Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2001
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of minidose lidocaine-fentanyl spinal anesthesia and local anesthesia/propofol infusion for outpatient knee arthroscopy.
Traditional methods of spinal anesthesia have proven problematic in the outpatient setting. Minidose lidocaine-fentanyl spinal anesthesia (SAB(MLF)) may be the adaptation necessary to reestablish spinal anesthesia in this venue. One hundred patients scheduled for outpatient knee arthroscopy were randomized to receive either local anesthesia plus a titrated IV propofol infusion (LA/PI) or SAB(MLF) using 20 mg lidocaine 0.5% + 20 microg fentanyl. Patients received midazolam 0.02-0.03 mg/kg IV and fentanyl 0.75-1.0 microg/kg IV upon arrival in the operating room before lumbar puncture or propofol infusion. The propofol infusion was begun at 50-75 microg. kg(-)(1). min(-)(1) and titrated to maintain patient comfort. Boluses (200-400 microg/kg) were given as needed. Local anesthesia included 30 mL lidocaine 1% with epinephrine 1:200,000 intraarticularly plus 10 mL at the portal sites. Three patients (6%) in the LA/PI group versus none in the SAB(MLF) group required general anesthesia. Airway support was required in 54% of the LA/PI patients and in none of the SAB(MLF) patients. Total operating room time (43 vs 45 min), time to home readiness (43 vs 45 min), actual discharge times (73.5 min in both groups), and the incidence of discharge >90 min (22% vs 24%) were the same for both LA/PI and SAB(MLF) groups. LA/PI and SAB(MLF) groups differed in terms of postoperative pruritus (8% vs 68%), pain (44% vs 20%), nausea (8% vs 22%), and ability to void before discharge (56% vs 32%). One patient in each group had mild difficulty initiating voiding at home, but neither required medical attention. In both groups, 90% of patients were either "satisfied" or "very satisfied" with their anesthetic. The two techniques provided comparable patient satisfaction and efficiencies both intraoperatively and in postoperative recovery and discharge. The efficiencies of these techniques were not dependent on special provisions of the physical plant or the practice model. ⋯ Both local anesthesia supplemented by a titrated IV propofol infusion and minidose lidocaine-fentanyl spinal anesthesia for outpatient knee arthroscopy provide high patient satisfaction with equally rapid recovery and discharge.
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Anesthesia and analgesia · Aug 2001
A study of the paravertebral anatomy for ultrasound-guided posterior lumbar plexus block.
We investigated the feasibility of posterior paravertebral sonography as a basis for ultrasound-guided posterior lumbar plexus blockades. Posterior paravertebral sonography proved to be a reliable as well as accurate imaging procedure for visualization of the lumbar paravertebral region except the lumbar plexus.
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Anesthesia and analgesia · Aug 2001
Designing meaningful industry metrics for clinical productivity for anesthesiology departments.
Clinical productivity measurements that account for differences in clinical settings and concurrencies provided more precise comparisons between two anesthesiology groups. The data show that different concurrencies confound the current industry standard, "per full-time equivalent" measurements, whereas "per operating room site" and "per case" measurements allowed for more meaningful comparisons.
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Anesthesia and analgesia · Aug 2001
The pharmacokinetics and pharmacodynamics of bupivacaine-loaded microspheres on a brachial plexus block model in sheep.
We evaluated bupivacaine-loaded microspheres (B-Ms) using a brachial plexus block model in sheep. In the first step, pharmacokinetic characterization of 75 mg bupivacaine hydrochloride (B-HCl) (IV infusion and brachial plexus block) was performed (n = 12). In the second step, a brachial plexus block dose response study of B-HCl was performed with 37.5 mg, 75 mg, 150 mg, 300 mg, and 750 mg. As a comparison, evaluations were performed using a 750-mg bupivacaine base (B). In the third step, evaluations of brachial plexus block were performed with B-Ms (750 mg of B as B-Ms) using two formulations, 60/40 and 50/50 (w/w %); drug-free microspheres were also evaluated. Toxicity evaluations were also performed after IV administration of B-HCl (750 mg and 300 mg), B-Ms (750 mg), and drug-free microspheres (30 mL over 1 min). As the B-HCl dose increased, the time of onset of block decreased and the duration of complete motor blockade increased at the expense of an increase in bupivacaine plasma concentrations. The time of maximum concentration appeared to be independent of the B-HCl dose. In brachial plexus block, a 37.5-mg dose of B-HCl did not induce motor blockade whereas a dose of 750 mg of B-HCl was clinically toxic. In the case of IV administration, doses of 300 mg of B-HCl were as toxic as 750 mg of B-HCl. Compared with the 75 mg of B-HCl administration for brachial plexus block, administration of 750 mg of B as B-Ms increased the duration of complete motor blockade without significant difference in maximum concentration. No significant clinical difference between the two formulations of B-Ms was demonstrated. The IV administration of B-Ms was safe. We conclude that the controlled release of bupivacaine from microspheres prolonged the brachial plexus block without obvious toxicity. ⋯ Administration of 750 mg of bupivacaine as loaded-microspheres resulted in prolongation of brachial plexus block in sheep. The peak plasma concentration was not significantly larger than that obtained with 75 mg of plain bupivacaine. The motor blockade was increased more than six times compared with 75 mg plain bupivacaine.