Canadian journal of anaesthesia = Journal canadien d'anesthésie
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Comparative Study Controlled Clinical Trial
Carbetocin at elective Cesarean delivery: a sequential allocation trial to determine the minimum effective dose.
The ED90 of carbetocin is approximately 15 mcg after elective cesarean section.
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Biography Historical Article
Special article: Horace Nelson MD, John Webster LDS - unrecognized Canadian anesthesia pioneers.
The timing of the earliest reported ether anesthetics in early 1847, in regions to become Canada in July 1867, was examined using information from on-line and library-based sources. Previous authors had identified the first reported ether anesthetic given by a visiting American dentist in January 1847 in Saint John, New Brunswick. Nevertheless, they had reported three different anesthetics as the second occurrence - which would denote the first anesthetic given by a resident of Canada. ⋯ Earlier authors, who may not have had access to the information now available, came to incorrect conclusions about the first ether anesthetic reported to have been given by a Canadian. Current information indicates that John Webster gave the first reported anesthetic in Montreal on February 20, 1847 following experiments with ether led by Horace Nelson. Both Webster and Nelson deserve recognition as Canadian anesthesia pioneers.
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Comparative Study
Estimation of equivalent threshold currents using different pulse widths for the epidural stimulation test in a porcine model.
The epidural stimulation test can help detect if a catheter is correctly positioned in the epidural space. Previous studies showed that a current of up to 16 mA was required to elicit a motor response, but few peripheral nerve stimulators can produce a current this high. Manipulating pulse width can produce a positive response at a lower current. To clarify the effects of pulse width on the epidural stimulation test, we performed a single-blinded study in a porcine model to estimate the equivalent current needed at varying pulse widths. ⋯ In situations where different pulse widths are needed, the nomograms presented here may be useful to estimate the equivalent threshold current which is required to elicit a motor response according to previously published criteria for epidural stimulation tests.
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Brain imaging studies suggest that loss of consciousness induced by general anesthetics is associated with impairment of thalamic function. There is, however, limited information on the time course of these changes. We recently obtained intracranial electroencephalogram (EEG) recordings from the ventroposterolateral (VPL) nucleus of the thalamus and from the motor cortex during induction of anesthesia in three patients to study the time course of the alterations of cortical and thalamic function. ⋯ We conclude that induction of anesthesia with propofol in these patients was associated with concurrent alterations of cortical and sensory thalamic activity.