Mechanical Ventilation
Conditions
Keywords
mechanical ventilation, pressure support, inspiratory effort, work of breathing, lung injury
Brief summary
Pressure support ventilation (PSV) is the most commonly used mode in mechanical ventilated patients. Studies have shown that over-assistance was prevalent in patients undergoing PSV. Up to now, no reliable method has been recommended to select an optimal inspiratory support level. Pressure muscle index (PMI) was introduced recently to evaluate the degree of spontaneous breathing effort. We hypothesize that PMI might be used as an indicator for over-assistance during PSV. In this randomized crossover study, inspiratory support is set at three levels according to negative, positive and zero PMI. Inspiratory effort, work of breathing, and respiratory mechanics are compared among the three inspiratory pressure support levels.
Interventions
PROCEDUREInspiratory support level
Inspiratory support is the pressure delivered by the ventilator during pressure support ventilation.
Sponsors
Capital Medical University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
SUPPORTIVE_CARE
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* Mechanical ventilated patients within 48 hours after the transition from a controlled mode to PSV
Exclusion criteria
* History of neuromuscular disease * History of diaphragm dysfunction and surgery * History of esophageal, gastric or lung surgery * Decreased level of consciousness * Central respiratory drive dysfunction * Considered withholding of life support
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Inspiratory effort | 30 minutes | Inspiratory effort is measured as pressure generated by inspiratory muscles using esophageal pressure monitoring. |
| Work of breathing | 30 minutes | Work of breathing is measured by the Campbell diagram and pressure-time-product using esophageal pressure monitoring. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Partial pressure of carbon dioxide in arterial blood (mmHg) | 30 minutes | Partial pressure of carbon dioxide in arterial blood is obtained by blood gas analysis. |
| Respiratory rate (breaths/min) | 30 minutes | Respiratory rate calculation includes ineffective trigger. |
| Respiratory system compliance (ml/cmH2O) | 30 minutes | Respiratory system compliance is calculated as the ratio between tidal volume and driving pressure. |
| Rapid shallow breathing index | 30 minutes | Rapid shallow breathing index is calculated as the ratio between respiratory rate and tidal volume. |
| The use of accessory respiratory muscle | 30 minutes | The use of accessory respiratory muscle is observed at the bedside. |
| Tidal volume (ml) | 30 minutes | Tidal volume is obtained by intergation of flow-time tracing. |
| Partial pressure of oxygen in arterial blood (mmHg) | Partial pressure of oxygen in arterial blood | Partial pressure of oxygen in arterial blood is obtained by blood gas analysis. |
Countries
China
Contacts
Primary ContactJian-Xin Zhou, MD
Outcome results
None listed