Anesthesia and analgesia
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Clinical TrialExpression of genes for proinflammatory cytokines in alveolar macrophages during propofol and isoflurane anesthesia.
Anesthesia and surgery induce macrophage aggregation and neutrophil influx, responses that characterize an inflammatory reaction in the distal airway. We thus evaluated the time-dependent expression of genes for proinflammatory cytokines during propofol and isoflurane anesthesia. We studied patients anesthetized with propofol (n = 20) or isoflurane (n = 20). Alveolar macrophages were harvested by bronchoalveolar lavage immediately, 2, 4, and 6 h after induction of anesthesia, and at the end of surgery. RNA was extracted from harvested cells and cDNA was synthesized by reverse transcription. Expression of interleukin-1beta (IL-1beta), IL-6, IL-8, interferon gamma, and tumor necrosis factor-alpha was measured by semiquantitative polymerase chain reaction using beta-actin as an internal standard. We observed two 10-fold increases in gene expression of all proinflammatory cytokines except IL-6. The increases in IL-8 and interferon gamma were 1.5-3 times greater during isoflurane than propofol anesthesia. Expression of the genes for IL-1beta and tumor necrosis factor-alpha was similar with each anesthetic. Our data thus indicate that the pulmonary inflammatory response accompanying anesthesia and surgery is accompanied by the expression of proinflammatory cytokines, and that this expression was in some cases greater during isoflurane than propofol anesthesia. ⋯ Gene expression of proinflammatory cytokines in alveolar macrophages increased significantly over time. The increases were greater during isoflurane than propofol anesthesia, suggesting that inflammatory responses at transcriptional levels in alveolar macrophages are modulated by the type and duration of anesthesia.
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Clinical TrialThe use of a remifentanil infusion for hemodynamic control during intracranial surgery.
Remifentanil is an extremely rapid and short-acting opioid analgesic which is effective in controlling acute stress responses during surgery. During neurosurgical anesthesia, laryngoscopy and intubation, application of the head holder, scalp incision, and the craniectomy can produce significant increases in mean arterial pressure (MAP). In this dose-response study, we evaluated the efficacy of a remifentanil infusion in maintaining hemodynamic stability during intracranial surgery under desflurane anesthesia. Forty-five patients were assigned randomly to one of the three remifentanil infusion groups. All patients received a standardized anesthetic induction consisting of midazolam, 2 mg IV, lidocaine 0.75 mg/kg IV, propofol 1.0 mg/kg IV, and remifentanil 0.5 microg/kg IV. Immediately after induction of anesthesia, a remifentanil infusion was started at 0.0625 microg x kg(-1) x min(-1) (Group 1), 0.125 microg x kg(-1) x min(-1) (Group 2), or 0.250 microg x kg (-1) x min(-1)(Group 3) according to a double-blinded study protocol. Maintenance of anesthesia consisted of desflurane 3% (end-tidal) in air/oxygen. If the MAP exceeded 80 mm Hg, a supplemental bolus of remifentanil, 0.5 microg/kg IV was administered, and when the MAP decreased below 65 mm Hg, the remifentanil infusion was discontinued temporarily. "Rescue" cardiovascular medications consisted of nitroprusside (100 microg IV) or phenylephrine (100 microg IV). Heart rate, systolic, diastolic, and MAP values, were recorded every minute for 20 min after each specific stimulus. The overall quality of the intraoperative hemodynamic control was evaluated by the attending anesthesiologist on a scale from 1 = poor to 5 = excellent. The overall quality of the hemodynamic control was superior in Group 2 compared with Group 1 (P < 0.05). Although the total dose of remifentanil administered during the study period did not differ among the three groups, Group 1 required significantly more supplemental boluses of remifentanil (66%-80%) than Groups 2 (13%-33%) and 3 (70% 13%), and the remifentanil infusion was discontinued more often in Group 3 (80%-93%) than in Groups 1 (0%-13%) and 2 (21%-40%). In conclusion, the recommended remifentanil infusion rate for controlling acute autonomic responses during neurosurgical anesthesia is 0.125 microg x kg(-1) x min(-1) when administered during a desflurane-based anesthetic. ⋯ Compared with remifentanil 0.0625 microg x kg(-1) x min(-1) and 0.250 microg x kg(-1) x min(-1), a remifentanil infusion rate of 0.125 microg x kg(-1) x min(-1) provided more stable hemodynamic conditions during intracranial surgery under desflurane anesthesia.
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Clinical TrialThe lateral approach to the sciatic nerve at the popliteal fossa: one or two injections?
It has not been proven whether one or multiple nerve stimulations and injections provide a higher rate of complete sensory block in both major sciatic nerve sensory distributions below the knee when a popliteal sciatic nerve block is performed using the lateral approach. This prospective, randomized, single-blinded study compared the success rate of the sciatic nerve block using this approach when one or both major components of this nerve (i.e., tibial nerve and common peroneal nerves) are stimulated in 50 patients undergoing foot or ankle surgery. In Group 1 STIM, 24 patients received a single injection of 20 mL of a mixture of 2% lidocaine and 0.5% bupivacaine with 1:200,000 epinephrine after foot inversion had been elicited. In Group 2 STIM (n = 26), 10 mL of the same solution was injected after stimulation of each sciatic nerve component. For patients with complete sensory motor block, there was no difference in onset between groups. However, Group 2 STIM showed a greater success rate compared with the Group 1 STIM (2 STIM: 88% vs 1 STIM :54%; P = 0.007). When two stimulations were used, the onset time of anesthesia in the cutaneous distribution of the common peroneal nerves was shorter than in the tibial nerve (17.5 vs 30 min; P < 0.0001). We conclude that a two-stimulation technique provides a better success rate than a single-injection technique when a popliteal sciatic nerve block is performed using the lateral approach with 20 mL of local anesthetic. ⋯ A better success rate is achieved with a double stimulation technique than with a single injection for the sciatic nerve block via the lateral approach at the popliteal fossa when 20 mL of local anesthetics is used.
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Comparative Study Clinical TrialLidocaine plus ropivacaine versus lidocaine plus bupivacaine for peribulbar anesthesia by single medical injection.
This study was designed to compare the effects of ropivacaine and bupivacaine, each combined with lidocaine, during peribulbar anesthesia by single medial injection for cataract surgery. One hundred patients were included and randomly divided into two groups of 50, given a mixture of 50% bupivacaine (0.5%) and 50% lidocaine (2%) or 50% ropivacaine (1%) and 50% lidocaine (2%), and 25 U hyaluronidase per mL with each combination. After the first injection, patients given ropivacaine exhibited significantly better akinesia than those given bupivacaine, and significantly fewer were reinjected (19/50 vs 31/50). Among the patients reinjected, peroperative akinesia and analgesia proved satisfactory in both groups. We observed three cases of diplopia caused by retraction of the internal rectus muscle and two cases of moderate ptosis after superonasal reinjection. Hemodynamic profiles were similar in the two groups, and no major side effects were noted during the observation. One percent ropivacaine may be a more appropriate agent than 0.5% bupivacaine for peribulbar anesthesia by single medial injection. ⋯ One percent ropivacaine may be a more appropriate agent than 0.5% bupivacaine for peribulbar anesthesia by single medial injection. Combined with lidocaine, it provides better akinesia and similar analgesia.