Lung Ultrasound for the Detection of Pulmonary Atelectasis in the Perioperative Period

Study Overview
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Brief Summary
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Atelectases (collapsed lung areas) of 15-20% of total lung occur in up to 90% of patients who are anaesthetized and intubated. The goal of the present prospective study is to detect atelectatic areas in the perioperative period in the lungs of patients undergoing elective laparoscopic surgery non-invasively and without x-ray exposure. Results of lung ultrasound (LUS) as the experimental method will be compared to the results of Electrical Impedance Tomography (EIT) as the reference technique for the detection of atelectasis. A device for peripheral Oxygen saturation measurement (MASIMO Radical-8) will detect changes in ventilation. The investigators want to confirm or disprove former findings of the appearance of intraoperative atelectases and to prove that ultrasound is a valid tool for detection of atelectases.

Official Title
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Lung Ultrasound for the Detection of Pulmonary Atelectasis in the Perioperative Period

Conditions
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Postoperative Pulmonary Atelectases

Intervention / Treatment
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* Device: Ultrasound of the lungs
* Device: Electric impedance tomography


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female, age 18 - 75 BMI < 30 Laparoscopic operation Exclusion Criteria: Pregnancy Pulmonary infection Chronic pulmonary diseases Morbid Obesity

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 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 |
| --- | --- |
| Laparoscopic surgery<br>Patients undergoing laparoscopic surgery under general anaesthesia, patients undergo ultrasound of the lungs and electric impedance tomography at 4 times during anaesthesia | Device: Ultrasound of the lungs<br>* Ultrasound examination of the lungs<br>* Other names: Sonosite ultrasound device (M-Turbo);Device: Electric impedance tomography<br>* Electric impedance tomography (EIT) is a noninvasive tool based on the measurement of electrical impedance changes within the thorax and lung tissue during ventilation and depicts the regional changes in ventilation in real time. To use electric impedance tomography 16 electrodes are applied in a circular fashion around the patient's chest, typically at the level of the 7th intercostal space.<br>* Other names: EIT (Pulmovista, Draeger);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation between evidence of atelectasis in lung ultrasound and evidence of atelectasis in electric impedance tomography | Measurements, requiring 5 minutes each, are performed before induction of anaesthesia, after intubation, immediately before extubation and immediately after extubation. Outcome measure: comparison of how often atelectases are detected by lung ultrasound (experimental method) versus by electric impedance tomography (standard method) | on the day of laparoscopic surgery, expected average 2 hours in total | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| respiratory variability of oxygen saturation | from induction of anaesthesia until extubation | on the day of laparoscopic surgery, expected average 2 hours in total |