Treatment of Muscle Weakness in Critically Ill Patients

Effect of Treatment With the Niveus Medical Muscle Stimulation System 110 on Quadriceps Strength In Mechanically Ventilated Patients

Patients who are admitted to the intensive care unit and require mechanical ventilation frequently develop profound respiratory and limb muscle weakness. Studies show that the development of weakness during the ICU stay results in poor outcomes. Currently there are no treatments for this muscle weakness, but it has been suggested that this weakness might improve with physical therapy. Electrical stimulation is a method to provide direct stimulation to the muscles potentially enhancing function and improving strength. The purpose of this study is to test the hypothesis that neuromuscular electrical stimulation of the quadriceps muscle will improve muscle strength in patients who are critically ill on mechanical ventilation.

The basic study design is to: Obtain informed consent from patient or the patients LAR Randomize subjects to treatment with either: Sham therapy, consisting of bilateral placement of Niveus Medical Muscle Stimulation System 110 electrodes for 30 minutes twice daily without activation of the electrical circuitry of the unit, or Active therapy, using the Niveus Medical Muscle Stimulation System 110 electrodes to actively produce a rhythmic quadriceps contraction for 30 minutes twice daily Measure magnetic stimulated quadriceps twitch (QuadTw) strength bilaterally as well as ultrasound assessment of quadriceps size Continue sham or active treatment daily for 7 days for a total of 14 sessions Repeat measurements of magnetic stimulated QuadTw strength and ultrasound assessment of quadriceps size on Day 8 or before Day 8 if the subject is to be discharged from the hospital prior to the allotted duration of sham or active treatment Functional measurement of the patient using the Functional Status Score for the ICU (FSS-ICU) at the end of the treatment period or upon discharge A member of the research team will visit the subject until hospital discharge and will record total duration (days) of mechanical ventilation, duration (days) of mechanical ventilation following study entry, duration of ICU stay, ventilator weaning time (days measured from time of first spontaneous breathing trial to extubation), and total duration (days) of hospitalization The investigators will also review each subject's medical record on entry into the study to obtain demographic information including the following: age, sex, diagnoses, medications, reason for institution of mechanical ventilation, vital signs at the time of the initial visit, bedside parameters of mechanical ventilation use (including mode of ventilation, duration of ventilation, level of oxygen, breath volume and rate, % triggered breaths), most recent arterial blood gas values, and chest radiograph readings at the time of the initial visit. The investigators will also record the subject's weight, BMI and total intake and output values since admission to the ICU. In addition, investigators will monitor each subject's progress in the ICU daily by reviewing the subject's medical record and recording the clinical parameters as well as recording daily weights and total intake and output. These parameters will also be assessed until the time that the patient is discharged from the ICU. In addition, the investigators will record and note all physical therapy and occupational therapy sessions that the subject receives as part of the standard of care in the ICU and in the hospital up until the time of discharge. In the University of Kentucky hospital, occupational therapy records the Barthel Index at each session which uses a scale of 0-100 to assess an individual's functional independence when performing activities of daily living (ADLs). Physical therapy assesses functional status using Kansas University Hospital Physical Therapy Acute Care Functional Outcomes, which also assesses functional status in the categories of bed mobility, transfer, gait and walking distance.

The active treatment group will receive neuromuscular electrical stimulation to both quadriceps muscle for 30 minutes twice daily for a total of 14 treatments.

Subjects will undergo the same protocol as the treatment group except no electrical stimulation will be applied.

Two thirty minute sessions of neuromuscular electrical stimulation applied to both quadriceps for seven days for a total of 14 treatments

Quadriceps twitch force generation will be measured using magnetic stimulation of each femoral nerve and compared to measurements obtained at the time of study entry (baseline-prior to randomization)

Rectus femorus thickness will be measured using ultrasound at baseline (study entry) and on Day 8 of study after either sham treatment or neuromuscular stimulation

Inclusion Criteria: Acute respiratory failure requiring mechanical ventilation Exclusion Criteria: Attending physician on service determines that patient too unstable to tolerate measurements Patient requires > 15mcg/min norepinephrine or > 15mg/kg/min of dopamine. Fraction of inspired oxygen > 80% or positive end expiratory pressure > 15 cm H20 requirements. Cardiac pacemaker or implanted defibrillator. Neuromuscular blocking agents delivered within 48 hours of preceding testing. Existing neuromuscular disease. Profound uncorrectable hypokalemia (< 2.5) OR hypophosphatemia (< 1.0) Acute lower extremity deep vein thrombosis Pregnancy Prisoner Institutionalized patient If primary attending determines that patient is terminal and will likely have care withdrawn within 7 days Do not resuscitate order Body mass index > 40 Patients requiring mechanical ventilation more than 4 days prior to study entry