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

University of Michigan16 enrolled

Overview

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).

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Acute Respiratory Distress Syndrome ARDS

Interventions

Usual careOTHER

Intervention is the standard basic lung protective ventilation strategy used at the University Hospital Respiratory Care at Michigan Medicine.

PEEP titration by EITDEVICE

PEEP Titration procedure involves two phases: a recruitment phase followed by a gradual reduction in the end-expiratory pressure phase (Decremental PEEP).

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

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

Locations (1)

The University of Michigan

Ann Arbor, Michigan, United States

Outcomes

Primary Outcomes

Mechanical Power

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-\[Pplat-PEEP/2\])

Time frame: 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.

Secondary Outcomes

Change in Lung Inflammation as Measured by Physiologic Parameter: Partial Pressure of Arterial Oxygen/Fraction of Inspired Oxygen (P/F Ratio)

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

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

Data from ClinicalTrials.gov

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Lung Inflammation as Measured by Physiologic Parameter: Driving Pressure

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

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

Partial Pressure of Arterial Oxygen (PaO2)

PaO2 is the partial pressure of arterial oxygen measured in mmHg. PaO2 determined for the difference between Intervention 1 and Intervention 2.

Dynamic Compliance (Cdyn)

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.

Change in Compliance Over the Last 20% of Inspiration (C20/Dyn)

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.

Ultrasound Surrogates of Lung Aeration

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.