Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2001
Oxidative stress status during exposure to propofol, sevoflurane and desflurane.
We evaluated the circulating and lung oxidative status during general anesthesia established with propofol, sevoflurane, or desflurane in mechanically ventilated swine. Blood samples and bronchoalveolar lavage fluid (BAL) specimens were respectively performed via an internal jugular vein catheter and a nonbronchoscopic BAL for baseline oxidative activity measurements: malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPX). A 4-h general anesthesia was then performed in the three groups of 10 swine: the Propofol group received 8 mg x kg(-1) x h(-1) of IV propofol as the sole anesthetic; the Desflurane group received 1.0 minimum alveolar concentration of desflurane; and the Sevoflurane group received 1.0 minimum alveolar concentration of sevoflurane. We observed significantly larger levels of MDA in plasma and BAL during desflurane exposure than with the other anesthetics. We also observed smaller concentrations of circulating GPX and alveolar GPX. We found a significant decrease for MDA measurements in the plasma and the pulmonary lavage during propofol anesthesia. We also found larger values of GPX measurements in the serum and the pulmonary lavage. No significant changes were observed when animals were exposed to sevoflurane. No significant changes were found for circulating concentrations of SOD during exposure to all anesthetics. In this mechanically ventilated swine model, desflurane seemed to induce a local and systemic oxidative stress, whereas propofol and sevoflurane were more likely to have antioxidant properties. ⋯ Superoxide is an unavoidable byproduct of oxygen metabolism that occurs in various inflammatory reactions. Inhalation of volatile anesthetics under mechanical ventilation induces an inflammatory response. We evaluated the bronchoalveolar and systemic oxidative stress in swine during exposure to propofol and newer volatile anesthetics. Desflurane induces more lipid peroxidation than do the other anesthetics.
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Anesthesia and analgesia · Oct 2001
Randomized Controlled Trial Clinical TrialIntrathecal morphine for postpartum tubal ligation postoperative analgesia.
Intrathecal morphine (ITM) provides effective postoperative cesarean delivery analgesia but has not been reported for postoperative postpartum tubal ligation (PPTL) analgesia. We designed this prospective, randomized, double-blinded study to determine the efficacy of 100 microg ITM for postoperative PPTL analgesia. Sixty-six women received spinal anesthesia with 60 mg (1.2 mL) of 5% hyperbaric lidocaine, 10 microg (0.2 mL) of fentanyl, and either 0.2 mL of 0.9% saline (normal saline; NS) or 100 microg (0.2 mL) of morphine (morphine sulfate, MS). Postoperative analgesia was limited to patient-controlled IV analgesia morphine. Six women (three NS and three MS) were excluded because of major protocol violations. Twenty-four-hour patient-controlled IV analgesia morphine use was (mean +/- SD) 39.6 +/- 19.6 mg in the NS group and 1.1 +/- 2.5 mg in the MS group (P < 0.0000001). Visual analog scale scores for crampy and incisional pain (rest and movement) were significantly higher in the NS group compared with the MS group at 4, 8, 12, and 24 h (P < 0.001). The adverse effect profile was similar between groups. Visual analog scale satisfaction scores (mean +/- SD) were 96.6 +/- 16.0 in the MS group and 84.2 +/- 23.6 in NS group (P < 0.05). The results of this study indicate that women experience significant postoperative pain after PPTL surgery, and this pain is effectively obviated by 100 microg ITM. ⋯ This investigation documents the extent of the significant postoperative pain experienced by women after routine postpartum tubal ligation surgery and demonstrates the efficacy of a small dose (100 microg) of intrathecal morphine to obviate this pain with minimal adverse effects.
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Anesthesia and analgesia · Oct 2001
Randomized Controlled Trial Comparative Study Clinical TrialLevobupivacaine combined with sufentanil and epinephrine for intrathecal labor analgesia: a comparison with racemic bupivacaine.
We performed a randomized, double-blinded study to compare levobupivacaine with racemic bupivacaine for labor analgesia. Eighty term parturients received either levobupivacaine 0.125% or racemic bupivacaine 0.125%, to which was added sufentanil 0.75 microg/mL and epinephrine 1.25 microg/mL. As part of a combined spinal-epidural procedure, 2 mL of this mixture was initially injected intrathecally, and the same solutions were subsequently administered epidurally. For both combinations, onset until the first painless contraction was 4 to 5 min. Most patients were pain free during the second contraction. The duration of initial spinal analgesia was 93.5 +/- 20 min and 94.7 +/- 31 min for levobupivacaine and racemic bupivacaine, respectively. The duration of analgesia for the first epidural top-up dose was also similar in the two groups. Total local anesthetic requirements during labor were not different. The only major difference observed was the absence of motor impairment in levobupivacaine-treated parturients as compared with the Racemic Bupivacaine group, in which the incidence of a Bromage-1 motor block was 34%. Other side effects and obstetric or neonatal outcomes were not different between groups. Intrathecal levobupivacaine has a similar clinical profile as racemic bupivacaine, but at equal doses it produced less motor block. ⋯ When used intrathecally and epidurally for labor analgesia, levobupivacaine had the same clinical profile as racemic bupivacaine, but at equal doses it produced less motor block.
