Blood Flow Restriction Training for Mechanically Ventilated Patients With ICU-Acquired Weakness

NCT07802743 | Not Yet Recruiting

• 3 other identifiers: 2025-11-C024MP-MS-2022-0102024YXNS081
• Study Type: interventional
• Target: 120
• Locations: 0 countries
• Sites: N/A

Brief Summary

Patients receiving mechanical ventilation in the intensive care unit (ICU) frequently develop ICU-acquired weakness - a condition marked by widespread muscle loss and weakness caused by prolonged bed rest, severe illness, and systemic inflammation. This complication can lengthen time on the ventilator, extend ICU stays, and lead to lasting physical disability. Standard rehabilitation therapies in the ICU have limited ability to slow muscle loss because critically ill patients cannot tolerate high levels of exercise. Blood flow restriction training (BFRT) is a rehabilitation technique that uses an inflatable cuff on the upper leg to partially restrict blood flow during low-intensity exercise. This approach is known to stimulate muscle growth and preserve strength with much lower physical effort than traditional strength training, making it a promising option for vulnerable ICU patients. This randomized controlled trial is designed to test the safety and effectiveness of BFRT in mechanically ventilated adults with ICU-acquired weakness. A total of 120 eligible patients will be randomly divided into three groups: A control group receiving standard ICU medical care and routine rehabilitation A group receiving standard care plus BFRT at 40% of individual limb occlusion pressure A group receiving standard care plus BFRT at 60% of individual limb occlusion pressure All patients will receive 2 weeks of intervention. The research team will measure and compare muscle strength, lower limb muscle size (via ultrasound), blood inflammatory markers, duration of mechanical ventilation, length of ICU stay, and ventilator weaning success rates across the three groups. This study aims to determine whether adding BFRT to standard rehabilitation can improve muscle function, reduce systemic inflammation, and shorten hospital recovery time for these patients, and which pressure level provides the optimal balance of benefits and safety.

Conditions

Intensive Care Unit Acquired Weakness

Keywords

Blood flow restriction training

Outcome Measures

Primary Outcomes (2)

• medical research council sum score

  The Medical Research Council sum score (MRC-SS) is a validated clinical scale for evaluating global limb muscle strength in critically ill patients. It assesses 6 bilateral muscle actions: shoulder abduction, elbow flexion, wrist extension, hip flexion, knee extension, and ankle dorsiflexion. Each item is scored from 0 (no visible muscle contraction) to 5 (full strength against maximum resistance), yielding a total score ranging from 0 to 60. A lower score indicates more severe generalized muscle weakness. All assessments are performed by trained evaluators blinded to patient group assignment.

  Measured at baseline (prior to randomization) and within 24 hours after completion of the 2-week intervention period.

• Lower Limb Muscle Morphology Assessed by Ultrasound

  Standardized musculoskeletal ultrasound is used to quantitatively evaluate lower limb muscle morphology. Four parameters are measured at fixed anatomical landmarks: cross-sectional area (CSA) and muscle thickness (MT) of the rectus femoris (15 cm above the superior patellar border), and CSA and MT of the medial gastrocnemius (10 cm above the medial malleolus). All scans are performed by sonographers blinded to group allocation, with the mean value of three independent measurements used for statistical analysis. Changes in these parameters reflect the degree of muscle atrophy or preservation over the intervention period.

  Measured at baseline (prior to randomization) and within 24 hours following completion of the 2-week intervention.

Secondary Outcomes (4)

• Serum Inflammatory Cytokine Levels

  Measured at baseline (prior to randomization) and within 24 hours following completion of the 2-week intervention.

• Duration of Invasive Mechanical Ventilation

  Recorded continuously from study enrollment through ICU discharge, with weaning success status verified at 48 hours after extubation.

• ICU Length of Stay

  From date of study enrollment until the date of ICU discharge, assessed up to 28 days after enrollment

• Ventilator Weaning Success Rate

  Assessed from study enrollment through ICU discharge, with weaning success status definitively confirmed at 48 hours after extubation.

Study Arms (3)

Conventional Rehabilitation Training

ACTIVE COMPARATOR

Participants in this arm will receive standard ICU medical care and routine rehabilitation therapy only, without additional blood flow restriction training. Standard medical care includes anti-infective treatment, mechanical ventilation support, enteral nutrition support, electrolyte and acid-base balance maintenance, and evidence-based bundle care. Routine rehabilitation is delivered by trained therapists 6 days per week for 2 weeks (40 minutes per session), covering passive range-of-motion exercises, progressive bed sitting training, diaphragmatic breathing training, and assisted active muscle strength training for all extremities. Training intensity is titrated to patient tolerance with continuous bedside hemodynamic and respiratory monitoring.

Other: Standard ICU Care and Routine Rehabilitation

40% Limb Occlusion Pressure Training Group

EXPERIMENTAL

Participants in this arm will receive standard ICU medical care and routine rehabilitation identical to the control group, with additional daily blood flow restriction training (BFRT) set at 40% of each patient's individual limb occlusion pressure (LOP). LOP is measured at baseline using an automated inflatable cuff system applied to the proximal thigh, with the patient in supine resting position. BFRT sessions are administered once daily, at least 6 hours apart from routine rehabilitation, for 2 consecutive weeks (≈20 minutes per session). Each session includes 3 lower-limb exercises: straight leg raise, isometric quadriceps contraction, and glute bridge, performed for 3 sets of 10 repetitions per exercise, with 30-second rest between sets and 3-minute rest between the two legs. Training intensity is controlled at Borg RPE 9-11, with continuous bedside monitoring of vital signs to ensure patient safety.

