Anesthesia and analgesia
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Anesthesia and analgesia · Feb 1998
Randomized Controlled Trial Clinical TrialThe analgesic effect of fentanyl, morphine, meperidine, and lidocaine in the peripheral veins: a comparative study.
Using venous retention with a tourniquet (70 mm Hg), we performed a randomized, double-blind study to assess the efficacy of I.V. pretreatment with fentanyl, morphine, meperidine, or lidocaine in reducing propofol injection pain. Immediately after venous occlusion with a tourniquet, I.V. fentanyl 150 microg (Group A, n = 35), morphine 4 mg (Group B, n = 35), meperidine 40 mg (Group C, n = 35), 2% lidocaine 3 mL (Group D, n = 35), or normal saline 3 mL (Group E, n = 35; as placebo control) was given to adult patients. The venous retention of the drug was maintained for 1 min, followed by tourniquet release and I.V. administration of propofol 100 mg. Pain assessment was made immediately after the propofol injection. Lidocaine and meperidine significantly reduced propofol injection pain more than placebo (P < 0.05), but there were more side effects in the meperidine group. Fentanyl and morphine reduced the intensity of propofol injection pain (P < 0.05) and had some effect in reducing the incidence of propofol injection pain, but the difference did not reach statistical significance. The order of efficacy was lidocaine approximately meperidine > morphine approximately fentanyl. We postulate that the peripheral analgesic effect of these opioid is due to their local anesthetic activity. ⋯ Propofol, a commonly used anesthetic, often causes pain on injection. Given as venous retention pretreatments 1 min before propofol, meperidine and lidocaine were found to significantly reduce the propofol injection pain, whereas fentanyl and morphine only slightly reduced the propofol injection pain.
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Anesthesia and analgesia · Feb 1998
A multimodal approach to control postoperative pathophysiology and rehabilitation in patients undergoing abdominothoracic esophagectomy.
This two-armed study was designed to determine whether recovery after esophageal resection may be improved by introducing a new multimodal approach. For 8 mo after the new approach was introduced, all patients undergoing abdominothoracic esophageal resection were studied (Group 2; n = 42). For comparison, a retrospective analysis was also conducted using the data of all patients who had undergone this operation in the 8 mo before the introduction of the new regimen, when the traditional therapy was still in use (Group 1; n = 49). All patients received an epidural catheter at the level of T6-9 before the induction of general analgesia. Afterward, Group 1 patients were operated under general anesthesia. For postoperative pain relief, a mixture of bupivacaine 1.25 mg/mL and sufentanil 1 microg/mL was administered during 5 days without titration of the quality of analgesia. Patients in Group 2 received a preoperative bolus of 10-15 mL bupivacaine 2.5 mg/mL and 20-30 microg sufentanil. After sensory block up to T4 was confirmed, general anesthesia was introduced and intraoperatively combined with a continuous infusion of 5 mL/h of a solution containing bupivacaine 1.75 mg/mL and sufentanil 1 microg/mL. Postoperatively, the epidural infusion rate was adjusted to the need of the individual patients, who were able to administer themselves additional bolus doses of 2 mL with a lockout time of 20 min. Early tracheal extubation and forced mobilization were pursued to improve recovery. Demographic data of both groups were comparable. The pain relief of Group 2 patients was superior to that of patients in Group 1. The nitrogen balance of a subgroup of nine matched pairs of patients with comparable nutritional status was less negative in Group 2 patients on Postoperative Days 1 and 2. Patients in Group 2 were tracheally extubated earlier (mean 6.7 vs 25.1 h after admission to the intensive care unit [ICU]), mobilized earlier (mean 1.2 vs 2.0 days after surgery), discharged from the ICU earlier (mean 1.7 vs 4.0 days), and fulfilled criteria for discharge from the ICU (mean 1.8 vs 4.1 days) and from the intermediate care unit earlier (4.9 vs 6.4 days). We conclude that the multimodal approach may improve recovery and thus reduce costs after abdominothoracic esophageal resection. ⋯ Analgesia and blockade of the perioperative stress response, combined with other aspects of postoperative therapy, may improve recovery after surgery. The intensive care unit stay after esophageal resection was reduced by a new regimen (thoracic epidural analgesia, early tracheal extubation, forced mobilization). This approach may influence the cost of major surgery.
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Anesthesia and analgesia · Feb 1998
The effect of anesthetic duration on kinetic and recovery characteristics of desflurane versus sevoflurane, and on the kinetic characteristics of compound A, in volunteers.
