Laser monitoring of chest wall displacement

Abstract

We developed a prototype laser monitor, consisting of a single laser sensor, to observe chest wall displacement during respiration. With this monitor, respiratory waveforms are expressed as an anterioposterior motion of the chest wall. The purpose of this study was to examine the characteristics and performance of this prototype. Performance was assessed: 1) under static conditions; 2) using a lung model ventilated in both conventional and high frequency oscillation (HFOV) modes; and 3) during spontaneous breathing in normal adults.In vitro, the monitor performed well both under static conditions and during mechanical ventilation. Reliable "respiratory" wave forms, with no frequency-dependent change in the relationship between displacement and volume, were produced during both conventional ventilation and HFOV at 15 Hz. In vivo, abdominal displacement, measured in the midline, was linearly correlated with the tidal volume signal integrated from flow. The waveforms produced by the monitor were adequate for monitoring respiration and for calculating respiratory timing variables.While a single laser sensor is unlikely to be sufficient for monitoring respiration in spontaneously breathing subjects, the performance of the prototype monitor was sufficiently impressive to encourage further development and further study of this type of truly noninvasive respiratory monitor.

Pletismografia respiratória por indutância: estudo comparativo entre calibração por manobra de isovolume e calibração qualitativa diagnóstica em voluntários saudáveis avaliados em diferentes posturas

“…(2)(3)(4)(5)(6)(7) The QDC method is performed during a given period of baseline breathing and uses a statistical placed horizontally on a stretcher, lying on their backs, with the hips and knees flexed; for the sitting position, the volunteers were sat on a chair without back support, with the hips and knees at a 90° angle; and for the orthostatic position, the volunteers were instructed to stand upright, with arms relaxed at their sides, and distribute their body weight evenly on both legs (Figure 1).…”

Impacto de fatores externos sobre a mecânica respiratória avaliada por um modelo fotogramétrico específico: biofotogrametria

“…Studies which established references for studies on respiratory kinematics (7,(14)(15)(16)(17)(18) laid the foundation for the model of irregular quadrilaterals. Planes transverse to the references were drawn, and the extent of the chest wall was delineated from the level of the acromioclavicular joint in the upper portion to the level of the umbilicus in the lower portion ( Figure 1, Step 1).…”

“…In pulmonology, such systems provide biomechanical, (6) morphometric (7) and kinematic evidence, (8)(9)(10)(11) involved in respiratory diseases or not, and can be applied in different scenarios while maintaining quality and reproducibility. (11) The type of photogrammetry used in study (5,12,13) represents a promising trend, whose operational differentiation from traditional photogrammetry is in the methodological improvement for the analysis of respiratory movement.…”

Applications of MIMO Techniques to Sensing of Cardiopulmonary Activity

“…To model the cardiopulmonary activity the position of each scatterer, with respect to the cluster center, is oscillating in time on two different frequencies with different amplitudes. The first frequency and amplitude model the cardio activity (typical frequency is 1 Hz and the amplitude is 0.1 mm), while the second frequency and amplitude model the pulmonary activity (typical frequency is 0.3 Hz and the amplitude is 10 mm) [5,6]. To analyze temporal variations in the MIMO channel, we collect a sequence of the channel state estimates h ij (k) (i = 1, ... , n rx and j = 1, ... , n tx ) where k is the temporal index.…”