Anesthesia and analgesia
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Anesthesia and analgesia · Oct 1991
Randomized Controlled Trial Comparative Study Clinical TrialIntradermal anesthesia and comparison of intravenous catheter gauge.
A double-blinded randomized prospective study was performed to determine whether alkalinization of lidocaine decreases the pain of intradermal injection and if a larger intravenous catheter (16 gauge) causes more discomfort on insertion than a smaller (20 gauge) catheter when intradermal anesthesia has been used. In a random manner, 100 patients received skin wheals with commercially prepared lidocaine or lidocaine with the addition of sodium bicarbonate before the insertion of a 16- or 20-gauge intravenous catheter. Visual analogue pain scores were obtained after the skin wheal was placed and after the intravenous catheter was inserted. ⋯ However, the catheter insertions pain scores were slightly, but statistically significantly larger in the 16-gauge group regardless of local anesthetic solution used. The addition of sodium bicarbonate to commercially prepared lidocaine does not decrease the pain associated with an intradermal skin wheal. There is a slight increase in patient discomfort upon insertion of a large-bore intravenous catheter, even with the prior use of local anesthetic.
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Anesthesia and analgesia · Oct 1991
Randomized Controlled Trial Clinical TrialOnset of epidural blockade after plain or alkalinized 0.5% bupivacaine.
This double-blind study investigated the effect of adding 1.4% bicarbonate to 0.5% bupivacaine on onset time of sensory and motor blockade after epidural administration. Forty patients were randomly divided into one of two groups. Group 1 received 20 mL of 0.5% bupivacaine (pH, 5.58 +/- 0.12) and group 2 received 20 mL of 0.5% bupivacaine + 0.6 mL of 1.4% bicarbonate (pH, 6.53 +/- 0.06). ⋯ Maximum motor blockade was reached after 30 min in group 1 and after 36 min in group 2. No difference in motor blockade or upward spread of anesthesia was noted between the two groups. The authors conclude that alkalinization of 0.5% bupivacaine offers no improvement in the onset of epidural blockade.
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Anesthesia and analgesia · Oct 1991
Randomized Controlled Trial Clinical TrialEpidural sufentanil for postoperative analgesia: dose-response in patients recovering from major gynecologic surgery.
To determine the lowest effective dose of epidural sufentanil given for analgesia, 41 patients undergoing elective abdominal gynecologic surgery during continuous epidural anesthesia (lidocaine 2%) were randomly assigned to one of four postoperative treatment groups. Patients received an epidural bolus of either 25 (group A), 40 (group B), 55 (group C), or 70 micrograms (group D) sufentanil in 10 mL of saline. They were evaluated for the next 8 h using a 10-cm visual analogue scale. ⋯ There were no differences among groups with regard to mean respiratory rate, level of sedation, 24-h narcotic requirements, or incidence of nausea, vomiting, and pruritus (P = NS). A single patient in group D suffered profound respiratory depression within seconds of administration. We conclude that, in patients recovering from lower abdominal surgery, a single 40-55-micrograms epidural bolus of sufentanil provides 3-3.5 h of effective analgesia, and that larger doses are not warranted.
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Anesthesia and analgesia · Oct 1991
Low concentrations of isoflurane abolish motor evoked responses to transcranial electrical stimulation during nitrous oxide/opioid anesthesia in humans.
To study the feasibility of noninvasive monitoring of motor pathways in anesthetized patients, we evaluated the effect of isoflurane on motor evoked responses to constant-voltage transcranial electrical stimulation (tce-MERs). Reproducible tce-MERs were recordable from the tibialis anterior muscle during nitrous oxide/opioid anesthesia in 11 patients. Before the introduction of isoflurane, tce-MER onset latency was 30.8 +/- 1.9 ms, and amplitude ranged from 19 microV to 2.6 mV (median, 209 microV). ⋯ The tce-MERs were completely obliterated in all subjects at end-tidal isoflurane concentrations between 0.2% and 0.6% (median, 0.24%). After discontinuation of isoflurane, the tce-MER returned in all patients. The authors conclude that, during nitrous oxide/opioid anesthesia, with the stimulus and recording variables used, isoflurane even at very low concentrations precludes recording of tce-MERs.