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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We describe a novel algorithm to estimate the pulse pressure variation index (PPV) from arterial blood pressure signals (ABP). PPV has been shown to be one of the best predictors of fluid responsiveness in mechanically ventilated subjects. Our PPV algorithm uses a non-linear technique for envelope estimation, eliminating the need for automatic beat detection. ⋯ The algorithm was validated against the continuous PPV output obtained from the commercially available PiCCOreg system and gold standard expert PPV manual annotations. The data consists of ABP taken from subjects who experienced rapid changes in hemodynamics. This data comprised over six hours of continuous ABP monitoring.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2006
Quantitative EEG assessment of brain injury and hypothermic neuroprotection after cardiac arrest.
In this paper we provide a quantitative electroencephalogram (EEG) analysis to study the effect of hypothermia on the neurological recovery of brain after cardiac arrest. We hypothesize that the brain injury results in a reduction in information of the brain rhythm. To measure the information content of the EEG a new measure called information quantity (IQ), which is the Shannon entropy of decorrelated EEG signals, is developed. ⋯ In addition, EEG signal recovery under normothermic (37 degrees C) and hypothermic (33 degrees C) resuscitation following 5, 7 and 9 minutes of cardiac arrest is recorded and analyzed. Experimental results show that the IQ is higher for hypothermic than normothermic rats. The results quantitatively support the hypothesis that hypothermia accelerates the recovery of brain injury after cardiac arrest.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2006
Heat transfer model of hyporthermic intracarotid infusion of cold saline for stroke therapy.
A 3-dimensional hemispheric computational brain model is developed to simulate infusion of cold saline in the carotid arteries in terms of brain cooling for stroke therapy. The model is based on the Pennes bioheat equation, with four tissue layers: white matter, gray matter, skull, and scalp. ⋯ The finite difference method was employed to solve the system of partial differential equations. This model demonstrated a reduction in brain temperature, at the stroke lesion, to 32 degrees C in less than 10 minutes.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2006
Using a generalized neural network to identify airway obstructions in anesthetized patients postoperatively based on photoplethysmography.
Photoplethysmography has been recently studied asa non-invasive indicator of circulatory and respiratory function. In this study, photoplethysmographic (PPG) data were recorded from patients under the influence of anesthesia, but not intubated. ⋯ This classifier considers inter-subject variability so that it generalizes well to a large population. This classifier provided 86.1%accuracy to classify segments as being times of 'obstructed' vs.'normal' airways status.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2005
Capacity of brain cooling via ventilating oxygen at low temperature over respiratory tract.
Cerebral hypothermia is a rather useful way to improve outcome after brain injury. In this paper, the capacity of cooling oxygen ventilation (COV) during cerebral circulation arrest was theoretically evaluated. ⋯ However, its capacity on lowering the deep brain temperature is very limited. Therefore more powerful cooling strategies should be investigated to realize an efficient cooling on the target cerebral tissue.