We evaluated an index of diaphragm efficiency (Eff(di)), diaphragm power output (Wdi) relative to electrical activation, in five healthy adults during tidal breathing at usual end-expiratory lung volume (EELV) and diaphragm length (L(di ee)) and at shorter L(di ee) during hyperinflation with expiratory positive airway pressure (EPAP). Measurements were repeated with an inspiratory threshold (7....

Studies on brainstem respiratory neurons suggest that eupnea consists of three phases; inspiration, post-inspiration and expiration. However it is not well understood how post-inspiration is organized in the diaphragm, i.e. whether post-inspiration differs in the crural and costal segments of the diaphragm and what the influence is of post-inspiratory neurons on diaphragm function during eupnea...

Purpose: Scoliosis is one of the most common spinal deformities that affect chest wall mechanics. Scoliosis results in ventilator disorders and respiratory muscle weakness. However, the mechanism of these disorders is still unknown. The main objective of this study was to identify the intensity of respiratory muscles activity in patients with idiopathic scoliosis compare with healthy indi...

A mixed semi-analytical cum numerical approach is presented in this paper which accounts for the coupled mechanical and electrical response of piezoelectric, functionally graded (FG) and layered composite hollow circular cylinders of finite length. Under axisymmetric mechanical and electrical loadings, the three-dimensional problem (3D) gets reduced to a two-dimensional (2D) plane strain proble...

Cervical magnetic stimulation is a new technique for stimulating the phrenic nerves, and may offer an alternative to percutaneous electrical stimulation for assessing diaphragmatic strength in normal subjects and patients in whom electrical stimulation is technically difficult or poorly tolerated. We compared cervical magnetic stimulation with conventional supramaximal bilateral percutaneous el...

The periaqueductal gray matter is an essential neural substrate for central integration of defense behavior and accompanied autonomic responses. The dorsal half of the periaqueductal gray matter (dPAG) is also involved in mediating emotional responses of anxiety and fear, psychological states that often are associated with changes in ventilation. However, information regarding respiratory modul...

We investigated whether an increase in transcutaneous electromyographic (EMG) activity of the diaphragm and intercostal muscles corresponds with the concentration of histamine that induces a 20% fall in the forced expiratory volume in one second (FEV1; PC20). Eleven asthmatic children (mean age 11.9 yr) were studied after they were given histamine challenge. EMG activity at PC20 or at the highe...