Comparison of Esophageal and Central Venous Pressure for Estimating Transpulmonary Pressure Changes

Study Overview
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Brief Summary
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Central venous pressure (CVP) is characterized by a low-frequency pleural-dependent as well as a high-frequency cardiac pulsatile component. The aim of the study is to compare the low-frequency component of CVP with the esophageal pressure (Pes), as surrogate of pleural pressure, to estimate trans-pulmonary pressure (PL).

Detailed Description
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The investigators will enroll mechanically ventilated patients admitted to the intensive care unit with the diagnosis of respiratory failure monitored with a dedicated nasogastric catheter and a central venous catheter for measuring Pes and CVP, respectively. Electrocardiogram trace, Pes, CVP and airway pressure (Paw) will be recorded at the end of inspiratory and expiratory pauses. The CVP waveforms will be analyzed off-line using a dedicated low-pass digital filter to obtain the low-frequency component of CVP (filtered CVP, fCVP). Paw, Pes and fCVP will be used to calculate PL using transpulmonary driving pressure formula (PL-Pes and PL-fCVP, respectively). The PL values obtained with fCVP and Pes will be compared to assess the correlation of the two methods.

Official Title
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Estimating the Transpulmonary Pressure From the Central Venous Pressure in Mechanically Ventilated Patients With Respiratory Failure

Conditions
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Mechanical Ventilation, Acute Respiratory Distress Syndrome

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: adult patients receiving invasive mechanical ventilation diagnosis of acute respiratory failure (defined as the ratio of partial oxygen pressure and fraction of inspired oxygen below 200 mmHg) esophageal balloon catheter central venous catheter Exclusion Criteria: age under 18 years old Hemodynamic instability Esophageal diseases (varices, stenosis..) Refusal of the patient evidence of active air leak from the lung (pneumothorax, pneumomediastinum, existing chest tube....) history of lung/abdominal surgery pregnancy severe coagulopathy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 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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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Transpulmonary pressure | Correlation and agreement between the transpulmonary pressure obtained from esophageal balloon catheter and central venous catheter | Within 72 hours from the starting of mechanical ventilation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Transpulmonary pressure in subgroups of patients | Agreement between trans pulmonary pressure obtained with the two methods in subgroup of patients such as those with acute respiratory distress syndrome or obesity | Within 72 hours from the starting of mechanical ventilation | 
| Transpulmonary pressure in patients at risk for ventilator-induced-lung-injury | Comparison of the transpulmonary pressure obtained with the two methods in patients at risk for ventilator-induced-lung-injury | Within 72 hours from the starting of mechanical ventilation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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esophageal pressure, transpulmonary pressure, central venous pressure, acute respiratory failure