Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
Comparative StudyAcoustic obstructive sleep apnea detection.
Obstructive sleep apnea (OSA) is a common respiratory disorder during sleep, in which the airways are collapsed and impair the respiration. Apnea is s cessation of airflow to the lungs which lasts at least for 10s. The current gold standard method for OSA assessment is full night polysomnography (PSG); however, its high cost, inconvenience for patients and immobility have persuaded researchers to seek simple and portable devices to detect OSA. ⋯ The method was evaluated on the data of 40 patients simultaneously with full night PSG study, and the results were compared with those of the PSG. The results show high correlation (96%) between our system and PSG. Also, the method has been found to have sensitivity and specificity values of more than 90% in differentiating simple snorers from OSA patients.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
Screening of patients with Obstructive Sleep Apnea Syndrome using C4.5 algorithm based on non linear analysis of respiratory signals during sleep.
To classify patients with possible diagnosis of Obstructive Sleep Apnea Syndrome (OSAS) into groups according to the severity of the disease using a decision tree producing algorithm based on nonlinear analysis of 3 respiratory signals instead of the use of full polysomnography. ⋯ It is possible to have reliable predictions of the severity of OSAS using linear and nonlinear indices from only two respiratory signals during sleep instead of performing full polysomnography. The proposed algorithm could be used for screening patients suspected to suffer from OSAS.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
Medical safety of TASER conducted energy weapon in a hybrid 3-point deployment mode.
TASER conducted energy weapons (CEW) deliver electrical pulses that can temporarily incapacitate subjects. The goal of this paper is to analyze the distribution of TASER CEW currents in the heart and surrounding organs and to understand theoretical chances of triggering cardiac arrhythmias, of capturing the vagus and phrenic nerves and producing electroporation of skeletal muscle structures. The CEW operates in either probe mode or drive-stun (direct contact) mode. There is also a hybrid mode in which current is passed from a single probe to either or both of 2 drive-stun electrodes on the weapon, presumed to be in direct contact with the skin. ⋯ Numerical modeling estimated that TASER CEWs were expected to be safe when deployed in 3-point mode. In drive-stun, probe-mode or 3-point deployments, the CEWs had high theoretically approximated safety margins for cardiac capture, VF, phrenic or vagus nerve capture and skeletal muscle damage by electroporation.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
Automated beat onset and peak detection algorithm for field-collected photoplethysmograms.
Recent reports suggest that photoplethysmography (PPG), which is a component of routine pulse oximetry, may be useful for detecting hypovolemia. An essential step in extracting and analyzing common PPG features is the robust identification of onset and peak locations of the vascular beats, despite varying beat morphologies and major oscillations in the baseline. Some prior reports used manual analysis of the PPG waveform; however, for systematic widespread use, an automated method is required. ⋯ We validated the algorithm by clinician evaluation of 100 randomly selected PPG waveform samples. For 99% of the beats, the algorithm was able to credibly identify the onsets and peaks of vascular beats, although the precise locations were ambiguous, given the very noisy data from actual clinical operations. The algorithm appears promising, and future consideration of its diagnostic capabilities and limitations is warranted.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
Estimation of blood pressure variability using independent component analysis of photoplethysmographic signal.
The maximum cross-correlation coefficient rho(max) between blood pressure variability and heart rate variability, whose frequency components are limited to the Mayer wave-related band, is a useful index to evaluate the state of the autonomic nervous function related to baroreflex. However, measurement of continuous blood pressure with an expensive and bulky measuring device is required to calculate rho(max). ⋯ In the proposed method, independent components are extracted from feature variables specified by the PPG signal by using the independent component analysis (ICA), and then the most appropriate component is chosen out of them so that the rho(max) based on the component can fit its true value. The results from the experiment with a postural change performed in 17 healthy subjects suggested that the proposed method is available for estimating rho(max) by using the ICA to extract blood pressure information from the PPG signal.