Journal of clinical monitoring and computing
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J Clin Monit Comput · Dec 2005
Analysis of nighttime activity and daytime pain in patients with chronic back pain using a self-organizing map neural network.
There may be a relationship between sleep and pain in patients with chronic back pain. We collected day-time pain and nighttime activity data from 18 patients diagnosed with chronic back pain. The patients were followed for 6 days and 5 nights. ⋯ Patients who experience large fluctuations in daytime pain levels also show a higher variability in their nighttime activity levels and patterns. Even though we were unable to show a direct relationship between daytime pain and sleep, it may be reasonable to assume that better pain control resulting in less daytime pain fluctuations can provide more stable nighttime activity levels and patterns in this limited group of patients. By using a neural network model, we were able to extract information from the nighttime activity levels even though a traditional statistical analysis was unsuccessful.
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J Clin Monit Comput · Dec 2005
Comparative StudyComparison of the EEG-based SNAP index and the Bispectral (BIS) index during sevoflurane-nitrous oxide anaesthesia.
The BIS monitor (Aspect Medical Inc, Newton, USA) was the first electroencephalogram (EEG)-based monitor of the hypnotic effect reflected by a dimensionless figure ranging from 100 (awake state) to 0 (flat line EEG). Its widespread use makes it the most-studied and the best-known among same intended devices. Its algorithm processes low-frequency EEG oscillations in order to provide the Bispectral index. ⋯ The Bland and Altman test showed a bias of 14.3 for SNAP index values with respect to BIS index values. We concluded that the SNAP index correlates with variations in the hypnotic effect induced by sevoflurane-nitrous oxide anaesthesia when compared with the BIS index. In this context, a SNAP index ranging from 58 to 70 would be equivalent to the BIS index range 40 to 60 and, therefore, the accurate for surgical performance.
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J Clin Monit Comput · Dec 2005
Comparative StudyCardiac output measurement by pulse dye densitometry: comparison with pulmonary artery thermodilution in post-cardiac surgery patients.
Pulse-dye densitometry (PDD) could be a suitable, low-invasive alternative to thermodilution using a pulmonary artery catheter (PAC) for monitoring cardiac output. The aim of our study was to assess the reproducibility and validity of PDD compared to PAC-thermodilution. ⋯ PDD correlates well with PAC-thermodilution and thus deserves consideration as a low-invasive alternative for measurement and follow-up of cardiac output.
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J Clin Monit Comput · Dec 2005
A mathematical model of differential tracheal tube cuff pressure: effects of diffusion and temperature.
The tracheal tube cuff performs an important function during anesthesia and critical care situations by allowing positive pressure ventilation and isolating the lungs from aspiration. Other maneuvers, such as pressure support ventilation and positive end-expiratory pressure, are also cuff-dependent. However, excessive cuff pressure, as well as long-term intubation without excessive cuff pressure, have been associated with significant morbidity and mortality. ⋯ This model incorporates compliance, temperature variation, and net molar diffusion in determining differential tracheal tube cuff pressure. In addition, temperature and diffusion are modeled as separate processes which effect differential cuff pressure independently. Support for the validity of this model is based upon an analysis of existing data from prior studies.
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J Clin Monit Comput · Dec 2005
Practice GuidelineIntraoperative monitoring of segmental spinal nerve root function with free-run and electrically-triggered electromyography and spinal cord function with reflexes and F-responses. A position statement by the American Society of Neurophysiological Monitoring.
Orthodromic ascending somatosensory evoked potentials and antidromic descending neurogenic somatosensory evoked potentials monitor spinal cord sensory function. Transcranial motor stimulation monitors spinal cord motor function but only activates 4-5% of the motor units innervating a muscle. Therefore, 95-96% of the motor spinal cord systems activating the motor units are not monitored. To provide more comprehensive monitoring, 11 techniques have been developed to monitor motor nerve root and spinal cord motor function. These techniques include: 1. neuromuscular junction monitoring, 2. recording free-run electromyography (EMG) for monitoring segmental spinal nerve root function, 3. electrical stimulation to help determine the correct placement of pedicle screws, 4. electrical impedance testing to help determine the correct placement of pedicle screws, 5. electrical stimulation of motor spinal nerve roots, 6. electrical stimulation to help determine the correct placement of iliosacral screws, 7. recording H-reflexes, 8. recording F-responses, 9. recording the sacral reflex, 10. recording intralimb and interlimb reflexes and 11. recording monosynaptic and polysynaptic reflexes during dorsal root rhizotomy. ⋯ The techniques reviewed in this paper may be helpful to those wishing to incorporate these techniques into their monitoring program.