oxygen therapy will be defined as Group 2 (Control group). HFNC application will be considered valid if initiated within 30 minutes of extubation.

LUS assessments will be performed by an independent investigator blinded to group assignment at four time points: T0 (preoperative), T1 (post-extubation), T2 (30th minute in the recovery unit), and T3 (discharge from the recovery unit). An additional LUS assessment is planned at postoperative 24 hours (T4). The Monastesse modified LUS score will be used at each assessment, evaluating 12 thoracic regions (6 segments per hemithorax along parasternal, anterior axillary, and posterior axillary lines), with a total LUS score ranging from 0 to 36 points.

HFNC parameters (flow rate, FiO₂, duration) and intraoperative variables (type and duration of surgery, anesthesia duration, insufflation duration, pneumoperitoneum pressure, Trendelenburg angle, total fluid intake, urine output) as well as postoperative variables (minimum SpO₂ in the recovery unit, length of hospital stay) will be considered as potential confounding factors in the statistical analysis.

Study Type

Observational

Enrollment (Estimated)

90

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adult patients aged 18-75 years scheduled for elective laparoscopic surgery (general surgery, urology, and gynecology) under general anesthesia.

Description

Inclusion Criteria:

  • Adult patients aged 18 years and older
  • Patients scheduled for elective laparoscopic surgery (general surgery, urology, gynecology)
  • 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
  • Patients with atelectasis or pleural effusion detected on preoperative lung ultrasonography
  • Patients requiring intraoperative recruitment maneuver
  • ASA physical status IV or above
  • Patients receiving spinal or epidural anesthesia
  • Cases requiring conversion to laparoscopy or laparotomy
  • Patients refusing to participate

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
HFNC Group
Patients in whom high-flow nasal cannula (HFNC) oxygen therapy is initiated by the clinician within 30 minutes of extubation after elective laparoscopic surgery.
Other: High-Flow Nasal Cannula (HFNC)
HFNC Group
Control Group
Patients receiving conventional oxygen therapy after extubation following elective laparoscopic surgery.
Other: Conventional Oxygen Therapy
Standard oxygen therapy administered via face mask or nasal cannula after extubation following elective laparoscopic surgery.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Total Lung Ultrasonography Score (LUS Score)
Time Frame: T0: preoperative; T1: 5th minute after extubation; T2: 30th minute in the recovery unit; T3: discharge from the recovery unit
Total lung ultrasonography score assessed using the Monastesse modified LUS scoring system. Each hemithorax is divided into 6 segments along parasternal, anterior axillary, and posterior axillary lines, evaluating a total of 12 thoracic regions with a total score ranging from 0 to 36 points. Scores are compared between HFNC and conventional oxygen therapy groups.
T0: preoperative; T1: 5th minute after extubation; T2: 30th minute in the recovery unit; T3: discharge from the recovery unit

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of Significant Atelectasis
Time Frame: T0: preoperative; T1: 5th minute after extubation; T2: 30th minute in the recovery unit; T3: discharge from the recovery unit
Proportion of patients with at least one lung region scoring ≥2 on the LUS scoring system (coalescing B-lines/irregular pleura or consolidation >1×2cm) at each time point.
T0: preoperative; T1: 5th minute after extubation; T2: 30th minute in the recovery unit; T3: discharge from the recovery unit
Minimum SpO₂ in the Post-Anesthesia Care Unit (PACU)
Time Frame: From extubation to PACU discharge, up to 2 hours
Minimum oxygen saturation recorded during the entire post-anesthesia care unit stay.
From extubation to PACU discharge, up to 2 hours
Incidence of Hypoxemia
Time Frame: From extubation to PACU discharge, up to 2 hours
Proportion of patients with SpO₂ below 95% during the post-anesthesia care unit stay.
From extubation to PACU discharge, up to 2 hours
Incidence of Severe Hypoxemia
Time Frame: From extubation to PACU discharge, up to 2 hours
Proportion of patients with SpO₂ below 90% during the post-anesthesia care unit stay.
From extubation to PACU discharge, up to 2 hours
Postoperative Complications
Time Frame: From surgery to hospital discharge, up to 7 days
Incidence and type of postoperative complications recorded during hospital stay.
From surgery to hospital discharge, up to 7 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Bursa Yuksek Ihtisas Training and Research Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

July 1, 2026

Primary Completion (Estimated)

July 1, 2027

Study Completion (Estimated)

July 1, 2027

Study Registration Dates

First Submitted

June 23, 2026

First Submitted That Met QC Criteria

June 27, 2026

First Posted (Actual)

June 30, 2026

Study Record Updates

Last Update Posted (Actual)

June 30, 2026

Last Update Submitted That Met QC Criteria

June 27, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • BursaYIERHTanriverdi-002

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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