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Anesthesia and analgesia · Oct 2001
Meta AnalysisEpidural analgesia reduces postoperative myocardial infarction: a meta-analysis.
Postoperative cardiac morbidity and mortality continue to pose considerable risks to surgical patients. Postoperative epidural analgesia is considered to have beneficial effects on cardiac outcomes. The use in high-risk cardiac patients remains controversial. No study has shown that postoperative epidural analgesia decreases postoperative myocardial infarction (PMI) or death. All studies are underpowered to show such a result, and the cost of conducting a large trial is prohibitive. We performed a metaanalysis to determine whether postoperative epidural analgesia continued for more than 24 h after surgery reduces PMI or in-hospital death. The available databases were searched for randomized controlled trials of epidural analgesia that was extended at least 24 h into the postoperative period. The search yielded 17 studies, of which 11 were randomized controlled trials comprising 1173 patients. Metaanalysis was conducted by using the fixed-effects model, calculating both an odds ratio and a rate difference. Postoperative epidural analgesia resulted in better analgesia for the first 24 h after surgery. The rate of PMI was 6.3%, with lower rates in the Epidural group (rate difference, -3.8%; 95% confidence interval [CI] -7.4%, -0.2%; P = 0.049). The frequency of in-hospital death was 3.3%, with no significant difference between Epidural and Nonepidural groups (rate difference, -1.3%; 95% CI, -3.8%, 1.2%, P = 0.091). Subgroup analysis of postoperative thoracic epidural analgesia showed a significant reduction in PMI in the Epidural group (rate difference, -5.3%; 95% CI, -9.9%, -0.7%; P = 0.04). ⋯ Postoperative epidural analgesia, especially thoracic epidural analgesia, continued for more than 24 h reduces postoperative myocardial infarctions.
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Anesthesia and analgesia · Oct 2001
Randomized Controlled Trial Comparative Study Clinical TrialA new posterior approach to the sciatic nerve block: a prospective, randomized comparison with the classic posterior approach.
To evaluate the efficacy and acceptance of a new posterior subgluteus approach to the sciatic nerve, as compared with the classic posterior approach, 128 patients undergoing foot orthopedic procedures were randomly allocated to receive either the classic posterior sciatic nerve block (Group Labat, n = 64) or a modified subgluteus posterior approach (Group subgluteus, n = 64). All blocks were performed with the use of a nerve stimulator (stimulation frequency, 2 Hz; intensity, 1-0.5 mA). In Group subgluteus, a line was drawn from the greater trochanter to the ischial tuberosity; then, from the midpoint of this line, a second line was drawn perpendicularly and extended caudally for 4 cm. The end of this line represented the needle entry. In both groups, a proper sciatic stimulation was elicited at 0.5 mA; then 20 mL of 0.75% ropivacaine was injected. The time from needle insertion to successful sciatic nerve stimulation was 60 s (range, 10-180 s) with the Labat's approach and 32 s (range, 5-120 s) with the new subgluteus approach (P = 0.0005). The depth of appropriate sciatic stimulation was 45 +/- 13 mm (mean +/- SD) after 2 (range, 1-7) needle redirections in Group subgluteus and 67 +/- 12 mm after 4 (range, 1-10) needle redirections in Group Labat (P = 0.0001 and P = 0.00001, respectively). The failure rate was similar in both groups. Severe discomfort during the procedure was less frequent and acceptance better in Group subgluteus (5 patients [8%] and 60 patients [94%], respectively) than in Group Labat (20 patients [31%] and 49 patients [77%], respectively) (P = 0.0005 and P = 0.005, respectively). We conclude that this new subgluteus posterior approach to the sciatic nerve is an easy and reliable technique and can be considered an effective alternative to the more traditional Labat's approach. ⋯ Evaluating the efficacy and acceptance of a new approach to the sciatic nerve block, this prospective, randomized study demonstrated that the new subgluteus posterior approach is an easy and reliable technique and can be considered an useful alternative to the more traditional Labat's approach in patients undergoing foot surgery, facilitating the performance of the sciatic nerve blocks.