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 2006
An evaluation of a PTT-based method for noninvasive and cuffless estimation of arterial blood pressure.
The aim of this study is to determine if a noninvasive and cuffless blood pressure (BP) estimation method using pulse transit time (PTT) can accurately track the changes in BP after a treadmill exercise. Experiments were conducted on 12 healthy subjects, who were directed to run on a treadmill at 10 kph for 4 minutes. For each subject, 13 trials were recorded in total, including 11 trials obtained immediately after exercise and during the 60-minute recovery period. ⋯ Both PTT-based device and Finometer were calibrated initially and Finometer calibration was also performed after exercise to the sphygmomanometer. Experimental results showed that there was only occasional discrepancy between BPs measured by Finometer and PTT-based device during the recovery period, i.e., at 5 minutes after exercise (p=0.008 for systolic BP and p=0.03 for diastolic BP). At all other post exercise time spots there were no significant differences between BPs measured by Finometer and PTT-based device.
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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.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2006
Continuous cardiac output and left atrial pressure monitoring by pulmonary artery pressure waveform analysis.
We introduce a novel technique for continuous (i.e., automatic) monitoring of cardiac output (CO) and left atrial pressure (LAP) by mathematical analysis of a pulmonary artery pressure (PAP) waveform. To obtain an initial evaluation of the technique, we applied it to PAP waveforms obtained from nine critically ill patients and compared the resulting CO and LAP estimates with standard operator-dependent thermodilution and pulmonary capillary wedge pressure measurements, respectively. We report that the technique achieved an overall CO error of 17.2% and an overall LAP error of 15.8%. With further testing, the technique may ultimately be employed so as to permit, for the first time, continuous CO and LAP monitoring in critically ill patients.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2006
Evaluation of external cardiac massage performance during hypogravity simulation.
Preservation of astronaut crew health during an exploration mission to the Moon or Mars will be crucial to mission success. The likelyhood of a life threatening medical condition occurring during a mission to Mars has been estimated by NASA to be 1% per year. Since basic life support is a vital skill in critical care medicine, plans must be in place for cardiopulmonary resuscitation in both microgravity and hypogravity (i.e. on the surface of the Moon or Mars). ⋯ Elbow flexion was measured using an electrogoniometer in order to assess the use of arm muscles to achieve chest compressions. This study found that depth (Lunar and Mars) and rate (Mars) of chest compression was below American Heart Association recommendations during hypogravity simulation in the female group. Furthermore, elbow flexion proved to be significantly greater during Lunar and Mars hypogravity simulation than that of the 1G control condition, suggesting that upper arm force may be used to counter the loss of body weight in an attempt to maintain adequate chest compression under these conditions.
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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.