Which Ventilatory Strategy is Better for Lung in Upper Abdominal Surgeries?

Study Overview
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Brief Summary
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Ventilated Patients especially those undergoing upper abdominal surgeries are prone to lung atelectasis. They are at risk of adverse effects secondary to inadequate lung ventilation. Applied PEEP and Recruitment maneuver are thought to enhance lung aeration under general anesthesia which could be assessed by ultrasound.

Detailed Description
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The aim of our study is to assess the effect of using PEEP with and without recruitment maneuver on atelectasis and lung aeration during open upper abdominal surgeries by ultrasonography. Application of PEEP improves intraoperative oxygenation and thus could minimize the incidence of postoperative atelectasis and respiratory complications during abdominal surgeries. A recent study found that PEEP and RM prevented intraoperative aeration loss, which didn't persist after extubation when comparing effects of positive end-expiratory pressure/recruitment maneuvers with zero end-expiratory pressure on atelectasis during open gynecological surgery by ultrasonography

Official Title
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Ultrasonographic Assessment of Atelectasis in Major Upper Abdominal Surgeries With Different Ventilatory Strategies

Conditions
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Anesthesia Induced Atelectasis

Intervention / Treatment
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* Procedure: Low PEEP
* Procedure: High PEEP
* Procedure: High PEEP/RM
* Device: Lung ultrasonogrphy assessment


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiologists' physical status grades I, II, and III. Exclusion Criteria: Patient refusal. Psychiatric diseases. Body Mass Index > 35 Kg/m2. Previous intrathoracic procedures. History of severe obstructive pulmonary disease. History of severe restrictive lung disease. Pulmonary arterial hypertension ( systolic pulmonary arterial pressure >40 mmHg). Pregnancy.

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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Low PEEP<br>Low positive end-expiratory pressure (PEEP) and no recruitment maneuver (RM) | Procedure: Low PEEP<br>* Patients will be ventilated with a PEEP of 4 cm H2O and no RMs throughout the study<br>Device: Lung ultrasonogrphy assessment<br>* The thorax will divided into 12 quadrants, each of them will be assigned a score of 0-3 as 0, normal lung sliding with fewer than three single B lines three or more B lines coalescent B lines consolidated lung. The LUS (0-36) will be calculated with higher scores indicating more aeration loss<br>|
| Active Comparator: High PEEP<br>High positive end-expiratory pressure (PEEP) | Procedure: High PEEP<br>* PEEP of 10 cm H2O will be applied<br>Device: Lung ultrasonogrphy assessment<br>* The thorax will divided into 12 quadrants, each of them will be assigned a score of 0-3 as 0, normal lung sliding with fewer than three single B lines three or more B lines coalescent B lines consolidated lung. The LUS (0-36) will be calculated with higher scores indicating more aeration loss<br>|
| Active Comparator: High PEEP/RM<br>High positive end-expiratory pressure (PEEP) and recruitment maneuver (RM) | Procedure: High PEEP/RM<br>* PEEP of 10 cm H2O and RM (30 cm H2O for 30 s) immediately after the second lung ultrasonographic examination and repeated every 30 minutes till emergence<br>Device: Lung ultrasonogrphy assessment<br>* The thorax will divided into 12 quadrants, each of them will be assigned a score of 0-3 as 0, normal lung sliding with fewer than three single B lines three or more B lines coalescent B lines consolidated lung. The LUS (0-36) will be calculated with higher scores indicating more aeration loss<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pre-emergence LUS score | Lung ultrasonography score (LUS score) between groups at the end of surgery (just before emergence) as a lower LUS indicates better lung aeration. | intraoperative before recovery from anesthesia | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Lung ultrasonography score (LUS score) | Lung ultrasonography score (LUS score) between groups | preoperative, intraoperative for anesthesia duration to 1 hour postoperative | 
| Heart rate | heart rate between groups at each time point of LUS score performance | preoperative, intraoperative for anesthesia duration to 1 hour postoperative | 
| Mean blood pressure | mean arterial blood pressure between groups at each time point of LUS score performance | preoperative, intraoperative to 1 hour postoperative | 
| oxygen saturation | patient oxygen saturation between groups at each time point of LUS score performance | preoperative, intraoperative to 1 hour postoperative | 
| End-tidal carbon dioxide tension | end tidal CO2 between groups post induction, post recruitment and before extubation | intraoperative for anesthesia duration | 
| Arterial partial pressure of oxygen (PaO2) | arterial blood gases post induction, before extubation and at the PACU | Intraoperative and 15 min postoperative | 
| Arterial partial pressure of carbon dioxide (PaCO2) | arterial blood gases post induction, before extubation and at the PACU | Intraoperative and 15 min postoperative | 
| PaO2/FiO2 | arterial blood gases post induction, before extubation and at the PACU | Intraoperative and 15 min postoperative | 
| Peak inspiratory pressure | peak inspiratory pressure between groups after intubation | intraoperative for anesthesia duration | 
| Postoperative pulmonary complications (PPCs) | PPCs include (pneumothorax, pleural effusion, pulmonary collapse, atelectasis, pneumonia, acute respiratory distress syndrome (ARDS), or pulmonary aspiration). | 5 days |