Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2004
Randomized Controlled Trial Clinical TrialAdding dexmedetomidine to lidocaine for intravenous regional anesthesia.
Dexmedetomidine is approximately 8 times more selective toward the alpha-2-adrenoceptors than clonidine. It decreases anesthetic requirements by up to 90% and induces analgesia in patients. We designed this study to evaluate the effect of dexmedetomidine when added to lidocaine in IV regional anesthesia (IVRA). We investigated onset and duration of sensory and motor blocks, the quality of the anesthesia, intraoperative-postoperative hemodynamic variables, and intraoperative-postoperative pain and sedation. Thirty patients undergoing hand surgery were randomly assigned to 2 groups to receive IVRA. They received 40 mL of 0.5% lidocaine and either 1 mL of isotonic saline (group L, n = 15) or 0.5 microg/kg dexmedetomidine (group LD, n = 15). Sensory and motor block onset and recovery times and anesthesia quality were noted. Before and after the tourniquet application at 5, 10, 15, 20, and 40 min, hemodynamic variables, tourniquet pain and sedation, and analgesic use were recorded. After the tourniquet deflation, at 30 min, and 2, 4, 6, 12, and 24 h, hemodynamic variables, pain and sedation values, time to first analgesic requirement, analgesic use, and side effects were noted. Shortened sensory and motor block onset times, prolonged sensory and motor block recovery times, prolonged tolerance for the tourniquet, and improved quality of anesthesia were found in group LD. Visual analog scale scores were significantly less in group LD in the intraoperative period and 30 min, and 2, 4, and 6 h after tourniquet release. Intra-postoperative analgesic requirements were significantly less in group LD. Time to first analgesic requirements was significantly longer in group LD in the postoperative period. We conclude that the addition of 0.5 microg/kg dexmedetomidine to lidocaine for IVRA improves quality of anesthesia and perioperative analgesia without causing side effects. ⋯ This study was designed to evaluate the effect of dexmedetomidine when added to lidocaine for IV regional anesthesia. This is the first clinical study demonstrating that the addition of 0.5 microg/kg dexmedetomidine to lidocaine for IV regional anesthesia improves quality of anesthesia and intraoperative-postoperative analgesia without causing side effects.
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Anesthesia and analgesia · Mar 2004
Randomized Controlled Trial Clinical TrialThe influence of ambulation time on the incidence of transient neurologic symptoms after lidocaine spinal anesthesia.
The cause of transient neurologic symptoms (TNSs) after lidocaine spinal anesthesia remains unclear. It has been proposed that early ambulation after spinal anesthesia contributes to the development of TNSs. We evaluated the influence of ambulation time on the occurrence of TNSs after spinal anesthesia with 50 mg of 2% plain lidocaine for knee arthroscopy. One-hundred-twenty patients undergoing knee arthroscopy (ASA physical status 1-2) were randomized into 3 groups, i.e., early (Group E), 6-h (Group 6-h), or late ambulation (Group L) groups. In Group E, ambulation was allowed as early as possible after regression of spinal block (on average 229 +/- 21 min; range, 135-247 min). In Group 6-h, the patients remained in bed for approximately 6 h after the block and in Group L until the next morning. The patient groups were comparable with respect to demographic, anesthetic, and surgical variables. The overall incidence of TNSs was 16%. TNSs occurred in 3 patients of Group E (7.5%), in 11 patients of Group 6-h (28%), and in 5 patients of Group L (13%). No significant differences were detected between the patients with and without TNSs. Early ambulation was not found to be a risk factor for TNSs after spinal anesthesia with 50 mg of 2% lidocaine. ⋯ This study shows that early ambulation time does not increase the incidence of transient neurologic symptoms after spinal anesthesia with 50 mg of 2% lidocaine for elective knee arthroscopy.
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Anesthesia and analgesia · Mar 2004
The incidence and prediction of automatically detected intraoperative cardiovascular events in noncardiac surgery.
