Journal of clinical monitoring and computing
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The Systolic pressure variation (SPV) is known to be a sensitive indicator of hypovolemia. However, the SPV may be elevated due to other reasons, such as changes in lung compliance or tidal volumes. Using the SPV to monitor the hemodynamic status of patients in the prone position may, therefore, be problematic due to possible effects of increased abdominal pressure on both venous return and lung compliance. The purpose of this study is to examine whether or not the SPV changes significantly when placing the patient in the prone position. ⋯ This study is important because it shows for the first time that the SPV does not change significantly in the prone position, and may therefore continue to be used as an indicator of the volume status. It also would appear to indicate that our methods for protecting the chest and abdomen in the prone position are effective.
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J Clin Monit Comput · Oct 2009
Clinical TrialA novel electronic algorithm for detecting potentially insufficient anesthesia: implications for the prevention of intraoperative awareness.
A recent clinical trial compared a minimum alveolar concentration (MAC)-based protocol to an electroencephalography (EEG)-based protocol for the prevention of intraoperative awareness. One limitation of this study design is that MAC-based protocols are not sensitive to the use of intravenous agents, while EEG-based protocols are. Our objective was to develop a MAC alert that incorporates intravenous agents. ⋯ Our novel electronic alerting system incorporates both age-adjusted MAC and intravenous anesthesia, and triggers with a higher frequency in cases of awareness. These data suggest the potential for our system to alert clinicians to insufficient anesthesia.
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J Clin Monit Comput · Oct 2009
Comparative Study Controlled Clinical TrialComparative pharmacodynamic modeling of desflurane, sevoflurane and isoflurane.
We compared dose-response curves of the hypnotic effects of desflurane, sevoflurane and isoflurane. In addition, we analyzed the k(e0) values of the different anesthetics. The EEG parameters Bispectral index (BIS, Aspect Medical Systems, Natick, MA, version XP) and Narcotrend index (MonitorTechnik, Bad Bramstedt, Germany, version 4.0) were used as measures of the pharmacodynamic effect. ⋯ The first order rate constant (k(e0) value) determining the equilibration between age-related MAC values and MAC effect site concentration is substantially higher for desflurane than for sevoflurane or isoflurane.
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J Clin Monit Comput · Oct 2009
Comparative StudyThe mean machine; accurate non-invasive blood pressure measurement in the critically ill patient.
Accurate indirect prehospital blood pressure measurement in the critically ill patient remains an important challenge to both patient management and prehospital research. Ambulatory blood pressure measuring devices have not been trialled for prehospital use in critically ill patients. Prior to prehospital validation where conditions are suboptimal, we aimed to test under favourable conditions in the Intensive Care Unit, a selection of ambulatory devices that may be suitable for use in the field. ⋯ In the Intensive Care Unit, the performance of one device, the Oscar 2, surpassed the others and fulfilled the AAMI protocol criteria for mean pressure measurement. This device is suitable for prehospital validation.
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J Clin Monit Comput · Oct 2009
Comparative StudyA comparison of vital signs charted by nurses with automated acquired values using waveform quality indices.
(1) To investigate if there exist any discrepancies between the values of vital signs charted by nurses and those recorded by bedside monitors for a group of patients admitted for neurocritical care. (2) To investigate possible interpretations of discrepancies by exploring information in the alarm messages and the raw waveform data from monitors. ⋯ Charted vital signs reflect in large the raw data as reported by bedside monitors. Poor signal quality could partially explain the existence of cases of large discrepancies.