Electrical Impedance Tomography in One-Lung Ventilation

Study Overview
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Brief Summary
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Mechanical ventilation can cause damage to the lung parenchyma, this is known as ventilatory induce lung injury (VILI).To avoid this damage, ventilatory strategies have been created, focused on the reduction of tidal volume, airway pressures and use of PEEP (positive end-expiratory pressure), which together are called protective ventilation. Although ventilation with protective parameters seems to reduce VILI in one-lung ventilation, the optimal parameters are not clear.

Detailed Description
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This research aims to describe the ventilation, perfusion and pulmonary mechanics on one-lung ventilation with different levels of tidal volume and PEEP. An extreme situation of VILI occurs in thoracic surgery, where the atelectasis of a lung is required, ventilating throughout the surgery only the contralateral one. This generates an inflammatory state, with the release of alveolar cytokines from both the non-ventilated and ventilated lungs, which potentiates the development of damage in the lung parenchyma. In addition, one lung ventilation has traditionally been performed with high tidal volume (Vt) values and low PEEP. In this context, the development of VILI is even more probable, so extreme measures of protection in this kind of ventilation are necessary. The electrical impedance tomography will allow the investigators to obtain a visual and quantitative representation of the areas of ventilation and perfusion of the lung. By relating the tidal volume and PEEP with the tomographic results, it is expected to define mechanical ventilation parameters that achieve the best ventilation/perfusion ratio for patients in one-lung ventilation. Specifically, analyze the distribution and deformation of the ventilated areas in the different lung regions and its correlation with respiratory mechanics and volumetric capnography. This will allow the investigators to make a better definition of the tidal volume and PEEP in patients undergoing one-lung ventilation. .

Official Title
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Tidal Volume and PEEP Titration in One-Lung Ventilation With Electrical Impedance Tomography

Conditions
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Ventilator Lung

Intervention / Treatment
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* Diagnostic Test: Electrical impedance tomography. Pulmonary mechanics measurement.Arterial gas measurement. Esophageal pressure measurement


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA (American Society of Anesthesiologists) classification I-III Age 18-75 Years Elective thoracic surgery One-Lung Ventilation Healthy non ventilated lung Exclusion Criteria: ASA classification > III BMI (Body mass index) > 30 Emergency surgery Pregnancy Patients includes in other protocols

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 |
| --- | --- |
| One-Lung Ventilarion<br>Thoracic surgery cases with one-lung ventilation strategy. | Diagnostic Test: Electrical impedance tomography. Pulmonary mechanics measurement.Arterial gas measurement. Esophageal pressure measurement<br>* After general anesthesia, patients will be ventilated with three tidal volume level (4, 6 and 8 cc / Kg / IBW), in two levels of PEEP, 6 cm2 H20, and best PEEP, the latter obtained after a recruitment maneuver and decremental titration.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ventilation/ perfusion ratio | Electrical impedance tomography. | 1 hour | 
| Pulmonary mechanics | Airway pressure ,esophageal pressure measurement. | 1 hour | 
| Arterial gas measurement | 5 samples per patient | 20 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Electrical impedance tomography, One-lung ventilation, Protective ventilation, Ventilator- Induce Lung injury