Journal of clinical monitoring and computing
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J Clin Monit Comput · Feb 1998
Assessment of pulmonary mechanics in mechanical ventilation: effects of imprecise breath detection, phase shift and noise.
In mechanical ventilation, the assessment of pulmonary mechanics, mainly of total compliance (Crs), total resistance (Rrs), and intrinsic positive end-expiratory pressure (PEEPint), is clinically important. By using airway pressure (Paw) and flow (V'aw), the least squares fit (LSF) method allows the continuous calculation of these parameters. The objective of this work was to study the influence of imprecise breath detection, phase shift between airway pressure and flow signals, and noise on the determination of Crs, Rrs, and PEEPint. ⋯ We conclude that the LSF method allows the assessment of Crs, Rrs, and PEEPint even with high levels of noise in patients with normal lungs provided that Paw and V'aw signals are precisely synchronised and a reliable breath detection algorithm is used.
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J Clin Monit Comput · Feb 1998
A formula to calculate oxygen uptake during low flow anesthesia based on FIO2 measurement.
Monitoring of oxygen uptake during general anesthesia would have several benefits, but unfortunately, this is usually not available in the clinical routine situation. The herein proposed formula to calculate oxygen uptake (. VO2) necessitates only the accurate measurement of FIO2 as well as fresh gas flow and composition. ⋯ In order to obtain representative results, calculation of. VO2 should be performed only after achievement of respiratory steady state conditions. Due to its simplicity and wide availability, it has the potential to become a valuable extension in anesthesia monitoring during the performance of routine general anesthesia.
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J Clin Monit Comput · Feb 1998
TWITCHER: a device to stimulate thumb twitch response to ulnar nerve stimulation.
To design and fabricate a device to simulate evoked thumb adduction in response to ulnar nerve stimulation. ⋯ TWITCHER has been well received by participants in simulation exercises including the use of neuromuscular blocking drugs.
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J Clin Monit Comput · Jan 1998
Randomized Controlled Trial Clinical TrialCraniofacial electromyogram activation response: another indicator of anesthetic depth.
After finding that craniofacial EMG preceding a stimulus was a poor predictor of movement response to that stimulus, we evaluated an alternative relation between EMG and movement: the difference in anesthetic depth between the endpoint of EMG responsiveness to a stimulus and endpoint of movement responsiveness to that stimulus. We expressed this relation as the increment of isoflurane between the two endpoints. ⋯ Our results suggest that, given the circumstances of our study, an EMG activation response by a nonmoving patient indicates that the patient is at an anesthetic level close to that at which movement could occur. However, because the first EMG activation response may occur simultaneously with movement, the EMG activation response cannot be relied upon to always herald a move response before it occurs. Our results also suggest that EMG responsiveness to a test stimulus may be used to estimate the anesthetic depth of an individual patient.