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...

OBJECTIVE To estimate contraceptive efficacy, safety, acceptability, and fit of a single-size diaphragm used with contraceptive gel. METHODS We conducted a multicenter trial in which 450 couples used the single-size diaphragm, 300 randomized to acid-buffering gel and 150 to nonoxynol-9, for at least 190 days and six menstrual cycles. Visits were at enrollment and after menstrual cycles 1, 3, ...

Diaphragm weakness commonly occurs in patients with congestive heart failure (CHF) and is an independent predictor of mortality. However, the pathophysiology of diaphragm weakness is poorly understood. We hypothesized that CHF induces diaphragm weakness at the single-fiber level by decreasing myosin content. In addition, we hypothesized that myofibrillar Ca(2+) sensitivity is decreased and cros...

BACKGROUND The role of the crural diaphragm during increased intra-abdominal pressure is not exactly known. We investigated the hypothesis that the crural diaphragm undergoes reflex phasic contraction on elevation of the intra-abdominal pressure with a resulting increase of the lower esophageal pressure and prevention of gastro-esophageal reflux. METHODS The esophageal pressure and crural dia...

Heart failure evokes diaphragm weakness, but the mechanism(s) by which this occurs are not known. We postulated that heart failure increases diaphragm free radical generation and that free radicals trigger diaphragm dysfunction in this condition. The purpose of the present study was to test this hypothesis. Experiments were performed using halothane-anesthetized sham-operated control rats and r...

RATIONALE Diaphragm thickness is increased in cystic fibrosis (CF), but it shows a marked variability between patients. The variable response of the diaphragm to loading may reflect the combined and opposite effects of training by the respiratory disease and systemic inflammation. OBJECTIVES To assess the impact of systemic inflammation on diaphragm and limb muscle strength and bulk in adult ...

RATIONALE Hypercapnic respiratory failure because of inspiratory muscle weakness is the most important cause of death in chronic obstructive pulmonary disease (COPD). However, the pathophysiology of failure of the diaphragm to generate force in COPD is in part unclear. OBJECTIVES The present study investigated contractile function and myosin heavy chain content of diaphragm muscle single fibe...

Garcia-Cazarin ML, Gamboa JL, Andrade FH. Rat diaphragm mitochondria have lower intrinsic respiratory rates than mitochondria in limb muscles. Am J Physiol Regul Integr Comp Physiol 300: R1311–R1315, 2011. First published March 9, 2011; doi:10.1152/ajpregu.00203.2010.—The mitochondrial content of skeletal muscles is proportional to activity level, with the assumption that intrinsic mitochondria...