Canadian journal of anaesthesia = Journal canadien d'anesthésie
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Review
Perioperative stroke. Part I: General surgery, carotid artery disease, and carotid endarterectomy.
Although stroke, defined as a focal neurological deficit lasting more than 24 hr, is uncommon in the perioperative period, its associated mortality and long-term disability are high. No large-scale data are available to identify the importance of recognized risk factors for stroke in the perioperative period. A review of the literature shows that the incidence and mechanism of its occurrence are influenced by the presence of cardiovascular disease and the type of surgery. ⋯ The risk of stroke associated with carotid endarterectomy is closely related to the preoperative neurological presentation, and the experience of the surgical/anaesthetic team. Symptomatic cerebrovascular disease, acute stroke, asymptomatic carotid lesions, preoperative assessment of risk, local and general anaesthesia, cerebral protection and monitoring during carotid endarterectomy are discussed with reference to reducing the risk of perioperative stroke. Adequate monitoring and protection have minimized the risk of ischaemia from carotid clamping, and the major mechanism of stroke is embolization.
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To avoid the high incidence of respiratory complications associated with general anaesthesia in premature neonates, 44 spinal anaesthetics for inguinal hernia repair in very low birthweight infants were administered in 47 attempts. Hyperbaric tetracaine with epinephrine 1:200,000 was administered in a dose range of 0.27-1.10 mg.kg-1. Attempted lumbar puncture failed in three infants. ⋯ No infant required tracheal intubation; there was no haemodynamic instability. Twenty-four infants required no postoperative analgesia. Our experience suggests that spinal anaesthesia for inguinal hernia repair in very low birth weight infants reduces but does not eliminate the risk of respiratory instability, and that supplementary anaesthesia is often necessary to provide satisfactory operating conditions.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of two esmolol bolus doses on the haemodynamic response and seizure duration during electroconvulsive therapy.
Twelve ASA physical status I-III patients were enrolled in a double-blind, prospective, randomized, three-way, within-patient crossover study designed to determine the effect of two standard esmolol bolus doses (100 and 200 mg) on the haemodynamic response and seizure duration during electro-convulsive therapy (ECT). Esmolol or placebo was administered one minute prior to induction of anaesthesia and exactly two minutes before ECT. Both the 100 and 200 mg bolus doses significantly blunted the maximum increase in heart rate (HR) and mean arterial pressure (MAP) following ECT in comparison with placebo. ⋯ No significant difference was found between the two esmolol doses at corresponding measurement points before and after ECT. Treatment with esmolol 200 mg resulted in a significantly shorter mean seizure duration than with placebo. As the 200 mg dose caused a shorter seizure duration and the haemodynamic effects of 100 mg and 200 mg doses were similar, it was concluded that the 100 mg esmolol bolus dose was the better dose for ECT.
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Neostigmine 0.06 mg.kg-1 or edrophonium 1 mg.kg-1 were administered to two groups of 15 patients each for antagonism of pipecuronium-induced neuromuscular block at 20% spontaneous recovery of the first twitch (T1) of the train-of-four (TOF) stimulation. The mean onset of action (+/-SEM) of edrophonium (18.1 +/- 2.4 sec) was significantly more rapid (P less than 0.01) than that of neostigmine (47.6 +/- 4 sec), as were the times taken to attain a TOF ratio of 0.25 and 0.5. Nevertheless, the reversal time (time taken from the end of injection of the antagonist until TOF ratio value had reached 0.75) was significantly shorter (P less than 0.01) in the neostigmine than in the edrophonium group (499.3 +/- 62 vs 767 +/- 52 sec respectively). ⋯ Administration of one additional dose (one-third of the initial dose) of the same antagonist resulted in adequate antagonism in the remaining five patients in the neostigmine group and in nine patients in the edrophonium group. Two such doses were required in the remaining three patients in the latter group. The mean total dose of neostigmine and edrophonium employed in this study was 0.067 +/- 0.002 and 1.3 +/- 0.05 mg.kg-1, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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The present study employed train-of-four (TOF) stimulation at a current of 20 mA to assess the incidence and degree of residual neuromuscular blockade in 64 randomly selected Post Anesthesia Care Unit (PACU) patients. Group C (Control, n = 10) had received anaesthesia without nondepolarizing muscle relaxant; Group V (n = 25) had received vecuronium; and Group P (n = 29) had received pancuronium. At the end of surgery, each patient had been considered by his anaesthetist to have adequate neuromuscular function on the basis of clinical signs and tactile or visual evaluation of responses to TOF stimulation. ⋯ This study indicates that residual curarization may be commonly encountered following long-acting relaxants despite qualitative intraoperative TOF monitoring. The present incidence, detected at a current of 20 mA, is consistent with previous reports which employed supramaximal TOF stimulation. We conclude that despite intraoperative monitoring, residual curarization following long-acting nondepolarizing agents is common and that it may be detected with TOF at a low stimulating current (20 mA).