Journal of clinical monitoring and computing
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J Clin Monit Comput · Feb 2014
Case ReportsUSCOM-window to the circulation: utility of supra-sternal Doppler in an elderly anaesthetized patient for a robotic cystectomy.
Supra-sternal Doppler (USCOM Ltd., Sydney, Australia) can be used during anaesthesia to measure cardiac output (CO) and related flow parameters. However, before the USCOM can be used routinely, its utility and limitations need to be fully understood and critical information about its use disseminated. In "Window to the Circulation" we use the example of an elderly man undergoing major urological robotic surgery to highlight the utility and limitations of intra-operative USCOM use. ⋯ However, achieving a good quality scan is important as it improves the reliability of USCOM data. The supra-sternal route is rich in flow signals and identifying the aortic valve signal is paramount. Recognizing the other characteristic waveforms in the signal helps greatly.
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J Clin Monit Comput · Feb 2014
A pilot study quantifying the shape of tidal breathing waveforms using centroids in health and COPD.
During resting tidal breathing the shape of the expiratory airflow waveform differs with age and respiratory disease. While most studies quantifying these changes report time or volume specific metrics, few have concentrated on waveform shape or area parameters. The aim of this study was to derive and compare the centroid co-ordinates (the geometric centre) of inspiratory and expiratory flow-time and flow-volume waveforms collected from participants with or without COPD. ⋯ A comparison of airflow waveforms show that in COPD, the breathing rate is faster (17 ± 4 vs 14 ± 3 min(-1)) and the time to reach peak expiratory flow shorter (0.6 ± 0.2 and 1.0 ± 0.4 s). The expiratory flow-time and flow-volume centroid is left-shifted with the increasing asymmetry of the expired airflow pattern induced by airway obstruction. This study shows that the degree of skew in expiratory airflow waveforms can be quantified using centroids.
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To control the three components of general anesthesia (hypnosis, analgesia, and neuromuscular blockade), an automated closed-loop, anesthesia-drug delivery system (McSleepy) was developed. Bispectral index was used as the control variable for hypnosis, the analgoscore for analgesia, and phonomyography for neuromuscular blockade. McSleepy can be used to control the induction, maintenance and emergence from general anesthesia. ⋯ Preliminary results of 15 patients are presented in this paper. Evaluation of McSleepy was done through an assessment of its clinical performance and using Varvel's performance indices. The system was found to be clinically useful by providing good precision in drug administration and reliable results for the duration of a general anesthesia.
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J Clin Monit Comput · Dec 2013
Exploration of key stakeholders' preferences for pre-hospital physiologic monitoring by emergency rescue services.
To gather preferences for novel pre-hospital physiologic monitoring technologies from emergency rescue services. Qualitative semi-structured interviews and focus groups were conducted with three groups from UK Search and Rescue (SAR); (1) Extractors (e.g. SAR teams), (2) Transporters (personnel primarily responsible for casualty transport), and (3) Treaters (e.g. ⋯ A range of more intuitive, physical properties was also raised (e.g. small/compact, lightweight). SAR-specific technology should be simple to operate by those with less medical training, which means that clinical data interpretation and presentation should be carefully considered. It would be beneficial if novel monitors carried out a majority of the interpretation, allowing rescuers to proceed with their priority task of removing the casualty to safety.
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J Clin Monit Comput · Dec 2013
Quantification of the proportion of motor neurons recruited by transcranial electrical stimulation during intraoperative motor evoked potential monitoring.
Transcranial motor evoked potentials (TcMEPs) are widely used to monitor motor function during spinal surgery. However, they are much smaller and more variable in amplitude than responses evoked by maximal peripheral nerve stimulation, suggesting that a limited number of spinal motor neurons to the target muscle are excited by transcranial stimulation. The aim of this study was to quantify the proportion of motor neurons recruited during TcMEP monitoring under general anesthesia. ⋯ The average ratios (test:control) were 17.1 % (range 1.8-38 %) for the amplitudes and 21.6 % (range 2.9-40 %) for the areas. The activity of approximately 80 % of the motor units to the target muscle cannot be detected by TcMEP monitoring. Therefore, changes in evoked potentials must be interpreted cautiously when assessing segmental motor function with TcMEP monitoring.