Anesthesia and analgesia
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Anesthesia and analgesia · Feb 2003
Randomized Controlled Trial Clinical TrialAnesthetic uptake of sevoflurane and nitrous oxide during an inhaled induction in children.
The uptake of sevoflurane and nitrous oxide (N(2)O) was characterized during the mask induction of anesthesia in healthy children. We assessed concentration and second gas effects by determining the influence of two different inspiratory N(2)O concentrations on the rate at which the estimated alveolar concentration (FA) increased to the inspired gas concentration (FI). Eighteen children aged 4-12 yr old were randomly assigned to receive a 6% sevoflurane mixture with either a large or a small N(2)O concentration with balance O(2). ⋯ Consistent with their respective blood/gas partition coefficients, the FA/FI for N(2)O increased more rapidly than that for sevoflurane. Increasing FI-N(2)O produced a leftward shift in gas equilibration curves. A concentration effect was confirmed with N(2)O and a brief second gas effect, probably explained by the higher solubility of sevoflurane.
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Anesthesia and analgesia · Feb 2003
Clinical TrialRelease of beta-endorphin immunoreactive material under perioperative conditions into blood or cerebrospinal fluid: significance for postoperative pain?
The function of beta-endorphin immunoreactive material (IRM) released under perioperative conditions remains to be clarified. In 17 patients undergoing orthopedic surgery, we determined beta-endorphin IRM in venous blood plasma and in cerebrospinal fluid (CSF) before surgery (t(A)); after termination of surgery and general anesthesia, but still under spinal anesthesia (t(B)); on occurrence of postoperative pain (t(C)); and 1 day after the operation (t(D)). ⋯ No correlation was found between beta-endorphin IRM CSF levels and pain severity. In conclusion, postoperative pain severity appears to be related to beta-endorphin IRM levels in plasma before surgery as well as with postoperative pain; the analgesic significance of this material remains to be elucidated.
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Anesthesia and analgesia · Feb 2003
Comparative Study Clinical TrialMidazolam premedication in children: a comparison of two oral dosage formulations on sedation score and plasma midazolam levels.
We compared two available oral formulations of midazolam with respect to sedation score and plasma midazolam levels in pediatric surgical patients 2-10 yr old. The commercially available oral syrup was compared with a mixture of the IV midazolam preparation in Syrpalta syrup at an equivalent concentration of 2 mg/mL. ASA status I-II patients were randomly assigned to receive 0.5 mg/kg of either the commercial syrup (Group 1) or the prepared mixture (Group 2) as anesthetic premedication. ⋯ Plasma midazolam levels were acquired exactly 45, 60, and 90 min after administration. Group 2 patients had a significantly lower median Observer's Assessment of Alertness/Sedation score (Group 1, 17; Group 2, 15) at 30 min (P < 0.03) and significantly higher mean plasma midazolam levels at all three acquisition times (mean +/- SD) (45 min: 63.1 +/- 23.9 ng/mL, Group 2; 43.4 +/- 19.6 ng/mL, Group 1; 60 min: 45.8 +/- 18.2 ng/mL, Group 2; 30.8 +/- 17.9 ng/mL, Group 1; 90 min: 28.9 +/- 12.6 ng/mL, Group 2; 21.0 +/- 8.9 ng/mL, Group 1) (P < 0.02). We conclude that IV midazolam mixed in Syrpalta syrup yields more reliable sedation and correspondingly higher plasma levels than an equivalent dose of the commercially formulated and marketed preparation.
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Anesthesia and analgesia · Feb 2003
Comparative Study Clinical TrialA comparison of the ProSeal laryngeal mask and the laryngeal tube in spontaneously breathing anesthetized patients.
In this multicenter, randomized study, we compared ease of insertion, postinsertion hemodynamic repercussion, quality of ventilation, and the capacity to achieve a "hands-free" anesthesia delivery between two new devices: the ProSeal laryngeal mask airway (PLMA) and the Laryngeal Tube (LT). The incidence of postoperative laryngopharyngeal discomfort was examined after short surgical interventions in spontaneously breathing patients. After induction with fentanyl and propofol, the respective airways were inserted into 70 adult ASA physical status I and II patients (35 patients in each group). ⋯ Positional maneuvers with the LT to correct ventilation deficiencies were not always completely effective (5 of 13). There were no differences in the incidence of intolerance, sore throat, dysphagia, and/or dysphonia between the two devices. We conclude that the PLMA showed greater ease of insertion and reliability than the LT for use in nonparalyzed anesthetized patients.
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Anesthesia and analgesia · Feb 2003
Clinical TrialIsoflurane and desflurane uptake during liver resection and transplantation.
When reducing fresh gas flows, the course of the vaporizer dial settings required to maintain a constant end-expired concentration of a potent inhaled anesthetic becomes more dependent on the uptake pattern of the inhaled anesthetic. However, the uptake pattern of potent inhaled anesthetics during prolonged procedures remains poorly quantified. Therefore, we determined isoflurane and desflurane uptake (V(iso) and V(des), respectively) during liver resection (LR, n = 17) and orthotopic liver transplantation (OLT, n = 18) using a liquid injection closed-circuit anesthesia technique maintaining the end-expired concentration at 0.8% and 4.5%, respectively. ⋯ The rate of uptake decreased more slowly then predicted by the uptake models. Because neither existing models nor patient characteristics accurately predict uptake in the individual patient, anesthesia techniques involving the use of low fresh gas flows will continue to have to rely on drug monitoring. However, the slowly decreasing rate of uptake during prolonged procedures suggests that the number of vaporizer adjustments to keep the end-expired concentration constant should be limited.