The Effect of Positive End-Expiratory Pressure on Functional Residual Capacity During Mechanical Ventilation
- Conditions
- Mechanical VentilationAcute Respiratory Distress SyndromeFunctional Residual Capacity
- Interventions
- Procedure: PEEP
- Registration Number
- NCT03511651
- Lead Sponsor
- Capital Medical University
- Brief Summary
Although positive end-expiratory pressure (PEEP) has been widely used in mechanical ventilated patients with acute respiratory distress syndrome (ARDS), how to select the "optimal" PEEP is far from consensus. The application of PEEP may result in beneficial effect by recruiting previously collapsed lung areas, harmful effect by over-distending previously aerated lung areas, or a combination of the both. The net effect of PEEP in a certain patient may depend on the recruitability. Because recruitability varies extremely in ARDS patients and strongly correlates with the response to PEEP, estimation of end-expiratory lung volume (EELV) may be essential for individualized setting of PEEP. Whether the FRC changes at different PEEP levels remains unknown.
- Detailed Description
Although positive end-expiratory pressure (PEEP) has been widely used in mechanical ventilated patients with acute respiratory distress syndrome (ARDS), how to select the "optimal" PEEP is far from consensus. The application of PEEP may result in beneficial effect by recruiting previously collapsed lung areas, harmful effect by over-distending previously aerated lung areas, or a combination of the both. The net effect of PEEP in a certain patient may depend on the recruitability. Because recruitability varies extremely in ARDS patients and strongly correlates with the response to PEEP, estimation of end-expiratory lung volume (EELV) may be essential for individualized setting of PEEP.
Passive spirometry has long been used to measure the lung recruitment volume (VREC). A prolonged expiration to zero end-expiratory pressure (ZEEP) or airway release maneuver is required and PEEP induced lung volume change above functional residual capacity (FRC) is measured. This technique assumes that FRC does not change at different PEEP levels.
This assumption that PEEP has no effect on FRC can date back to the study of Valta et al in the early 1990s. Using respiratory inductive plethysmography (RIP), they found that in ALI/ARDS patients, after expiring from different PEEP levels to ZEEP, the plethysmography signal returned to the same baseline value. They concluded that FRC does not change with PEEP, and that changes of EELV are attributable only to change in ∆EELV. Ranieri et al arrived at similar conclusions by measuring differences in lung volumes at different PEEP levels using standardized pressure-volume (P-V) curves derived from the ventilator circuit monitors. However, Patroniti et al found an elevation of FRC as increasing of PEEP in patients with ARDS. In this study, FRC was measured with the helium dilution technique, and concluded that neglecting this effect resulted in marked underestimation of VREC. Whether the FRC changes at different PEEP levels remains controversial. The aim of the study is to assess the effect of PEEP on FRC during mechanical ventilation.
Recruitment & Eligibility
- Status
- UNKNOWN
- Sex
- All
- Target Recruitment
- 30
Not provided
Not provided
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Arm && Interventions
Group Intervention Description FRC at clinical PEEP + 5cmH2O PEEP Increasing PEEP to clinical PEEP + 5cmH2O FRC at clinical PEEP level PEEP Measuring FRC at clinical PEEP level
- Primary Outcome Measures
Name Time Method The change of FRC 1) One hour after using clinical PEEP 2) One hour after using clinical PEEP + 5cmH2O EELV measurement by ICU ventilator; PEEP Volume measured through airway release. FRC will be calculated as EELV minus PEEP volume. Correlation between EELV, PEEP volume, FRC at two different PEEP levels are tested by linear regression analysis.
- Secondary Outcome Measures
Name Time Method The change of driving Pressure 1) One hour after using clinical PEEP 2) One hour after using clinical PEEP + 5cmH2O The change of driving pressure will be measured.
The change of PaO2/FiO2 Ratio 1) One hour after using clinical PEEP 2) One hour after using clinical PEEP + 5cmH2O Obtaining PaO2 according to blood gas analysis, and FiO2 according to the ventilator
The change of regional EELV 1) One hour after using clinical PEEP 2) One hour after using clinical PEEP + 5cmH2O Regional EELV will be measured at clinical PEEP and clinical PEEP +5cmH2O
The change of blood pressure 1) One hour after using clinical PEEP 2) One hour after using clinical PEEP + 5cmH2O The change of blood pressure will be measured
The change of homogeneity of distribution of tidal volume 1) One hour after using clinical PEEP 2) One hour after using clinical PEEP + 5cmH2O EIT is used to monitoring the homogeneity of distribution of tidal volume that was divided into two contiguous regions of interest (ROI) equally, the dependent and non-dependent area. The ratio of relative distribution of tidal ventilation of two ROI was calculated.
The change of regional FRC 1) One hour after using clinical PEEP 2) One hour after using clinical PEEP + 5cmH2O Regional FRC will be measured at clinical PEEP and clinical PEEP +5cmH2O
Trial Locations
- Locations (1)
Jian-Xin Zhou
🇨🇳Beijing, Beijing, China