Anesthesia and analgesia
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Anesthesia and analgesia · Nov 2003
Randomized Controlled Trial Comparative Study Clinical TrialThe relative motor blocking potencies of bupivacaine and levobupivacaine in labor.
Minimum local analgesic concentrations (MLAC) have been used to determine the epidural analgesic potencies of bupivacaine and its levo- counterpart. There are no reports of the motor blocking potencies of these drugs. In this study we sought to determine the motor block MLAC of both drugs and determine the relative potency ratio. Sixty ASA physical status I-II parturients were randomized. The first woman in each group received 0.25% wt/vol. Up-down sequential allocation was used to determine subsequent concentrations at a testing interval of 0.025% wt/vol. Effective motor block was defined as a Bromage score <4 within 30 min. The up-down sequences were analyzed with the Dixon and Massey method and probit regression. Two-sided P < 0.05 defined significance. The motor block MLAC for bupivacaine was 0.27% wt/vol (95% confidence interval [CI], 0.25-0.30) and for levobupivacaine was 0.31% wt/vol (95% CI, 0.29-0.34) (P = 0.024), with a levobupivacaine/bupivacaine potency ratio of 0.87 (95% CI, 0.77-0.98). This is the first study to estimate the motor-blocking potency ratio of bupivacaine and levobupivacaine in labor. This study demonstrates that the S-enantiomer of bupivacaine is less potent at motor block than the racemate. ⋯ We estimated the motor-blocking potency ratio of bupivacaine and levobupivacaine in labor and demonstrated that the S-enantiomer of bupivacaine is less potent at motor block than the racemate.
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Anesthesia and analgesia · Nov 2003
Randomized Controlled Trial Clinical TrialIntrathecal morphine for postoperative analgesia: a randomized, controlled, dose-ranging study after hip and knee arthroplasty.
In this series, we examined analgesia and side effects of intrathecal morphine sulfate (ITMS) after hip and knee arthroplasty over a dose range of 0.0-0.3 mg. Eighty patients undergoing hip (n = 40) or knee (n = 40) arthroplasty were randomized to receive ITMS (0.0, 0.1, 0.2, or 0.3 mg). A patient-controlled analgesia (PCA) device provided free access to additional analgesics. Morphine use, pain relief, and side effects were recorded for 24 h. Data were analyzed with analysis of variance and linear regression. After hip arthroplasty, morphine use was less in patients receiving 0.1, 0.2, or 0.3 mg of ITMS than in control patients (P < 0.05). After knee arthroplasty, ITMS did not reduce postoperative morphine requirements. Nausea and vomiting and the incidence of oxygen saturation <93% were similar in all groups. Pruritus was more common after ITMS. Patients receiving 0.2 or 0.3 mg of ITMS were more satisfied with their pain control than those receiving 0.0 or 0.1 mg after both hip and knee arthroplasty. Analgesic needs are greater after knee arthroplasty than after hip arthroplasty. We conclude that combining small-dose (0.2 mg) ITMS with PCA morphine provides good to excellent pain control in most patients after total hip or knee arthroplasty. However, PCA morphine use was reduced by the addition of ITMS only after hip arthroplasty. ⋯ This series examined the need for supplemental analgesics, the quality of analgesia, and the incidence of side effects with intrathecal morphine sulfate (ITMS) for analgesia after hip and knee arthroplasty. Analgesic needs are greater after knee arthroplasty than hip arthroplasty. Combining small-dose (0.2 mg) ITMS with standard doses of PCA morphine provided good to excellent pain control in most patients and reduced patient-controlled analgesia morphine use after hip, but not knee, arthroplasty.
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Anesthesia and analgesia · Nov 2003
Randomized Controlled Trial Clinical TrialMannitol and dopamine in patients undergoing cardiopulmonary bypass: a randomized clinical trial.
In this prospective, randomized, placebo-controlled, double-blinded study, we determined the effects of two commonly used adjuncts, mannitol and dopamine, on beta(2)-microglobulin (beta(2)M) excretion rates in patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass (CPB). beta(2)M excretion rate has been described as a sensitive marker of proximal renal tubular function. One-hundred patients with a preoperative serum creatinine level
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Anesthesia and analgesia · Nov 2003
Randomized Controlled Trial Clinical TrialUltrasound guidance speeds execution and improves the quality of supraclavicular block.
