Articles: nerve-block.
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Comparative Study
The interpretation of pain relief and sensory changes following sympathetic blockade.
A comparative study of the effects of sympathetic blockade by stellate ganglion block (SGB) and intravenous phentolamine infusion (PhI) was carried out in 24 patients with presumed sympathetically maintained pain of an upper extremity. A total of 15 SGBs and 16 PhIs were performed, with seven patients undergoing both procedures. All patients developed a Horner's syndrome with SGB and nasal stuffiness and cardiovascular changes with PhI. ⋯ When SGB produces pain relief but PhI does not, systemic absorption of local anaesthetic and/or sensory blockade by spread to somatic nerves may be the reason. Thus, PhI appears to be a less sensitive but more specific test than SGB. These two procedures provide complementary information and both may be needed to establish the diagnosis of sympathetically maintained pain.
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Randomized Controlled Trial Comparative Study Clinical Trial
Prophylactic oral ephedrine reduces the incidence of hypotension after subarachnoid block.
The purpose of this study was to demonstrate the efficacy of oral ephedrine in preventing hypotension following subarachnoid block. Two hundred women, ASA physical status I or II, undergoing lower abdominal surgery were randomly divided into two groups (n = 100 each). All patients were given routine oral premedication consisting of diazepam 10 mg and ranitidine 150 mg at bed time and at 90 min before surgery. ⋯ Despite a similar level of block (T3-T4) and i.v. fluids, the total dose of ephedrine supplement in Group I was 4.3 +/- 4.8 mg compared with 11.6 +/- 9.4 mg in Group II (P < 0.01). Also, 55 patients in Group I required intraoperative inotrope supplement compared with 83 in Group II (P < 0.01). We conclude that oral ephedrine premedication is a simple and effective way of reducing the incidence of hypotension in patients undergoing lower abdominal surgery under subarachnoid block.
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Randomized Controlled Trial Comparative Study Clinical Trial
A comparative study of the percutaneous versus intraoral technique for mental nerve block.
Mental nerve block is frequently used to aid repair of facial lacerations; both percutaneous and intraoral approaches to blocking this nerve are used, but have never been compared. The authors compared the two techniques for pain of administration and effectiveness of anesthesia. ⋯ The intraoral approach to the mental nerve block with adjunctive topical anesthesia was subjectively and objectively less painful than the percutaneous approach without adjunctive anesthesia. While the intraoral approach had a greater efficacy of lower-lip anesthesia and a longer duration of action, these differences were not statistically significant.
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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.