Neuro-muscular electrical stimulation for the treatment of orthostatic hypotension in an older community dwelling population

Orthostatic hypotension (OH) is highly prevalent in older people and is associated with increased morbidity and mortality. Current treatment options include pharmacological and non-pharmacological approaches, although robust evidence regarding therapeutic efficacy is lacking. The overarching aim of this thesis is to investigate the potential benefit of neuromuscular electrical stimulation (NMES) in attenuating blood pressure (BP) reductions in community dwelling older subjects with OH. The first study incorporated two surveys to evaluate patient and physician practices and perceptions of using elastic compression stockings (ECS), which are currently frequently used for this indication. This study found that only one third of patients wear ECS daily, with practical difficulties limiting their use specifically in an older age group. The physician survey concluded that although ECS are prescribed frequently, there is significant discrepancy between physician prediction of patient compliance, and actual patient compliance which may reflect the current lack of convincing evidence regarding their efficacy. The second study incorporated a randomised crossover design investigating the use of both simultaneous and alternate leg calf muscle NMES during head-up tilt table testing. In this feasibility study, a trend toward benefit was demonstrated with alternate leg NMES setting. The third study evaluated the effect of both alternate and simultaneous NMES in a young, healthy population during head-up tilting and demonstrated a more favourable haemodynamic response and tolerability profile with alternate NMES. The final study compared the effect of alternate leg calf muscle NMES and ECS during both passive and active orthostatic challenges. Both NMES and ECS significantly attenuated BP reductions during orthostasis in comparison to control, with NMES resulting in significantly higher venous blood flow responses and demonstrated to be tolerable. There was no significant difference in systolic or diastolic BP between NMES and ECS interventions. In conclusion, NMES has been demonstrated to be as effective as ECS in attenuating BP reductions in an older subject group with OH during active and passive orthostatic challenges and is tolerable. Future study should evaluate the longer term efficacy and practicality of NMES for this indication.