Journal of clinical monitoring
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Comparative Study
EEG Predicts movement response to surgical stimuli during general anesthesia with combinations of isoflurane, 70% N2O, and fentanyl.
Our objective was to evaluate the performance of the EEG as an indicator of anesthetic depth by measuring EEG prediction of movement response to surgical stimuli. ⋯ The EEG, expressed as F95, predicted movement response to surgical stimuli during combinations of isoflurane, 70% N2O, and fentanyl. The F95-response curves shifted upward on the frequency scale for the less intense stimuli and for anesthetic techniques using 70% N2O, fentanyl, or both. F95 prediction of movement response appeared to be related to anesthetic agent doses. Our F95-response curves may provide helpful guidelines for using F95 to titrate the administration of anesthetic agents and for assessing the depth of general anesthesia.
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To compare values measured by a continuous intra-arterial blood gas monitoring system with those measured by conventional blood gas analyzer for the assessment of the clinical performance of a new device for measurement of PaO2, PaCO2, and arterial pH. ⋯ The PO2 and pH values derived from an intra-arterial blood gas monitoring system agreed well with the values measured by a conventional blood gas analyzer. However, the PCO2 value must be corrected due to an increase of drift, especially with extended use for more than 72 hours.
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The Ultima SV respiratory monitor can be used to monitor the intraoperative effects of the lateral decubitus position and one-lung ventilation on ventilatory mechanics. ⋯ One-lung ventilation caused several changes in the whole respiratory system (lung, thorax, and endotracheal tube). Continuous monitoring of flow-rate-volume or pressure-volume loops with in-line spirometry provided comprehensive information regarding parameters in one-lung ventilation.
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Comparative Study
Performance of erroneously filled sevoflurane, enflurane and other agent-specific vaporizers.
Erroneous filling of an agent-specific anesthesia vaporizer may result in concentration and potency outputs that are very different from those expected from the concentration dial setting. Enflurane and sevoflurane have relatively similar saturated vapor pressures (SVPs 175 mmHg and 160 mmHg, respectively, at 20 degrees C) and potencies (MACs 1.68% and 2%, respectively). We derived an equation to relate the vapor concentration output of an agent-specific vaporizer to the gas inflow splitting ratio (SR) created by the vaporizer and the SVP of the potent inhaled agent. ⋯ When an agent-specific variable bypass vaporizer is erroneously filled, the vapor concentration outputs can be predicted from the splitting ratio created by setting the vaporizer concentration dial and the SVP of the agent.
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To test whether a neural network-based method could differentiate between tracheal and esophageal intubation in anesthetized patients by recognizing breathing circuit pressure and flow waveform patterns. ⋯ A neural network differentiated consistently tracheal from esophageal intubation when the ventilation test mode was used. The ventilation mode employed is feasible in most adult patients undergoing elective procedures under general anesthesia. Further research is required to train neural networks to recognize esophageal intubation in different age groups and when different ventilation modes are applied.