Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2016
Near-infrared spectroscopy determined cerebral oxygenation with eliminated skin blood flow in young males.
We estimated cerebral oxygenation during handgrip exercise and a cognitive task using an algorithm that eliminates the influence of skin blood flow (SkBF) on the near-infrared spectroscopy (NIRS) signal. The algorithm involves a subtraction method to develop a correction factor for each subject. For twelve male volunteers (age 21 ± 1 yrs) +80 mmHg pressure was applied over the left temporal artery for 30 s by a custom-made headband cuff to calculate an individual correction factor. ⋯ With the use of both source-detector distances, handgrip exercise and a cognitive task increased O2Hb (P < 0.01) but O2Hb was reduced when SkBF became eliminated by pressure on the temporal artery for 5 s. However, when the estimation of cerebral oxygenation was based on the algorithm developed when pressure was applied to the temporal artery, estimated O2Hb was not affected by elimination of SkBF during handgrip exercise (P = 0.666) or the cognitive task (P = 0.105). These findings suggest that the algorithm with the individual correction factor allows for evaluation of changes in an accurate cerebral oxygenation without influence of extracranial blood flow by NIRS applied to the forehead.
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J Clin Monit Comput · Apr 2016
Comparative StudyComparison of foot finding methods for deriving instantaneous pulse rates from photoplethysmographic signals.
The suitability of different methods of finding the foot point of a pulse as measured using earlobe photoplethysmography during stationary conditions was investigated. Instantaneous pulse period (PP) values from PPG signals recorded from the ear in healthy volunteer subjects were compared with simultaneous ECG-derived cardiac periods (RR interval). Six methods of deriving pulse period were used, each based on a different method of finding specific landmark points on the PPG waveform. ⋯ No significant differences between PP and RR were seen for all PPG methods, however the PRV variables derived using all methods showed significant differences to HRV, attributable to the sensitivity of PRV parameters to pulse transients and artifacts. The results suggest that the intersecting tangents method shows the most promise for extracting accurate pulse rate variability data from PPG datasets. This work has applications in other areas where pulse arrival time is a key measurement including pulse wave velocity assessment.
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J Clin Monit Comput · Apr 2016
Comparative Study Controlled Clinical TrialDifferences in anatomical relationship between vertebral artery and internal jugular vein in children and adults measured by ultrasonography.
Cannulation of the internal jugular vein (IJV) under ultrasound guidance can reduce complications, such as common carotid artery (CCA) puncture, accidental vertebral artery (VA) puncture. However, these complications still occur, especially in pediatric patients probably due to anatomical predisposition of VA. This study compared differences in anatomical location of VA and IJV between pediatric and adult patients. ⋯ The anatomical relationships between IJV and CCA and that between IJV and VA were not different between children and adults. In children, VA was relatively larger and located closer to IJV than adults. The results call for careful attention to the position of VA during ultrasound-guided IJV cannulation especially in children.
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J Clin Monit Comput · Apr 2016
Assessment of the time-dependent need for stay in a high dependency unit (HDU) after major surgery by using data from an anesthesia information management system.
Admittance to a high dependency unit (HDU) is expensive. Patients who receive surgical treatment with 'low anterior resection of the rectum' (LAR) or 'abdominoperineal resection of the rectum' (APR) at our hospital are routinely treated in an HDU the first 16-24 h of the postoperative (PO) period. The aim of this study was to describe the extent of HDU-specific interventions given. ⋯ Another one-third of the patients had a need for HDU-specific therapies for more than ten consecutive hours, primarily an infusion of nor-epinephrine. Most patients treated with LAR or APR was in need of an HDU-specific intervention during the first 6 h of the PO-period, with a marked decline after this time period. The applied methodology, using an AIMS, demonstrates that there is great variability in individual patients' postoperative needs after major surgery, and that these needs are dynamic in their nature.