Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2001
Randomized Controlled Trial Clinical TrialThe effect of the preemptive use of the NMDA receptor antagonist dextromethorphan on postoperative analgesic requirements.
Both central sensitization after peripheral tissue injury and the development of opiate tolerance involve activation of N-methyl-D-aspartate receptors. In this double-blinded, randomized study, we investigated the preemptive versus postincisional effects of dextromethorphan, an N-methyl-D-aspartate receptor antagonist, on postoperative pain management. Sixty ASA I and II patients undergoing elective upper abdominal surgery were randomly allocated to three equally sized groups. The Preincisional group patients received dextromethorphan (120 mg) IM 30 min before skin incision and a placebo (isotonic saline) 30 min before the end of surgery. The Postincisional group received the same dose of dextromethorphan 30 min before the end of surgery and a placebo 30 min before skin incision, and the Control group received a placebo both 30 min before skin incision and 30 min before the end of surgery. A standard general anesthetic technique including fentanyl, propofol, isoflurane, and atracurium was used. Postoperative meperidine patient-controlled analgesia (PCA) was used. There were no significant group differences in the median pain scores except in the visual analog scale at 6 h both at rest and on movement; these were significantly lower in the Preincisional group than the other two groups (P < 0.05). The mean time to initiation of PCA was significantly longer in the Preincisional than in the Postincisional and Control groups (mean [SD]: 10.7 [2.2 h], 5.4 [2.1 h], and 3.7 [1.6 h], respectively; P < 0.001]. The 24-h PCA-meperidine consumption was significantly less in the Preincisional than in the Postincisional and Control groups (mean [SD]: 140 [60 mg], 390 [80 mg], and 570 [70 mg], respectively; P < 0.001]. The incidence of postoperative hypoxemia (SpO(2) < 90%) and nausea was significantly less in the Preincisional group (P < 0.05). In conclusion, preincisional IM 120 mg dextromethorphan compared with the same postincisional dose significantly reduced postoperative meperidine consumption. ⋯ IM administration of preincisional dextromethorphan (120 mg), allowing the use of a larger dose sufficient to block the central sensitization caused by activation of the N-methyl-D-aspartate receptors, provides preemptive analgesia and has a supportive role in postoperative pain relief, as shown by a significant decrease in 24-h meperidine consumption.
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Anesthesia and analgesia · Mar 2001
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of two constant-dose continuous infusions of remifentanil for severe postoperative pain.
We evaluated the analgesic efficacy and safety of two continuous constant-dose infusions of IV remifentanil, without infusion rate increments or the addition of boluses, in patients with severe postoperative pain during the first 4 h after general anesthesia with IV propofol-remifentanil. Thirty patients were randomly assigned to two groups of 15 subjects each according to the remifentanil dose administered: 0.1 microg. kg(-1). min(-1) IV (Group A) or 0.05 microg. kg(-1). min(-1) IV (Group B). Rescue analgesia was provided with meperidine (0.5 mg/kg IV) when pain intensity on the simple verbal scale (SVS) > or =2. The criteria for adequate analgesia (SVS 0-1, respiratory frequency >8/min. and SpO(2) >90%) after 4 h were met by 78% and 75% of the patients in Groups A and B, respectively (P = ns). "Meperidine rescue" analgesia was significantly more in Group B (26%) than in Group A (6%) (P < 0.05). There were no cases of respiratory depression, and nausea and emesis occurred in one patient in each group (6.5%). We conclude that IV remifentanil is an effective and safe opioid for the treatment of postoperative pain at a constant dose of 0.1 microg. kg(-1). min(-1) with a need for rescue analgesia 4 times less than a constant dose of 0.05 microg. kg(-1). min(-1). ⋯ Our study suggests that the use of a constant continuous infusion of remifentanil 0.1 microg.kg(-1).min(-1)IV is an effective alternative in the treatment of severe postoperative pain.
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Anesthesia and analgesia · Mar 2001
Randomized Controlled Trial Clinical TrialRegional hemostatic status and blood requirements after total knee arthroplasty with and without tranexamic acid or aprotinin.
