Journal of clinical monitoring and computing
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J Clin Monit Comput · Jun 2013
Near real-time notification of gaps in cuff blood pressure recordings for improved patient monitoring.
Blood pressure monitoring during anesthesia is an American Society of Anesthesiology standard. However, the anesthesia provider sometimes fails to engage the patient monitor to make periodic (generally every 3-5 min) measurements of Non-Invasive Blood Pressure (NIBP), which can lead to extended periods (>5 min) when blood pressure is not monitored. We describe a system to automatically detect such gaps in NIBP measurement and notify clinicians in real-time to initiate measurement. ⋯ The maximum gap encountered before SAM was 64 min, while it was 27 min with SAM notification. Real-time notification using SAM is an effective way to reduce both the number of instances and the duration of inadvertent, extended (>15 min) gaps in blood pressure measurements in the operating room. However, the frequency of gaps <15 min could not be reduced using the current configuration of SAM.
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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.
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Heart rate variability (HRV) is a non-invasive method to measure cardiac autonomic function. Impairments in HRV have been proposed as independent risk factor for increased cardiac mortality and morbidity. Cardio protective phenomenon in females has been hypothesized to be due to differential autonomic tone. ⋯ Sympathetic tone predominates and vagal tone diminishes with aging process. Females showed greater vagal tone than male. This differential autonomic tone indicate age, gender related predisposition to cardiovascular disease.
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J Clin Monit Comput · Jun 2013
Clinical TrialDevelopment of a practicable non-contact bedside autonomic activation monitoring system using microwave radars and its clinical application in elderly people.
We developed a practicable, non-contact, autonomic activation monitoring system using microwave radars without imposing any stress on monitored individuals. Recently, the rapid increase in the aging population has raised concerns in developed countries. Thus, hospitals and care facilities will need to perform long-term health monitoring of elderly patients. ⋯ Previous studies using conventional ECG reveal that diabetic neuropathy decreases LF, and also MI causes parasympathetic attenuation which leads to HF reduction. Our study showed that average SDNN of post-MI patients is smaller than 50 ms which is known to have high mortality. The non-contact autonomic activation monitoring system allows a long-term health management especially during sleeping hours for elderly people at healthcare facilities.
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J Clin Monit Comput · Jun 2013
Reference values for volumetric capnography-derived non-invasive parameters in healthy individuals.
The aim of this study was to determine typical values for non-invasive volumetric capnography (VCap) parameters for healthy volunteers and anesthetized individuals. VCap was obtained by a capnograph connected to the airway opening. We prospectively studied 33 healthy volunteers 32 ± 6 years of age weighing 70 ± 13 kg at a height of 171 ± 11 cm in the supine position. ⋯ Volunteers showed better clearance of CO₂ compared to anesthetized patients as indicated by (median and interquartile range): (1) an increased elimination of CO₂ per mL of VT of 0.028 (0.005) in volunteers versus 0.023 (0.003) in anesthetized patients, p < 0.05; (2) a lower normalized slope of phase III of 0.26 (0.17) in volunteers versus 0.39 (0.38) in anesthetized patients, p < 0.05; and (3) a lower Bohr dead space ratio of 0.23 (0.05) in volunteers versus 0.28 (0.05) in anesthetized patients, p < 0.05. This study presents reference values for non-invasive volumetric capnography-derived parameters in healthy individuals. Mechanical ventilation and anesthesia altered these values significantly.