Stress Index to Individualize Mechanical Ventilation in ARDS

Right-Sizing Tidal Volume in ARDS: Using the Stress Index to Optimize Mechanical Ventilation to Individual Respiratory Mechanics

Acute respiratory distress syndrome (ARDS) is a widely prevalent and morbid disease for which the current standard treatment is supportive care and avoidance of complications with lung-protective ventilation. Lower-tidal volume ventilation has been largely accepted as a means of lung protective ventilation, but the mechanism for its effectiveness is not yet clear, and debate remains as to how best to choose positive end-expiratory pressure (PEEP). Reduction in driving pressure (plateau pressure minus PEEP) has been suggested as a possible means to minimize ventilator-induced lung injury. This protocol aims to identify the range of safe paired-settings of PEEP and tidal volume, with selection guided by driving pressure and the stress index, a tool to recognize potential lung hyperinflation during mechanical ventilation.

Study Overview

• Status: Terminated
• Conditions: Acute Respiratory Distress Syndrome
• Intervention / Treatment: Procedure: Recruitment Maneuver with PEEP and Tidal Volume Optimization

• Study Type: Interventional
• Enrollment (Actual): 4
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Tennessee
    • Nashville, Tennessee, United States, 37232
      • Vanderbilt University Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Admitted to the Intensive Care Unit
• Receiving invasive mechanical ventilation via endotracheal or tracheostomy tube
• Presence of ARDS by Berlin Criteria (acute onset bilateral pulmonary infiltrates incompletely explained by left heart failure together with a PaO2/FiO2 of <300 or SpO2/FiO2 <315)

Exclusion Criteria:

• Inability to obtain surrogate consent

• Presence of specified comorbidities:

  1. pregnancy
  2. pre-existing severe chronic obstructive pulmonary disease, defined as FEV1 documented < 1L or baseline hypercapnia
  3. cerebral edema
  4. known intra-cranial abnormality
  5. acute coronary syndrome
• Endotracheal or tracheostomy cuff leak
• Chest tube with persistent air leak
• Severe hemodynamic instability (defined as attending judgment that the patient is unable to safely tolerate ventilator manipulations)
• Presence of spontaneous respiratory activity as evidenced by examination of the ventilator waveform tracing
• Intrinsic PEEP of > 5 cmH2O
• Assessment of study staff or patient's attending physician that the patient would not be a good study participant

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Intervention Arm

Procedure: Recruitment Maneuver with PEEP and Tidal Volume Optimization; A staircase recruitment maneuver will be performed on pressure control ventilation followed by a decremental PEEP trial. During the decremental PEEP trial inspiratory tidal volumes will be varied at each step between 3 ml/kg and 10 ml/kg predicted body weight while recording the continuous pressure and flow tracings from the mechanical ventilator. With each PEEP and tidal volume combination, end expiratory and end-inspiratory plateau pressure and stress index will be assessed. At the completion of the decremental PEEP trial, the patient will be returned to ARDSnet-recommended ventilator settings.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Comparison of ARDSnet-optimized and protocol-optimized tidal volume	Mean absolute difference between tidal volume in cc/kg PBW prescribed by ARDSnet settings on ARDSnet PEEP versus maximal protective tidal volume defined by stress index <1.05 at the ARDSnet PEEP on experimental protocol.	Completion of the study intervention, less than 1 day
Comparison of ARDSnet-optimized and protocol-optimized driving pressure	Mean difference in driving pressure prescribed by ARDSnet settings versus at lowest measured possible driving pressure that achieves equivalent minute ventilation as ARDSnet table with respiratory rate < or = 35 per minute and SI <1.05.	Completion of the study intervention, less than 1 day

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Comparison of ARDSnet-optimized and protocol-optimized PEEP	Mean absolute difference between safest PEEP as determined by experimental protocol with tidal volume of 6 mL/kg PBW (defined as the PEEP at which 6 mL/kg PBW yields the lowest driving pressure with a SI <1.05) versus the PEEP established by ARDSnet table.	Completion of the study intervention, less than 1 day
Comparison of ARDSnet-optimized and protocol-optimized elastance	Mean difference in elastance prescribed by ARDSnet settings versus at lowest measured possible elastance achieving equivalent minute ventilation as ARDSnet table with respiratory rate < or = 35 per minute.	Completion of the study intervention, less than 1 day

