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 2012
EEG-based detection of awakening from isoflurane anesthesia in rats.
In animal studies, reliable measures for depth of anesthesia are frequently required. Previous findings suggest that the continuous depth of anesthesia indices developed for humans might not be adequate for rats whose EEG changes during anesthesia represent more of quick transitions between discrete states. In this paper, the automatic EEG-based detection of awakening from anesthesia was studied in rats. ⋯ The method was tested with EEGs recorded from ten rats recovering from isoflurane anesthesia. The algorithm was shown to be able to detect the sudden change in the EEG related to the moment of awakening with a precision comparable to careful visual inspection. Our findings suggest that monitoring such signal changes may offer an interesting alternative to the application of continuous depth of anesthesia indices when avoiding the awakening of the animal during e.g. a clinical experiment.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2012
Comparisons of predictors of fluid responsiveness in major surgery.
The majority of studies on fluid responsiveness is focused on volume expansion maneuvers in intensive care unit (ICU), while fewer studies have analyzed the same problem during major surgery. Among them, the results are contrasting. ⋯ Our results showed that pulse pressure variation (PPV) estimated according to the definition, i.e. within single respiratory cycles, and PPV estimated by PiCCO monitor system are coherent and very similar. Moreover, PPV and stroke volume variation (SVV) produced good values of sensitivity and specificity in separating the subjects into responsive and non responsive to maneuvers.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2012
Frequency dependent transmission characteristics between arterial blood pressure and intracranial pressure in rats.
The pulsatile energy transmission between arterial blood pressure (BP) and intracranial pressure (ICP) is affected by cerebrospinal fluid (CSF) and brain tissue. Studies in dogs have shown that the transfer function (TF) between BP and ICP shows damping of pulsatile energy around heart rate frequency (1-3Hz) with notch filter characteristics, and the amount of damping is sensitive to cerebral compliance. This investigation aimed to assess whether this notch filter characteristic is an intrinsic property of the brain enclosed in a rigid skull and therefore applies across species with a large difference in body size. ⋯ Findings show that the rat brain acts as a selective frequency pulsation absorber of energy centered at heart rate frequency. This similarity with larger animals indicates a possible allometric mechanism underlying this phenomenon, with notch filter characteristic frequency scaled to body size. This study suggests that the TF between arterial BP and ICP is an intrinsic property of the brain tissue and CSF enclosed in a rigid compartment and can be used to assess changes in cerebral compliance due to abnormal CSF pressure and flow as occur in hydrocephalus.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2012
Wireless photoplethysmographic device for heart rate variability signal acquisition and analysis.
The photoplethysmographic (PPG) signal has the potential to aid in the acquisition and analysis of heart rate variability (HRV) signal: a non-invasive quantitative marker of the autonomic nervous system that could be used to assess cardiac health and other physiologic conditions. A low-power wireless PPG device was custom-developed to monitor, acquire and analyze the arterial pulse in the finger. The system consisted of an optical sensor to detect arterial pulse as variations in reflected light intensity, signal conditioning circuitry to process the reflected light signal, a microcontroller to control PPG signal acquisition, digitization and wireless transmission, a receiver to collect the transmitted digital data and convert them back to their analog representations. ⋯ Kubios was able to generate a report sheet with the time domain and frequency domain parameters of the acquired data. These features were then compared against those calculated by MATLAB. The preliminary results demonstrate that the prototype wireless device could be used to perform HRV signal acquisition and analysis.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2012
Stroke volume obtained from the brachial artery using transbrachial electrical bioimpedance velocimetry.
Stroke volume (SV) is the quantity of blood ejected by the cardiac ventricles per each contraction. When SV is multiplied by heart rate, cardiac output is the result. Cardiac output (CO), in conjunction with hemoglobin concentration and arterial oxygen saturation are the cornerstones of oxygen transport. ⋯ The technique involves passage of a constant magnitude, high frequency, and low amperage ac from the upper arm to the antecubital fossa. In all other respects, the operational aspects of TBEV are consistent with ICG. There is good evidence suggesting that the TBEV waveform and its derivatives are generated by blood resistivity changes only.