PT  - JOURNAL ARTICLE
AU  - Giovanni Tagliabue
AU  - Micheal Ji
AU  - Jenny Jagers
AU  - Devin Dean
AU  - Eric Wilde
AU  - Paul Easton
TI  - Limitations of superficial EMG estimate of parasternal intercostal muscle activity
AID  - 10.1183/1393003.congress-2017.PA1866
DP  - 2017 Sep 01
TA  - European Respiratory Journal
PG  - PA1866
VI  - 50
IP  - suppl 61
4099  - http://erj.ersjournals.com/content/50/suppl_61/PA1866.short
4100  - http://erj.ersjournals.com/content/50/suppl_61/PA1866.full
SO  - Eur Respir J2017 Sep 01; 50
AB  - Introduction: Recently, surface EMG estimating parasternal intercostal muscle (PARA) activity has been presented as neural respiratory drive (NRD). Historically the deep anatomy of PARA risked undesired EMG “crosstalk” signals from neighboring chest wall muscles. To date, no study compared PARA EMG activity recorded from direct fine wire implants, to surface EMG estimates.Aims: To assess whether surface EMG reliably represents intramuscular PARA EMG activity recorded by implanted fine wires.Methods: We implanted fine wires into PARA 2nd right intercostal space, with a matching pair of surface electrodes. Ventilation, PARA activity from implanted wires, and surface estimated activity were recorded while seated: 1) during rest and hypercapnia, 2) during apnoea with extraneous upper chest wall movement.Results: During resting breathing, we found significant variability in surface EMG estimate versus implanted wire EMG. During hypercapnia, surface estimate diverged significantly away from implanted PARA EMG (slope 3.27 vs 1.30; P<0.05;N=7). During quiet breathing with any chest wall movement, surface estimate EMG appeared unreliable. With voluntary apnoea and chest wall movement, surface EMG estimate showed “pseudobreathing” activity while PARA fine wire was silent[fig.1 ].Conclusion: As an estimate of parasternal intercostal muscle activity, surface EMG has significant challenges that may constrain use in clinical applications.