Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2014
Case ReportsImpact of changes in systemic vascular resistance on a novel non-invasive continuous cardiac output measurement system based on pulse wave transit time: a report of two cases.
The inaccuracy of arterial waveform analysis for measuring continuos cardiac output (CCO) associated with changes in systemic vascular resistance (SVR) has been well documented. A new non-invasive continuous cardiac output monitoring system (esCCO) mainly utilizing pulse wave transit time (PWTT) in place of arterial waveform analysis has been developed. However, the trending ability of esCCO to measure cardiac output during changes in SVR remains unclear. ⋯ In each case, the trending ability of esCCO to measure cardiac output and time component of PWTT were analyzed. Recorded data suggest that the time component of PWTT may have a significant impact on the accuracy of estimating stroke volume during changes in SVR. However, further prospective clinical studies are required to test this hypothesis.
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J Clin Monit Comput · Aug 2014
An autocalibrating algorithm for non-invasive cardiac output determination based on the analysis of an arterial pressure waveform recorded with radial artery applanation tonometry: a proof of concept pilot analysis.
We aimed to describe and evaluate an autocalibrating algorithm for determination of cardiac output (CO) based on the analysis of an arterial pressure (AP) waveform recorded using radial artery applanation tonometry (AT) in a continuous non-invasive manner. To exemplarily describe and evaluate the CO algorithm, we deliberately selected 22 intensive care unit patients with impeccable AP waveforms from a database including AP data obtained with AT (T-Line system; Tensys Medical Inc.). When recording AP data for this prospectively maintained database, we had simultaneously noted CO measurements obtained from just calibrated pulse contour analysis (PiCCO system; Pulsion Medical Systems) every minute. ⋯ Bland-Altman analysis demonstrated a bias of +0.1 L/min (standard deviation 0.8 L/min; 95% limits of agreement -1.5 to 1.7 L/min, percentage error 23%). CO can be computed based on the analysis of the AP waveform recorded with AT. In the selected patients included in this pilot analysis, a percentage error of 23% indicates clinically acceptable agreement between AT-CO and PC-CO.
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J Clin Monit Comput · Aug 2014
LetterContinuous real time endotracheal tube cuff pressure waveform.
Endotracheal tube cuff pressure monitoring is one of the standard degrees of care afforded to anesthetized patients in the operative theater. Traditional pressure transducer when used to monitor cuff pressure provides real time continuous sine wave pressure waveform which has not been described in literature so far. This unique waveform needs to be further processed and evaluated to check its utility in airway pressure monitoring.
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J Clin Monit Comput · Aug 2014
Accurate and stable continuous monitoring module by mainstream capnography.
End-tidal partial pressure of [Formula: see text] is an important index in clinical monitoring. Medical mainstream capnography has become widely used, but there are still limitations in accuracy and stability. A type of mainstream capnometer based on the principle of non-dispersive infrared was designed. ⋯ Several digital filtering techniques are used to process various interferences and improve capnogram quality. Clinical tests and targeted experiments show this mainstream capnometer can accurately monitor respiratory CO2 concentrations, especially at the end-tidal peak point. This capnometer also shows high accuracy and stability in long-term continuous monitoring.