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
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.
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Intense neuromuscular blockade (NMB) measured by post tetanic count (PTC) was monitored, reversed and verified in this pig model. In a cross-over assessor blinded design six pigs were randomized to either no NMB followed by intense NMB, or intense NMB followed by no NMB. Neuromuscular measurements were performed with acceleromyography [train-of-four (TOF) Watch SX]. ⋯ We established a pig model for monitoring intense NMB with surface stimulation electrodes and acceleromyography. We verified total relaxation of the diaphragm and the abdominal muscles at the PTC 0-1 by suction test and with surface electromyography. This pig model is suitable for studies with experimental abdominal surgery with monitoring of intense NMB, and where relaxation of the diaphragm and the abdominal muscles are required.