Three Methods for Best PEEP Determination Compared With PEEP Determination Guided by Adult Respiratory Distress Syndrome (ARDS) Network
ARDS
About this trial
This is an interventional treatment trial for ARDS focused on measuring ARDS, Lung compliance
Eligibility Criteria
Inclusion Criteria:
20 Man and women older than 18 years will be recruited. Patients with acute respiratory failure of any cause who are mechanically ventilated according to the ARDS network recommendations will be considered for inclusion to the study.
To be included in the study a prerequisite of high peak Inspiratory pressure (plateau pressure of 25 to 30 cmH2O) has to be present, and at least one of the following four severity inclusion criteria has to be met.
1 - Low Total Respiratory system compliance (CT), defined as less than 50ml/cmH2O. 2 - PaO2 /FIO2 ratio of less than 300. 3 - Need for a PEEP greater than 10 cmH2O to maintain arterial oxygen saturation (SaO2) of > 90%.
4 - carbon dioxide partial pressure (PCO2) over 60 mmHg, or PH less than 7.2 that is attributed to respiratory acidosis.
Exclusion Criteria:
Patients with any of the following will be excluded from the study. Previous lung or chest wall surgery, previous esophageal surgery, known Achalasia or any other esophageal motility or spasm disorder, presence of chest thoracostomy tube, and any significant chest wall abnormality such as kyphoscoliosis.
Sites / Locations
- E. Wolfson MC
Arms of the Study
Arm 1
Arm 2
Arm 3
Experimental
Experimental
Experimental
PEEP by Best oxygenation
PEEP by Best Compliance
PEEP by Esophageal pressure
Set Positive End Expiratory Pressure (PEEP) at 25 cmH2O with fixed driving pressure that will result in delivery of a fixed Tidal Volume (TV) of 6ml/kg Ideal Body Weight (IBW). fraction of inspired oxygen (FiO2) is set to 60%. Then decrease PEEP in steps of 4 cmH2O every 10 min until PEEP of 5 cm H2O is reached. In each step static compliance of respiratory system and lung compliance will be measured along with arterial blood gas (ABGs), and hemodynamic parameters such as cardiac output and mixed venous O2 saturation. Best or optimal PEEP will be defined as the PEEP below which PaO2 /FIO2 falls by at least 20%. If at least 20% Partial Oxygen tension (PaO2) PaO2 /FIO2 decrement is not obtained, then PEEP that will result in the highest PaO2 will be selected.
In this group assessment begins with measuring intrinsic PEEP by an expiratory hold. Thereafter, plateau pressures will be recorded after a 0.5-sec inspiratory pause. Applied PEEP will be increased by steps of 4 cm H2O, after each incremental step the patient will be observed for 10 minutes to allow for lung unit recruitment and equilibration. Plateau pressure will be measured after each incremental step of PEEP. Applied PEEP will be increased sequentially by 4 cm H2O increments until peak inspiratory pressure of 50 cm H2O, or plateau pressure of 40 cm H2O reached, or hypotension or decrease of 20% in cardiac output is observed.
Upon patient recruitment Esophageal balloon will be inserted and esophageal / pleural pressure will be measured. Thereafter, Inspiratory pressures and PEEP will be adjusted according to well established criteria. Inspiratory pressure and PEEP will be adjusted to achieve the best lung compliance possible while not exceeding transpulmonary end Inspiratory pressure of 25 to 30 cm H2O, and at the same time maintaining a positive transpulmonary end expiratory pressure of not more than 5 cm H2O.