Role of Lung Ultrasound Imaging for Intraoperative Monitoring of Atelectasis During Laparoscopic Surgery

Study Overview
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Brief Summary
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General anesthesia results in the development of atelectasis in the dependent areas of the lungs exposing patients to an increased risk of hypoxemia. During laparoscopic procedures, pneumoperitoneum increases already present atelectasis. Several methods have been suggested to reduce the impact of atelectasis during surgery. However, few intraoperative modalities for the diagnosis and monitoring of atelectasis are available. Lung ultrasound imaging is a promising non-invasive, non-radiant, portable and easy to use tool that as yet to be studied in the intraoperative setting. This observational study will aim to clarify the role of lung ultrasound imaging during laparoscopic surgery for the diagnostic and monitoring of atelectasis. This study is designed to: Demonstrate a link between the lung ultrasound aeration score, the partial pressure of oxygen in arterial blood (PaO2) / fraction of inspired oxygen (FiO2) ratio and the oxygenation index. In the event of intraoperative desaturation, study the impact of positive end-expiratory pressure (PEEP) and/or increase of FiO2 on the aeration score. Study the impact of pain on diaphragmatic function and the aeration score. Our hypothesis is that lung ultrasound imaging allows detection of lung aeration changes associated with induction of general anesthesia, pneumoperitoneum, emergence from anesthesia and changes occurring during the stay in the recovery room.

Detailed Description
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On arrival in the operating theatre, each patient will undergo a baseline lung ultrasound examination. The anesthetic technique and monitoring will be standardized. The radial artery will be cannulated after induction of anesthesia for blood gas monitoring. Lung ultrasound examinations will be performed 5 minutes following induction of general anesthesia and 5 minutes after insufflation of the abdomen with carbon dioxide. In the event of a desaturation needing an intervention (increase of FiO2 or PEEP), ultrasound imaging will be repeated before and after the intervention. Presence of a pneumothorax or endobronchial intubation will be assessed during each examination. Fifteen minutes after arrival and immediately before discharge from the recovery room, lung ultrasound examinations will also be performed. FiO2 and vital signs will be recorded at each ultrasound examination. Arterial blood samples will be collected simultaneously. Pain rating using the visual analog scale and diaphragmatic function will be assessed during the preoperative ultrasound examination and before discharge from the recovery room.

Official Title
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Role of Lung Ultrasound Imaging for Intraoperative Monitoring of Atelectasis During Laparoscopic Surgery

Conditions
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Atelectasis

Intervention / Treatment
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* Other: Lung ultrasound imaging examinations


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients aged 18 years and older Scheduled for laparoscopic surgery Physical status 1-3 Exclusion Criteria: Previous thoracic procedure (thoracic drain, thoracotomy, thoracoscopy) Contraindication to the placement of an arterial line Very severe chronic obstructive pulmonary disease

Ages Eligible for Study
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Minimum Age: 18 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Lung ultrasound imaging<br>Lung ultrasound imaging examinations performed during the perioperative period for the monitoring of atelectasis associated with laparoscopic surgery | Other: Lung ultrasound imaging examinations<br>* Lung ultrasound examinations performed at different time-points immediately before surgery, during surgery under general anesthesia and after surgery in the recovery room to detect and monitor atelectasis related to laparoscopic procedures.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Lung aeration | Estimate lung aeration by ultrasound imaging using a four point aeration score (0 = normal lung, 1 = moderate aeration loss, 2 = severe aeration loss, 3 = complete aeration loss and consolidation) | From arrival in the operating theatre to immediately before discharge from the recovery room (Day 0) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Gas exchange | Assess the impact of the different stages of anesthesia and surgery on gas exchange by measuring arterial blood gases. | From 5 minutes following induction of anesthesia to immediately before discharge from the recovery room (Day 0) | 
| Diaphragmatic function | Assess diaphragmatic function by ultrasound imaging | On arrival in the operating theatre and immediately before discharge from the recovery room (Day 0) | 
| Incidence of pneumothorax | Estimate the incidence of pneumothorax by ultrasound imaging | From 5 minutes following induction of anesthesia to immediately before discharge from the recovery room (Day 0) | 
| Incidence of endobronchial intubation | Estimate the incidence endobronchial intubation by ultrasound imaging | From 5 minutes following induction of anesthesia to immediately before discharge from the recovery room (Day 0) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Atelectasis, Pneumoperitoneum, Hypoxemia