Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2004
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialPosttetanic potentiation and fade in the response to tetanic and train-of-four stimulation during succinylcholine-induced block.
We designed this study to confirm anecdotal observations that neuromuscular block after a single administration of succinylcholine is characterized by fade to train-of-four (TOF) or tetanic stimulation, as well as posttetanic potentiation. This prospective, randomized, 2-center observational study involved 100 patients. Patients were allocated to 1 of 5 groups and received 0.1, 0.3, 0.5, 0.75, or 1.0 mg/kg succinylcholine during propofol/fentanyl/nitrous oxide anesthesia. Neuromuscular function was monitored by TOF using mechanomyography. At 10%-20% spontaneous recovery of the first twitch of TOF, the mode of stimulation was changed from TOF to 1-Hz single-twitch stimulation followed by a tetanic stimulus (50 Hz) for 5 s. Three seconds later, the single twitch (1 Hz) was applied again for approximately 30 s followed by TOF stimulation until full recovery of the TOF response. Succinylcholine-induced neuromuscular block had the following characteristics: 1) twitch augmentation before twitch depression, which was seen more frequently in patients given smaller doses (0.1 and 0.3 mg/kg) than in those given larger doses (0.5-1.0 mg/kg); 2) TOF fade during onset and recovery of the block; 3) tetanic fade; and 4) and posttetanic potentiation. Posttetanic potentiation was related to the pretetanic twitch height but was not related to the dose of succinylcholine administered. Some characteristics of Phase II block were detectable during onset and recovery from doses of succinylcholine as small as 0.30 mg/kg. Posttetanic potentiation and fade in response to train-of-four and tetanic stimuli are characteristics of neuromuscular block after bolus administration of different doses of succinylcholine. ⋯ Posttetanic potentiation and fade in response to train-of-four and tetanic stimuli are characteristics of neuromuscular block after bolus administration of different doses of succinylcholine. We also conclude that some characteristics of a Phase II block are evident from an initial dose (i.e., as small as 0.3 mg/kg) of succinylcholine.
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Anesthesia and analgesia · Jun 2004
Randomized Controlled Trial Comparative Study Clinical TrialMethadone for the induction of anesthesia: plasma histamine concentration, arterial blood pressure, and heart rate.
Despite the widespread use of methadone for the treatment of acute and chronic pain, the hemodynamic effects of methadone administered by IV bolus have not been studied. We compared the hemodynamic effects of an IV bolus of methadone 20 mg with those of fentanyl 10 microg/kg for the induction of anesthesia in combination with etomidate 0.3 mg/kg. Forty-three patients undergoing major surgery were randomized to one of the two treatments in a double-blinded fashion. Plasma concentrations of histamine were measured before and 2 min after opioid administration. Heart rate and arterial blood pressure were measured via an arterial line just before opioid administration, etomidate administration, and tracheal intubation; during intubation; and 1 min after intubation. There were no significant differences in mean heart rate between the methadone and fentanyl groups at any time point. Systolic and diastolic blood pressures were significantly lower (P < 0.05) in the fentanyl group just before intubation, during intubation, and 1 min after intubation. Mean plasma concentrations of histamine before and after the administration of methadone or fentanyl were 1.54 ng/mL (SD, 0.65 ng/mL) and 1.57 ng/mL (SD, 1.37 ng/mL) or 1.00 ng/mL (SD, 0.58 ng/mL) and 1.04 ng/mL (SD, 0.47 ng/mL), respectively. Despite the lack of a significant change in mean plasma concentrations of histamine, substantial increases in plasma histamine occurred in 2 of 23 patients who received methadone. There were no obvious hemodynamic effects associated with histamine concentrations up to 6.2 ng/mL. Methadone appears to have the potential for producing histamine release. Although methadone administration did not produce hemodynamic instability in this study, the possible hemodynamic side effects of histamine release should be considered when IV boluses of methadone are given. ⋯ The same dose of IV methadone (20 mg) that is effective for postoperative pain is also suitable for the induction of anesthesia in combination with etomidate. The plasma histamine concentration was notably increased in two patients, without obvious hemodynamic sequelae. Therefore, methadone appears to have the potential for producing histamine release.
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Anesthesia and analgesia · Jun 2004
Randomized Controlled Trial Comparative Study Clinical TrialModerate-to-severe pain after knee arthroscopy is relieved by intraarticular saline: a randomized controlled trial.