This study documents the differences in kinetics of 2 h (n = 7) and 4 h (n = 9) of 1.25 minimum alveolar anesthetic concentration (MAC) of desflurane (9.0%) versus (on a separate occasion) sevoflurane (3.0%), both administered in a fresh gas inflow of 2 L/min. These data are extensions of our previous 8-h (n = 7) studies of these anesthetics. By 10 min of anesthetic administration, average inspired (F(I)) and end-tidal concentration (F(A)) (F(I)/F(A); the inverse of the more commonly used F(A)/F(I)) decreased to less than 1.15 for both anesthetics, with the difference from 1.0 nearly twice as great for sevoflurane as for desflurane. During all sevoflurane administrations, F(A)/F(I) for Compound A [CH2F-O-C(=CF2) (CF3); a vinyl ether resulting from the degradation of sevoflurane by Baralyme] equaled approximately 0.8, and the average inspired concentration equaled approximately 40 ppm. Compound A is of interest because at approximately 150 ppm-h, it can induce biochemical and histological evidence of glomerular and tubular injury in rats and humans. During elimination, F(A)/F(A0) for Compound A (F(A0) is the last end-tidal concentration during anesthetic administration) decreased abruptly to 0 after 2 h and 4 h of anesthesia and to approximately 0.1 (F(A) approximately 3 ppm) after 8 h of anesthesia. In contrast, F(A)/F(A0) for desflurane and sevoflurane decreased in a conventional, multiexponential manner, the decrease being increasingly delayed with increasing duration of anesthetic administration. F(A)/F(A0) for sevoflurane exceeded that for desflurane for any given duration of anesthesia, and objective and subjective measures indicated a faster recovery with desflurane. Times (mean +/- SD) to initial response to command (2 h 10.9 +/- 1.2 vs 17.8 +/- 5.1 min, 4 h 11.3 +/- 2.1 vs 20.8 +/- 4.8 min, 8 h 14 +/- 4 vs 28 +/- 8 min) and orientation (2 h 12.7 +/- 1.6 vs 21.2 +/- 4.6 min, 4 h 14.8 +/- 3.1 vs 25.3 +/- 6.5 min, 8 h 19 +/- 4 vs 33 +/- 9 min) were shorter with desflurane. Recovery as defined by the digit symbol substitution test, P-deletion test, and Trieger test results was more rapid with desflurane. The incidence of vomiting was greater with sevoflurane after 8 h of anesthesia but not after shorter durations. We conclude that for each anesthetic duration, F(I) more closely approximates F(A) with desflurane during anesthetic administration, F(A)/F(A0) decreases more rapidly after anesthesia with desflurane, and objective measures indicate more rapid recovery with desflurane. Finally, it seems that after 2-h and 4-h administrations, all Compound A taken up is bound within the body. ⋯ Regardless of the duration of anesthesia, elimination is faster and recovery is quicker for the inhaled anesthetic desflurane than for the inhaled anesthetic sevoflurane. The toxic degradation product of sevoflurane, Compound A, seems to bind irreversibly to proteins in the body.
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Anesthesia and analgesia · Feb 1998
Pharmacokinetics of the enantiomers of bupivacaine and mepivacaine after epidural administration of the racemates.
We investigated the pharmacokinetics of the enantiomers of bupivacaine and mepivacaine after epidural injection of the racemate of each drug into six surgical patients. After epidural administration of either bupivacaine/HCl (115 mg) or mepivacaine/HCl (460 mg), blood samples were collected for 24 h. Unbound fractions were determined by using ultrafiltration for bupivacaine and equilibrium dialysis for mepivacaine. Concentrations in plasma, ultrafiltrate, and dialysate were determined by using stereoselective high-performance liquid chromatography. Peak plasma concentrations of R(+)-bupivacaine (389 +/- 93 ng/mL) and R(-)-mepivacaine (1350 +/- 430 ng/mL) were smaller than those of S(-)-bupivacaine (449 +/- 109 ng/mL, P < 0.0001) and S(+)-mepivacaine (1740 +/- 490 ng/mL, P < 0.002), respectively. However, the unbound peak concentrations of R(+)-bupivacaine (20 +/- 11 ng/mL) were larger than those of S(-)-bupivacaine (15 +/- 9 ng/mL, P < 0.005); unbound peak concentrations of R(-)-mepivacaine (485 +/- 158 ng/mL) and S(+)-mepivacaine (460 +/- 139 ng/mL) did not differ. These observations reflect differences in the systemic disposition (distribution and elimination) of the enantiomers, because the systemic absorption was not enantioselective with either drug. This study supports the opinion that the use of single enantiomers, rather than racemates, is preferable, particularly for bupivacaine. ⋯ Measurements of the plasma concentrations of the enantiomers of bupivacaine and mepivacaine after epidural administration of the racemates demonstrated that the systemic disposition, but not the systemic absorption, of these drugs is enantioselective and supports the opinion that the use of single enantiomers, rather than racemates, is preferable.