Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2016
Comparative StudyAccuracy of CO2 monitoring via nasal cannulas and oral bite blocks during sedation for esophagogastroduodenoscopy.
Esophagogastroduodenoscopy procedures are typically performed under conscious sedation. Drug-induced respiratory depression is a major cause of serious adverse effects during sedation. Capnographic monitoring of respiratory activity improves patient safety during procedural sedation. ⋯ The two nasal cannulas without oral cups failed to provide sufficient CO2 for breath detection when the mouth was fully open and oxygen was delivered at 10 L/min. Our simulation found that respiratory rate can be accurately monitored during the procedure using a CO2 sampling bite block or a nasal cannula with oral cup. The accuracy of PETCO2 measurements depends on the device used, the amount of supplement oxygen, the amount of oral breathing and the patient's minute ventilation.
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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.