Journal of clinical monitoring
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Comparative Study
Measurement of respiratory rate and timing using a nasal thermocouple.
The aims of this study were to assess aspects of the response of a small thermocouple to temperature change, and to evaluate whether such a thermocouple could be used intermittently to measure respiratory rate and timing by detecting the changes in nasal temperature occurring with breathing. ⋯ Intermittent measurements of respiratory rate and timing using a nasal thermocouple accurately reflected measurements obtained from nasal airflow using a pneumotachograph.
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The objective of our study was to establish the refractive indices and the virial coefficients of the volatile anesthetic vapors. These indices and coefficients will allow refractometry to be used by manufacturers to produce accurate calibration, without requiring expensive high-precision calibration gases. ⋯ If refractometry replaced calibration gases in cylinders, as a calibration standard, manufacturers might avoid errors that now occur because calibration gases manufactured by numerous companies seem to differ. We propose that our values serve as an interim database.
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Medical mass spectrometers are configured to detect and measure specific respiratory and anesthetic gases. Unrecognized gases entering these systems may cause erroneous readings. We determined how the Advantage 1100 (Perkin-Elmer, now Marquette Gas Systems, Milwaukee, WI) and PPG-SARA (PPG Biomedical Systems, Lenexa, KS) systems that were not configured to measure desflurane or sevoflurane respond to increasing concentrations of these new potent volatile anesthetic agents. ⋯ Advantage 1100 and PPG-SARA systems not configured for desflurane or sevoflurane display erroneous anesthetic agent readings when these new agents are sampled. Advantage 1100 also displays falsely elevated carbon dioxide readings when desflurane is sampled.