Journal of clinical monitoring and computing
-
J Clin Monit Comput · Apr 2016
Case ReportsEndovascular coil detachment causing EMG artefact in BIS: a mechanistic exploration.
Deployment of endovascular coils used in interventional neuroradiology commonly involves electrolytic detachment of the coil from the pusher catheter. This report describes a case of artefactual increase in electromyography (EMG) values of bispectral index (BIS) monitor during coil detachment. An explanation of this event is provided connecting mechanism of coil detachment and derivation of EMG values in a BIS monitor. While rising EMG values are thought to arise from frontalis contraction, they may as well be an unrecognized electrical artefact, especially in context of undistorted electroencephalography waveform.
-
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.
-
J Clin Monit Comput · Apr 2016
The effects of oxygen induced pulmonary vasoconstriction on bedside measurement of pulmonary gas exchange.
In patients with respiratory failure measurements of pulmonary gas exchange are of importance. The bedside automatic lung parameter estimator (ALPE) of pulmonary gas exchange is based on changes in inspired oxygen (FiO2) assuming that these changes do not affect pulmonary circulation. This assumption is investigated in this study. ⋯ Changes were immediately reversed on returning FiO2 towards baseline. In this study changes in MPAP and PVR are small and immediately reversible consistent with small changes in pulmonary gas exchange. This indicates that mild deoxygenation induced pulmonary vasoconstriction does not have significant influences on the ALPE parameters in patients after CABG.
-
J Clin Monit Comput · Apr 2016
Clinical TrialUltrasound evaluation of the radial artery for arterial catheterization in healthy anesthetized patients.
The purpose of this study was to assess the anatomy of the radial artery using ultrasound in anesthetized patients, and to correlate its anatomical data with patients' characteristics. The success rate of radial artery cannulation using ultrasound was also evaluated to analyze the relationship between the anatomical data and the success rate. Study 1 One hundred ninety-five patients scheduled for general anesthesia were enrolled. ⋯ Study 2 The first attempt success rate of arterial catheterization using ultrasound was 92.5 % using long-axis in-plane technique, regardless of patient's characteristics. For small sized adult patients, a 22G angio-catheter should be used during radial artery cannulation, because the radial artery diameter significantly correlated with BSA in healthy anesthetized patients. In addition, ultrasound-guided catheterization is recommended in elderly patients because the incidence of abnormal angle between the radial artery and skin surface was high.