Direct Muscle Stimulation in Critical Illness Myopathy
Research type
Research Study
Full title
Direct Muscle Stimulation in Critical Illness Myopathy
IRAS ID
190585
Contact name
Ramamurthy Arunachalam
Contact email
Sponsor organisation
Southampton University Hospitals NHS Foundation Trust
Duration of Study in the UK
0 years, 7 months, 6 days
Research summary
Critical Illness Myopathy (CIM) is a common cause of muscle weakness in the intensive care unit (ICU). It usually presents with difficulty weaning a patient off a ventilator. There is often difficulty in differentiating this from other causes of neuromuscular weakness in the ICU setting. Neurophysiology has proven to be very valuable in diagnosing CIM. Although structural changes have been shown using histopathology, much of the weakness in this condition is probably due to changes in muscle excitability. Several studies have shown reduction in muscle fibre excitability in these patients. Nerve conduction studies show a reduction in the amplitude of the motor responses from affected muscles. Direct muscle stimulation is a well established technique in clinical neurophysiology, which is now routinely used in such cases. Several studies, including one conducted previously by the supervisor have shown changes in muscle fibre conduction velocities and changes in excitability (Published in Muscle and Nerve, 37:14-22, 2008). We plan to investigate this further using a technique known as ‘jitter measurements’. Jitter refers to the variability in the firing of muscle fibres following an electrical stimulus. This method was originally developed for studying neuromuscular transmission disorders where there is increased jitter. What we aim to do in this study is to stimulate the muscle fibres directly and measure jitter values. In published literature muscle fibre jitter with direct stimulation is minimal as there is no neuromuscular transmission involved. We hypothesise that jitter will be increased in patients with CIM due to alteration in excitability providing further evidence that the weakness is from functional alteration rather than structural changes in the muscle fibres.
REC name
North East - York Research Ethics Committee
REC reference
15/NE/0344
Date of REC Opinion
23 Oct 2015
REC opinion
Further Information Favourable Opinion