Anesthesia and analgesia
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Anesthesia and analgesia · Aug 1995
Randomized Controlled Trial Comparative Study Clinical TrialAutologous platelet-rich plasmapheresis: risk versus benefit in repeat cardiac operations.
Preoperative platelet-rich plasmapheresis has been suggested as a means of reducing homologous blood transfusions in cardiac surgical patients. The current study evaluated this technique in patients undergoing repeat cardiac operations. Fifty-two patients undergoing repeat myocardial revascularization and/or valve replacement were evaluated in a prospective randomized controlled study design. ⋯ No patient who completed the study returned to the operating room for postoperative bleeding. These data suggest that PRP did not reduce postbypass bleeding or transfusion requirements in repeat cardiac surgical patients. Moreover, the incidence of hypotension during PRP reinfusion introduces a potential risk to the procedure in the absence of any obvious benefit.
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Anesthesia and analgesia · Aug 1995
Differential age effects of mean arterial pressure and rewarming on cognitive dysfunction after cardiac surgery.
Central nervous system dysfunction is a common consequence of otherwise uncomplicated cardiac surgery. Many mechanisms have been postulated for the cognitive dysfunction that is part of these neurologic sequelae. The purpose of our investigation was to evaluate the effects of mean arterial pressure (MAP) during cardiopulmonary bypass (CPB) and the rate of rewarming on cognitive decline after cardiac surgery. ⋯ Multivariable linear regression revealed that the rate of rewarming and MAP were unrelated to cognitive decline. However, interactions significantly associated with cognitive decline were found between age and MAP area less than 50 mm Hg on one measure, and between age and rewarming rate in another, identifying susceptibility of the elderly to these factors. Although MAP and rewarming were not the primary determinates of cognitive decline in this surgical population, hypotension and rapid rewarming contributed significantly to cognitive dysfunction in the elderly.
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Anesthesia and analgesia · Aug 1995
Comparative StudyLocal anesthetic neurotoxicity does not result from blockade of voltage-gated sodium channels.
To investigate whether local anesthetic neurotoxicity results from sodium channel blockade, we compared the effects of intrathecally administered lidocaine, bupivacaine, and tetrodotoxin (TTX), the latter a highly selective sodium channel blocker, on sensory function and spinal cord morphology in a rat model. First, to determine relative anesthetic potency, 25 rats implanted with intrathecal catheters were subjected to infusions of lidocaine (n = 8), bupivacaine (n = 8), or TTX (n = 9). The three drugs produced parallel dose-effect curves that differed significantly from one another: the EC50 values for lidocaine, bupivacaine, and TTX were 28.2 mM (0.66%), 6.6 mM (0.19%), and 462 nM, respectively. ⋯ Significant sensory impairment again occurred after infusion of bupivacaine, but not after infusion of TTX or saline. Neuropathologic evaluation revealed moderate to severe nerve root injury in bupivacaine-treated animals; histologic changes in TTX- and saline-treated animals were minimal, similar, and restricted to the area adjacent to the catheter. These results indicate that local anesthetic neurotoxicity does not result from blockade of the sodium channel, and suggest that development of a safer anesthetic is a realistic goal.
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Anesthesia and analgesia · Aug 1995
Electroencephalographic characteristics of emergence from propofol/sufentanil total intravenous anesthesia.
We recorded the electroencephalogram (EEG) in 16 patients during propofol/sufentanil total intravenous anesthesia to determine whether EEG changes might predict imminent awakening during emergence. Changes in absolute and relative power in four frequency bands, median frequency (MF), 95th percentile frequency (F95), and two frequency band power ratios (beta/alpha and (alpha+beta)/delta) were quantified. ⋯ Of the individual spectral variables, only a 50% decrease in absolute alpha power was more than 90% sensitive and specific in predicting eye opening. We conclude that, although pronounced EEG changes occur during emergence from propofol/sufentanil anesthesia, the EEG does not reliably predict eye opening.