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Updated: Apr 23, 2026

Acquisition and Semi-Automated Analysis of Respiratory Muscle Surface Electromyography
Published on: January 24, 2025
Relation between peak and integral of the diaphragm electromyographic activity at different levels of support during
Stefano Muttini1, Pier Giorgio Villani2, Roberta Trimarco1
1UOS Rianimazione, Department of Emergency Medicine and Intensive Care, "Ospedale Civile" Vimercate, Vimercate, MB, Italy.
Purpose:
To investigate the relationship between peak (EAdipeak) and area under the curve (EAdiAUC) of diaphragm electrical activity, and to evaluate the validity of their ratio (P/I index) as a measure of the imbalance between drive and sustainability of effort demand at different support levels.
Materials:
Prospective physiological study on 18 ready-to-wean patients ventilated with neurally adjusted ventilatory assist (NAVA) undergoing 2 levels of NAVA (NAVA100% and NAVA50%) followed by a weaning trial with continuous positive airway pressure, according to which patients were classified as success or failure. Tidal volume (VT), respiratory rate, EAdipeak, EAdiAUC, rapid shallow breathing index (respiratory rate/VT), neuroventilatory index (VT/EAdipeak), and P/I index were obtained at the end of each step.
Results:
The slopes of regression line between EAdipeak and EAdiAUC (a mathematical equivalent of P/I index) and P/I index were significantly higher in failures. At variance with other variables, P/I index did not vary with level of support. P/I index was inversely correlated with inspiratory time at all support levels.
Conclusions:
The relationship between EAdipeak and EAdiAUC and the P/I index may give important information on the balance between respiratory drive and inspiratory demand sustainability.
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