Other: Blood flow restriction training; Other: Standard ICU Care and Routine Rehabilitation

60% Limb Occlusion Pressure Training Group

EXPERIMENTAL

Participants in this arm will receive standard ICU medical care and routine rehabilitation identical to the control group, with additional daily blood flow restriction training (BFRT) set at 60% of each patient's individual limb occlusion pressure (LOP). LOP is measured at baseline using an automated inflatable cuff system applied to the proximal thigh, with the patient in supine resting position. BFRT sessions are administered once daily, at least 6 hours apart from routine rehabilitation, for 2 consecutive weeks (≈20 minutes per session). Each session includes 3 lower-limb exercises: straight leg raise, isometric quadriceps contraction, and glute bridge, performed for 3 sets of 10 repetitions per exercise, with 30-second rest between sets and 3-minute rest between the two legs. Training intensity is controlled at Borg RPE 9-11, with continuous bedside monitoring of vital signs to ensure patient safety.

Other: Blood flow restriction training; Other: Standard ICU Care and Routine Rehabilitation

Interventions

Blood flow restriction training OTHER

Blood flow restriction training (BFRT) is administered using a wireless automated pneumatic cuff system (BFR Cuffs 2.0) placed on the proximal thigh. Training pressure is individually calibrated as a percentage of each patient's resting limb occlusion pressure (LOP), measured via the device's built-in pressure sensor and algorithm to accommodate differences in limb circumference and vascular tone. The intervention partially restricts venous return while preserving arterial inflow, combining low-intensity lower-extremity resistance movements with localized hypoxic and metabolic stress to stimulate muscle anabolic pathways. It is delivered at very low perceived exertion (Borg RPE 9-11) with continuous bedside vital sign monitoring, specifically adapted for hemodynamically stable critically ill patients with ICU-acquired weakness.

40% Limb Occlusion Pressure Training Group; 60% Limb Occlusion Pressure Training Group

Standard ICU Care and Routine Rehabilitation OTHER

This arm serves as the control reference, delivering the standard-of-care clinical pathway for critically ill mechanically ventilated patients. It includes comprehensive ICU medical management (anti-infective treatment, ventilatory support, enteral nutrition, hemodynamic maintenance, electrolyte balance correction, and evidence-based nursing bundles) plus standardized early rehabilitation administered by certified therapists per institutional ICU rehabilitation protocols. No investigational blood flow restriction intervention is applied in this group; all care follows routine clinical practice without additional study-specific exercise modifications.

40% Limb Occlusion Pressure Training Group; 60% Limb Occlusion Pressure Training Group; Conventional Rehabilitation Training

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age ≥ 18 years;
• Received invasive mechanical ventilation for ≥ 48 hours;
• Meets the clinical diagnosis criteria for ICUAW: The patient has reached a level of consciousness that allows for reliable assessment of voluntary muscle strength, is able to execute standardized motor commands, has an MRC-SS \< 48 points, and has no other clearly identifiable cause that explains the muscle weakness;
• RASS score of -1 to 0, and is able to cooperate with the prescribed muscle strength assessment and rehabilitation training;
• Current vital signs and respiratory and circulatory status are stable, meeting the safety conditions for rehabilitation training, as assessed by clinical physicians and rehabilitation therapists;
• The patient or their legal representative has signed the informed consent form, voluntarily participating in the study.

You may not qualify if:

• The presence of pre-existing central or peripheral nervous system diseases, neuromuscular diseases, or severe motor function disorders that significantly affect limb strength or motor function prior to ICU admission;
• The presence of active deep vein thrombosis, pulmonary embolism, significant peripheral arterial disease, limb ischemia, or other severe lower limb vascular diseases;
• Severe coagulation function abnormalities, active bleeding, or a clinically judged unacceptable risk of thrombosis/hemorrhage;
• The presence of fractures, open wounds, local infections, significant skin damage, or other conditions in the target lower limb that are unsuitable for cuff compression and exercise training;
• Recent acute coronary syndrome, decompensated heart failure, uncontrolled severe arrhythmias, or other active cardiovascular diseases that are unsuitable for BFRT;
• Instability in respiratory or circulatory status at the time of screening, or the need for new or significantly increased use of vasoactive drugs, failing to meet the safety criteria for rehabilitation training; such individuals may be rescreened after their condition stabilizes;
• Anticipation of imminent death, or a decision to limit or withdraw life support treatment;
• Allergy to the cuff material, or the circumference of the target limb is not compatible with the cuff being used;
• Inability to reliably complete specified assessments such as MRC-SS after adequate arousal.

Sponsors & Collaborators

• Affiliated Hospital of Jining Medical University: lead

MeSH Terms

Interventions

Blood Flow Restriction Therapy

Intervention Hierarchy (Ancestors)

Exercise Therapy; Rehabilitation; Aftercare; Continuity of Patient Care; Patient Care; Therapeutics; Physical Therapy Modalities

Study Officials

• Xiang Li

  Affiliated Hospital of Jining Medical University

  STUDY DIRECTOR

Central Study Contacts

Rangrang Wang

CONTACT

+86 155-8877-6876; chinawrr1124@163.com

Fang Xu

CONTACT

+86 130-1261-5163

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 26, 2026
• First Posted: September 3, 2026
• Study Start: September 15, 2026
• Primary Completion (Estimated): May 1, 2027
• Study Completion (Estimated): September 1, 2027
• Last Updated: September 4, 2026

Record last verified: 2026-09