Open Lung Approach Versus Conventional Protective Ventilation in Obese Patients Undergoing Open Abdominal Surgery

Study Overview
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Brief Summary
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the purpose of this study is to compare open lung approach versus conventional protective ventilation in obese patients undergoing open abdominal surgery

Detailed Description
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after being informed about the study and potential risks. All patients giving written consent will be randomized by double blind manner into 2 groups each one containing 24 patients Group SPV: will be ventilated using volume controlled ventilation (7ml/kg tidal volume) with addition of 5 cm H₂O fixed PEEP till the end of the surgery . Group OLA: The patients will undergo ARM followed by personalized PEEP.

Official Title
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Open Lung Approach Versus Conventional Protective Ventilation in Obese Patients Undergoing Open Abdominal Surgery: A Randomized Controlled Trial

Conditions
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Abdominal Surgery, Obese Patients

Intervention / Treatment
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* Other: ARM
* Other: spontanous ventilation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient aged between 18 - 65 years BMI between 30-40 kg/m² ASA I and II,open elective abdominal surgery which is expected to last for more than 2 hours under general anesthesia and planned to be extubated at the end of surgery Exclusion Criteria: Emergency surgery, pregnancy, chronic obstructive pulmonary disease (FEV1 < 80% of the predicted value) active asthma, acute respiratory distress syndrome history of pneumothorax, lung cyst, Difficult airway, obstructive sleep apnea,ischemic heart disease, heart failure significant arrhythmias and intracranial hypertension. Exposure to radiotherapy and chemotherapy within 2 months before surgery. Advanced Cardiovascular ,liver, renal diseases ischemic heart disease, heart failure, significant arrhythmias and intracranial hypertension

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Health Services Research
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: SPV spontanous ventilation<br>The patients will be ventilated using volume controlled ventilation (7ml/kg tidal volume) with addition of 5 cm H₂O fixed PEEP till the end of the surgery . | Other: spontanous ventilation<br>* volume controlled ventilation (7ml/kg tidal volume) with addition of 5 cm H₂O fixed PEEP till the end of the surgery .<br>|
| Active Comparator: OLA open lung ventilation<br>The patients will undergo ARM followed by personalized PEEP. | Other: ARM<br>* The ARM is performed by setting the peak inspiratory pressure to 45 cmH₂O then changing the mode of ventilation to pressure controlled ventilation (PCV) with the inspiratory pressure set to give a tidal volume equal to that given during VCV, I:E ratio of 1:1 and a PEEP of 5 cmH₂O. The PEEP level is then increased in 5 cmH₂O steps every minute till it reaches 20 cmH₂O and inspiratory pressure is increased to get an airway opening pressure (inspiratory pressure + PEEP) of 40 cmH₂O which is maintained for one minute after which the ventilation returned to the original setting except for the PEEP level which is kept at 20 cmH₂O. The titration of individualized PEEP is done by decremental reduction of the 20 cmH₂O PEEP level in 2 cmH₂O steps every 2 minutes and measuring static compliance of the respiratory system (CRS) at each step.<br>* Other names: followed by personalized PEEP.;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| post-operative pulmonary complications | Pulmonary function tests will be done before surgery as a baseline then repeated after the surgery when the patient is fully awake using bedside spirometer in the sitting position. | one week postoperative | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| heart rate | hemodynamic changes | Baseline (before surgery) and intraoperative | 
| airway pressure | During mechanical ventilation airway pressures will be continuously monitored. | intraoperative | 
| pulmonary complications. | 1. Postoperative pulmonary complications which are defined as having one or more of the following: 1.Pneumonia 2. Respiratory failure requiring mechanical ventilation (Postoperative PaO2 < 60 mm Hg on room air, a PaO2:FiO2 ratio < 300 mm Hg) or peripheral oxygen saturation (SpO₂) <90% and requiring oxygen therapy ). 3. Atelectasis requiring bronchoscopic intervention 4. Pulmonary edema ( postoperative acute lung injury or ARDS). 5. Delayed tracheal extubation ( >24 hours postoperatively) or need for reintubation (because of respiratory distress, hypoxia, hypercarbia, or respiratory acidosis). 6. Pneumothorax 7. Bronchospasm (Newly detected refractory expiratory wheeze requiring bronchodilators | one week postoperative | 
| length of hospital stay, | the length of hospital stay, and 30 days mortality. | postoperative up to one month | 
| mean arterial blood pressure | hemodynamic changes | Baseline (before surgery) and intraoperative | 
| ETCO2 | hemodynamic changes | Baseline (before surgery) and intraoperative | 
| tidal volume | During mechanical ventilation tidal volume will be continuously monitored. | intraoperative | 
| SpO2 | hemodynamic changes | Baseline (before surgery) and intraoperative | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Open lung approach, conventional ventilation