Anesthesia and analgesia
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Anesthesia and analgesia · Nov 2000
Randomized Controlled Trial Comparative Study Clinical TrialPart II: total episode costs in a randomized, controlled trial of the effectiveness of four anesthetics.
Newer anesthetics promise improved clinical outcomes, but usually come at a higher price per dose. Previous studies have found few economic benefits in the immediate postoperative period, but have hypothesized that earlier recovery may lead to lower costs for the whole episode of hospitalization. This study uses cost data for patients enrolled in a randomized, controlled clinical trial comparing four anesthetics to test whether the higher costs of the newer anesthetics would be offset against decreased use of other hospital resources. Five hundred general surgery patients were randomly assigned to one of four anesthetic regimens. Estimates from the hospital's patient costing system were used, with validated cost records for a subset of 360 patients. Five patients admitted to the intensive care unit or requiring prolonged hospitalization skewed the distribution of costs, but none of these complications could be attributed to anesthesia. No significant differences were found on length of stay, mean episode cost, operating room costs, ward costs, or readmission rate within 3 mo. The study was not powered to sufficiently show differences in intensive care unit admission or other uncommon outcomes. Patient quality of recovery did not vary among groups, but neither patient willingness-to-pay nor satisfaction were directly measured. ⋯ Propofol and sevoflurane do not offer any significant economic advantages over thiopental and isoflurane in adults undergoing elective inpatient surgery.
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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.
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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
Multicenter StudyIs there a learning curve associated with the use of remifentanil?
This study prospectively determined whether there was a learning curve with the use of remifentanil, as indicated by decreased hemodynamic variability, improved recovery profile, and decreased incidence of opioid-related adverse events with increasing experience. Patients undergoing diverse surgical procedures (outpatient [n = 1340] and inpatient [n = 560]) were enrolled by investigators (n = 190) who had no previous experience with remifentanil use. Each investigator enrolled 10 patients. A standardized protocol for administration of remifentanil was used. Data were analyzed to determine differences between the first three patients and the last three patients enrolled for each anesthesiologist in the study. There were no differences in hemodynamic variables between the first triad and the last triad in either outpatients or inpatients. Requirements for hypnotic drugs and the doses of remifentanil used were also similar between groups. Analgesic medications administered at the end of surgery and in the postanesthesia care unit (PACU) were similar between groups, except that the last triad in the outpatient group received smaller doses of fentanyl compared with the first triad. Times to response to verbal command, tracheal extubation, and operating room discharge did not differ between groups. However, patients in the last triad undergoing outpatient surgery had shorter times to eligibility for PACU discharge, but times to eligibility for discharge home did not differ. The overall incidence of all adverse events (i.e., hypotension, hypertension, muscle rigidity, respiratory depression, apnea, nausea, and vomiting) was less in the last triad as compared with the first triad. When analyzed separately, only the incidence of vomiting (in the outpatient group) was decreased in the last triad as compared with the first triad. This study suggests that there is a learning curve that aids reduction of minor adverse effects associated with the use of analgesic medications administered at the end of surgery in outpatients, which might have reduced the incidence of postoperative vomiting and the duration of PACU stay. ⋯ This study demonstrated that anesthesiologists rapidly acquire the ability to use remifentanil with limited experience. However, there is a learning curve that aids reduction of minor adverse effects associated with the use of analgesic medications administered at the end of surgery in outpatients, which might have reduced the incidence of postoperative vomiting and the duration of postanesthesia care unit stay.
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Anesthesia and analgesia · Nov 2000
Comparative Study Clinical TrialThromboelastography as a perioperative measure of anticoagulation resulting from low molecular weight heparin: a comparison with anti-Xa concentrations.
Low molecular weight heparin (LMWH) is commonly used to prevent postoperative thromboembolism. Currently, there is no convenient test to measure the degree of anticoagulation from LMWH. This prospective study examines the relationship of thromboelastography and serum anti-Xa concentration in patients treated with enoxaparin. Twenty-four adult patients scheduled for orthopedic surgery using epidural anesthesia were enrolled. Epidural catheters were removed the morning after surgery before the commencement of subcutaneous enoxaparin 30 mg twice daily. Venous blood samples were obtained at 1) the induction of anesthesia (baseline), 2) immediately before the third dose of enoxaparin postoperatively (Day 2-trough), 3) 4 h after the third dose postoperatively (Day 2-peak), and 4) immediately before the fifth dose postoperatively (Day 3-trough). Whole blood samples were obtained for thromboelastography, activated clotting time, and anti-Xa level analyses at each of the four time intervals. At the four sample intervals, the r time (mean +/- SEM). (20 +/- 1, 25 +/- 2, 51 +/- 6, 31 +/- 3 mm) and the k time (9 +/- 0. 7, 12 +/- 1, 27 +/- 5, 14 +/- 2 mm) of the thromboelastograph were significantly correlated with the expected peak and trough levels of LMWH and serum anti-Xa levels (P: < 0.05). At the Day 3-trough, thromboelastograph r times exceeded the normal range in 6 of 25 patients (25%). Prolongation of r time and k time on postoperative Day 3 may indicate an exaggerated response to LMWH. Thromboelastography is a test that could potentially correlate with the degree of anticoagulation produced by low molecular weight heparin. ⋯ Thromboelastography is a test that could potentially correlate with the degree of anticoagulation produced by low molecular weight heparin. The r time from the thromboelastogram correlates with serum anti-Xa concentration.