Journal of clinical monitoring and computing
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J Clin Monit Comput · Oct 2016
Respiratory modulations in the photoplethysmogram (DPOP) as a measure of respiratory effort.
DPOP is a measure of the strength of respiratory modulations present in the pulse oximetry photoplethysmogram (pleth) waveform. It has been proposed as a non-invasive parameter for the prediction of the response to volume expansion in hypovolemic patients. The effect of resistive breathing on the DPOP parameter was studied to determine whether it may have an adjunct use as a measure of respiratory effort. ⋯ Further, a relationship between DPOP and percent modulation of the pleth waveform was observed. A version of the DPOP algorithm that corrects for low perfusion was implemented which resulted in an improved relationship between DPOP and PPV. Although a limited cohort of seven volunteers was used, the results suggest that DPOP may be useful as a respiratory effort parameter, given that the fluid level of the patient is maintained at a constant level over the period of analysis.
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J Clin Monit Comput · Oct 2016
Investigation of peripheral photoplethysmographic morphology changes induced during a hand-elevation study.
A hand-elevation study was carried out in the laboratory in order to alter peripheral blood flow with the aim of increasing understanding of factors affecting the morphology of peripheral photoplethysmographic signals. Photoplethysmographic (PPG) signals were recorded from twenty healthy volunteer subjects during a hand-elevation study in which the right hand was raised and lowered relative to heart level, while the left hand remained static. Red and infrared (IR) PPG signals were obtained from the right and left index fingers using a custom-made PPG processing system. ⋯ Changes in hand position relative to heart level can significantly affect the morphology of the peripheral ac PPG waveform. These alterations are due to a combination of physical effects and physiological responses to changes in hand position, which alter vascular resistance. Care should be taken when interpreting morphological data derived from PPG signals and methods should be standardized to take these effects into account.
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J Clin Monit Comput · Oct 2016
Review Meta AnalysisAccuracy and precision of minimally-invasive cardiac output monitoring in children: a systematic review and meta-analysis.
Several minimally-invasive technologies are available for cardiac output (CO) measurement in children, but the accuracy and precision of these devices have not yet been evaluated in a systematic review and meta-analysis. We conducted a comprehensive search of the medical literature in PubMed, Cochrane Library of Clinical Trials, Scopus, and Web of Science from its inception to June 2014 assessing the accuracy and precision of all minimally-invasive CO monitoring systems used in children when compared with CO monitoring reference methods. Pooled mean bias, standard deviation, and mean percentage error of included studies were calculated using a random-effects model. ⋯ Although the pooled bias was small, the mean pooled percentage error was in the gray zone of clinical applicability. In the sub-group analysis, electrical cardiometry was the device that provided the most accurate measurement. However, a high heterogeneity between studies was found, likely due to a wide range of study characteristics.
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J Clin Monit Comput · Oct 2016
Review Case ReportsIntraoperative non invasive intracranial pressure monitoring during pneumoperitoneum: a case report and a review of the published cases and case report series.
Non-invasive measurement of ICP (nICP) can be warranted in patients at risk for developing increased ICP during pneumoperitoneum (PP). Our aim was to assess available data on the application of nICP monitoring during these procedures and to present a patient assessed with an innovative combination of noninvasive tools. Literature review of nICP assessment during PP did not find any studies comparing different methods intraprocedurally and only few studies of any nICP monitoring were available: transcranial Doppler (TCD) studies used the pulsatility index (PI) as an estimator of ICP and failed to detect a significant ICP increase during PP, whereas two out of three optic nerve sheath diameter (ONSD) studies detected a statistically significant ICP increase. ⋯ Considering the high intraoperative risk of developing intracranial hypertension, he was monitored through parallel ONSD ultrasound measurement and TCD derived formulae (flow velocity diastolic formula, FVdnICP, and PI). ONSD and FVdnICP methods indicated a significant ICP increase during PP, whereas PI was not significantly increased. Our experience, combined with the literature review, seems to suggest that PI might not detect ICP changes in this context, however we indicate a possible interest of nICP monitoring during PP by means of ONSD and of TCD derived FVdNICP, especially for patients at risk for increased ICP.