Hypoxic Respiratory Failure, Ventilators, Mechanical
Conditions
Keywords
Transpulmonary pressure, Airway pressure release ventilation, Volumen controlled mechanical ventilation, Esophageal pressure, Esophageal manometry
Brief summary
The study examines individuals admitted to the intensive care unit due to breathing difficulties resulting in not getting enough oxygen into their bodies. These patient will receive mechanical ventilation and this study aims to determine how the pressure inside the lungs changes when using two different modes of mechanical ventilation. The goal is to improve management and care of breathing difficulties by gaining insight into changes in lung pressure during mechanical ventilation, as well as comparing the effectiveness of the two ventilator modes.
Detailed description
As hypoxic respiratory failure is an acute condition, this trial will enrol temporarily incompetent patients and obtain consent from the patient's next of kin and an independent medical doctor (trial guardian) as soon as possible after enrolment. When included in the study, patients will be randomized 1:1 centrally in the RedCap system, using a computer-generated concealed assignment sequence, with permuted blocks of varying sizes, to start with either the intervention (APRV) followed by control (volume controlled mechanical ventilation) or control followed by intervention. Esophageal manometry will be used as a surrogate to measure the transpulmonary pressure. Arterial blood gasses, blood samples and lung ultrasound will be used to investigate oxygenation, ventilation and aeration. Treatment targets for both groups during the study are pH \>7.20, saturation ≥ 88% and PaO2 ≥ 8.0 kPa, with FiO2 titrated as low as possible while complying to the oxygenation targets (PaO2 and saturation). Both arms start with an 'adjustment phase' where the ventilator is adjusted so the respiratory values are within the targets. The intervention adjustment phase is at least 30 minutes. The adjustments will follow standardized protocols. When the respiratory values are within range, the 'observation period begins' and no changes are made to the ventilator for 3 hours, unless it is necessary to achieve ventilatory treatment targets or deemed necessary by the treating physician. During the trial, the patient must be positioned in a supine position with the headboard elevated 0-30 degrees. After the first 'observation period', the patient is switched to the opposite ventilation mode and will go through an 'adjustment phase' and 'observation period' again. Once a patient regains competence, they will be provided with both written and oral information regarding the trial By comparing volume controlled mechanical ventilation and APRV and their transpulmonary pressures, valuable insight can be gained regarding optimal ventilation strategy for patients with hypoxic respiratory failure. Understanding how various ventilation modes influence transpulmonary pressure and their potential effects on respiratory mechanics can potentially inform designs of trials with individualized respiratory care.
Interventions
Mechanical ventilation mode
OTHERVolumen controlled mechanical ventilation
Mechanical ventilation mode
Sponsors
University Hospital Bispebjerg and Frederiksberg
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Admitted to the ICU * Invasive mechanical ventilation with FiO2 ≥ 50% OR PaO2-to-FiO2 ratio \<20 kPa, including PEEP 3 5 cmH20 for at least 6 hours
Exclusion criteria
* Meeting inclusion criteria for more than 24 hours * Severe bronchospasm, defined as warranting treatment aimed at reversing this i.e. inhalation of anticholinergic or bronchodilator beyond what the patient normally use * Emphysema where treating physician judges the patient at increased risk for pneumothorax from APRV * Restrictive lung disease defined as a pre-admission diagnosis of restrictive lung disease * Undrained pneumothorax * Hemodynamic instability defined as more than 0.20 microgram/kg/min of norepinephrine or any dose of adrenaline infusion to maintain MAP ≥ 65 mmHg * Age \< 18 years * Patients who have received APRV previously during the current ICU admission * Patients in prone position within the last 24 hours
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Median peak transpulmonary pressure | During the observation period; 1-6 hours after randomization | Measured with esophageal manometry in cmH20. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Proportion of patients with peak transpulmonary pressure > 12 cmH2O | During observation period; 1-6 hours after randomization | Measured with esophageal manometry |
| Change in peak transpulmonary pressure in cmH20 | During observation period; 1-6 hours after randomization | Measured with esophageal manometry. Calculated as beginning - end of observation period |
| Fluctuations in transpulmonary pressure in cmH20 | During observation period; 1-6 hours after randomization | Measured with esophageal manometry. Difference between peak and nadir transpulmonary pressure during respiratory cycle |
| Change in fluctuations of transpulmonary pressure in cmH20 | During observation period; 1-6 hours after randomization | Measured with esophageal manometry. Calculated as beginning - end of observation period. |
| Peak FiO2 in % | During observation period; 1-6 hours after randomization | FiO2 from ventilator settings |
| Peak PaCO2 in kPa | During observation period; 1-6 hours after randomization | PaCO2 from arterial blood gasses |
| Nadir pH | During observation period; 1-6 hours after randomization | pH from arterial blood gasses |
| Lung ultrasound aeration according to LUS | During observation period; 1-6 hours after randomization | Evaluating lung aeration by Lung Ultrasound Score |
| Nadir PaO2-to-FiO2 ratio | During observation period; 1-6 hours after randomization | Calculated by PaO2/FiO2. PaO2 from arterial blood gasses and FiO2 from ventilator setting |
Other
| Measure | Time frame | Description |
|---|---|---|
| Proportion of patients unable to tolerate observation period without increasing ventilator settings | During observation period; 1-6 hours after randomization | Defined as measures aimed at increasing either oxygenation or ventilation |
Countries
Denmark
Outcome results
None listed