An interventional study of PEEP titration for Minimum Driving Pressure and Lung Protective Ventilation in Postoperative Atelectasis, Postoperative Pulmonary Atelectasis and Postoperative Pulmonary Complications (PPCs), sponsored by University General Hospital of Patras. Completed at 1 site in Greece. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-02-11.
Sponsored by University General Hospital of Patras · Not applicable, Interventional, and Prevention
Brief summary The goal of this clinical trial is to compare two different types of perioperative mechanical ventilation (MV), specifically Protective Mechanical Ventilation (PMV) and MV with the lowest possible Driving Pressure (ΔP), in relation to the appearance of postoperative lung closing, eg atelectasis, in adult patients who are operated. Atelectasis will be evaluated via lung ultrasound.
The main questions it aims to answer are:
Researchers will use lung ultrasound to compare MV with the lowest possible Driving Pressure (ΔP) to Protective Mechanical Ventilation (PMV) to see if any of this is more protective than the other concerning lung atelectasis.
All participants will receive perioperative MV.
Half of them will receive conventional Protective Mechanical Ventilation (PMV). This will include well known generally protective settings for mechanical ventilation of patients, concerning volumes, pressures, respiratory rate, inspiratory gases and ventilation maneuvers.
The rest of participants will be ventilated with the lowest possible Driving Pressure (ΔP). This will be similar to PMV in the chosen volumes, respiratory rate, inspiratory gases and ventilation maneuvers. However, the pressure inside lung at the end of expiration, eg Positive End Expiratory Pressure (PEEP), will be not be preset for every patient. Initially, we will perform a maneuver that will quantify each individual's lung characteristics and mechanics. According to this, we will find the exact PEEP that seems to suit each patients lungs most, and use this perioperatively, trying to provide lungs the best conditions every time.
After the completion of the operation, all the patients will be screened for atelectasis, via lung ultrasound, using a well established protocol for the quantification of atelectasis. The results will be statistically analyzed trying to find if any of the forementioned strategies of mechanical ventilation surpasses the other concerning atelectasis appearance.
Furthermore efficiency of lung oxygen absorption, hospital stay, ICU need and mortality will be noted.
377 studies on the registry are indexed under Pulmonary Atelectasis; 93 are open to participants now.
This study's enrollment of 70 is above the median of 60 across 268 interventional studies indexed under Pulmonary Atelectasis.
Browse Pulmonary Atelectasis studies →University General Hospital of Patras is the lead sponsor of 4 studies on the registry; 3 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CONVENTIONAL LUNG PROTECTIVE VENTILATION This group is mechanically ventilated with Invasive Mechanical Ventilation with PEEP 8 cm H20 Tidal Volume (VT) 8 ml/kg Ideal Body Weight (IBW) Respiratory Rate (RR) --\> PaCO2 = 35-45 mmHg Inspired Oxygen Fraction (FiO2) 0.4 - 0.5 --\> Pulse Saturation Oxygen (SpO2) \> 93% Recruitment Maneuver (as described) every hour
Procedure: Lung Protective Ventilation
This group is mechanically ventilated with Invasive Mechanical Ventilation with PEEP; Initially 8 cm H20, titrated at level with Minimum Driving Pressure after first recruitment - titration maneuver followed by new recruitment maneuver VT 8 ml/kg IBW RR --\> PaCO2 = 35-45 mmHg FiO2 0.4 - 0.5 --\> SpO2 \> 93% Recruitment Maneuver (as described) every hour
Procedure: PEEP titration for Minimum Driving Pressure
This group is mechanically ventilated with Invasive Mechanical Ventilation with Volume Control Ventilation mode with PEEP Initially 8 cm H2O. Afterwards, the lungs are recruited with the aforementioned maneuver. During subsequent derecruitment, PEEP is decreased by 2 cm H20 and compliance is noted in each stage. The goal is to find PEEP with maximum compliance (Cmax). A new recruitment maneuver follows and during derecruitment PEEP is set at the optimum value that was previously defined. VT 8 ml/kg IBW RR --\> PaCO2 = 35-45 mmHg FiO2 0.4 - 0.5 --\> SpO2 \> 93% Recruitment Maneuver (as described) every hour
Also known as: Maximum compliance mechanical ventilation, Cmax Mechanical Ventilation
This group is mechanically ventilated with Invasive Mechanical Ventilation with Volume Control Ventilation mode with PEEP 8 cm H2O. VT 8 ml/kg IBW RR --\> PaCO2 = 35-45 mmHg FiO2 0.4 - 0.5 --\> SpO2 \> 93% Recruitment Maneuvers (as described) every hour
Lung Ultrasound Score (LUS)
12 Position Lung Ultrasound will be performed in Post Anesthesia Care Unit (PACU) within 20 minutes postoperatively. In each position the potential scores will be 0,1,2 and 3. 0 --\> 0-2 B-lines 1. --\> \>2 B-lines or presence of small sublpleural consolidations with normal pleural line. 2. --\> Multiple coalescent B-lines or multiple small sublpleural consolidations with thickened or irregular pleural line. 3. --\> Total air loss or subpleural consolidation with diameter bigger than 1x2cm. The total sum of ultrasound scores of each position is marked as LUS.
Time frame: Within 20 minutes in PACU.
Rate of Postoperative Respiratory Failure
Postoperative Respiratory Failure based on Arterial Blood Gases in PACU (type I and/or II) Type I --\> Arterial Oxygen Partial Pressure / Arterial Oxygen Saturation (P/F) ratio \<300 Type II --\> PaCO2 \> 45mmHg
Time frame: Within 30 minutes in PACU
Rate of NIMV need
Potential need for NIMV in PACU due to Respiratory Failure. CPAP / BIPAP / High-Flow Nasal Canula
Time frame: Period of stay in Post Anesthesia Care Unit (PACU). From time of postoperative transfer to PACU until time of discharge from PACU and return to general clinic, an average of 1 hour.
Hospital Stay
Total hospital stay days from day of operation until hospital discharge.
Time frame: From day of operation until the end of patient stay inside hospital, because of return to home or due to death.
ICU need.
Potential Need for ICU admission.
Time frame: From day of operation until the end of patient stay inside hospital, because of return to home or due to death.
ICU stay
In case of ICU need, total days of ICU stay.
Time frame: From day of operation until the end of patient stay inside hospital, because of return to home or due to death.
28 Day mortality
Incidence of death in 28 days in each group.
Time frame: From day of operation until up to 28 days.
Mechanical Power (MP)
o To calculate MP, the following must be recorded: RR, Peak Airway Pressure (Ppeak), Plateau Pressure (Pplat), and PEEP. The simplified equation will be used; MP = 0.098 × RR × \[Ppeak - (Plat-PEEP)/2\]
Time frame: From the moment of beginning of operation until the moment of the end of operation and mechanical ventilation
Volume-normalized Mechanical Power (MPcrs)
MPcrs = MP/Respiratory System Compliance (Crs)
Time frame: From the moment of beginning of operation until the moment of the end of operation and mechanical ventilation
Elastic Power (EP)
To calculate EP, the following must be recorded: RR, VT, Pplat, and PEEP. The following equation will be used: EP = 0.098 × RR × VT × \[(Plat+PEEP)/2\]
Time frame: From the moment of beginning of operation until the moment of the end of operation and mechanical ventilation
Volume-normalized Elastic Power (EPcrs)
EPcrs = EP/Crs
Time frame: From the moment of beginning of operation until the moment of the end of operation and mechanical ventilation
Plan to share: Yes
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University General Hospital of Patras