Journal of clinical monitoring and computing
-
J Clin Monit Comput · Jun 2013
Heart rate variability analysis during central hypovolemia using wavelet transformation.
Detection of hypovolemia prior to overt hemodynamic decompensation remains an elusive goal in the treatment of critically injured patients in both civilian and combat settings. Monitoring of heart rate variability has been advocated as a potential means to monitor the rapid changes in the physiological state of hemorrhaging patients, with the most popular methods involving calculation of the R-R interval signal's power spectral density (PSD) or use of fractal dimensions (FD). However, the latter method poses technical challenges, while the former is best suited to stationary signals rather than the non-stationary R-R interval. ⋯ Results demonstrate that the proposed DWT-based model outperforms individual PSD and FD methods as well as the combination of these two traditional methods at both sample rates of 500 Hz (p value <0.0001) and 125 Hz (p value <0.0001) in detecting the degree of hypovolemia. These findings indicate the potential of the proposed DWT approach in monitoring the physiological changes caused by hemorrhage. The speed and relatively low computational costs in deriving these features may make it particularly suited for implementation in portable devices for remote monitoring.
-
J Clin Monit Comput · Jun 2013
Clinical refinement of the automatic lung parameter estimator (ALPE).
The automatic lung parameter estimator (ALPE) method was developed in 2002 for bedside estimation of pulmonary gas exchange using step changes in inspired oxygen fraction (FIO₂). Since then a number of studies have been conducted indicating the potential for clinical application and necessitating systems evolution to match clinical application. This paper describes and evaluates the evolution of the ALPE method from a research implementation (ALPE1) to two commercial implementations (ALPE2 and ALPE3). ⋯ Also for ALPE2, the automated FIO2 selection method was successfully applied in 287 patient cases, taking 7.2 ± 2.4 min and was shown to be safe with only one patient having SpO₂ < 86 % when the clinician disabled the alarms. The ALPE method has evolved into two practical, usable systems targeted at clinical application, namely ALPE2 for spontaneously breathing patients and ALPE3 for mechanically ventilated patients. These systems may promote the exploration of the use of more detailed descriptions of pulmonary gas exchange in clinical practice.
-
J Clin Monit Comput · Jun 2013
Comparative Study Observational StudyCardiac output monitoring in septic shock: evaluation of the third-generation Flotrac-Vigileo.
Continuous cardiac index (CI) monitoring is frequently used in critically ill patients. Few studies have compared the pulse contour-based device FloTrac/Vigileo to pulmonary artery thermodilution (PAC) in terms of accuracy for CI monitoring in septic shock. The aim of our study was to compare the third-generation FloTrac/Vigileo to PAC in septic shock. ⋯ The overall correlation coefficient between PAC-CI and FloTrac/Vigileo CI was 0.47 (p < 0.01), with r(2) = 0.22. The area under the curve of the ROC curve for detecting concordant and significant changes in CI was 0.72 (0.53; 0.87). In our study, third-generation Flowtrac-Vigileo appears to be too inaccurate to be recommended for CI monitoring in septic shock.
-
J Clin Monit Comput · Jun 2013
Randomized Controlled TrialThe effects of DEX premedication on volatile induction of mask anesthesia (VIMA) and sevoflurane requirements.
We investigated the effect of intravenous premedication with single dose of dexmedetomidine (DEX) on volatile anesthetic induction time and sevoflurane requirements of anesthesia maintenance in adults by monitoring the bispectral index (BIS). Sixty adult patients with status of ASA I-II undergoing general anesthesia with endotracheal intubation were randomly divided into two groups: The first group; a control group (group C, n = 30) and the second group; DEX group (group D, n = 30). Each patient in group D was premedicated with intravenous DEX 0.5 μg/kg or placebo 10 min before the induction of anesthesia. ⋯ Analgesic requirement was noted in postoperative 24 h-period. The time to induction of anesthesia (p < 0.0001) and Etsevoflurane at 1 min (p < 0.05) were significantly lower in group D than in group C. Intravenous premedication with 0.5 μg/kg of DEX decreased the induction time by almost 75 % and provided a significant decrease in Etsevoflurane.
-
J Clin Monit Comput · Jun 2013
Randomized Controlled TrialDifferential effects of propofol and sevoflurane on QT interval during anesthetic induction.
There have been conflicting reports on whether propofol prolongs, shortens, or does not change QT interval. The aim of this study was to determine the effect of target-controlled infusion (TCI) of propofol on heart rate-corrected QT (QTc) interval during anesthetic induction. We examined 50 patients undergoing lumbar spine surgery. ⋯ HR decreased after anesthetic induction and recovered after tracheal intubation in group P, whereas it did changed in group S throughout the study period. QTc interval was shortened at T3 and T4 in group P, but prolonged at T3, T4, and T5 in group S, as compared with T1. Propofol TCI shortens QTc interval, whereas sevoflurane prolongs QTc interval during anesthetic induction.