Continuous Evaluation of Diaphragm Function

Study Overview
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Brief Summary
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Aim of mechanical ventilation is to improve gas exchange and to unload the respiratory muscles delivering a form of mechanical support to the ventilation. At the same time, it is essential that the support is individually-tailored to avoid the development of muscular atrophy, a process called ventilatory-induced diaphragm dysfunction Aim of the present study is that the continuous ultrasonographic assesment of diaphragm function, as obtained by the device under investigation (DiaMon, Respinor AS, Oslo, Norway) is related to the degree of effort of inspiratory muscles, as measured by gold-standard indices such as esophageal and gastric pressure measurement. A secondary aim is that the data assessed by the device are related to a standard ultrasonographic examination performed by expert operators. In particular, we will enroll a population of critically ill patients undergoing mechanical ventilation in assisted mode, and we will perform a decremental pressure support trial, with the following aims: to evaluate the performance of a continuous and automated device for the monitoring of diaphragm contractile activity, as compared to standard mechanical indices of respiratory effort such as the pressure-time product (PTP) to evaluate the performance of a continuous and automated device for the monitoring of diaphragm contractile activity, as compared to the ultrasonographic assesment of muscle function performed by an expert operator.

Official Title
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Continuous Evaluation of Diaphragm Function During Assisted Mechanical Ventilation in Critically Ill Patients

Conditions
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Respiration, Artificial, Mechanical Ventilation, Critical Illness

Intervention / Treatment
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* Diagnostic Test: Assesment of diaphragm function


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Acute respiratory failure which necessitated endotracheal intubation and mechanical ventilation, with ventilation in pressure-support mode. Positive end-expiratory pressure (PEEP) lower than 10 cmH2O Pressure support level between 4 and 10 cmH2O Ratio between PaO2 and FiO2 >200 mmHg Resolution of the cause of respiratory failure Exclusion Criteria: Diagnosis of Chronic Obstructive Pulmonary Disease (COPD) Pregnancy Circulatory failure

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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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Clinical pressure support<br>The level of inspiratory pressure support will be selected by the attending physician | Diagnostic Test: Assesment of diaphragm function<br>* Diaphragm function will be assessed by standard mechanical parameters as assessed by esophageal and gastric pressure measurement, as well as by an ultrasonographic examination performed by an expert operator and by the continuous ultrasonographic assessment provided by the device under investigation<br>|
| Active Comparator: Reduced pressure support<br>The level of inspiratory pressure support will be reduced by 25% | Diagnostic Test: Assesment of diaphragm function<br>* Diaphragm function will be assessed by standard mechanical parameters as assessed by esophageal and gastric pressure measurement, as well as by an ultrasonographic examination performed by an expert operator and by the continuous ultrasonographic assessment provided by the device under investigation<br>|
| Active Comparator: Lowest pressure support<br>The level of inspiratory pressure support will be reduced by 50% | Diagnostic Test: Assesment of diaphragm function<br>* Diaphragm function will be assessed by standard mechanical parameters as assessed by esophageal and gastric pressure measurement, as well as by an ultrasonographic examination performed by an expert operator and by the continuous ultrasonographic assessment provided by the device under investigation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Diaprhagm excursion | Excursion (in mm) between expiration and inspiration | Study 1 day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Esophageal pressure swing | Difference (in cmH2O) in esophageal pressure between expiration and inspiration | Study 1 day | 
| Pressure-time product | Integral of the area under the esophageal pressure over time (in cmH2O*sec) | Study 1 day | 
| Pressure-time product | Integral of the area under the trasndiaphragmatic pressure over time (in cmH2O*sec) | Study 1 day |