Can Mechanomyography and Heart Rate Be Used to Guide Neuromuscular Electrical Stimulation Delivery in the Non-Responsive Patient? A Cross-Sectional Study in Healthy Adults.

Purpose: Neuromuscular electrical stimulation (NMES) may be used to prevent ICU-acquired weakness. Heart rate variability (HRV), mechanomyography (MMG), and pain objectively assess patient experience and muscle response during NMES, which may facilitate its delivery in non-responsive patients. This study investigated the associations between the secondary outcomes of MMG and HRV with the primary outcomes, quality of contraction (QoC), and pain during NMES. Method: Using a cross-sectional design, an NMES protocol supervised remotely was delivered to the tibialis anterior muscle in 12 healthy participants. Data on MMG assessed using accelerometry, HRV using photoplethysmography, QoC using a modified version of the MRC scale, and self-reported pain using a numeric pain rating scale (NPRS) were collected. A Spearman rank-order correlation was used to determine associations between MMG and NPRS/QoC and between HRV and NPRS/QoC.

Results

Positive correlations were found between MMG and NPRS scores, and between MMG and QoC. No significant correlations were observed between HRV and NPRS scores, and between HRV and QoC.

Conclusion

MMG, but not HRV, is useful for assessing muscle QoC and pain during NMES. Findings from this study may help guide selection of variables to use in delivery of NMES in non-responsive patients. Further studies with larger sample sizes of non-responsive patients should be explored.