Anesthesia and analgesia
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Anesthesia and analgesia · Jun 1994
Comparative StudyTranstracheal Doppler cardiac output monitoring: comparison to thermodilution during noncardiac surgery.
The validity of transtracheal Doppler (TTD) cardiac output (CO) monitoring during noncardiac surgery has not been established. A prospective evaluation was undertaken in 30 patients undergoing noncardiac surgery to assess the agreement between TTD and thermodilution measurements of CO. Linear regression, Bland-Altman analysis, and receiver operator characteristic (ROC) techniques were employed to evaluate the accuracy, reliability, and trending capability of TTD monitoring. ⋯ Changes in TTD CO were highly correlated to changes in thermodilution CO (r = 0.81). ROC plots showed that changes in TTD CO reliably identified large (greater than 15%) changes in thermodilution CO with a sensitivity of 92% and a specificity of 87%. Clinical experience with the TTD device is needed to obtain accurate measurements.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Jun 1994
Specific gravities of desflurane, enflurane, halothane, isoflurane, and sevoflurane.
We determined the specific gravities of presently available volatile anesthetics in order to supply a consistent quantitative basis for calibration standards. Using four 50-mL volumetric flasks, we obtained the following values at 20 degrees C: desflurane 1.4651 +/- 0.0004 g/mL (mean +/- SD); enflurane 1.5230 +/- 0.0003 g/mL; halothane 1.8680 +/- 0.0007 g/mL; isoflurane 1.5019 +/- 0.0006 g/mL; and sevoflurane 1.5203 +/- 0.0008 g/mL. Measurements made at 0 degree C, 10 degrees C, 20 degrees C, and 25 degrees C (not for desflurane at 25 degrees C) revealed a decrease in specific gravity of 0.00250 +/- 0.00014 g/mL for each degree of increase in temperature. These data bear on the issue of cost for anesthetics that are stored as liquids, but used as gases.
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Anesthesia and analgesia · Jun 1994
A "bubble-tip" (Airguide) tracheal tube system: its effects on incidence of epistaxis and ease of tube advancement in the subglottic region during nasotracheal intubation.
Epistaxis and tubal obstruction in the subglottic region are difficulties encountered during nasotracheal intubation. Trauma to the nasal airway must be avoided, especially in patients receiving anticoagulant therapy. In addition, smooth passage of the tracheal tube through the larynx is desired. ⋯ The Airguide group had a significantly lower incidence of epistaxis (9/39 vs 13/26; P < 0.05; bleeding was not checked in one patient in the Standard group) and provided a significantly smoother passage in the subglottic region than the Standard group (tube impingement in the subglottic region, 0/39 vs 11/27; P < 0.01). There was no significant difference in the incidence of epistaxis between the subgroups with and without topical application of epinephrine. The Airguide helps to minimize epistaxis and increases navigability in the subglottic region during nasotracheal intubation.
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Anesthesia and analgesia · Jun 1994
Augmentation of calf blood flow by epinephrine infusion during lumbar epidural anesthesia.
Lower rates of deep vein thrombosis after hip surgery performed under epidural anesthesia were noted in patients who received intravenous epinephrine infusion. To determine whether this effect could be mediated by enhanced lower extremity blood flow, 12 patients were studied immediately preoperatively. ⋯ Calf vascular resistance decreased from 27.7 +/- 13.5 to 7.9 +/- 4.6 mmHg.mL-1.100 mL-1.min-1 after epidural anesthesia with epinephrine (2.7 +/- 1.0 micrograms/min) but was unchanged when norepinephrine (0.8 +/- 0.7 microgram/min) was infused. The augmentation of lower extremity blood flow when epinephrine is used in conjunction with epidural anesthesia may in part explain the low frequency of deep vein thrombosis with conduction anesthesia.