Anesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
Onset and duration of rocuronium and succinylcholine at the adductor pollicis and laryngeal adductor muscles in anesthetized humans.
Rocuronium, a new nondepolarizing muscle relaxant, has a rapid onset of activity and may be suitable as a component of a rapid-sequence induction of anesthesia. We evaluated a range of doses on onset and duration of effect at the larynx and the adductor pollicis and compared these characteristics with those of succinylcholine. ⋯ The laryngeal adductors are more resistant to the action of rocuronium than is the adductor pollicis. Consequently, the onset of effect of rocuronium, in doses greater than 0.8 mg/kg, is similar to that of succinylcholine at the adductor pollicis but is significantly delayed compared with that of succinylcholine at the laryngeal adductors.
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Randomized Controlled Trial Clinical Trial
Pharmacokinetics of ropivacaine and bupivacaine for bilateral intercostal blockade in healthy male volunteers.
Intercostal blockade produces the highest serum local anesthetic concentrations of all regional anesthetic techniques. The purpose of this study was to determine the pharmacokinetic properties of ropivacaine and bupivacaine after bilateral intercostal blockade. ⋯ The results of this pharmacokinetic study indicate that 0.25% ropivacaine and 0.25% bupivacaine (56 ml, 140 mg) produce peak plasma levels less than those considered toxic when used in bilateral intercostal blockade. Studies of ropivacaine for intercostal blockade in surgical patients are necessary before the optimum concentration for efficacy and anesthetic/analgesic duration is identified.
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Randomized Controlled Trial Clinical Trial
A double-blind, placebo-controlled trial of transdermal fentanyl after abdominal hysterectomy. Analgesic, respiratory, and pharmacokinetic effects.
A randomized, double-blind, placebo-controlled trial was conducted to assess the analgesic, pharmacokinetic, and clinical respiratory effects of 72-h application of two transdermal fentanyl (TTSF) patch sizes in patients undergoing abdominal hysterectomy. ⋯ Application of TTSF patches 2 h preoperatively is associated with moderate supplementary opioid requirements for analgesia in the early postoperative period and ongoing opioid supplementation for at least 72 h. Although good analgesia is the result of this combination therapy, it is associated with a high incidence of respiratory depression requiring intensive monitoring oxygen supplementation, removal of the TTSF patches in approximately 11% of the patients and opioid reversal with naloxone in approximately 8% of the patients.
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Randomized Controlled Trial Clinical Trial
Pharmacology of epidural fentanyl, alfentanil, and sufentanil in volunteers.
Despite a large number of clinical investigations in postoperative patients, the pharmacology of epidural fentanyl, alfentanil, and sufentanil has not been well characterized in a human laboratory setting. In this double-blind, placebo-controlled crossover study, we evaluated analgesia and side effects produced by epidural fentanyl (30 and 100 micrograms), alfentanil (300 and 1,000 micrograms), and sufentanil (3 and 10 micrograms) in volunteers. ⋯ Lumbar epidural fentanyl, alfentanil, and sufentanil produce selective lower-extremity analgesia. Low plasma opioid concentrations measured after small epidural opioid doses suggest a spinal mechanism for analgesia. Larger doses of epidural opioids result in systemic absorption and are likely to produce supraspinal analgesia and other side effects.
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Tachyphylaxis to local anesthetics has been shown to be promoted by longer interanalgesic intervals between injections. We hypothesized that thermal hyperalgesia also would accelerate the development of tachyphylaxis. The n-methyl-D-aspartate antagonist ((+)-5 methyl-10,11-dihydro-5H-dibenzo (a,d) cyclohepten-5,10-imine, or dizocilpine) (MK-801) has been shown to prevent thermal hyperalgesia. We therefore also hypothesized that MK-801 would prevent tachyphylaxis. ⋯ Thermal hyperalgesia accelerates the development of tachyphylaxis to rat sciatic nerve blockade, and MK-801 prevents tachyphylaxis in this model. n-Methyl-D-aspartate receptor antagonists may have future clinical utility in increasing the duration of effectiveness of prolonged local anesthetic administration.