The objective of this study was to evaluate prognostic models for quality assurance purposes in predicting automatically detected intraoperative cardiovascular events (CVE) in 58458 patients undergoing noncardiac surgery. To this end, we assessed the performance of two established models for risk assessment in anesthesia, the Revised Cardiac Risk Index (RCRI) and the ASA physical status classification. We then developed two new models. CVEs were detected from the database of an electronic anesthesia record-keeping system. Logistic regression was used to build a complex and a simple predictive model. Performance of the prognostic models was assessed using analysis of discrimination and calibration. In 5249 patients (17.8%) of the evaluation (n = 29437) and 5031 patients (17.3%) of the validation cohorts (n = 29021), a minimum of one CVE was detected. CVEs were associated with significantly more frequent hospital mortality (2.1% versus 1.0%; P < 0.01). The new models demonstrated good discriminative power, with an area under the receiver operating characteristic curve (AUC) of 0.709 and 0.707 respectively. Discrimination of the ASA classification (AUC 0.647) and the RCRI (AUC 0.620) were less. Neither the two new models nor ASA classification nor the RCRI showed acceptable calibration. ASA classification and the RCRI alone both proved unsuitable for the prediction of intraoperative CVEs. ⋯ The objective of this study was to evaluate prognostic models for quality assurance purposes to predict the occurrence of automatically detected intraoperative cardiovascular events in 58,458 patients undergoing noncardiac surgery. Two newly developed models showed good discrimination but, because of reduced calibration, their clinical use is limited. The ASA physical status classification and the Revised Cardiac Risk Index are unsuitable for the prediction of intraoperative cardiovascular events.
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Anesthesia and analgesia · Mar 2004
Clinical TrialAssessing residual neuromuscular blockade using acceleromyography can be deceptive in postoperative awake patients.
Postoperative awake patients may have significant residual neuromuscular block. In awake patients, the results of accelerometry are affected by extra movements to which the thumb may be subject. In this study, we evaluated the repeatability of train-of-four (TOF) ratio using acceleromyography in 253 patients recovering from anesthesia. Immediately after arrival in the postanesthesia care unit, the ulnar nerve was stimulated with TOF stimulation. The evoked response at the thumb was measured by the TOF-Watch apparatus. The current intensity was 30 mA. Two TOF stimulations were applied and recorded at 30-s intervals. A Bland-Altman test was used. The Kappa (kappa) test for clinical agreement between the two measurements was also calculated according to the presence or absence of a residual neuromuscular blockade, defined as a TOF ratio <0.9. According to the presence of a residual neuromuscular blockade, the paired TOF ratios were discordant in 61 patients (24%; 95% confidence interval, 21%-27%). The kappa test indicated a moderate agreement (k = 0.47). We demonstrated that accelerometry as used in this study is not always accurate. Two isolated acceleromyograph TOF ratios are not an accurate representation of the neuromuscular status of the patient recovering from anesthesia. ⋯ Clinicians should be aware that acceleromyography as used in this study does not always provide precise train-of-four ratio measurements. Two isolated acceleromyograph train-of-four ratios are not an accurate representation of the neuromuscular status of the patient recovering from anesthesia.
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Anesthesia and analgesia · Mar 2004
Clinical TrialContinuous parasacral sciatic block: a radiographic study.
Parasacral sciatic blockade results in anesthesia of the entire sacral plexus. In this study we sought to determine the spread of the local anesthetic injected through a parasacral catheter, the anatomical location of the inserted catheters, and the extent and reliability of the blockade. In this study, 87 consecutive patients undergoing major lower limb surgery were enrolled. After placement of the catheter and injection of 8 mL of radio-opaque contrast dye, radiographic images were evaluated for dispersion of the injectate. Sensory and motor evaluations were also performed. Radiographic analysis of the injectates revealed that nearly all catheters (86 catheters, 99%) were in the correct anatomical position. The mean volume of local anesthetic injection was 21 +/- 3 mL. All patients developed a full sensory block of all three major components of the sciatic plexus (tibial, common peroneal, and posterior cutaneous nerve of the thigh). We conclude that the parasacral sciatic block results in frequent success of blockade of all three major components of the sciatic plexus and it has a small risk of complications. Contrast radiography can be used to document the catheter placement. ⋯ The parasacral sciatic block results in a frequent success rate of blockade of all three major components of the sciatic plexus (tibial, common peroneal, and cutaneous nerve of thigh). A contrast radiography can be used to confirm the proper position of the catheter.