Anesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
Bispectral analysis of the electroencephalogram correlates with patient movement to skin incision during propofol/nitrous oxide anesthesia.
Bispectral analysis is a signal-processing technique that determines the harmonic and phase relations among the various frequencies in the electroencephalogram. Our purpose was to compare the accuracy of a bispectral descriptor, the bispectral index, with that of three power spectral variables (95% spectral edge, median frequency, and relative delta power) in predicting patient movement in response to skin incision during propofol-nitrous oxide anesthesia. ⋯ The bispectral index of the electroencephalogram is a more accurate predictor of patient movement in response to skin incision during propofol-nitrous oxide anesthesia than are standard power spectrum parameters or plasma propofol concentrations.
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Randomized Controlled Trial Clinical Trial
An intrathecal fentanyl dose-response study in lower extremity revascularization procedures.
Intrathecal opioids routinely are administered to surgical patients to provide prolonged postoperative analgesia. This study evaluated the dose-response effects of intrathecal fentanyl in an elderly patient population undergoing lower extremity revascularization procedures. ⋯ Results indicate that 40 micrograms intrathecal fentanyl provides satisfactory analgesia for approximately 5 h in an elderly patient population, with a low incidence of side effects.
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Randomized Controlled Trial Clinical Trial
Hemodynamic response to induction and intubation. Propofol/fentanyl interaction.
When given as an intravenous bolus for induction of anesthesia, propofol can decrease postintubation hypertension but can also create moderate to severe postinduction, preintubation hypotension. The addition of fentanyl usually decreases the postintubation hypertension but can increase the propofol-induced preintubation hypotension. The goal of the study was to determine the relation between propofol and fentanyl doses and the hemodynamic changes post-induction, preintubation and postintubation. ⋯ Hemodynamic changes after induction with propofol or propofol/fentanyl, pre- or postintubation, are not modified when the propofol dose is increased from 2 to 3.5 mg.kg-1. Maximal hypotension preintubation occurs with a fentanyl dose of 2 micrograms.kg-1, whereas the magnitude of postintubation hypertension is significantly decreased with an increase in the fentanyl dose to 4 micrograms.kg-1.
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Comparative Study
Thermoregulatory and anesthetic-induced alterations in the differences among femoral, radial, and oscillometric blood pressures.
A decrease in radial artery blood pressure relative to central arterial blood pressure is commonly associated with the rewarming phase of cardiopulmonary bypass. Decreased hand vascular resistance has been suggested as a possible mechanism. Although decreased blood viscosity due to hemodilution may contribute to decreased hand vascular resistance, thermoregulatory vascular responses to core hyperthermia also may be important. ⋯ Thermoregulatory and anesthetic-induced alterations in upper-extremity blood flow substantially influence the relations among femoral artery, radial artery, and oscillometric blood pressure measurements.
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Comparative Study Clinical Trial
Antagonism of mivacurium-induced neuromuscular blockade in humans. Edrophonium dose requirements at threshold train-of-four count of 4.
Mivacurium's rapid rate of recovery has led to the suggestion that routine reversal of its residual effects may be unnecessary once signs of spontaneous recovery are evident. When antagonism is attempted at 90% twitch depression, the time saved to return to train-of-four (TOF) ratios > 0.70 compared to control has been reported to average < or = 8 min. This study was an attempt to determine whether similar savings in time could be achieved once spontaneous recovery was well underway. Also investigated was the ability of a TOF count of 4 to serve as a marker that might predict the dose of edrophonium necessary for satisfactory antagonism of mivacurium. ⋯ After recovery from profound mivacurium-induced neuromuscular block, TOF counts of 1, 2, 3, and 4 approximate 10%, 20%, 30%, and 40% return to control twitch height, respectively. Finally, > or = 0.3 mg/kg edrophonium will accelerate recovery from mivacurium by approximately 7-8 min.