RESUMO
The hypothesis of this study is that muscular activity measured through surface electromyography (sEMG) is useful to estimate the work of breathing (WOB) and respiratory mechanics. Thirty-two healthy volunteers were non-invasively ventilated, and an airflow resistor was attached to the airway circuit. sEMG signals from diaphragm, intercostal and sternocleidomastoid muscles were processed and compared with WOB changes. The airway resistance was increased from a median of 9.58 to 22.51 cmH2O/L/s adding a resistance of 20 cmH2O/L/s, achieving the lower compliance too. The respiratory mechanics changes implied linear increases in WOB, with Pearson correlation of 88.43% respect to changes in resistance. Muscles increased their activity in agreement with changes of WOB, being higher the increment in diaphragm followed by sternocleidomastoid. The non-invasively monitored respiratory muscles activity allowed evaluating the changes in WOB when it depends on addition of obstructive loads, confirming that it could be used to improve the available respiratory mechanics and WOB monitoring tools.