Journal of clinical monitoring and computing
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J Clin Monit Comput · Oct 2015
Clinical TrialEffect of propofol and remifentanil on a somatosensory evoked potential indicator of pain perception intensity in volunteers.
Somatosensory evoked potentials (SEPs) have been linked to noxious activation and stimulus intensity. In this exploratory study we investigated the impact of anaesthetic drugs on SEPs and pain ratings, to assess their applicability as an objective measure of the nociception/anti-nociception balance. Following institutional approval and written informed consent, 10 healthy adult volunteers were enrolled (29.5 ± 9.1 years, 63.0 ± 8.9 kg and 171.4 ± 7.2). ⋯ An individually adjusted/normalized ratio based on cortical SEPs amplitude and interpeak latency is proposed([Formula: see text]): [Formula: see text] and NSR were significantly correlated in three out of nine subjects, and [Formula: see text] and remifentanil Ce were significantly correlated in two (low number of evaluation points). [Formula: see text] was shown to decrease with increasing doses of propofol and remifentanil (P < 0.05). The proposed metric was depressed by anaesthetics and reflected pain evaluations. Further research is necessary to increase the number of volunteers and drugs' combination, to assess its applicability during surgically adequate anesthetic leves.
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J Clin Monit Comput · Oct 2015
Comparative StudyEvaluation of filtering methods for acquiring radial intra-artery blood pressure waveforms.
The methods for evaluating noninvasive blood pressure (NIBP) monitors using an intra-arterial reference are detailed in the ANSI/AAMI/ISO 81060-2:2009 standard. In a recent study, GE Healthcare obtained invasive radial arterial blood pressure waveforms. The work presented here describes the development of filtering strategies for obtaining high fidelity intra-arterial pressure waveforms for NIBP accuracy testing using the 81060-2 standard. ⋯ Clinicians need to understand that resonance artifacts potentially exist in intra-arterial waveforms and that the adjustments of monitoring systems may not be adequate. Optimal filters for obtaining intra-arterial waveforms should take into account the damping factor and natural frequency of the measuring system. In research and device evaluation studies it is necessary that optimal filtering be done to minimize the effects of under-damping.
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J Clin Monit Comput · Oct 2015
Comparative Study Controlled Clinical TrialIsocapnic hyperpnea with a portable device in Cystic Fibrosis: an agreement study between two different set-up modalities.
To evaluate the bias and precision of the respiratory muscle training device formulas to predict respiratory minute volume (RMV) and volume of the reservoir bag (BV) on a cohort of subjects with Cystic Fibrosis (CF). CF patients with available pulmonary function tests and maximal voluntary manoeuvres were included in the study. Vital capacity and maximal voluntary ventilation were extracted from subjects' records and then inserted to the manufacturer's formulas to obtain RMV and BV (measured setting). ⋯ Concordance correlation coefficients for RMV were -0.03 in males and 0.02 in females; 0.22 in males and 0.03 in females for BV, reinforcing an unsatisfactory concordance between measured and manufacturer setting. This study shows considerable discrepancies between the two methods, making the degree of agreement not clinically acceptable. This might cause inappropriate setting and disservice to patients with CF.
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J Clin Monit Comput · Oct 2015
Reliability of the volatile agent consumption display in the Draeger Primus™ anesthesia machine.
Knowledge of the consumed amount of volatile anesthetic (VA) expressed in liquid agent is necessary to enable agent sparing dosing measures and for billing purposes. The widespread Draeger Primus™ anesthesia machine displays in its logbook the amount of consumed VA at the end of each anesthesia, but the reliability of this parameter is yet unknown. The objective was to evaluate the precision and reliability of the inbuilt VA consumption display in Draeger Primus™ anesthesia machines as compared with the gold standard of weighing the vaporizer before and after anesthesia. ⋯ The displayed desflurane consumption underestimated the measured values by -3.5 ± 6.3 ml (6.2%). Nine from 10 sevoflurane pairs of values and all desflurane pairs of values were within ±1.96 SD. The displayed VA consumption calculations for sevoflurane and desflurane in the Draeger Primus™ are sufficiently reliable to estimate the pharmacoeconomic impact of VA delivery during inhalational anesthesia.
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J Clin Monit Comput · Oct 2015
Comparative StudyCutaneous microcirculation in preterm neonates: comparison between sidestream dark field (SDF) and incident dark field (IDF) imaging.
Incident dark field imaging (IDF) is a new generation handheld microscope for bedside visualization and quantification of microcirculatory alterations. IDF is the technical successor of sidestream dark field imaging (SDF), currently the most used device for microcirculatory measurements. In (pre)term neonates the reduced thickness of the skin allows non-invasive transcutaneous measurements. ⋯ The perfusion of vessels could be determined more accurately in the IDF images, resulting in a significant lower PPV (88.7 vs. 93.9%, p value 0.002). The IDF video images scored optimal in a higher percentage compared to the SDF video images. IDF imaging of the cutaneous microcirculation in preterm neonates resulted in a higher vessel density and lower perfusion compared to the existing SDF device.