Journal of clinical monitoring and computing
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A review of the literature shows that current "standard" laboratory measurements for hemoglobin are subject to numerous factors that affect both accuracy and reliability. In addition, total hemoglobin concentration measurements are subject to numerous factors that affect the "true" hemoglobin value. This article discusses both the physiologic factors that influence hemoglobin levels and the technical aspects and variability among the different measurement methodologies currently available.
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J Clin Monit Comput · Oct 2013
Clinical TrialDetermination of breath isoprene allows the identification of the expiratory fraction of the propofol breath signal during real-time propofol breath monitoring.
Real-time measurement of propofol in the breath may be used for routine clinical monitoring. However, this requires unequivocal identification of the expiratory phase of the respiratory propofol signal as only expiratory propofol reflects propofol blood concentrations. Determination of CO2 breath concentrations is the current gold standard for the identification of expiratory gas but usually requires additional equipment. ⋯ Overall bias between the two data extraction methods was -0.12 ppb. The lower and the upper limits of the 95 % CI were -0.69 and 0.45 ppb. Determination of isoprene breath concentrations allows the identification of the expiratory propofol signal during real-time breath monitoring.
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J Clin Monit Comput · Oct 2013
Review Meta AnalysisHeart rate variability indices for very short-term (30 beat) analysis. Part 1: survey and toolbox.
Heart rate variability (HRV) analysis over very short (<60 s) periods may be useful for monitoring dynamic changes in autonomic nervous system activity where steady-state conditions are not maintained (e.g. during drug administration, or the start or end of exercise). From the 1980s there has been a wealth of HRV indices produced in the quest for better measures of the change in parasympathetic and sympathetic activity. Many of the indices have been sparingly used and have not been investigated for application to short-term use. ⋯ The survey identified a comprehensive list of 115 indices that were subsequently coded and screened. Of these, 70 were unique and produced a finite number with 60 s data, so are included in the Toolbox. These indices require validation against physiological data before they can be applied to short-term HRV analysis of cardiac autonomic nervous system activity.
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J Clin Monit Comput · Oct 2013
Case ReportsAssessment and confirmation of tracheal intubation when capnography fails: a novel use for an USB camera.
A 62 year old male with a right pyriform fossa lesion extending to the right arytenoid and obscuring the glottic inlet was planned for laser assisted excision. Direct laryngoscopic assessment after topicalization of the airway, showed a Cormack Lehane grade 3 view. ⋯ Capnography may not be reliable as a sole indicator of confirmation of correct endotracheal tube placement. Video laryngoscopy may provide additional confirmation of endotracheal intubation.
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J Clin Monit Comput · Oct 2013
Clinical TrialMonitoring nociception during general anesthesia with cardiorespiratory coherence.
A novel wavelet transform cardiorespiratory coherence (WTCRC) algorithm has been developed to measure the autonomic state. WTCRC may be used as a nociception index, ranging from 0 (no nociception, strong coherence) to 100 (strong nociception, low coherence). The aim of this study is to estimate the sensitivity of the algorithm to nociception (dental dam insertions) and antinociception (bolus doses of anesthetic drugs). ⋯ A bolus dose of anesthetics changed the WTCRC by -15 (-50 %) [-21 to -9.3], HRmean by -4.8 beats/min (4.6 %) [-6.6 to -2.9], and NIBPmean by -2.6 mmHg (3.4 %) [-4.7 to -0.50]. A nociception index based on cardiorespiratory coherence is more sensitive to nociception and antinociception than are HRmean or NIBPmean. The WTCRC algorithm shows promise for noninvasively monitoring nociception during general anesthesia.