A Modified Mathematical Model to Calculate Power Received by Mechanically Ventilated Patients With Different Etiologies

Study Overview
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Brief Summary
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Ventilator-induced lung injury is a common complication. The latest and most noticeable theory of its pathogenesis is called 'ergotrauma' by Gattinoni in 2016. The theory uses ventilator-imposed 'energy' or 'power' to encompass several known forms of injury-inducing factors such as pressure,volume, flow, rate, etc. However, to quantify power imposed by ventilator is no easy task in clinical practice. So, Gattinoni proposed a mathematical formula for easy power calculation. However, Gattinoni did not compare the difference between various etiologies of acute lung injury. We will enroll 100 patients (50 with acute respiratory distress syndrome and 50 with normal lung). The ventilator-imposed power at various tidal volume (6, 8, 10 ml/Kg) and positive end-expiratory pressure (5, 10 cmH2O) will be calculated by the formula. The area enclosed by hysteresis of pressure-volume curve, and hence the work it implies, will be measured as a standard. Our study will aim to compare the formula in different patient groups and in Taiwanese people.

Official Title
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A Modified Mathematical Model to Calculate Power Received by Mechanically Ventilated Patients With Different Etiologies

Conditions
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Acute Respiratory Distress Syndrome, Mechanical Ventilation, Respiratory Mechanics, Ventilator-induced Lung Injury

Intervention / Treatment
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* Diagnostic Test: work of breath measurement and calculation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Intubated patients aged 20 to 90 years old Exclusion Criteria: Fraction of inspired oxygen (FiO2) higher than 60% Acute physiology and chronic health evaluation (APACHE) II score more than 30 Plateau pressure or peak airway pressure more than 30 cmH2O High risk for barotrauma Unstable hemodynamic status Under airway pressure release ventilation or high frequency oscillation ventilation therapy Under extra-corporeal membrane oxygenation support On prone position

Ages Eligible for Study
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Minimum Age: 20 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| normal lungs<br> | Diagnostic Test: work of breath measurement and calculation<br>* The ventilator-imposed power at various tidal volume (6, 8, 10 ml/Kg) and positive end-expiratory pressure (5, 10 cmH 2 O) will be calculated by the formula.<br>|
| Acute respiratory distress syndrome (ARDS) group<br> | Diagnostic Test: work of breath measurement and calculation<br>* The ventilator-imposed power at various tidal volume (6, 8, 10 ml/Kg) and positive end-expiratory pressure (5, 10 cmH 2 O) will be calculated by the formula.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| correlation of calculated and measured work of breath | The ventilator-imposed power at various tidal volume (6, 8, 10 ml/Kg) and positive end-expiratory pressure (5, 10 cmH 2 O) will be calculated by the formula. | The measurement and calculation will be performed only once when the ventilator was in use. The estimated time frame of measurement is less than one hour. |