British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Haemostatic changes caused by i.v. regional anaesthesia with lignocaine.
The various components of i.v. regional anaesthesia (IVRA), that is ischaemia, tourniquet compression and the presence of high concentrations of local anaesthetics in the blood vessels of the extremity, may affect haemostatic mechanisms. We performed a cross-over study in 10 healthy male volunteers to examine the role of lignocaine in IVRA on several haemostatic variables, and those indicating fibrinolysis and platelet function in particular. Venous blood samples were obtained from the test arm and the opposite arm before IVRA, at the time of tourniquet cuff deflation and 30 min thereafter. ⋯ Although IVRA appeared to induce some platelet dysfunction, there was a small increase in TEG amplitude indicative of improved fibrin-platelet interaction in the lignocaine-exposed arm at the time of cuff deflation. We conclude that the presence of high i.v. lignocaine concentrations (median 144.4 micrograms ml-1 in cubital veins at the end of the tourniquet time) potentiated ischaemia-induced fibrinolysis activation during IVRA. Concomitant platelet dysfunction was not aggravated by lignocaine.
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Randomized Controlled Trial Comparative Study Clinical Trial
Efficiency of a circle system for short surgical cases: comparison of desflurane with isoflurane.
Patients undergoing short surgical procedures but requiring ventilation of the lungs were allocated randomly to receive either desflurane or isoflurane by circle absorption system, initially at a high fresh gas flow. The inspired and expired concentrations of the volatile agent were measured and the fresh gas flows reduced to low flow (500 ml min-1 total when FE/FI = 0.8), as measured on a multigas analyser. In patients receiving desflurane (n = 32), the median time at which flows were reduced was 5 min (interquartile range (IQR) 1 min) while with isoflurane (n = 32), the median time was 19 (IQR 12) min. ⋯ In the isoflurane group the concentration continued to decrease during anaesthesia. In the desflurane group the initial decrease was followed by a slow recovery. We conclude that the circle system can be used efficiently for short anaesthetics using desflurane.
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Comparative Study
Differential effects of desflurane and halothane on peripheral airway smooth muscle.
Volatile anaesthetics have been shown to have direct relaxant effects on airway smooth muscle. We have examined the effects of 0.9, 1.9, and 2.8 dog MAC of desflurane and halothane on isolated proximal and distal canine airways precontracted with acetylcholine. The proximal and distal airway smooth muscle relaxed with increasing concentration of each anaesthetic in a dose-related manner. ⋯ The distal airway smooth muscle was more sensitive to volatile anaesthetics than the proximal airway smooth muscle with either halothane or desflurane at all concentrations tested. This effect may be a result of differences in cartilage content, myosin content, epithelium-dependent effects, receptor density, myofilament sensitivity to Ca2+, sarcoplasmic reticulum Ca2+ control, or ionic fluxes in the proximal airway compared with the distal airway. The increased sensitivity of airway smooth muscle to desflurane compared with halothane is not known but may be related to possible differences in the effects of Ca2+ homeostasis.
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Randomized Controlled Trial Comparative Study Clinical Trial
Combination of ondansetron and dexamethasone in the prophylaxis of postoperative nausea and vomiting.
We studied 100 ASA I-II females undergoing general anaesthesia for major gynaecological surgery, in a prospective, double-blind, placebo-controlled, randomized study. Patients received one of four regimens for the prevention of postoperative nausea and vomiting (PONV): ondansetron 4 mg (n = 25), dexamethasone 8 mg (n = 25), ondansetron with dexamethasone (4 mg and 8 mg, respectively, n = 25) or placebo (saline, n = 25) There were no differences in background factors or factors related to operation and anaesthesia, morphine consumption, pain or side effects between groups. The incidence of nausea and emetic episodes in the ondansetron with dexamethasone group was lower than in the placebo (P < 0.01), ondansetron (P < 0.05) and dexamethasone (P = 0.057) groups. ⋯ Dexamethasone appeared to be preferable in preventing nausea than emetic episodes. Fewer patients in the ondansetron with dexamethasone group needed antimetic rescue (P < 0.01 vs placebo and P < 0.05 vs ondansetron). We conclude that prophylactic administration of combined ondansetron and dexamethasone is effective in preventing PONV.