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 2008
A target control Infusion method for neuromuscular blockade based on hybrid parameter estimation.
The paper presents a new method for target control infusion (TCI) for neuromuscular blockade (NMB) level control of patients subject to general anaesthesia. The method combines an inversion of the pharmacokinetic/pharmacodynamic (PK/PD) model with a hybrid parameter estimation method that uses on-line data from the initial bolus response to estimate the model parameters. Although atracurium is considered as relaxant, the newly proposed method may be applied to other drugs for which the PK/PD model is available. Simulation results on a bank of 100 patient models are presented to demonstrate the achievable performance.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2008
Hypnotic administration for anesthesia using sliding-mode control.
Nowadays general anesthesia is maintained using as the controller the human intervention, relying only on the quick and certain response of the anesthesiologist to the surrounding conditions, in order to provide the adequate state of anesthesia for the three main components - hypnosis, analgesia and paralysis. One of the most advantageous breakthroughs in anesthesia has been the appearance of depth of anesthesia monitors, assisting anesthesiologists in the hard job of knowing the hypnotic state of a patient. This information allows a way of closing the loop for administration of the hypnotic drug, and a more secure maintenance of hypnosis. The objective of this work was to apply sliding-mode control techniques to the model structure of the hypnotic in the human body (measured by the effect), and evaluate the robustness of this method to expected deviations from the average patient.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2008
Asymmetry in lung sound intensities detected by respiratory acoustic thoracic imaging (RATHI) and clinical pulmonary auscultation.
RATHI was introduced as an attempt to further improve the association between anatomical zones and specific breathing activity, both spatially and temporally. This work compares RATHI with clinical pulmonary auscultation (PA) to assess the concordance between both procedures to detect asymmetries in lung sound (LS) intensities. Twelve healthy young males participated in the study and were auscultated by two experts. ⋯ By RATHI, most of the subjects showed asymmetries between apical and basal regions higher than 20%, whereas between left and right hemithorax asymmetries higher than 20% occurred only half of the time. RATHI and PA agreed 83 to 100% when apical to base acoustical information was compared, but when left to right asymmetries were considered these figures were about 40 to 50%. We concluded that RATHI has advantages as it gave more detailed and measurable information on LS than clinicians, who could not detect intensity asymmetries mainly below 20%.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2008
Preliminary study on physiological changes of hemorrhagic shock in rats.
Hemorrhagic shock is a common cause of death in emergency rooms. The objective evaluation of hemorrhagic shock is very important for early diagnosis and treatment. ⋯ We constructed an integrated system to be able to control bleeding and to simultaneously measure bio-signals such as ECG, blood pressure, temperature, and respiration. In order to verify the system, we measured the bio-signals mentioned above while hemorrhagic shock was induced by withdrawing blood (2.5 ml / 100 g / 15 min) from a femoral vein for 10 rats.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2008
Investigation of photoplethysmogram morphology for the detection of hypovolemic states.
Medics and first responders to emergencies are often faced with monitoring and assessing victims with very limited resources. Therefore, there is an inherent need for a real-time ambulatory monitoring capability that is portable and low power. This is particularly important for physiological monitoring of life-threatening conditions such as internal hemorrhaging. ⋯ In this paper, we compared the PPG morphology with pulse transit time (PTT), which has been investigated for clinical and ambulatory applications. The indicators were tested on data obtained from experiments using lower body negative pressure (LBNP) as a model to simulate hemorrhage in humans. The results of this study indicate that PPG morphology is associated with pulse pressure (systolic minus diastolic blood pressure) and is therefore a promising feature for detection and real-time tracking of hypovolemic states.