Journal of clinical monitoring and computing
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J Clin Monit Comput · Jul 2002
Pulmonary blood flow (cardiac output) and the effective lung volume determined from a short breath hold using the differential Fick method.
This work attempts to show how pulmonary blood flow (Qp), cardiac output (CO(Fick)) and the lung volume of effective gas exchange (ELV) can be determined from breath-by-breath measurements of the tidal exhaled CO2 elimination V (litre/min) and the end tidal CO2 concentration P (%) using the differential Fick method. The measurements are made during steady state ventilation and when the CO2 balance in the lungs changes subsequent to a perturbation of the gas exchange conditions. ⋯ With a single breath perturbation, the differential Fick method can yield cardiopulmonary information using 2-3 breaths only and with a minimum of interference with the patient. Complete data analysis results in multiple determinations of the Qp and ELV values which improve the attainable precision. Our investigation points to the possibility to determine Qp, CO(Fick) and ELV also during spontaneous breathing, by using the natural tidal variations of V and P.
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J Clin Monit Comput · Jul 2002
Learning about new anesthetics using a model driven, full human simulator.
New pharmacological agents are introduced into medical practice at an ever-increasing pace. Teaching how to use new medications in the clinical setting presents educational challenges and puts patients at risk. ⋯ Patient simulation is a novel method of introducing new drugs to the medical community and is perceived by anesthesia providers as a valuable addition to available teaching methods.
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J Clin Monit Comput · Jul 2002
Diagnosis of anesthetic-induced upper airway obstruction in children using respiratory inductance plethysmography.
Upper airway obstruction is the most rapid and clinically relevant cause of hypoxia during sedation and anesthesia. This study was designed to determine if respiratory inductance plethysmography (RIP) could quantify the degree of upper airway obstruction caused by induction of general anesthesia. ⋯ We investigated two methods for analyzing RIP tracings during varying degrees of upper airway obstruction in anesthetized children. We found that neither technique was sufficiently accurate for predicting the severity of upper airway obstruction and would not be useful as a predictor of upper airway obstruction in the clinical or research settings.
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J Clin Monit Comput · Jul 2002
Case ReportsMonitoring of motor evoked potentials with high intensity repetitive transcranial electrical stimulation during spinal surgery.
Clinical utility of high voltage repetitive transcranial electrical stimulation (TES) was investigated in 46 patients undergoing spine surgery. ⋯ The findings suggest that intraoperative MEP monitoring is feasible method, however, its immediate prognostic value for adequacy of neuronal decompression and improvement requires further studies with larger patient population.
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J Clin Monit Comput · Apr 2002
Performance of a real-time dicrotic notch detection and prediction algorithm in arrhythmic human aortic pressure signals.
A novel algorithm for real-time detection and prediction of the dicrotic notch from aortic pressure waves was evaluated in arrhythmic aortic pressure signals from heart failure patients. A simplified model of the arterial tree was used to calculate real-time aortic flow from aortic pressure. The dicrotic notch was detected at the first negative dip from the calculated flow, prediction of the notch was performed using a percentage of the decreasing flow. ⋯ Prediction of the dicrotic notch was tested at 40%, 20%, and 0% of the decreasing calculated aortic flow. The mean time-delays to the notch were 68 +/- 14 ms, 55 +/- 12 ms, and 43 +/- 8 ms, respectively. Given these small variability, intra-beat prediction of the dicrotic notch may be used for real-time intra-aortic balloon counterpulsation inflation timing.