Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Comparative Study Clinical TrialSelective spinal anesthesia: a comparison of hyperbaric bupivacaine 4 mg versus 6 mg for outpatient knee arthroscopy.
A low-dose (4 mg), low-volume (0.8 mL), low-flow (2 min) technique with hyperbaric bupivacaine toward the dependent side oriented injection and maintenance of the lateral decubitus position for 10 min produced selective spinal anesthesia with rapid recession of motor block and early discharge home.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialLong-duration low-flow sevoflurane and isoflurane effects on postoperative renal and hepatic function.
Sevoflurane degradation by carbon dioxide absorbents during low-flow anesthesia forms the haloalkene Compound A, which causes nephrotoxicity in rats. Numerous studies have shown no effects of Compound A formation on postoperative renal function after moderate-duration (3-4 h) low-flow sevoflurane; however, effects of longer exposures remain unresolved. We compared renal function after long-duration low-flow (<1 L/min) sevoflurane and isoflurane anesthesia in consenting surgical patients with normal renal function. To maximize degradant exposure, Baralyme was used, and anesthetic concentrations were maximized (no nitrous oxide and minimal opioids). Inspired and expired Compound A concentrations were quantified. Blood and urine were obtained for laboratory evaluation. Sevoflurane (n = 28) and isoflurane (n = 27) groups were similar with respect to age, sex, weight, ASA status, and anesthetic duration (9.1 +/- 3.0 and 8.2 +/- 3.0 h, mean +/- SD) and exposure (9.2 +/- 3.6 and 9.1 +/- 3.7 minimum alveolar anesthetic concentration hours). Maximum inspired Compound A was 25 +/- 9 ppm (range, 6-49 ppm), and exposure (area under the concentration-time curve) was 165 +/- 95 (35-428) ppm. h. There was no significant difference between anesthetic groups in 24- or 72-h serum creatinine, blood urea nitrogen, creatinine clearance, or 0- to 24-h or 48- to 72-h urinary protein or glucose excretion. Proteinuria and glucosuria were common in both groups. There was no correlation between Compound A exposure and any renal function measure. There was no difference between anesthetic groups in 24- or 72-h aspartate aminotransferase or alanine aminotransferase. These results show that the renal and hepatic effects of long-duration low-flow sevoflurane and isoflurane were similar. No evidence for low-flow sevoflurane nephrotoxicity was observed, even at high Compound A exposures as long as 17 h. Proteinuria and glucosuria were common and nonspecific postoperative findings. Long-duration low-flow sevoflurane seems as safe as long-duration low-flow isoflurane anesthesia. ⋯ Postoperative renal function after long-duration low-flow sevoflurane (with Compound A exposures greater than those typically reported) and isoflurane anesthesia were not different, as assessed by serum creatinine, blood urea nitrogen, and urinary excretion of protein and glucose. This suggests that low-flow sevoflurane is as safe as low-flow isoflurane, even at long exposures.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialA randomized multicenter study of remifentanil compared with halothane in neonates and infants undergoing pyloromyotomy. I. Emergence and recovery profiles.
Pyloric stenosis is sometimes associated with hemodynamic instability and postoperative apnea. In this multicenter study we examined the hemodynamic response and recovery profile of remifentanil and compared it with that of halothane in infants undergoing pyloromyotomy. After atropine, propofol, and succinylcholine administration and tracheal intubation, patients were randomized (2:1 ratio) to receive either remifentanil with nitrous oxide and oxygen or halothane with nitrous oxide and oxygen as the maintenance anesthetic. Pre- and postoperative pneumograms were done and evaluated by an observer blinded to the study. Intraoperative hemodynamic data and postanesthesia care unit (PACU) discharge times, PACU recovery scores, pain medications, and adverse events (vomiting, bradycardia, dysrhythmia, and hypoxemia) were recorded by the study's research nurse. There were no significant differences in patient age or weight between the two groups. There were no significant differences in hemodynamic values between the two groups at the various intraoperative stress points. The extubation times, PACU discharge times, pain medications, and adverse events were similar for both groups. No patient anesthetized with remifentanil who had a normal preoperative pneumogram had an abnormal postoperative pneumogram, whereas three patients with a normal preoperative pneumogram who were anesthetized with halothane had abnormal pneumograms after. ⋯ The use of ultra-short-acting opioids may be an appropriate technique for infants less than 2 mo old when tracheal extubation after surgery is anticipated.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Comparative Study Clinical TrialA dose response study of clonidine with local anesthetic mixture for peribulbar block: a comparison of three doses.
