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

Official 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)

Overview

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.

Interventions

• Behavioral Progressive Pressure Support Reduction (IRT-PS)
  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 stop
• Other Standard ICU Care
  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 outcome measures

• Maximal Inspiratory Pressure (PImax) [Time frame: Day 7 from randomization]

Secondary outcome measures (11)

• Diaphragm Thickening Fraction (DTF) [Time frame: Days 0, 3, 7 and 14 from randomization]
• 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)]
• Time to Successful Extubation [Time frame: From randomization until extubation, up to 14 days]
• Weaning Success Rate [Time frame: Days 7 and 14 from randomization]
• Sustained Pressure Support Reduction [Time frame: days 1, 3, 5 and 7 from randomization]
• Total Days on Mechanical Ventilation [Time frame: From randomization until ICU discharge, up to 30 days]
• ICU Mortality [Time frame: At the time of ICU discharge (up to 24 weeks)]
• 30-day Mortality [Time frame: Day 30 from randomization]
• ICU Readmission at 30 days [Time frame: Day 30 from randomization]
• Borg CR10 Score during training session [Time frame: Periprocedural (from the start of the session until 30 minutes post-intervention)]
• Adverse events during training sessions [Time frame: Periprocedural (from the start of the session until 30 minutes post-intervention)]

Eligibility criteria

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

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Treatment

Study locations

Spain · 1 center

• Hospital Álvaro Cunqueiro — Vigo

Identifiers

NCT: NCT07689110 · INSPIRA-RCT-2026-HACunqueiro

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