Diagnosing Intensive Care Unit (ICU) Acquired Weakness

Study Overview
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Brief Summary
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The goal of this study is to develop a non-invasive test to diagnose intensive care unit (ICU) acquired weakness that can be administered to both responsive and non-responsive patients. Study participation will involve the measurement of muscle fatigue during a single 30 minute session. Skeletal muscle will be stimulated with an FDA approved clinical electrical stimulator and accelerations will be passively recorded with an accelerometer.

Detailed Description
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The primary purpose of this study is to develop a procedure to identify intensive care unit (ICU) acquired weakness. This condition occurs in a subset of people admitted into the ICU, and is associated with a 30% increased risk of death before discharge from the ICU. There are currently major limitations in the ability to diagnose ICU acquired weakness, making it difficult to study. The goal is to develop a non-invasive test that can be administered to both responsive and non-responsive patients. The current proposal will focus on replicating the results of previous research using motion detecting accelerometers to measure fatigue in human skeletal muscles. This study is designed to test out the procedures in patients who have been transferred from the ICU to a lower level of care so that follow-on studies can be designed to help mitigate this condition in the ICU.

Official Title
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Accelerometer Motion to Measure Muscle Fatigue in Critically Ill Patients

Conditions
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ICU Acquired Weakness

Intervention / Treatment
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* Device: Clinical Electrical Stimulator


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients transferred from the ICU to a lower level of care within the past 7 days Mechanical ventilation for greater than 7 days while in the ICU Ability to understand English and provide written consent Exclusion Criteria: Vulnerable populations including: patients who are pregnant or prisoners Patients who are unable to understand English or provide written consent

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: ICU Acquired Weakness Group<br>Participants with a score less than 48 on the Medical Research Council (MRC) Scale will be classified as having ICU acquired weakness. All participants will have their skeletal muscles tested with a clinical electrical stimulator. | Device: Clinical Electrical Stimulator<br>* Conductive electrodes will be on the skin at each end of the tested muscle(s). Each subject will have two target muscle groups tested (extensor carpi radialis longus, and tibialis anterior). Each muscle will be stimulated at three separate stimulation frequencies (2 Hz, 4 Hz, and 6Hz) over 3 minutes each, for a total of 9 minutes of stimulation per muscle. The clinical electrical stimulator will deliver mild electrical stimulations to the muscle (20-100 mA).<br>* Other names: Vectra Genisys Therapy System;|
| Experimental: No ICU Acquired Weakness Group<br>Participants with a score of 48 or greater on the Medical Research Council (MRC) Scale will be classified as not having ICU acquired weakness. All participants will have their skeletal muscles tested with a clinical electrical stimulator. | Device: Clinical Electrical Stimulator<br>* Conductive electrodes will be on the skin at each end of the tested muscle(s). Each subject will have two target muscle groups tested (extensor carpi radialis longus, and tibialis anterior). Each muscle will be stimulated at three separate stimulation frequencies (2 Hz, 4 Hz, and 6Hz) over 3 minutes each, for a total of 9 minutes of stimulation per muscle. The clinical electrical stimulator will deliver mild electrical stimulations to the muscle (20-100 mA).<br>* Other names: Vectra Genisys Therapy System;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Peak Acceleration Measured in Extensor Carpi Radialis Longus | The highest acceleration over a single muscle twitch will be used as the peak acceleration. Peak acceleration will be measured in acceleration in number of times gravity (g). Higher twitch acceleration is a better response. | Day 1 | 
| Peak Acceleration Measured in Tibialis Anterior | The highest acceleration over a single muscle twitch will be used as the peak acceleration. Peak acceleration will be measured in acceleration in number of times gravity (g). Higher twitch acceleration is a better response. | Day 1 | 
| Time to Peak Acceleration Measured in Extensor Carpi Radialis Longus | The time, in seconds, until peak acceleration is reached will be assessed at 2, 4 and 6 Hz. There is not a reference range for the time to peak force and at this time it is unclear if a shorter or longer time to peak force indicates a more desirable state of health. | Day 1 at 2 Hz, Day 1 at 4 Hz, Day 1 at 6 Hz | 
| Time to Peak Acceleration Measured in Tibialis Anterior | The time, in seconds, until peak acceleration is reached will be assessed. There is not a reference range for the time to peak force and at this time it is unclear if a shorter or longer time to peak force indicates a more desirable state of health. | Day 1 | 
| End Acceleration Measured in Extensor Carpi Radialis Longus | End acceleration is the twitch acceleration averaged over 5 twitches over the last second of stable twitches within the stimulation period. A reference range has not yet been established for this measurement. | Day 1 | 
| End Acceleration Measured in Tibialis Anterior | End acceleration is the twitch acceleration averaged over 5 twitches over the last second of stable twitches within the stimulation period. A reference range has not yet been established for this measurement. | Day 1 | 
| Fatigue Ratio Measured in Extensor Carpi Radialis Longus | Fatigue ratio is the ending acceleration divided by peak acceleration during a given stimulation period. A reference range has not yet been established for this measurement. A higher ratio indicates less change from maximum. A lower score would indicate worse outcome. | Day 1 | 
| Fatigue Ratio Measured in Tibialis Anterior | Fatigue ratio is the ending acceleration divided by peak acceleration during a given stimulation period. A reference range has not yet been established for this measurement. | Day 1 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Biofeedback, Muscular disorders, Neuromuscular disorders, Rehabilitation