Postoperative Atelectasis
Conditions
Keywords
Electrical Impedance Tomography, Incentive Spirometry, Visual Feedback, Pulmonary Rehabilitation, Dorsal Ventilation
Brief summary
This single-center randomized controlled trial will evaluate whether real-time visual feedback from electrical impedance tomography (EIT) improves the immediate distribution of lung ventilation during incentive spirometry in adults with postoperative atelectasis. Approximately 60 participants will be randomized 1:1 to receive either EIT-guided visual feedback or standardized verbal guidance during one session of 30 incentive-spirometry breaths. The primary outcome is the change in dorsal ventilation fraction from before training to 5 minutes after training. Secondary outcomes include inspiratory capacity, ventilation homogeneity, dependent silent spaces, end-expiratory lung impedance, oxygenation, in-hospital intubation or reintubation, and intervention-related adverse events.
Detailed description
Eligible adults recovering from major thoracic or upper-abdominal surgery will be screened using bedside lung ultrasound and baseline EIT. Participants must be spontaneously breathing, clinically stable, able to follow instructions, and have a baseline dorsal ventilation fraction below 50%. After a 2-minute baseline EIT recording in a 30- to 45-degree semi-recumbent position, participants will be randomized through a central randomization system using stratified variable blocks based on baseline dorsal ventilation fraction. Both groups will complete three sets of 10 incentive-spirometry breaths. In the experimental group, the EIT screen will be visible and trained staff will provide real-time, target-directed feedback intended to increase ventilation in dependent dorsal lung regions. In the control group, the EIT screen will be concealed and participants will receive standardized verbal instructions without imaging feedback. After training, participants will rest for 5 minutes and undergo a second 2-minute EIT recording under stable oxygen-therapy conditions. EIT outcomes will be calculated offline by assessors blinded to group assignment. Respiratory-support outcomes will be recorded through hospital discharge. Intervention-related adverse events will be recorded from the start of the single intervention session through 24 hours after completion of the session.
Interventions
BEHAVIORALEIT-Guided Incentive Spirometry
Participants perform three sets of 10 incentive-spirometry breaths while viewing real-time electrical impedance tomography images. Trained staff provide standardized, target-directed feedback to increase ventilation in dependent dorsal lung regions.
BEHAVIORALStandardized Incentive Spirometry Guidance
Participants perform three sets of 10 incentive-spirometry breaths with the EIT screen concealed. Trained staff provide standardized verbal instructions on posture, slow sustained inspiration, a 2- to 3-second breath hold, and rest between breaths, without imaging feedback.
Sponsors
Shanghai Zhongshan Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Masking description
Participants and bedside intervention staff cannot be masked because the experimental group views the EIT screen. EIT data analysts and outcome assessors remain blinded to group assignment.
Intervention model description
Participants are randomized 1:1 to EIT-guided visual feedback or standardized verbal guidance during a single session of incentive spirometry.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
1. Age 18 years or older. 2. Admitted to an intensive care unit or postoperative monitoring unit after major thoracic or upper-abdominal surgery; tracheal tube removed; spontaneously breathing; and clinically stable. 3. Alert and able to understand and follow incentive-spirometry and EIT instructions. 4. Bedside lung ultrasound shows atelectasis or markedly reduced aeration in dorsal or posterolateral lung regions, with the lung-ultrasound assessment recorded. 5. Baseline EIT during quiet breathing in a semi-recumbent position shows insufficient dorsal ventilation with potential for improvement; dorsal ventilation fraction below 50%. 6. Written informed consent provided by the participant or legally authorized representative according to the ethics-approved process, with participant re-consent when decision-making capacity returns.
Exclusion criteria
1. Ongoing invasive mechanical ventilation or noninvasive ventilation, or high-flow nasal oxygen when study conditions cannot be maintained stably. 2. Hemodynamic instability or inability to tolerate a semi-recumbent position. 3. Inability to cooperate with training or impaired consciousness. 4. Unsuitable for EIT monitoring, including an implanted pacemaker or defibrillator incompatible with the device, severe skin disease at the electrode-belt site, or known relevant allergy. 5. Severe underlying pulmonary disease likely to substantially affect ventilation distribution and obscure the intervention effect. 6. Chest-wall deformity or severe scoliosis affecting EIT image quality. 7. Body mass index greater than 35 kg/m2. 8. Pregnancy or breastfeeding. 9. Current participation in another interventional clinical trial that could interfere with study outcomes. 10. Any other condition that, in the investigator's judgment, makes participation inappropriate.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Dorsal Ventilation Fraction | Baseline and 5 minutes after completion of the single intervention session | Dorsal ventilation fraction is the percentage of tidal ventilation occurring in the dorsal lung region during stable spontaneous breathing. The outcome is calculated as DVF at T1 minus DVF at T0 using 2-minute EIT recordings and a fixed offline analysis algorithm. Higher values indicate a greater shift of ventilation toward the dorsal region. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Mean Inspiratory Volume | Day 1, during the single intervention session of 30 incentive-spirometry breaths | Mean volume or device scale reached across the 30 incentive-spirometry breaths performed during the training session. |
| Change in Global Inhomogeneity Index | Baseline and 5 minutes after completion of the single intervention session | The EIT-derived global inhomogeneity index at T1 minus the value at T0. Lower values indicate improved ventilation homogeneity. |
| Change in End-Expiratory Lung Impedance | Baseline and 5 minutes after completion of the single intervention session | End-expiratory lung impedance at T1 minus the value at T0, derived from EIT. An increase generally indicates an increase in end-expiratory lung volume. |
| Change in Dependent Silent Spaces | Baseline and 5 minutes after completion of the single intervention session | Percentage of dependent silent spaces at T1 minus the percentage at T0, derived from EIT. A decrease indicates fewer dependent lung regions with little or no ventilation. |
| Change in Oxygen Saturation to Inspired Oxygen Ratio | Baseline and 5 minutes after completion of the single intervention session | The SpO2/FiO2 ratio at T1 minus the ratio at T0. SpO2 is averaged over a stable 30- to 60-second interval and FiO2 is determined from the concurrent oxygen-delivery settings. |
| In-Hospital Intubation or Reintubation | From enrollment through hospital discharge, up to 30 days | Proportion of participants who undergo tracheal intubation or reintubation after study enrollment. |
Countries
China
Outcome results
None listed