Anesthesiology
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Randomized Controlled Trial Clinical Trial
Dose-response relationships for edrophonium and neostigmine as antagonists of atracurium and vecuronium neuromuscular blockade.
To determine the potencies of edrophonium and neostigmine as antagonists of nondepolarizing neuromuscular blockade produced by atracurium and vecuronium, dose-response curves were constructed for both antagonists when given at 10% spontaneous recovery of first twitch height. Ninety ASA physical status 1 and 2 adults were given either 0.4 mg/kg atracurium or 0.08 mg/kg vecuronium during thiopental-nitrous oxide-enflurane anesthesia. Train-of-four stimulation was applied to the ulnar nerve every 12 s, and the force of contraction of the adductor pollicis muscle was recorded. ⋯ The edrophonium ED80 was 0.44 +/- 0.11 mg/kg with atracurium and 0.46 +/- 0.12 mg/kg with vecuronium, giving a neostigmine:edrophonium potency ratio of 20. Atracurium train-of-four fade could be antagonized more easily with edrophonium, whereas that of vecuronium was more easily antagonized by neostigmine. It is concluded that edrophonium and neostigmine are not equally effective against atracurium and vecuronium.
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Comparative Study
Effect of ropivacaine on cutaneous capillary blood flow in pigs.
The effect of subcutaneous infiltration of ropivacaine and bupivacaine on local cutaneous blood flow was assessed by the laser Doppler method. One milliliter of each of ten test solutions (ropivacaine 0.25% and 0.75%, bupivacaine 0.25% and 0.75%, and saline, each with and without added epinephrine 5 micrograms/ml) was injected subcutaneously at separate sites on the side of each pig (n = 6). Skin blood flow was measured by laser Doppler at all sites before and 5, 10, 15, and 30 min after injection. ⋯ Cutaneous blood flow after the injection of ropivacaine was significantly lower than after injection of bupivacaine or saline, and was also lower than at the uninjected control site (P = 0.0009). All of the solutions with epinephrine decreased blood flow to a similar extent (48-73%, P = 0.3). The ability of ropivacaine to produce cutaneous vasoconstriction offers several advantages over the other local anesthetics presently available for infiltration anesthesia.
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The effects of iv succinylcholine (SCh) on cerebral blood flow (CBF), muscle afferent activity (MAA), electromyographic activity (EMG), visible fasciculations, and PaCO2 were tested in 12 dogs anesthetized with 0.87% end-expired halothane (1 MAC). Six dogs (group I) received treatments of both SCh 1.0 mg/kg iv and saline placebo 3.0 ml iv. Fasciculations and substantial increases in EMG activity were observed in all six dogs given SCh. ⋯ The peak MAA value of 255% +/- 56% of control occurred at the 1-min measurement point and was followed by a gradual decline in MAA. CBF increases were greatest during the periods of greatest MAA (i.e., the 1- to 3-min measurement points). The largest increase in CBF (128% +/- 9% of control) occurred at the 3-min measurement point.(ABSTRACT TRUNCATED AT 250 WORDS)
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Intraoperative changes in blood coagulation were observed in eight children undergoing liver transplantation using a simplified coagulation profile (prothrombin time [PT], activated partial thromboplastin time [aPTT], and platelet count) and thrombelastography. Preoperatively, PT and aPTT were moderately prolonged (1.5 times control), and platelet count was greater than 100,000/mm3 in all patients but one (91,000/mm3). During the preanhepatic and anhepatic stages, PT, aPTT, reaction time, and coagulation time improved toward normal values, but platelet count and maximum amplitude did not change. ⋯ Fibrinolysis occurred during the operation in five patients and was treated with Epsilon-aminocaproic acid (EACA) in one. Blood coagulation improved slowly, and values were close to baseline 90 min after reperfusion. In general, the coagulation changes seen in these children are similar to those in adults but less severe, possibly because of the preponderance of cholestatic disease in children compared with the more common hepatocellular disease in adults.