Anesthesia and analgesia
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Anesthesia and analgesia · Nov 2000
Randomized Controlled Trial Clinical TrialTranexamic acid reduces blood loss in total hip replacement surgery.
Intraoperatively administered, tranexamic acid (TA) does not reduce bleeding in total hip replacement (THR). Therefore, its prophylactic use was attempted in the present study because this has been shown to be more effective in cardiac surgery. We investigated 40 patients undergoing THR in a prospective, randomized, double-blinded study. Twenty patients received TA given in two bolus doses of 10 mg/kg each, the first just before surgical incision and the second 3 h later. In addition, a continuous infusion of TA, 1.0 mg. kg(-1). h(-1) for 10 h, was given after the first bolus dose. The remaining 20 patients formed a control group. Both groups used preoperative autologous blood donation and intraoperative autotransfusion. Intraoperative bleeding was significantly less (P: = 0.001) in the TA group compared with the control group (630 +/- 220 mL vs 850 +/- 260 mL). Postoperative drainage bleeding was correspondingly less (P: = 0.001) (520 +/- 280 vs 920 +/- 410 mL). Up to 10 h postoperatively, plasma D-dimer concentration was halved in the TA group compared with the control group. One patient in each group had an ultrasound-verified late deep vein thrombosis. In conclusion, we found TA, administrated before surgical incision, to be efficient in reducing bleeding during THR. ⋯ In a prospective, double-blinded study of 40 patients undergoing total hip replacement, the preoperative administration of tranexamic acid reduced bleeding by 35%, probably by decreasing induced fibrinolysis. Whether tranexamic acid therapy can replace predonation of autologous blood or intraoperative autotransfusion requires further study.
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Anesthesia and analgesia · Nov 2000
Randomized Controlled Trial Clinical TrialThe efficacy of hemodynamic and T wave criteria for detecting intravascular injection of epinephrine test doses in anesthetized adults: a dose-response study.
Recent studies have shown that an epidural test dose containing 15 microg of epinephrine has a sensitivity and specificity of 100% for detecting intravascular injection based on the systolic blood pressure (SBP) (positive if > or =15-mm Hg increase) and the T wave criteria (positive if > or =0.1 mV and 25% decrease in amplitude), whereas the modified heart rate (HR) criterion (positive if > or =10-bpm increase) produced uncertain results in sevoflurane-anesthetized adults. Because a fractional dose of the test dose may be injected intravascularly in actual clinical situations, we designed this study to determine, in a dose-related manner, the efficacy and minimum effective dose of epinephrine based on those hemodynamic and the T wave criteria. Eighty healthy adult patients were randomly assigned to one of four groups according to a simulated IV test dose under 2% end-tidal sevoflurane and nitrous oxide anesthesia after endotracheal intubation (n = 20 each). The saline group received 3 mL of normal saline IV; the epinephrine-15 group received 3 mL of 1.5% lidocaine containing 15 microg of epinephrine (1); and the epinephrine-10 and -5 groups received 2 and 1 mL of the test dose of the identical components, respectively. HR, SBP, and lead II of the electrocardiograph were recorded continuously for 5 min after the IV injection of the study drug. Sensitivities and specificities of 100% were obtained based on the HR and the SBP criteria only if 15 microg of epinephrine was injected IV, whereas sensitivities and specificities of 100% were obtained based on both T wave criteria after 15 and 10 microg of epinephrine was injected IV. Two blinded observers were able to detect all T wave changes in patients who received 15, 10, and 5 microg of epinephrine IV, resulting in 100% efficacy (P: < 0.05 versus HR and SBP criteria). We conclude that minimum effective epinephrine doses for detecting accidental intravascular injection are 15 microg on the HR and the SBP criteria, and 10 microg on both T wave criteria, and that observing T wave changes may detect even smaller (5 microg) doses of epinephrine injected IV in adult patients anesthetized with sevoflurane and nitrous oxide. ⋯ To determine whether an epidural catheter is in a blood vessel, an epidural test dose containing 15 microg of epinephrine is used. We found that a decrease in T wave amplitude appears to be more sensitive than heart rate and systolic blood pressure change for detecting accidental intravascular injection of a small dose of epinephrine-containing test dose in sevoflurane-anesthetized patients.
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Anesthesia and analgesia · Nov 2000
Randomized Controlled Trial Clinical TrialCervical spine motion during airway management: a cinefluoroscopic study of the posteriorly destabilized third cervical vertebrae in human cadavers.
We conducted a randomized, controlled, crossover study to determine cervical spine motion for six airway management techniques in human cadavers with a posteriorly destabilized third cervical (C-3) vertebra. A destabilized C-3 segment was created in 10 cadavers (6-24 h postmortem). Cervical motion was recorded by continuous lateral fluoroscopy. The following airway management techniques were performed in random order on each cadaver with manual in-line stabilization applied: face mask ventilation (FM), laryngoscope-guided orotracheal intubation (OETT), fiberscope-guided nasal intubation (FOS-NETT), esophageal tracheal Combitube((R)) (Kendall-Sheridan, Neustadt, Germany) insertion (ETC), intubating laryngeal mask insertion with fiberscope-guided tracheal intubation (ILM-OETT), and laryngeal mask airway insertion (LMA). Afterward, maximum head-neck flexion (FLEX-MAX) and maximum head-neck extension (EXT-MAX) without manual in-line stabilization was performed to determine maximum motion. The maximum posterior displacement of C-3 and the maximum segmental sagittal motion of C2-3 were determined. There was a significant increase in posterior displacement for the FM (1.9 +/- 1.2 mm, P: < 0.01), OETT (2.6 +/- 1.6 mm, P: < 0.0001), ETC (3.2 +/- 1.6 mm, P: < 0.0001), ILM-OETT (1.7 +/- 1.3 mm, P: < 0. 01), LMA (1.7 +/- 1.3 mm, P: < 0.01), FLEX-MAX (3.7 +/- 1.9 mm, P: < 0.0001), EXT-MAX (1.8 +/- 1.7, P: < 0.01), however, not for FOS-NETT (0.1 +/- 0.7 mm). Posterior displacement was less for the ILM-OETT and LMA than for the ETC (both P: < 0.04). There were no significant increases in segmental sagittal motion with any airway manipulation other than with FLEX-MAX (-4.5 +/- 4.0 degrees, P: < 0.01). Posterior displacement was similar to FLEX-MAX for the OETT and ETC; however, it was less for the FM, FOS-NETT, ILM-OETT, and LMA (all P: < 0.01). Posterior displacement was similar to EXT-MAX for all airway manipulations other than for FOS-NETT (P: < 0.001). For cervical motion and the techniques tested, the safest method of airway management in a patient with a posteriorly destabilized C-3 segment is FOS-NETT. LMA devices may be preferable to the ETC. ⋯ In the cadaver model of a destabilized third cervical vertebrae, significant displacement of the injured segment occurs during airway management with the face mask, laryngoscope-guided oral intubation, the esophageal tracheal Combitube (Kendall-Sheridan, Neustadt, Germany), the intubating and standard laryngeal mask airway; but not with fiberscope-guided nasal intubation. For cervical motion and the techniques tested, the safest airway technique with this injury is fiberscope-guided nasotracheal intubation. Laryngeal mask devices are preferable to the esophageal tracheal Combitube.