Abstract
BackgroundThe physiological and prognostical significance of accessory and expiratory muscles activation is unknown during a spontaneous breathing trial (SBT). We hypothesized that, in patients experiencing weaning failure, accessory and expiratory muscles are activated to cope with an increased respiratory workload.PurposeTo describe accessory and expiratory muscle activation non-invasively by surface electromyography (sEMG) during an SBT and to assess differences in electrical activity (EA) of the inspiratory and expiratory muscles in successful vs. failing weaning patients.MethodsIntubated patients on mechanical ventilation for more than 48 h undergoing an SBT were enrolled in a medical and surgical third-level ICU of the University Teaching Hospital. Baseline characteristics and physiological variables were recorded in a crossover physiologic prospective clinical study.ResultsOf 37 critically ill mechanically ventilated patients, 29 (78%) patients successfully passed the SBT. Rapid shallow breathing index (RSBI) was higher in patients who failed SBT compared with the successfully weaned patients at baseline and over time (group-by-time interaction p < 0.001). EA of both the diaphragm (EAdisurf) and of accessory muscles (ACCsurf) was higher in failure patients compared with success (group-by-time interaction p = 0.0174 and p < 0.001, respectively). EA of expiratory muscles (ESPsurf) during SBT increased more in failure than in weaned patients (group-by-time interaction p < 0.0001).ConclusionNon-invasive respiratory muscle monitoring by sEMG was feasible during SBT. Respiratory muscles EA increased during SBT, regardless of SBT outcome, and patients who failed the SBT had a higher increase of all the inspiratory muscles EA compared with the patients who passed the SBT. Recruitment of expiratory muscles—as quantified by sEMG—is associated with SBT failure.
Highlights
Difficult weaning from the mechanical ventilation leads to the prolonged intensive care unit (ICU) stay and increased mortality [1]
Surface electromyography has been applied in previously physiological studies to explore the relationship between accessory muscles Electrical Activity (EA) and respiratory load [6, 7, 11, 12] subjective dyspnea [8], and patient-ventilator asynchrony [13]. This technique bears some technical constrains [14], we recently demonstrated that surface electromyography (sEMG) can be reliably used to measure surface electrical activity of the diaphragm (EAdi) that well correlates with inspiratory effort measured by esophageal pressure [15]
Among 37 patients included into the final analysis, 29 (78%) patients passed the spontaneous breathing trial (SBT) and were successfully weaned
Summary
Difficult weaning from the mechanical ventilation leads to the prolonged intensive care unit (ICU) stay and increased mortality [1]. Respiratory muscles dysfunction is a common determinant of difficult weaning, and the reduction of the force-generating capacity of the diaphragm can be observed already after a few days of mechanical ventilation [2]. Expiratory muscles recruitment has been demonstrated recently by Doorduin et al [5], who observed that expiratory muscles recruitment progressively increases during a spontaneous breathing trial (SBT) in weaning failure patients, while remaining stable in successfully extubated patients. In patients experiencing weaning failure, accessory and expiratory muscles are activated to cope with an increased respiratory workload. Purpose: To describe accessory and expiratory muscle activation non-invasively by surface electromyography (sEMG) during an SBT and to assess differences in electrical activity (EA) of the inspiratory and expiratory muscles in successful vs failing weaning patients
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call