Respiratory devices volume

Hexoskin Carre Technologies Vest, tank top ECG, respiratory (breathing volume), movement, including activity, steps, cadence Electronic device inserted into pocket at the waist (Hexoskin, 2012)... 

Schonhofer B, Sonnegom M, Haidl P, et al. Comparison of two different modes for noninvasive mechanical ventilation in chronic respiratory failure volume versus pressure controlled device. Eur Respir J 1997 10 184-191. 

Respiratory problems are diagnosed using a spirometer. The patient exhales as hard and as fast as possible into the device. The spirometer measures (1) the total volume exhaled, called the forced vital capacity (FVC), with units in liters (2) the forced expired volume measured at 1 second (FEV,), with units in liters per second (3) forced expiratory flow in the middle range of the vital capacity (FEV 25-75%), measured in liters per second and (4) the ratio of the observed FEVj to FVC X 100 (FEVj/FVC%). 

Many different techniques are available for flow measurement and for recording of respiratory functions or flow parameters in particular (e.g. [115,116]). However, not all methods are appropriate for measurement of inhalation flows, either because they have low frequency responses or they influence the shape of the inspiratory flow curve by a large volume or by the inertia of the measuring instrument (e.g. rotameters). They may also interfere with the aerosol cloud from the inhalation device during drug deposition studies. 

A third method for measuring lung volumes uses a device known as a body plethysmograph, also referred to as a body box. The body box is a large rigid-walled structure in which the patient is seated, after which the door is closed and sealed completely. In one variety, a small hole in the wall of the cabinet leads to a spirometer or flow sensor. Respiratory efforts within the box cause changes in volume to be recorded on this spirometer as chest wall movement displaces air within the box. In a second variety of body box, there is no hole in the wall of the box and respiratory efforts instead... 

National Dreager Inc., manufacturer of detector tubes and respiratory equipment, has developed two versions of the Model 80 facemask fit-test device using 2% by volume ethylene as the test gas. This method uses either a detector tube or an electronic leak detector to measure the concentration of test gas exhaled in the breath. With detector tubes, 0.5-10 ppm of ethylene leakage tests can be detected in the range of 0.0025 to 0.05%. 

Drug delivery from holding chambers with attached facemask has been studied (202). The authors used a model to simulate respiratory pattern of individuals and determination of deposition on a filter. The dose dehvered to the filter was dependent on the combination tidal volume and size of spacer device. The dose deposited on the filter ranged from less than 1% up to maximum 5.3%. The authors could also show that the introduction of a large dead space decreased drug delivery. 

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