Medical engineering & physics
-
Using a time-lapse image acquired from a CCD camera, we developed a non-contact and non-invasive device, which could measure both the respiratory and pulse rate simultaneously. The time-lapse image of a part of the subject's skin was consecutively captured, and the changes in the average image brightness of the region of interest (ROI) were measured for 30s. The brightness data were processed by a series of operations of interpolation as follows a first-order derivative, a low pass filter of 2 Hz, and a sixth-order auto-regressive (AR) spectral analysis. ⋯ Using AR spectral analysis, two clear peaks could be detected at approximately 0.3 and 1.2 Hz. The peaks were thought to correspond to the respiratory rate and the heart rate. Correlation coefficients of 0.90 and 0.93 were obtained for the measurement of heart rate and respiratory rate, respectively.
-
The research aims to carry out a detailed analysis of the loads applied by the ambulance workers when loading/unloading ambulance stretchers. The forces required of the ambulance workers for each system are measured using a load cell in a force handle arrangement. The process of loading and unloading is video recorded for all the systems to register the posture of the ambulance workers in different stages of the process. ⋯ The evaluation is extended to a biomechanical failure analysis of the ambulance worker's lower back using 3DSSPP software developed at the Centre for Ergonomics at the University of Michigan. The critical tasks of each ambulance worker during the loading and unloading operations for each system are identified. Design recommendations are made to reduce the forces exerted based on loading requirements from the kinetic analysis.
-
Analogous to vertebroplasty, cement-augmentation of the proximal femur ("femoroplasty") could reinforce osteoporotic bones. This study was to evaluate (i) the feasibility of femoroplasty with a composite cement (Cortoss), (ii) its influence on femoral strength by mechanical testing and (iii) the feasibility of stable osteosynthesis of the augmented fractured bones. ⋯ Augmentation of the proximal femur with composite bone cement could be of use in prophylaxis of fractures in osteoporotic femurs. Osteosynthesis of the fractured augmented bones is a challenging procedure but has a good chance to restore strength.
-
The present paper describes the functional features of an advanced lung ventilation system (ALVS) properly designed for the optimization of conventional dual-controlled ventilation (DCV), i.e. with pressure-controlled ventilation with ensured tidal or minute volume. Considering the particular clinical conditions of patients treated with controlled ventilation the analysis and synthesis of ALVS control have been performed assuming a linear respiratory mechanics. ⋯ This is obtained through the implementation of a compensation procedure making the desired airways pressure waveform independent on patient airways resistance and lung compliance variations along with a complete real-time monitoring of respiratory system parameters leading the ventilator setting. The experimental results obtained with a lung simulator agree with the theoretical ones and show that ALVS performance is useful for the research activity aiming at the improvement of both diagnostic evaluation and therapeutic outcome relative to mechanical ventilation treatments.
-
The prompt and adequate detection of abnormal cardiac conditions by computer-assisted long-term monitoring systems depends greatly on the reliability of the implemented ECG automatic analysis technique, which has to discriminate between different types of heartbeats. In this paper, we present a comparative study of the heartbeat classification abilities of two techniques for extraction of characteristic heartbeat features from the ECG: (i) QRS pattern recognition method for computation of a large collection of morphological QRS descriptors; (ii) Matching Pursuits algorithm for calculation of expansion coefficients, which represent the time-frequency correlation of the heartbeats with extracted learning basic waveforms. ⋯ Although the GLS was selected to comprise almost all types of appearing heartbeat waveforms in each file, the guaranteed accuracy (sensitivity between 90.7% and 99%, specificity between 95.5% and 99.9%) was reasonably improved when including patient-specific local learning set (sensitivity between 94.8% and 99.9%, specificity between 98.6% and 99.9%), with optimal size found to be about 3 min. The repeating waveforms, like normal beats, blocks, paced beats are better classified by the Matching Pursuits time-frequency descriptors, while the wide variety of bizarre premature ventricular contractions are better recognized by the morphological descriptors.