Pulmonary Disease, Respiratory Failure
Conditions
Keywords
Respiratory Failure, Pulmonary disease, Intensive care, Respiratory Mechanics
Brief summary
The effects of different degrees of head-of-bed elevation on respiratory mechanics are poorly explored in the literature, and no study has investigated such effects using electrical impedance tomography, esophageal and gastric balloons to identify the ideal angle for optimizing respiratory mechanics. The hypothesis is that there is a optimal degree for the respiratory mechanics.
Detailed description
Respiratory mechanics and regional ventilation will be monitored using electrical impedance tomography (Enlight 2100, Timpel Medical®, Brazil) . Esophageal and gastric pressures will be obtained through esophageal and gastric balloon catheters (Nutrivent®) (validation concerning to modified Baydur maneuver - slope delta esophageal pressure/delta airway pressure (0,8-1,2). We are using the hardware Pneumodrive (Biônica, Recife, Brazil) to record and store the esophageal, gastric and airway pressures, these data will be analyzed using LabVIEW 7.1 (Pneumobench). Initially, patients will be positioned at 0 degrees of head-of-bed elevation, and after stabilization of the plethysmogram, data from electrical impedance tomography, hemodynamics, and arterial blood gas will be collected (arterial blood will be drawn by a nurse or physician). Sequentially and in the same manner, the bed will be adjusted to 10, 20, 30, and 40 degrees (the same data will be collected, except for the arterial blood sample, which will only be collected at the 40-degree elevation). Then, an alveolar recruitment maneuver will be performed, followed by a PEEP titration with 10-degree of head-of-bed elevation.
Interventions
OTHERSequencial increasing of head of the bed elevation and alveolar recruitment maneuver followed by a PEEP titration with 10° of head of the elevation
Patients will be sequentially positioned at 0, 10, 20, 30, and 40 degrees of head-of-bed elevation. An alveolar recruitment maneuver will be performed. For patients with body mass index ≤ 30 kg/m\^2, the maneuver will be conducted in pressure control mode, pressure control = 15 cmH2O, respiratory rate = 20 breaths per minute, and the PEEP will be increased in steps of 5 up to 30 cmH2O. For patients with body mass index \> 30, the PEEP will be increased up to 35. Then, a PEEP titration will be performed, tidal volume = 5 mL/Kg, respiratory rate = 25 breaths per minute, and the PEEP will be decreased from 24 down to 4 cmH2O in steps of 2 cmH2O with 30 seconds in each PEEP level. The PEEP titration software of Enlight 2100 will be used to determine the ideal PEEP, defined as the PEEP level with a collapse less than 5%. The alveolar recruitment maneuver will be performed again to reopen the lungs. Then, data will be collected, as with the 0 and 40-degree steps, with ideal PEEP.
Sponsors
University of Sao Paulo General Hospital
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
All the participants will be exposed to the same situations (head-of-bed elevations), in the same order. An alveolar recruitment maneuver followed by a PEEP titration with 10-degree head-of-bed elevation will be performed.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Patients under invasive mechanical ventilation, intubated due to respiratory failure
Exclusion criteria
* Hemodynamics instability, contraindication for monitoring with esophageal and gastric catheters, and Electrical impedance tomography, no authorization of medical team of the intensive care unit, and contraindication for lung recruitment maneuver
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Respiratory system compliance | At 0, 10, 20, 30, 40-degrees of head-of-bed elevation, and with titrated PEEP at 10-degrees of head-of-bed elevation | Respiratory system compliance (mL/cmH2O) will be measured using electrical impedance tomography monitoring (Enlight 2100, Timpel Medical®, Brazil). |
| Lung compliance | At 0, 10, 20, 30, 40-degrees of head-of-bed elevation, and with titrated PEEP at 10-degrees of head-of-bed elevation | Lung compliance (mL/cmH2O) will be measured offline using the esophageal pressure tracings. By knowing the respiratory system and chest wall compliance, the lung compliance will be calculated. (1/respiratory system compliance = 1/chest wall compliance + 1/lung compliance) |
| Chest wall compliance | At 0, 10, 20, 30, 40-degrees of head-of-bed elevation, and with titrated PEEP at 10-degrees of head-of-bed elevation | Chest wall compliance (mL/cmH2O) will be measured offline using the esophageal pressure tracings. Chest wall compliance = tidal volume / delta esophageal pressure |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Oxygenation | At 0 and 40-degrees of head-of-bed elevation, and with titrated PEEP at 10-degrees of head-of-bed elevation | Oxigenation will be assessed using the partial pressure arterial oxygen/fraction inspired oxygen ratio. Partial pressure arterial oxygen measured in the blood sample at the of each step and the fraction inspired oxygen set during the blood sample collection will be used. |
| Gastric pressure | At 0 and 40-degrees of head-of-bed elevation, and with titrated PEEP at 10-degrees of head-of-bed elevation | Gastric pressure will be measured offline using the gastric pressure tracings. |
| Pressure between patient skin surface and the mattress | At 0, 10, 20, 30, 40-degrees of head-of-bed elevation | ForeSite PT (XSENSOR Technology Corporation, Patient Monitoring System) will be used to measure the pressure between patient's skin surface and the mattress. A monitor connected to this sensor provides continuous pressure monitoring, and the data will exported for subsequent offline analysis of the sacral and occipital regions. |
| Hemodynamics satefy of keeping low degrees of head of the elevation | At 0, 10, 20, 30, 40-degrees of head-of-bed elevation | Arterial blood pressure provided by the multiparameter monitor. Data will be noted in each degree. |
Countries
Brazil
Contacts
Primary ContactMarcelo BP Amato, MD, PhD
Backup ContactAna C Cardoso dos Santos, PT
Outcome results
None listed