Anesthesia and analgesia
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Anesthesia and analgesia · Feb 1995
Randomized Controlled Trial Clinical TrialEfficacy of an epidural test dose in adult patients anesthetized with isoflurane: lidocaine containing 15 micrograms epinephrine reliably increases arterial blood pressure, but not heart rate.
When continuous epidural anesthesia is combined with general anesthesia, the only objective sign of intravascular migration of the epidural catheter are the increments of heart rate (HR) or arterial blood pressure after a local anesthetic test dose containing epinephrine. However, the efficacy of a simulated intravenous (IV) test dose in adult patients under general anesthesia has not been determined. Thirty adult patients were randomly assigned to one of two groups, each of which was anesthetized with 1% end-tidal isoflurane and nitrous oxide after endotracheal intubation. ⋯ In the epinephrine group, significant increases in HR compared with the baseline value were observed from 40 to 80 s after the IV test dose with a mean maximum HR increase of 24 +/- 2 bpm (mean +/- SEM) occurring at 48 +/- 3 s. However, 5 of 15 patients in the epinephrine group developed HR increments smaller than 20 bpm (sensitivity 67%). Since HRs were essentially unchanged in the saline group, specificity, positive predictive value (+PV), and negative predictive value (-PV) were 100%, 100%, and 75%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Feb 1995
Randomized Controlled Trial Clinical TrialPharmacokinetics and pharmacodynamics of oxycodone when given intravenously and rectally to adult patients with cancer pain.
The single-dose pharmacokinetics and pharmacodynamics of oxycodone administered by the intravenous and rectal routes were determined in 12 adult cancer patients with moderate to severe cancer pain (visual analog scale [VAS] score, approximately 5). Oxycodone was administered by the intravenous and rectal routes with open drug administration and a cross-over design. After single-dose intravenous administration (7.9 +/- 1.5 mg, mean +/- SD), the mean (+/- SD) terminal half-life was 3.4 h (+/- 1.1), the mean (+/- SD) plasma clearance was 45.4 L/h (+/- 10.1), and the mean (+/- SD) volume of distribution in the terminal phase was 3.0 L/kg (+/- 1.1). ⋯ However, rectal oxycodone provided analgesia of much longer duration (approximately 8-12 h) than did intravenous oxycodone (approximately 4 h). There were no significant differences (P > 0.05) in the incidence and severity of side effects between intravenous and rectal oxycodone. The marked interindividual variation observed in the pharmacokinetics and pharmacodynamics of oxycodone in this study emphasizes the need for individualized dosing regimens.
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Anesthesia and analgesia · Feb 1995
Case ReportsThe risk of infection from epidural analgesia in children: a review of 1620 cases.
We reviewed cases to determine whether suspected or confirmed epidural infection was associated with epidural analgesia for 1620 infants, children, and adolescents treated over a 6-yr period at Children's Hospital, Boston. Postoperative patients (1458/1620) received epidural infusions for a median of 2 days (range, 0-8 days). No postoperative patient had an epidural abscess. ⋯ A second oncology patient and two patients with reflex sympathetic dystrophy were evaluated for epidural abscess, but none was found. We conclude that the risk of epidural infection is quite low in pediatric postoperative patients receiving short-term catheterization. Use of prolonged epidural analgesia in the management of chronic pain in children requires careful monitoring of warning signs of infection.
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A fiberoptic bronchoscope is used to facilitate tracheal intubation in cases of difficult direct laryngoscopy. Occasionally, difficulty is encountered in advancing the endotracheal tube after the fiberoptic bronchoscope has been introduced into the trachea. This study tested the feasibility of providing jet ventilation through the suction channel of the fiberoptic bronchoscope as an interim measure under those or similar circumstances. ⋯ Jet ventilation was manually performed at the rate of 12/min for 10 min. In the mechanical test lung, the tidal volumes with 1.2-, 1.5-, and 2-mm suction channels were as follows: 280 mL, 490 mL, and 880 mL, respectively, at a compliance of 50 mL/cm H2O and normal resistance; 260 mL, 470 mL, and 820 mL, respectively, at a compliance of 50 mL/cm H2O and high resistance to simulate bronchospasm; 130 mL, 270 mL, and 890 mL, respectively, at a compliance of 20 mL/cm H2O and normal resistance; 120 mL, 220 mL, and 810 mL, respectively, at a compliance of 20 mL/cm H2O and high resistance. In anesthetized, paralyzed patients, oxygen saturation was 96% or more throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Feb 1995
Detection of tissue hypoxia by arteriovenous gradient for PCO2 and pH in anesthetized dogs during progressive hemorrhage.
The present study tested the hypothesis that, during acute bleeding, the development of tissue hypoxia might be reflected by an abrupt widening in arteriovenous gradient for PCO2 (AV PCO2) and for pH (AV pH) as accurately as by an increase in blood lactate levels. Twenty-four anesthetized (isoflurane 1.4% end-tidal), paralyzed, and mechanically ventilated dogs submitted to progressive hemorrhage were studied. Oxygen uptake (VO2) was derived from expired gas analysis and oxygen delivery (DO2) was calculated by the product of the thermodilution cardiac index and the arterial O2 content. ⋯ The critical value of DO2 obtained from blood lactate, AV PCO2 and AV pH were similar to those obtained from VO2 (8.60 +/- 1.12; 8.73 +/- 1.40; 8.78 +/- 1.37, respectively; P = not significant). A significant correlation was found, during the hemorrhage protocol, between blood lactate and AV PCO2 (r = 0.84; P < 0.001) or AV pH (r = 0.78; P < 0.001). Therefore, AV PCO2 and AV pH represent simple but reliable indicators of tissue hypoxia during hemorrhagic shock.