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

N/ANot Yet RecruitingNCT07689110

University of Santiago de Compostela60 enrolled

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Enrollment

Conditions

Respiratory Muscle Weakness

Interventions

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 CareOTHER

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.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. Age ≥ 18 years 2. Admitted to ICU with invasive mechanical ventilation for more than 48 hours at the time of randomization 3. Expected to remain intubated for at least 24 additional hours, at the discretion of the attending intensivist 4. Active pressure support ventilation (PSV) mode with PS level ≥ 5 cmH2O 5. Richmond Agitation-Sedation Scale (RASS) score between -1 and +1 6. Arterial pH ≥ 7.35 and serum lactate ≤ 2.0 mmol/L 7. Peripheral oxygen saturation (SpO2) ≥ 90% with current FiO2 8. Informed consent obtained from patient or legal representative Exclusion Criteria: 1. Neurological condition affecting central respiratory control (high cervical spinal cord injury, ALS, myasthenia gravis, active Guillain-Barré syndrome) 2. Established tracheostomy at the time of inclusion 3. Restriction on head-of-bed elevation to ≥ 30 degrees 4. Decision to limit therapeutic effort (LET) or life expectancy \< 48 hours 5. Active hemodynamic instability (requirement for ≥ 2 vasopressors or vasopressor adjustment within the last 6 hours) 6. Multiple rib fractures or undrained pneumothorax 7. Simultaneous participation in another interventional clinical trial 8. Previous inclusion in this study

Outcomes

Primary Outcomes

Maximal Inspiratory Pressure (PImax)

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.

Time frame: Day 7 from randomization

Secondary Outcomes

Diaphragm Thickening Fraction (DTF)

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

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

P0.1 (Airway Occlusion Pressure at 100ms

respiratory drive indicator, read directly from ventilator display

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

hours from randomization to extubation without reintubation within 48 hours

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

Weaning Success Rate

proportion of patients extubated without reintubation within 48 hours

Time frame: Days 7 and 14 from randomization

Sustained Pressure Support Reduction

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

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

perceived respiratory exertion (0-10)

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

Adverse events during training sessions

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