Abstract: Provided herein are systems for determining a stretch condition of a tissue and assessing the stiffness of the tissue. Also provided herein are methods for using the systems for measuring stiffness of a tissue, assessing the effect of an agent on a tissue, and identifying subjects having a disease or disorder associated with increased or decreased stiffness of a tissue.

Abstract: A system and method for ventilating a lung in a living being by varying the peak inspiratory pressure. The peak inspiratory pressure may deviate about a mean that is chosen to correspond with a knee in a pressure-volume curve of the lung.

Abstract: A system and method for ventilating a lung in a living being by varying the peak inspiratory pressure. The peak inspiratory pressure may deviate about a mean that is chosen to correspond with a knee in a pressure-volume curve of the lung.

Abstract: A novel ventilator waveform having an enhanced inspiratory flow pattern is ideally suited for determining an effective “inspiratory impedance” in ventilator-dependent patients, and/or patients with severe obstruction resulting in expiratory flow-limitation. This waveform is referred to herein as the “Enhanced Ventilator Waveform” (EVW). The EVW maintains ventilatory support while simultaneously providing an accurate and sensible assessment of the mechanical status of the lungs or total respiratory system. The EVW technique of the present invention ensures that normal (tidal) volume levels are delivered during each inspiration, and that expiration remains passive. Furthermore, accurate estimation of lung resistance and elastance is established for several frequencies surrounding the primary ventilator breathing rate. From the resistance and elastance data, the mean level and structural distribution of airway versus tissue constriction conditions in the lung can be inferred.