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NCT Number: NCT07689110

Progressive Pressure Support Reduction as Inspiratory Muscle Endurance Training in Mechanically Ventilated Patients

Mechanical ventilation causes rapid diaphragm muscle atrophy, detectable within 18 hours of ventilator support, which is a major contributor to weaning failure and prolonged ICU stay.

This randomized controlled trial tests whether a physiotherapist-guided inspiratory endurance training program - achieved by progressively reducing pressure support (PS) levels on the ventilator - can preserve or improve inspiratory muscle strength and diaphragm structure in critically ill adults on mechanical ventilation, compared to standard ICU care.

Participants will be randomly assigned to one of two groups. The intervention group will receive twice-daily training sessions (weekdays only) in which the physiotherapist gradually reduces PS by up to 50% of the baseline level, causing the patient to breathe with greater muscular effort - equivalent to progressive endurance exercise for the diaphragm. The control group will receive standard weaning care as directed by the attending intensivist.

The primary outcome is maximal inspiratory pressure (PImax) at day 7. Secondary outcomes include diaphragm thickening fraction measured by ultrasound, time to successful extubation, weaning success rate, and mortality.

All measurements are performed by the ICU physician (blinded to group allocation) using airway occlusion maneuvers recorded on the ventilator and diaphragm ultrasound, following a standardized protocol.

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Key information

Conditions

Respiratory Muscle Weakness Endurance Training Mechanical Ventilation Weaning Physiotherapy

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age ≥ 18 years
  • Admitted to ICU with invasive mechanical ventilation for more than 48 hours at the time of randomization
  • Expected to remain intubated for at least 24 additional hours, at the discretion of the attending intensivist
  • Active pressure support ventilation (PSV) mode with PS level ≥ 5 cmH2O
  • Richmond Agitation-Sedation Scale (RASS) score between -1 and +1
  • Arterial pH ≥ 7.35 and serum lactate ≤ 2.0 mmol/L
  • Peripheral oxygen saturation (SpO2) ≥ 90% with current FiO2
  • Informed consent obtained from patient or legal representative

Exclusion criteria

  • Neurological condition affecting central respiratory control (high cervical spinal cord injury, ALS, myasthenia gravis, active Guillain-Barré syndrome)
  • Established tracheostomy at the time of inclusion
  • Restriction on head-of-bed elevation to ≥ 30 degrees
  • Decision to limit therapeutic effort (LET) or life expectancy < 48 hours
  • Active hemodynamic instability (requirement for ≥ 2 vasopressors or vasopressor adjustment within the last 6 hours)
  • Multiple rib fractures or undrained pneumothorax
  • Simultaneous participation in another interventional clinical trial
  • Previous inclusion in this study

Treatment and study plan

Progressive Pressure Support Reduction (IRT-PS)

Behavioral

Progressive reduction of pressure support (PS) during ventilator-assisted breathing, performed by a physiotherapist twice daily (weekdays only). Sessions consist of 1-3 sets of 5-15 minutes with 2-minute rest intervals at baseline PS. PS is reduced by 25% initially up to a maximum of 50% of baseline (minimum 5 cmH2O) for PS ≥10 cmH2O; by 1-2 cmH2O for PS 5-9 cmH2O; and by 1 cmH2O down to 0 cmH2O for PS <5 cmH2O. Target perceived exertion: Borg CR10 3-5. P0.1 monitored continuously; session stopped if P0.1 >4 cmH2O sustained >2 minutes (Goligher et al. criteria). Safety stop criteria: RR >35 rpm, SpO2 <90%, HR >120 bpm.

Standard ICU Care

Other

Conventional weaning managed by the attending intensivist according to standard clinical practice, without a structured inspiratory muscle training protocol. Conventional physiotherapy (early mobilization, chest physiotherapy) permitted in both groups.

Primary outcomes

  1. Maximal Inspiratory Pressure (PImax)

    Time frame: Day 7 from randomization

    Measured by manual airway occlusion at end-expiration with pressure curve recorded on the ventilator. Standardized verbal instruction given to the patient. Best of 3 valid maneuvers recorded. Performed by the ICU physician blinded to group allocation.

Secondary outcomes

  1. Diaphragm Thickening Fraction (DTF)

    Time frame: Days 0, 3, 7 and 14 from randomization

    measured by ultrasound (linear probe 7-15 MHz, zone of apposition, M-mode, average of 3 cycles). Performed by ICU physician per standardized protocol.

  2. P0.1 (Airway Occlusion Pressure at 100ms

    Time frame: Baseline and days 3, 7 and 14; and at start, mid and end of each training session (intervention group)

    respiratory drive indicator, read directly from ventilator display

  3. Time to Successful Extubation

    Time frame: From randomization until extubation, up to 14 days

    hours from randomization to extubation without reintubation within 48 hours

  4. Weaning Success Rate

    Time frame: Days 7 and 14 from randomization

    proportion of patients extubated without reintubation within 48 hours

  5. Sustained Pressure Support Reduction

    Time frame: days 1, 3, 5 and 7 from randomization

    difference in cmH2O between baseline PS at Day 0 and Day 7

  6. Total Days on Mechanical Ventilation

    Time frame: From randomization until ICU discharge, up to 30 days

  7. ICU Mortality

    Time frame: At the time of ICU discharge (up to 24 weeks)

  8. 30-day Mortality

    Time frame: Day 30 from randomization

  9. ICU Readmission at 30 days

    Time frame: Day 30 from randomization

  10. Borg CR10 Score during training session

    Time frame: Periprocedural (from the start of the session until 30 minutes post-intervention)

    perceived respiratory exertion (0-10)

  11. Adverse events during training sessions

    Time frame: Periprocedural (from the start of the session until 30 minutes post-intervention)

    episodes of RR >35, SpO2 <90%, HR >120 bpm

Study contacts

Contact information is provided by the study sponsor or research team.

Ricardo Miguel Rodrigues-Gomes

CONTACT

[email protected]

+34618060702

Sponsors and collaborators

Lead sponsor

University of Santiago de Compostela

Other

Registry information

Official study title

Progressive Pressure Support Reduction as Inspiratory Muscle Endurance Training in Mechanically Ventilated Critically Ill Patients: Effect on Maximal Inspiratory Pressure, Diaphragm Thickening Fraction, Weaning Success and Extubation (INSPIRA-RCT)

Acronym: inspira-rct

Important dates

Study start
2026
Primary completion
2027
Study completion
2028
First posted
Jul 8, 2026
Registry last updated
Jul 8, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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