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
ICU-free days to 14 days after enrollment	Comparison of ICU-free days to 14 days after enrollment between groups of those patients who are ventilated with settings that coincide with those determined to be most protective by the experimental protocol (within 0.5 cc/kg PBW tidal volume and 1 cmH2O of PEEP) versus those not.	14 days post-enrollment
Ventilator-free days to 14 days after enrollment	Comparison of ventilator-free days to 14 days after enrollment between groups of those patients who are ventilated with settings that coincide with those determined to be most protective by the experimental protocol (within 0.5 cc/kg PBW tidal volume and 1 cmH2O of PEEP) versus those not.	14 days post-enrollment
ICU mortality at 28 days	Comparison of 28-day ICU mortality post-enrollment between groups of those patients who are ventilated with settings that coincide with those determined to be most protective by the experimental protocol (within 0.5 cc/kg PBW tidal volume and 1 cmH2O of PEEP) versus those not.	28 days post-enrollment
In-hospital mortality at 28 days	Comparison of 28-day in-hospital mortality post-enrollment between groups of those patients who are ventilated with settings that coincide with those determined to be most protective by the experimental protocol (within 0.5 cc/kg PBW tidal volume and 1 cmH2O of PEEP) versus those not.	28 days post-enrollment
Time-varying elastance	Assessment of the stability of a model-imputed estimate of time-varying elastance for a given insufflation volume independent of total tidal volume per breath.	Completion of the study intervention, less than 1 day
Comparison of ARDSnet-optimized and time-varying elastance-optimized tidal volume	Mean absolute difference between tidal volume in cc/kg PBW prescribed by ARDSnet settings on ARDSnet PEEP versus maximal protective tidal volume defined by the point of rise of model-imputed time-varying elastance at ARDSnet PEEP on experimental protocol.	Completion of the study intervention, less than 1 day
Comparison of ARDSnet-optimized and time-varying elastance-optimized driving pressure	Mean difference in driving pressure prescribed by ARDSnet settings versus at lowest measured possible driving pressure that achieves equivalent minute ventilation as ARDSnet table with respiratory rate < or = 35 per minute and time-varying elastance not rising.	Completion of the study intervention, less than 1 day
Comparison of ARDSnet-optimized and time-varying elastance-optimized PEEP	Mean absolute difference between safest PEEP as determined by experimental protocol with tidal volume of 6 mL/kg PBW (defined as the PEEP at which 6 mL/kg PBW yields the lowest driving pressure without a rising time-varying elastance) versus the PEEP established by ARDSnet table.	Completion of the study intervention, less than 1 day

Collaborators and Investigators

• Sponsor: Vanderbilt University

Publications and helpful links

General Publications

• McKown AC, Semler MW, Rice TW. Best PEEP trials are dependent on tidal volume. Crit Care. 2018 May 2;22(1):115. doi: 10.1186/s13054-018-2047-4.

Study record dates

Study Major Dates

• Study Start: August 1, 2016
• Primary Completion (Actual): December 1, 2017
• Study Completion (Actual): December 1, 2017

Study Registration Dates

• First Submitted: August 10, 2016
• First Submitted That Met QC Criteria: August 12, 2016
• First Posted (Estimate): August 18, 2016

Study Record Updates

• Last Update Posted (Actual): June 7, 2018
• Last Update Submitted That Met QC Criteria: June 5, 2018
• Last Verified: June 1, 2018

More Information

Terms related to this study

• Keywords: mechanical ventilation; respiratory mechanics; acute respiratory distress syndrome; positive end-expiratory pressure; tidal volume
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Respiration Disorders; Lung Diseases; Infant, Newborn, Diseases; Lung Injury; Infant, Premature, Diseases; Respiratory Distress Syndrome; Respiratory Distress Syndrome, Newborn; Acute Lung Injury
• Other Study ID Numbers: 160770