Journal of clinical monitoring and computing
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J Clin Monit Comput · Jun 2018
Photoplethysmography for blood volumes and oxygenation changes during intermittent vascular occlusions.
Photoplethysmography (PPG) is an optical technique that measures blood volume variations. The main application of dual-wavelength PPG is pulse oximetry, in which the arterial oxygen saturation (SpO[Formula: see text]) is calculated noninvasively. However, the PPG waveform contains other significant physiological information that can be used in conjunction to SpO[Formula: see text] for the assessment of oxygenation and blood volumes changes. ⋯ A[Formula: see text] indicated significant changes for occlusion pressures exceeding 20 mmHg (p < 0.05) and correlation with tissue oxygenation changes measured by NIRS, while SpO[Formula: see text] had significant changes after 40 mmHg (p < 0.05). Relative changes in haemoglobin concentrations can be estimated from PPG signals and they showed a good level of accuracy in the detection of perfusion and oxygenation changes induced by different degrees of intermittent vascular occlusions. These results can open up to new applications of the PPG waveform in the detection of blood volumes and oxygenation changes.
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J Clin Monit Comput · Jun 2018
LetterMonitoring tissue oxygen heterogeneities and their influence on optical glucose measurements in an animal model.
The purpose of this study was to characterize the heterogeneity of oxygen partial pressure in different adipose tissue zones and to assess the possibility of compensating these heterogeneities during optical glucose measurements. In this proof of concept study, the heterogeneity of oxygen partial pressure was determined in the adipose tissue of a pig by using 48 oxygen sensors in 3 zones of the abdominal region at two different blood oxygen levels. ⋯ The low heterogeneity on one cannula allows the compensation of physiological oxygen variations for optical glucose measurements by using an additional oxygen sensor in close proximity to the glucose sensor. In addition, this setup can be used to continuously monitor tissue oxygenation e.g. in patients with adipose tissue dysfunction or serve limb ischemia.
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J Clin Monit Comput · Jun 2018
Correction to: The oxygen reserve index (ORI): a new tool to monitor oxygen therapy.
In the original publication of the article, the authors have realized an error in Fig. 1. The corrected version of Fig. 1 is given below.
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J Clin Monit Comput · Jun 2018
Comparative StudyComparing volume-clamp method and intra-arterial blood pressure measurements in patients with atrial fibrillation admitted to the intensive or medium care unit.
International guidelines highlight the importance of blood pressure (BP) in patients with atrial fibrillation (AF). However, BP measurement in AF is complicated by beat-to-beat fluctuation. Automated BP measurement devices are not validated for patients with AF and no consensus exists on how to measure BP in AF manually. ⋯ Accuracy of VCM in AF was similar to sinus rhythm. In conclusion, in patients with AF, accurate and precise measurement of non-invasive beat-to-beat BP measurement using the VCM is possible, the one exception being the precision of systolic BP. Beat-to-beat variability can be accurately reproduced.