In this prospective study, we assessed the quality, safety, and execution time of supraclavicular block of the brachial plexus using ultrasonic guidance and neurostimulation compared with a supraclavicular technique that used anatomical landmarks and neurostimulation. It was hypothesized that ultrasonic guidance would increase the proportion of successful blocks, decrease block execution time, and reduce the incidence of complications such as pneumothorax and neuropathy. Eighty patients were randomized into two groups of 40, Group US (supraclavicular block guided in real time by a two-dimensional ultrasonic image, with neurostimulator confirmation of correct needle position) and Group NS (supraclavicular block using the subclavian perivascular approach, also with neurostimulator confirmation). Blocks were performed using bupivacaine 0.5% and lidocaine 2% (1:1 vol) with epinephrine 1:200000 as the anesthetic mixture. The onset of motor and sensory block for the musculocutaneous, median, radial, and ulnar nerves was evaluated over a 30 min period. At 30 min 95% of patients in Group US and 85% of patients in Group NS had a partial or complete sensory block of all nerve territories (P = 0.13) and 55% of patients in Group US and 65% of patients in Group NS had a complete block of all nerve territories (P = 0.25). Surgical anesthesia without supplementation was achieved in 85% of patients in Group US and 78% of patients in Group NS (P = 0.28). No patient in Group US and 8% of patients in Group NS required general anesthesia (P = 0.12). The quality of ulnar block was significantly inferior to the quality of block in other nerve territories in Group NS, but not in Group US; the quality of ulnar block was not significantly different between Groups NS and US. The block was performed in an average of 9.8 min in Group NS and 5.0 min in Group US (P = 0.0001). No major complication occurred in either group. We conclude that ultrasound-guided neurostimulator-confirmed supraclavicular block is more rapidly performed and provides a more complete block than supraclavicular block using anatomic landmarks and neurostimulator confirmation. ⋯ Ultrasound-guided neurostimulator-confirmed supraclavicular block is more rapidly performed and provides a block of better quality than supraclavicular block using anatomic landmarks and neurostimulator confirmation.
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Anesthesia and analgesia · Nov 2003
Randomized Controlled Trial Clinical TrialA silicone-based wire-reinforced tracheal tube with a hemispherical bevel reduces nasal morbidity for nasotracheal intubation.
We tested the hypothesis that a silicone-based wire-reinforced tracheal tube with a hemispherical bevel is superior to a polyvinyl chloride (PVC)-based precurved tube with a conventional diagonal bevel for nasotracheal intubation. Eighty anesthetized paralyzed adults (ASA physical status I-II) requiring nasotracheal intubation for tonsillectomy were randomly allocated into two equal-sized groups for airway management with the silicone tracheal tube or PVC tracheal tube. Intubation was subdivided into three phases: 1). passage through the nose into the pharynx, 2). laryngoscope-guided passage into the glottic inlet, and 3). laryngoscope-guided passage into the trachea. A specific sequence of airway maneuvers was followed at each stage if it was unsuccessful. The number of attempts and intubation time were documented by an unblinded observer. The frequency of epistaxis and postoperative nasal complications was documented by blinded observers. There were no intubation failures. The number of attempts at pharyngeal (47 versus 56; P = 0.04) and tracheal (43 versus 55; P = 0.005) placement was smaller for the silicone tracheal tube, but the number of attempts at glottic placement was more (72 versus 49; P < 0.0001). Intubation time was similar. The frequency (32% versus 80%; P < 0.0001) and severity of epistaxis were less for the silicone tracheal tube. The total number of postoperative nasal symptoms was smaller for the silicone tracheal tube (10 versus 21; P < 0.05). We conclude that the pharyngeal and tracheal placement phases of nasotracheal intubation require fewer attempts with the silicone tracheal tube than the PVC tracheal tube but that the glottic placement phase requires more attempts. Nasal morbidity is less common with the silicone tracheal tube. ⋯ The pharyngeal and tracheal placement phases of nasotracheal intubation require fewer attempts with a silicone-based wire-reinforced tracheal tube with a hemispherical bevel than with a polyvinyl chloride-based precurved tracheal tube with a conventional diagonal bevel, but the glottic placement phase requires more attempts. Nasal morbidity is less common with the silicone tracheal tube.