Recent studies proposed that mechanical inactivity of the human diaphragm during mechanical ventilation rapidly causes diaphragm atrophy and weakness. However, conclusive evidence for the notion that diaphragm weakness is a direct consequence of mechanical inactivity is lacking. To study the effect of hemidiaphragm paralysis on diaphragm muscle fiber function and structure in humans, biopsies w...

Patients with heart failure (HF) have diaphragm abnormalities that contribute to disease morbidity and mortality. Studies in animals suggest that reactive oxygen species (ROS) cause diaphragm abnormalities in HF. However, the effects of HF on ROS sources, antioxidant enzymes, and protein oxidation in the diaphragm of humans is unknown. NAD(P)H oxidase, especially the Nox2 isoform, is an importa...

[Purpose] This study investigated the effects of progressive load and fixed load high-intensity inspiratory muscle training on the asymmetry of diaphragm thickness in stroke patients. [Subjects] Twenty-one stroke patients were assigned to one of three groups: progressive load high-intensity inspiratory muscle training (n = 8), fixed load high-intensity inspiratory muscle training (n = 6), and c...

During isolated phrenic nerve stimulation, the muscles of the diaphragm shorten by 40-50% of their optimal length, and the force in the muscle and transdiaphragmatic pressure (Pdi) depend on the final muscle length. The muscle shortening depends on the load imposed on the diaphragm by pleural and abdominal pressures during a particular maneuver. The mechanics of the interaction between the diap...

OBJECTIVE To investigate the relationship between excursion of the diaphragm muscle and spinal curvatures in mouth breathing children. METHODS A total of 52 children of both sexes, aged from 5 to 12 years, were studied. After otorhinolaryngological assessment, the children were divided into two groups: mouth breathers and nose breathers. All of the children underwent videofluoroscopic examina...

Loading of skeletal muscles is associated with increased generation of oxidants, which in turn may impair muscle contractility. We investigated whether the load on the hamster diaphragm imposed by pulmonary emphysema induces oxidative stress, as indicated by glutathione oxidation, and whether the degree of glutathione oxidation is correlated with contractility of the diaphragm. In addition, the...

The weight of the diaphragm has been investigated in 103 male patients and 81 female patients, and the relationship between body weight and emphysema has been assessed in 662 male and 431 female patients. Diaphragm weight is related to body weight in both male (r = + 0.76) and female patients (r = +0.77) and is relatively larger in the former. Dissecting the diaphragm free of fat or freeze dryi...

BACKGROUND The recovery of diaphragmatic function is vital for successful extubation from mechanical ventilation. Recent studies have detected diaphragm atrophy in ventilated adults by using ultrasound, but no similar report has been conducted in children. In the current study, we hypothesized that mechanically ventilated children may also develop diaphragm atrophy and diaphragmatic dysfunction...

The majority of patients admitted to the ICU require mechanical ventilation as a part of their process of care. However, mechanical ventilation itself or the underlying disease can lead to dysfunction of the diaphragm, a condition that may contribute to the failure of weaning from mechanical ventilation. However, extended time on the ventilator increases health-care costs and greatly increases ...

Multilayer thin-film PZT diaphragm has been designed and modeled. Commercial Finite element software, ANSYS was implemented to model the diaphragm. This multi-layer diaphragm can be used as both sensor and actuator. A simplified model is introduced to reduce the CPU time. Dynamic characteristics of the multilayer diaphragm have been investigated. The important parameters of the multilayer PZT d...