We have previously studied intraarticular (IA) analgesics compared with saline 10 mL in 2 randomized clinical trials. The patients who were given IA saline experienced rapid pain relief. Hypothetically, saline may produce a local analgesic effect by cooling or by diluting IA algogenic substances. This randomized double-blind study compared the analgesic effect of IA saline 10 mL with saline 1 mL, which should be a pure placebo. A soft catheter was left IA in 79 patients. We included 60 patients who developed moderate-to-severe pain within 1 h after knee arthroscopy under general anesthesia. A randomized, double-blind controlled comparison of IA saline 10 mL with saline 1 mL followed. Outcome measures were pain intensity, pain relief, and analgesic consumption. Within 1 h pain intensity decreased in both groups from approximately 50 to approximately 27 on a 0-100 mm visual analog scale. Pain intensity remained low and other pain outcome measures were similar during the 36-h observation period. The patients experienced equally good pain relief after IA injection of saline 10 mL and 1 mL. Our finding of a major placebo effect may have implications for the interpretation of previously published placebo-controlled IA analgesia studies. ⋯ In a randomized controlled trial we showed that pain after knee arthroscopy is modest and short-lived and can successfully be treated with intraarticular saline as placebo.
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Anesthesia and analgesia · Jun 2004
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialPreoperative parenteral parecoxib and follow-up oral valdecoxib reduce length of stay and improve quality of patient recovery after laparoscopic cholecystectomy surgery.
In this randomized, double-blinded, placebo-controlled study, we evaluated the effects of preoperative IV parecoxib sodium (parecoxib) followed by postoperative oral valdecoxib on length of stay, resource utilization, opioid-related side effects, and patient recovery after elective laparoscopic cholecystectomy. Patients were randomized to receive a single IV dose of parecoxib 40 mg (n = 134) or placebo (n = 129) 30-45 min before the induction of anesthesia. Six to 12 h after the IV dose, the parecoxib group received a single oral dose of valdecoxib 40 mg, followed by valdecoxib 40 mg once daily on postoperative Days 1-4 and then 40 mg once daily as needed on Days 5-7. Patients in the parecoxib/valdecoxib group had a shorter length of stay in the postanesthesia care unit (78 +/- 47 min) compared with those taking placebo (90 +/- 49 min; P < 0.05). Patients in the parecoxib/valdecoxib group also had reduced pain intensity and, after discharge, experienced a significant reduction in vomiting in the first 24 h, slept better, returned to normal activity earlier, and expressed greater satisfaction than placebo patients (P < 0.05). Preoperative parecoxib followed by postoperative valdecoxib is a valuable adjunct for treating pain and improving patient outcome after laparoscopic cholecystectomy. ⋯ The administration of preoperative IV parecoxib followed by oral valdecoxib after surgery resulted in a shorter length of stay in the postoperative anesthesia care unit, a better quality of postoperative recovery, and a faster return to normal activity, with greater patient satisfaction, after laparoscopic cholecystectomy.
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Anesthesia and analgesia · Jun 2004
Randomized Controlled Trial Comparative Study Clinical TrialThe impact of heparin-coated cardiopulmonary bypass circuits on pulmonary function and the release of inflammatory mediators.
Reduction of the inflammatory reaction with the use of heparin coating has been found during and after cardiopulmonary bypass (CPB). The question remains whether this reduced reaction also decreases the magnitude of CPB-induced pulmonary dysfunction. We therefore evaluated the effects of a heparin-coated circuit versus a similar uncoated circuit on pulmonary indices as well as on inflammatory markers of complement activation (C3b/c), elastase-alpha(1)-antitrypsin complex, and secretory phospholipase A(2) (sPLA(2)) during and after CPB. Fifty-one patients were randomly assigned into two groups undergoing coronary artery bypass grafting with either a heparin-coated (Group 1) or an uncoated (Group 2) circuit. During CPB, a continuous positive airway pressure of 5 cm H(2)O and a fraction of inspired oxygen (FIO(2)) of 0.21 were maintained. Differences in favor of the coated circuit were found in pulmonary shunt fraction (P < 0.05), pulmonary vascular resistance index (P < 0.05), and PaO(2)/FIO(2) ratio (P < 0.05) after CPB and in the intensive care unit. During and after CPB, the coated group demonstrated lower levels of sPLA(2). After CPB, C3b/c and the elastase-alpha(1)-antitrypsin complex were significantly less in the coated group (P < 0.001). The coated circuit was associated with a reduced inflammatory response, decreased pulmonary vascular resistance index and pulmonary shunt fraction, and increased PaO(2)/FIO(2) ratio, suggesting that the coated circuit may have beneficial effects on pulmonary function. The correlation with sPLA(2), leukocyte activation, and postoperative leukocyte count suggests reduced activation of pulmonary capillary endothelial cells. ⋯ Heparin coating of the extracorporeal circuit reduces the inflammatory response during cardiopulmonary bypass. Analysis of indices of pulmonary function indicates that use of heparin coating may result in less impaired gas exchange.