Abnormalities in Lung Computed Tomography and Physiological Alterations in Patients With Acute Respiratory Distress Syndrome

Study Overview
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Brief Summary
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The objective of the study is to determine the correlation between the physiological variables and the degree of consolidation in lung computed tomography in patients with acute respiratory distress syndrome

Detailed Description
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Acute respiratory distress syndrome (ARDS) involves respiratory failure from different causes, but with a common pathologic manifestation in the form of inflammatory pulmonary edema. Histopathological examination of tissue obtained from patients with ARDS suggests that the pathology is heterogeneous and involves 3 phases: exudative, inflammatory, and fibroproliferative. Such alterations are associated with a decreased lung compliance leading to an increased pressure in the airways under mechanical ventilation (MV) that becomes more pronounced with increasing severity of ARDS, so that the consequent respiratory mechanics has thus been shown to be determinant of patient outcomes. In addition, computed tomography (CT) has revealed a heterogeneous pattern of lung injury, with areas of normal lung interspersed with morphologically altered regions, among which abnormalities the ground-glass opacification and consolidation are the most frequent. It has been performed quantitative assessments of ARDS by means of CT, thus enabling a correlation of such pathologic details with physiologic and clinical parameters as well as with patient outcomes. From the above, the investigators hypothesize that in patients with ARDS, a greater involvement in oxygenation and higher mechanical alterations will be correlated with a more advanced consolidation in the CT scan. Therefore, the primary objective of the study will be to determine the correlation between the extent of oxygenation (assessed by the PaO2/FiO2 ratio) and the degree of consolidation (total CO) in the CT scan. The secondary objectives will be: (1) to determine the correlation between the driving pressure and the total CO as evidenced by CT; (2) to determine the correlation between the static pressure and the total CO; (3) to determine the correlation between the static compliance and the total CO; (4) to determine the correlation between oxygenation index and the total CO; (5) to determine the correlation between the lung injury score (LIS) and the total CO; (6) to determine the correlation between ventilator free days and the total CO; (7) to determine the independent variables associated with total CO; (8) to determine differences in the CT with respect to the total lung-disease score [total CO plus total value of ground-glass opacification (total GC)] between survivors and nonsurvivors.

Official Title
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Abnormalities in Lung Computed Tomography and Physiological Alterations in Patients With Acute Respiratory Distress Syndrome

Conditions
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Respiratory Distress Syndrome, Adult

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients 15 years of age or older who have been receiving MV and have been defined as with ARDS according to the Berlin definition Exclusion Criteria: Patients with chronic pulmonary disease, with an expected duration of MV shorter than 48 h, or with a high risk of death within 3 months for reasons other than ARDS as well as patients having made the decision to withhold life-sustaining treatment along with those exhibiting clinical instability that could not be moved to the radiology department in order to perform CT scans.

Ages Eligible for Study
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Minimum Age: 15 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 |
| --- | --- |
| Computed tomography in acute respiratory distress syndrome<br>The lung on computed tomography (CT) in patients with acute respiratory distress syndrome (ARDS) has revealed a heterogeneous pattern of lung injury, with areas of normal lung interspersed with altered regions: ground-glass opacification and consolidation among the most frequent. It has been performed quantitative assessments of ARDS by means of CT, thus enabling a correlation of such pathologic details with physiologic, clinical parameters and with patient outcomes. Therefore, the primary objective of the study is to determine the correlation between the extent of oxygenation (PaO2/FiO2) and the degree of consolidation (total CO) in the CT. The secondary objectives are to determine: the correlation between the driving pressure, ventilator variables and the total CO; the independent variables associated with total CO; differences in the CT with respect to the total lung-disease score (total CO plus total value of ground-glass opacification) between survivors and nonsurvivors. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation between the extent of oxygenation and the degree of consolidation (total CO) in the CT scan. | The extent of oxygenation will be assessed by the PaO2/FiO2 ratio obtained the day of diagnosis of ARDS | Within the first 60 days (plus or minus 3 days) after admission to Hospital | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation between the driving pressure and the total CO as evidenced by CT | The driving pressure will be obtained over the first 24 hours after randomization | Within the first 60 days (plus or minus 3 days) after admission to Hospital | 
| Correlation between the static pressure and the total CO evidenced by CT | The static pressure will be obtained over the first 24 hours after randomization | Within the first 60 days (plus or minus 3 days) after admission to Hospital | 
| Correlation between the static compliance and the total CO evidenced by CT | The static compliance will be obtained over the first 24 hours after randomization | Within the first 60 days (plus or minus 3 days) after admission to Hospital | 
| Correlation between oxygenation index and the total CO evidenced by CT | The oxygenation index will be obtained over the first 24 hours after randomization | Within the first 60 days (plus or minus 3 days) after admission to Hospital | 
| Correlation between the lung injury score (LIS) and the total CO evidenced by CT | The lung injury score (LIS) will be obtained over the first 24 hours after randomization | Within the first 60 days (plus or minus 3 days) after admission to Hospital | 
| Correlation between ventilator free days and the total CO evidenced by CT |  | Within the first 60 days (plus or minus 3 days) after admission to Hospital | 
| Independent variables associated with total CO | A multivariate logistic-regression model will be used to independent assess variables that showed correlation with total CO. The investigators also will be introduced in the model the potential confounders: age, gender, APACHE-II score and SOFA score. | Within the first 60 days (plus or minus 3 days) after admission to Hospital | 
| Differences in the CT with respect to the total lung-disease score [total CO plus total value of ground-glass opacification (total GC)] between survivors and nonsurvivors. |  | Within the first 60 days (plus or minus 3 days) after admission to Hospital |