Effect of All-Stim 2 Quadriceps Treatments on Limb Muscle Strength In Mechanically Ventilated Patients

Effect of All-Stim 2 Quadriceps Treatments on Limb Muscle Strength In Mechanically Ventilated Patients.

Patients that are on mechanical ventilators in medical intensive care units (MICU) have extremely weak leg muscles. Currently there is no treatment to prevent or reverse this weakness. Treatments with a thigh muscle stimulator, called an All Stim 2, can improve leg muscle strength and help patients regain leg function after knee surgery. The purpose of the present study is to determine if treatments with the All Stim 2 device can also improve leg muscle strength in patients on mechanical ventilation.

The objective for this study is to determine if daily exercise using All-Stim 2 stimulation of quadriceps muscles will increase leg strength and improve outcomes (duration of hospitalization, long term mobility, long term disability) for mechanically ventilated MICU patients. The investigators plan to randomize patients accepted into this protocol to administration of either sham exercise (i.e. placement of All-Stim 2 units on the legs for 30 minutes a day without activation of the electrical stimulation program) or active exercise (placement of All-Stim 2 electrodes on both legs and stimulating quadriceps muscles to rhythmically contract for 30 minutes a day). The two groups (sham and active exercise) will be treated for 30 minutes a day for seven days. The effects of exercise on quadriceps strength will be assessed by measuring quadriceps force generation (QuadTw) in response to magnetic stimulation of the femoral nerves. The QuadTw assessment will be made immediately before institution of sham or active exercise and will repeated one day after the conclusion of the seven day training regimen. Chart review and patient follow-up will be used to determine if this treatment regimen also has an impact on clinical outcome measures, i.e. duration of hospitalization.

Inclusion Criteria:

• Adult patients requiring mechanical ventilation for more than 48 hours
• Respiratory failure present

Exclusion Criteria:

• The physician caring for the patient determines that the patient is too unstable
• Use of high dose pressors (more than 15 mcg/min of norepinephrine or more than 15 mg/kg/min of dopamine)
• Use of more than 80% FiO2 (fractional concentration of oxygen) or more than 15 cm H2O (water) of PEEP (positive end expiratory pressure)
• Presence of a cardiac pacemaker or implanted defibrillator
• Use of neuromuscular blocking agents within the 48 hours preceding testing
• History of a preexisting neuromuscular disease
• Presence of profound and uncorrectable hypokalemia (less than 2.5) or hypophosphatemia (less than 1.0)
• Pregnancy
• If the patient is a prisoner
• If the patient is institutionalized
• If it is thought that the patient will have care withdrawn within 7 days