Electrical Impedance Tomography for Optimization of Positive End-Expiratory Pressure: Acute Respiratory Distress Syndrome

Not Applicable

Completed

Conditions: Acute Respiratory Distress Syndrome
ARDS

Interventions: Other: Usual care
Device: PEEP titration by EIT

Registration Number: NCT03793842

Lead Sponsor: University of Michigan

Brief Summary: Doctors follow a standard ventilator management strategy when making adjustments to the breathing machine to optimize the amount of oxygen into the lungs. The purpose of this study is to assess whether the EIT (electrical impedance tomography) device can be an additional useful tool for ventilator management and identifying the ideal positive end-expiratory pressure (PEEP).

Detailed Description: Not available

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 16

Inclusion Criteria

Endotracheal ventilation for < 1 week (168 hours)
Presence of all of the following conditions for < 48 hours i. Partial pressure of oxygen to percentage of inspired oxygen (PaO2/FiO2) < 150 with PEEP > 5 cm water for > 30 min.

ii. bilateral opacities not fully explained by effusions, lobar/lung collapse, or nodules iii. respiratory failure not fully explained by cardiac failure or fluid overload

-All criteria listed in (3) developed within 1 week of a known clinical insult or new or worsening respiratory symptoms

Exclusion Criteria

Lack of informed consent
Known pregnancy
Extracorporeal membrane oxygenation (ECMO) use
Severe chronic respiratory disease requiring home oxygen therapy or ventilation
Calculated BMI of greater than 50

Study & Design

Study Type: INTERVENTIONAL

Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
PEEP titration by EIT then usual care	PEEP titration by EIT	Patients in the high PEEP titration by EIT first will have receive ventilation with a PEEP determined by EIT titration procedure.
Usual care then PEEP titration by Electrical Impedance Tomography (EIT)	Usual care	Patients in the usual care first group will continue to receive mechanical ventilation according to the University of Michigan Acute Respiratory Distress Syndrome (ARDS) protocol high-PEEP arm
Usual care then PEEP titration by Electrical Impedance Tomography (EIT)	PEEP titration by EIT	Patients in the usual care first group will continue to receive mechanical ventilation according to the University of Michigan Acute Respiratory Distress Syndrome (ARDS) protocol high-PEEP arm
PEEP titration by EIT then usual care	Usual care	Patients in the high PEEP titration by EIT first will have receive ventilation with a PEEP determined by EIT titration procedure.

Primary Outcome Measures

Name	Time	Method
Mechanical Power	Participants received Treatment 1 (either Usual Care or PEEP EIT) for approximately 6 hours after randomization and then received Treatment 2 for an additional 14-18 hours following crossover. Measurement was done at end of treatment.	Mechanical power (MP) is the energy imparted to the lung from the mechanical ventilator. It is calculated as listed below, where respiratory rate = RR, tidal volume = TV, Ppeak = peak airway pressure, Pplat = plateau airway pressure and PEEP = positive end-expiratory pressure. Mechanical power determined for the difference between Treatment 1 and Treatment 2. Values shown represent data gathered at the end of the designated assignment listed below, regardless of whether that assignment was Treatment 1 or Treatment 2. MP = 0.098 X RR X TV (Ppeak-\[Pplat-PEEP/2\])

Secondary Outcome Measures

Name	Time	Method
Change in Lung Inflammation as Measured by Physiologic Parameter: Partial Pressure of Arterial Oxygen/Fraction of Inspired Oxygen (P/F Ratio)	Participants received Treatment 1 (either Usual Care or PEEP EIT) for approximately 6 hours after randomization and then received Treatment 2 for an additional 14-18 hours following crossover. Measurement was done at baseline and end of treatment.	P/F ratio is a measurement of oxygenation and, where arterial oxygen in mmHg is PaO2 and percentage of inspired oxygen is FiO2. It calculated as: PaO2/FiO2. P/F ratio determined for the difference between Intervention 1 and Intervention 2
Change in Lung Inflammation as Measured by Physiologic Parameter: Plateau Pressure	Participants received Treatment 1 (either Usual Care or PEEP EIT) for approximately 6 hours after randomization and then received Treatment 2 for an additional 14-18 hours following crossover. Measurement was done at baseline and end of treatment.	Plateau pressure is a measurement of lung compliance and is the airway pressure obtained during a brief inspiratory hold after delivering a tidal volume breath during invasive mechanical ventilation. Plateau pressure determined for the difference between Intervention 1 and Intervention 2
Lung Inflammation as Measured by Physiologic Parameter: Driving Pressure	Participants received Treatment 1 (either Usual Care or PEEP EIT) for approximately 6 hours after randomization and then received Treatment 2 for an additional 14-18 hours following crossover. Measurement was done at end of treatment.	Driving pressure is the force of airway push into the lung while receiving invasive mechanical ventilation and is calculated as Plateau pressure - Positive end-expiratory pressure. Driving pressure determined for the difference between Intervention 1 and Intervention 2
Change in Lung Inflammation as Measured by Physiologic Parameter: Static Compliance	Participants received Treatment 1 (either Usual Care or PEEP EIT) for approximately 6 hours after randomization and then received Treatment 2 for an additional 14-18 hours following crossover. Measurement was done at baseline and end of treatment.	Static lung compliance is a measurement of lung stiffness due to disease, with a lower compliance representing stiffer lungs. It is calculated as: Tidal volume / (Plateau pressure - PEEP). Static compliance determined for the difference between Intervention 1 and Intervention 2
Dynamic Compliance (Cdyn)	Participants received Treatment 1 (either Usual Care or PEEP EIT) for approximately 6 hours after randomization and then received Treatment 2 for an additional 14-18 hours following crossover. Measurement was done at end of treatment.	Dynamic compliance is a measurement of the resistance of the lungs and airways to gas installation from the mechanical ventilator and is measured as Peak airway pressure / Plateau airway pressure - PEEP). Dynamic compliance determined for the difference between Intervention 1 and Intervention 2.
Ultrasound Surrogates of Lung Aeration	Participants received Treatment 1 (either Usual Care or PEEP EIT) for approximately 6 hours after randomization and then received Treatment 2 for an additional 14-18 hours following crossover. Measurement was done at end of treatment.	Lung ultrasound inflation scores are calculated by summing regional scores (0-3 points), with higher scores indicating worse condition of the lung. Scores were obtained in six regions of each lung (i.e., up and down anterior, medial, and posterior chest wall). This is a unit-less measure. Ultrasound lung surrogates of lung inflation determined for the difference between Intervention 1 and Intervention 2.
Change in Compliance Over the Last 20% of Inspiration (C20/Dyn)	Participants received Treatment 1 (either Usual Care or PEEP EIT) for approximately 6 hours after randomization and then received Treatment 2 for an additional 14-18 hours following crossover. Measurement was done at baseline and end of treatment.	C20 is the compliance that results when only the upper 20% of the applied pressure range is taken into account. The C20/Dyn ratio appears to effectively quantitate evidence of lung over distention during mechanical ventilation. This is a unit-less measure as both numerator and denominator are measured in cm water. C20/dyn determined for the difference between Intervention 1 and Intervention 2.
Partial Pressure of Arterial Oxygen (PaO2)	Participants received Treatment 1 (either Usual Care or PEEP EIT) for approximately 6 hours after randomization and then received Treatment 2 for an additional 14-18 hours following crossover. Measurement was done at end of treatment.	PaO2 is the partial pressure of arterial oxygen measured in mmHg. PaO2 determined for the difference between Intervention 1 and Intervention 2.