Antifibrinolytics seem to reduce postoperative blood loss after total knee arthroplasty. Few studies have shown the impact of these drugs on the mechanisms of coagulation. The purpose of this study was to examine coagulation/fibrinolysis variables as well as blood loss after total knee arthroplasty with and without antifibrinolytics in the operated limb on a regional level. Thirty-six patients were randomized into one of three groups to receive aprotinin, tranexamic acid, or no medication. We took blood samples of the femoral vein before deflating the tourniquet and after 5, 10, 30, 60, 120 min and on the first postoperative day. The implantation of a knee prosthesis in artificial ischemia caused a significant activation of coagulation and fibrinolysis in the regional circulation. Tranexamic acid and aprotinin did not cause a significant modulation of fibrinolysis variables or a significant reduction of postoperative bleeding and transfusion requirements. One of the differences in comparison to other studies was the decreased total blood loss. The use of bone cement as well as surgical hemostasis before wound closure may be regarded as reasons for this. Therefore, primarily these methods should be used because there is no increased risk of adverse drug effects. ⋯ After total knee arthroplasty total blood loss may be kept in a low range if methods such as cemented knee prosthesis and surgical hemostasis are used. In this case aprotinin and tranexamic acid did not cause a significant modulation of fibrinolysis variables or a significant reduction of postoperative bleeding.
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Anesthesia and analgesia · Mar 2001
Randomized Controlled Trial Clinical TrialThe effect of dexamethasone on postoperative vomiting after tonsillectomy.
In this double-blinded, randomized, placebo-controlled study, we assessed the effect of dexamethasone 0.5 mg/kg IV administered preoperatively in 110 children 2-12 yr old, undergoing electrodissection adenotonsillectomy, using a standardized anesthetic technique. The incidence of early and late vomiting, the time to first oral intake, the quality of oral intake, the satisfaction scores, and the duration of IV hydration were compared in both groups. The overall incidence of vomiting, as well as the incidence of late vomiting, was significantly less in the Dexamethasone group as compared with the Saline group (23% and 19% vs 51% and 34%, respectively). The time to first oral intake and the duration of IV hydration were shorter in the Dexamethasone group compared with the Saline group (P < 0.05). The quality of oral intake and the satisfaction scores were better in the Dexamethasone group than in the Saline group (P < 0.05). This report confirms the beneficial effect of IV dexamethasone on both vomiting and oral intake in children undergoing electrodissection adenotonsillectomy. ⋯ In this double-blinded, placebo-controlled study, we examined the efficacy of a single dose of dexamethasone 0.5 mg/kg IV on posttonsillectomy vomiting and oral intake in children 2-12 yr old. Dexamethasone significantly decreased the incidence of postoperative vomiting during the first 24 h, shortened the time to the first oral intake and the duration of IV hydration, and improved the quality of oral intake and the satisfaction scores of the patients.
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Anesthesia and analgesia · Mar 2001
Randomized Controlled Trial Clinical TrialThe effects of lactated Ringer's solution infusion on cardiac output changes after spinal anesthesia.
We evaluated the effects of an infusion of lactated Ringer's (LR) solution on changes in cardiac output (CO) after spinal anesthesia. Seventy-five patients scheduled for lower extremity surgery under spinal anesthesia were studied. We measured CO (impedance cardiography method) and blood pressure for 25 min before and 30 min after spinal anesthesia. Patients were randomly assigned to three groups. In the No Infusion group, no LR solution was given during the period of measurements. The LR Before group received 12 mL/kg of LR solution within 20 min before spinal anesthesia. The LR After group received 12 mL/kg of LR solution within 20 min starting immediately after spinal anesthesia. After spinal anesthesia, CO decreased by 13.9% in the No Infusion group. In the LR Before group, CO increased after the infusion by 20% and returned to baseline value 30 min after spinal anesthesia. In the LR After group, CO increased after spinal anesthesia, and 30 min after spinal anesthesia, CO was 11.3% above baseline. We conclude that the decrease in CO after spinal anesthesia can be prevented by the infusion of an LR solution, with CO reaching the highest value while the infusion is running. ⋯ We studied the effects of lactated Ringer's solution infusion on cardiac output changes after spinal anesthesia. If the patients received no infusion, cardiac output decreased after spinal anesthesia. However, if the patients received lactated Ringer's solution infusion, cardiac output was maintained.