Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2002
A prototype device for standardized calibration of pulse oximeters II.
There is no commonly accepted in vivo calibration method for pulse oximeters available up to now. On the basis of a prototype device for the calibration of pulse oximeters which was introduced recently, a second approach based on the same concept was tackled in order to design a reliable method for standardized calibration of pulse oximeters. ⋯ Compared to the first prototype the current version is simpler and less expensive in production. Many of previously existing problems are solved and the applicability to a large variety of pulse oximeters and sensors is given. The novel concept for the calibration of pulse oximeters is a tool for assessing the performance of pulse oximeters.
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J Clin Monit Comput · Apr 2002
Case ReportsCompartment syndrome of the arm: a complication of noninvasive blood pressure monitoring during thrombolytic therapy for myocardial infarction.
We report a rare case of tricep compartment syndrome caused by a hematoma which resulted from noninvasive blood pressure monitoring (NIBPM) during thrombolytic therapy. Clinicians administering thrombolytic agents should be aware of the risk of bleeding and compartment syndrome at the site of NIBPM. Appropriate preventative measures should be instituted when using automated pneumatic cuffs. An understanding of the pathophysiology and clinical presentation of an arm compartment syndrome will allow for prompt diagnosis and surgical treatment.
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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.
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J Clin Monit Comput · Apr 2002
Improving accuracy of the chemiluminescent analyser for measurement of nitric oxide and nitrogen dioxide in respired gas.
The aim of this study was to improve the accuracy of the chemiluminescent analyser in the measurement of nitric oxide (NO) and nitrogen dioxide (NO2) in both dry and humidified gas mixtures containing oxygen (O2) in varying concentrations. This work was performed because initial attempts to determine rate constants for the decay of NO and rates of formation of NO2 were unsuccessful. ⋯ This study indicates that for accurate analysis of NO and NO2 concentrations in airway gases a rigorous calibration of the instrument for the conditions applying in the experiment is mandatory. Once this is achieved the instrument is capable of precise analysis of both gases.
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J Clin Monit Comput · Apr 2002
Representation of somatosensory evoked potentials using discrete wavelet transform.
Somatosensory evoked potentials (SEP) have been shown to be a useful tool in monitoring of the central nervous system (CNS) during anaesthesia. SEP analysis is usually performed by an experienced human operator. For automatic analysis, appropriate parameter extraction and signal representation methods are required. The aim of this work is to evaluate the discrete wavelet transform (DWT) as such a method for an SEP representation. ⋯ The discrete wavelet transformation provides an efficient tool for SEP representation and parameterisation. Depending on the specific problem the DWT, can be adjusted to the desired accuracy, which is important for the subsequent development of automatic SEP analysers.