Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2006
Comparative StudyComparison of heart rate variability signal features derived from electrocardiography and photoplethysmography in healthy individuals.
The heart rate variability (HRV) signal is indicative of autonomic regulation of the heart rate (HR). It could be used as a noninvasive marker in monitoring the physiological state of an individual. Currently, the primary method of deriving the HRV signal is to acquire the electrocardiogram (ECG) signal, apply appropriate QRS detection algorithms to locate the R wave and its peak, find the RR intervals, and perform suitable interpolation and resampling to produce a uniformly sampled tachogram. ⋯ We used autoregressive (AR) modeling, Poincare' plots, cross correlation, standard deviation, arithmetic mean, skewness, kurtosis, and approximate entropy (ApEn) to derive and compare different measures from both ECG and PPG signals. This study demonstrated that our PDA-based system was a convenient and reliable means for acquisition of PPG-derived and ECG-derived HRV signals. The excellent agreement between different measures of HRV signals acquired from both methods provides potential support for the idea of using PPGs instead of ECGs in HRV signal derivation and analysis in ambulatory cardiac monitoring of healthy individuals.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2006
Controlled Clinical TrialInformation flow to assess cardiorespiratory interactions in patients on weaning trials.
Nonlinear processes of the autonomic nervous system (ANS) can produce breath-to-breath variability in the pattern of breathing. In order to provide assess to these nonlinear processes, nonlinear statistical dependencies between heart rate variability and respiratory pattern variability are analyzed. ⋯ The results show lower complexity with an increase of information flow in group A than in group B. Furthermore, a more (weakly) coupled nonlinear oscillator behavior is observed in the series of group A than in B.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2006
Coma duration prediction in diffuse axonal injury: analyses of apparent diffusion coefficient and clinical prognostic factors.
The purpose of this paper is to evaluate the hypothesis that the Apparent Diffusion Coefficient (ADC) values combined with initial clinical factors indicates the depth of shearing lesions in the brain structure and therefore relates to coma duration of diffuse axonal injury (DAI). Seventy-four adult patients (48 male and 26 female patients) with diffuse axonal injury were examined with convention MR imaging and diffusion weighted MR imaging between 2 hours and 20 days after injury. Apparent diffusion coefficient (ADC) maps were obtained and the mean ADC values of each Region of Interest (ROI) were measured using MRI console software. ⋯ Post-traumatic coma duration of DAI could be predicted by cerebral MRI findings in the acute to subacute stage after head injury combined with clinical prognostic factors. Age, ADC scores, GCS, number of lesions are highly significant in predicting coma duration. The technique presented herein might provide a tool for in vivo detection of DAI for the coma duration at the early stages in patients with traumatic brain injury.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2006
Implementation of a burn scar assessment system by ultrasound techniques.
Tissue injury and its ensuing healing process cause scar formation. In addition to physical disability, the subsequent disfigurements from burns often bring negative psychological impacts on the survivors. Scar hypertrophy and contracture limit the joint motion and body function of the patient. ⋯ In this report, the quantitative assessment system was used to evaluate the scar of a seriously burned patient. In order to verify the reliability of systematic reconstruction method, we constructed a phantom to imitate the scar tissue. The results show that it can achieve more than 90% in accuracy.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2006
Transpulmonary dilution system identification for pulmonary blood volume measurements by contrast echocardiography.
Pulmonary blood volume (PBV) is an important parameter to assess the condition of the lungs and the transpulmonary circulation. Unfortunately, its measurement is limited by the need for central catheterization. Contrast ultrasonography allows overcoming this problem. ⋯ Volume measurements show accurate in-vitro results with a correlation coefficient higher than 0.99. The clinical feasibility is confirmed by 70 measurements in patients. Beyond an accurate quantification of pulmonary blood volume, the proposed method also permits the characterization of the transpulmonary hemodynamics, possibly adding novel diagnostic value to the measurement.