Clonidine prolongs anesthesia and analgesia of local anesthetics in various neural blocks as well as the duration of retrobulbar block. We assessed the dose-response relationship of clonidine added to lidocaine in peribulbar block. Sixty patients undergoing cataract surgery were given peribulbar block with 7 mL of 2% lidocaine and hyaluronidase with either saline (Control) or clonidine in 0.5-microg/kg (0.5 Clon), 1.0-microg/kg (1.0 Clon), or 1.5-microg/kg (1.5 Clon) doses. The onset and duration of lid and globe akinesia, globe anesthesia and analgesia, postoperative analgesic requirement, and adverse effects (hypotension, bradycardia, hypoxia, sedation, and dizziness) were recorded. The success rate and onset of block were comparable in all groups. The duration of lid and globe akinesia, globe anesthesia and analgesia was significantly (P < 0.01) prolonged in patients receiving 1.0 and 1.5 microg/kg clonidine as compared with the Control group. Perioperative pain scores and analgesic requirement were significantly less in these groups. 0.5 microg/kg clonidine did not increase the duration of anesthesia and analgesia significantly. Hypotension and dizziness were observed more in patients receiving 1.5 microg/kg clonidine as compared with other groups. We conclude that 1.0 microg/kg clonidine with a mixture of lidocaine (2%) significantly prolonged the duration of anesthesia and analgesia after peribulbar block with limited side effects. ⋯ We studied the effect of the addition of 0.5, 1.0 and 1.5 microg/kg clonidine to a lidocaine-hyaluronidase mixture on the onset and duration of peribulbar block and perioperative analgesia. A dose of 1.0 microg/kg produced a significant increase in duration of anesthesia and analgesia with minimal side effects.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Clinical TrialEsmolol promotes electroencephalographic burst suppression during propofol/alfentanil anesthesia.
This study examined the effects of an esmolol infusion on the electroencephalogram during propofol/alfentanil IV anesthesia. After informed consent, 20 patients were randomly assigned into four groups on the basis of two target alfentanil concentrations (alfentanil 50 or 150 ng/mL) and of a saline or esmolol infusion. Bispectral index (BIS), burst suppression ratio (SR), and physiologic variables were continuously monitored. A 30-min blinded infusion of saline or esmolol was started after establishing a stable baseline and followed by a washout period. The electroencephalogram was significantly suppressed by esmolol (BIS, 37 +/- 6 to 22 +/- 6, 40% decrease [mean +/- SD]; SR, 5 +/- 7 to 67 +/- 23, 13.4-fold increase) compared with baseline in the small-dose alfentanil groups. Discontinuation of esmolol reversed the response. BIS and SR were unaffected by placebo infusion. Twelve-minute to 16-min hysteresis between esmolol administration and the onset of half-maximal cortical suppression was observed. Physiologic variables and serum propofol and alfentanil concentrations were not significantly altered by esmolol. Although the mechanism remains unclear, significant cortical depression and the onset of burst suppression during a stable, computer-controlled propofol/alfentanil anesthetic was associated with esmolol infusion. ⋯ This study demonstrated the suppression of cerebral cortical electrical activity after blinded esmolol infusion during propofol/alfentanil anesthesia. A significant lag was noted between infusion and half-maximal effect (12-16 min). Whether esmolol, a metabolite, or a secondary process was responsible for this cortical suppression remains unknown and requires further study.