Postoperative Pulmonary Complications, Mechanical Ventilation
Conditions
Keywords
Driving Pressure, Individualized PEEP, Positive End-Expiratory Pressure, PEEP Titration, Lung Recruitment Maneuver, Lung-Protective Ventilation, Upper Abdominal Surgery, ARISCAT Score, Perioperative Mechanical Ventilation
Brief summary
This randomized clinical trial compares two methods of setting positive end-expiratory pressure (PEEP) during general anesthesia in adults undergoing upper abdominal digestive surgery who are at moderate or high risk of postoperative pulmonary complications. All participants will receive lung-protective mechanical ventilation. Participants will be randomly assigned to one of two groups. In the individualized PEEP group, PEEP will be adjusted to achieve the lowest driving pressure following a lung recruitment maneuver. In the standard PEEP group, PEEP will be fixed at 5 cmH2O. The main question is whether driving pressure-guided individualized PEEP reduces the proportion of participants who develop one or more postoperative pulmonary complications during the first 7 days after surgery compared with standard PEEP.
Detailed description
Postoperative pulmonary complications are common after upper abdominal surgery and can increase postoperative morbidity and length of hospital stay. Although positive end-expiratory pressure may help prevent alveolar collapse during general anesthesia, a fixed PEEP level may be insufficient for some patients and excessive for others. Driving pressure is calculated as plateau pressure minus PEEP and reflects the pressure required to deliver the tidal volume to the respiratory system. Individualizing PEEP according to the lowest driving pressure may improve respiratory-system compliance while limiting both alveolar collapse and overdistension. In this prospective, randomized, controlled, parallel-group trial, eligible participants will be randomly allocated in a 1:1 ratio to either driving pressure-guided individualized PEEP or standard PEEP. In the individualized PEEP group, a lung recruitment maneuver will be followed by a decremental PEEP trial. The PEEP level associated with the lowest driving pressure will be selected, provided that adequate oxygenation and hemodynamic stability are maintained. In the standard PEEP group, PEEP will be maintained at 5 cmH2O. All other aspects of lung-protective ventilation and perioperative care will be standardized between the groups. Participants and the independent postoperative outcome assessor will remain unaware of treatment allocation. Postoperative pulmonary complications will be assessed from the day of surgery through postoperative day 7.
Interventions
PROCEDUREDriving Pressure-Guided Individualized PEEP
Participants assigned to this experimental arm receive a lung recruitment maneuver followed by a decremental PEEP trial. Driving pressure is calculated as plateau pressure minus PEEP at each tested level. The PEEP associated with the lowest driving pressure is selected and maintained during surgery, provided that adequate oxygenation and hemodynamic stability are preserved.
PROCEDUREStandard PEEP
Participants receive lung-protective mechanical ventilation with PEEP fixed at 5 cmH2O throughout the intraoperative ventilation period. The other components of perioperative ventilation and care are standardized between the two groups.
Sponsors
Hopital Charles Nicolle
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
DOUBLE (Subject, Outcomes Assessor)
Masking description
Participants are unaware of their assigned group because the intervention is performed during general anesthesia. Postoperative outcomes are assessed by an independent investigator who is unaware of treatment allocation. The anesthesia team applying the ventilation strategy cannot be masked but does not participate in postoperative outcome assessment.
Intervention model description
Two-arm, parallel-group, randomized controlled trial. Participants are assigned in a 1:1 ratio to either driving pressure-guided individualized PEEP or standard PEEP. Each participant remains in the assigned group throughout the intraoperative intervention, with no crossover between groups.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Age 18 years or older. * Scheduled for supra-mesocolic upper abdominal digestive surgery. * American Society of Anesthesiologists (ASA) physical status I, II, or stable III. * Moderate or high risk of postoperative pulmonary complications, defined by an Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) score of 26 or higher. * Provision of written informed consent.
Exclusion criteria
* Refusal to participate or inability to provide written informed consent. * Pregnancy. * ASA physical status greater than III. * History of acute respiratory distress syndrome. * Pulmonary hypertension. * Bronchopleural fistula. * Chronic obstructive pulmonary disease with severe emphysema. * Pre-existing cardiac arrhythmia. * Decompensated heart failure. * Known condition associated with increased intracranial pressure. * Intra-abdominal hypertension.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| postoperative pulmonary complications | From the end of surgery through postoperative day 7 (up to 7 days) | Incidence of postoperative pulmonary complications occurring within the first 7 postoperative days, according to the study-defined criteria. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Length of hospital stay | From the day of surgery through hospital discharge, assessed up to 30 days after surgery. | Length of hospital stay will be calculated as the number of days from the date of surgery to the date of hospital discharge. |
| Postoperative Intensive Care Unit Admission | From the end of surgery through hospital discharge, assessed up to 30 days after surgery. | Number and percentage of participants requiring admission to an intensive care unit after surgery. |
| Intensive Care Unit Length of Stay | At intensive care unit discharge, assessed up to 30 days after surgery. | Among participants admitted to the intensive care unit, length of stay measured in calendar days from intensive care unit admission to intensive care unit discharge. |
| Intraoperative Tidal Volume | 10 minutes after tracheal intubation; 1, 2, and 3 hours after intubation; and at the end of surgery. | Tidal volume delivered during mechanical ventilation, expressed in mL/kg of ideal body weight and recorded at predefined intraoperative time points. |
| Median Intraoperative Positive End-Expiratory Pressure | 10 minutes after tracheal intubation; 1, 2, and 3 hours after intubation; and at the end of surgery. | Median positive end-expiratory pressure (PEEP) applied during intraoperative mechanical ventilation, expressed in cmH2O and calculated from values recorded at the predefined intraoperative assessment points. |
| Intraoperative Peak Airway Pressure | 10 minutes after tracheal intubation; 1, 2, and 3 hours after intubation; and at the end of surgery. | Peak airway pressure measured during intraoperative mechanical ventilation, expressed in cmH2O. |
| Intraoperative Plateau Pressure | From initiation of mechanical ventilation after tracheal intubation through the end of surgery | Plateau pressure measured during an end-inspiratory occlusion lasting 2 to 3 seconds, expressed in cmH2O. |
| Intraoperative Static Respiratory System Compliance | From initiation of mechanical ventilation after tracheal intubation through the end of surgery | Static respiratory system compliance calculated as tidal volume divided by the difference between plateau pressure and positive end-expiratory pressure, expressed in mL/cmH2O. |
| Intraoperative Dynamic Respiratory System Compliance | From initiation of mechanical ventilation after tracheal intubation through the end of surgery | Dynamic respiratory system compliance calculated as tidal volume divided by the difference between peak airway pressure and positive end-expiratory pressure, expressed in mL/cmH2O. |
| Intraoperative Systolic Arterial Pressure | From anesthetic induction through the end of surgery | Systolic arterial pressure measured every 5 minutes during surgery and expressed in mmHg. |
| Intraoperative Diastolic Arterial Pressure | From anesthetic induction through the end of surgery | Diastolic arterial pressure measured every 5 minutes during surgery and expressed in mmHg. |
| Intraoperative Mean Arterial Pressure | From anesthetic induction through the end of surgery | Mean arterial pressure measured every 5 minutes during surgery and expressed in mmHg. |
| Intraoperative Heart Rate | From anesthetic induction through the end of surgery | Heart rate measured continuously and recorded every 5 minutes during surgery, expressed in beats per minute. |
Countries
Tunisia
Contacts
CONTACTHallouma Ben Fredj, MD
Outcome results
None listed