Anesthesiology
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Randomized Controlled Trial Clinical Trial
Clonidine and lidocaine inhibition of isoflurane-induced tachycardia in humans.
A rapid increase in isoflurane concentration can induce tachycardia and hypertension and increase plasma catecholamine concentrations. To investigate a possible mechanism, we measured hemodynamic responses to isoflurane administered via mask; we also administered clonidine for premedication, lidocaine topically to the nasal mucosa, or lidocaine intravenously to evaluate the effect of these drugs on the hemodynamic responses. ⋯ Stepwise increases in isoflurane concentration elicited hypertension and tachycardia as well as increments in plasma catecholamine concentrations during mask anesthesia. Nasal administration of lidocaine and clonidine premedication significantly blunted the circulatory responses to isoflurane. Intravenous lidocaine did not significantly weaken the responses to changes in isoflurane concentration.
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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
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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Randomized Controlled Trial Clinical Trial
Fentanyl, esmolol, and clonidine blunt the transient cardiovascular stimulation induced by desflurane in humans.
A rapid increase in the end-tidal concentration of desflurane to greater than 1 MAC transiently increases heart rate, arterial blood pressure, and circulating epinephrine and vasopressin concentrations. We hypothesized that drugs that block sympathetic activity or decrease sympathetic outflow (an opioid, a beta-adrenergic antagonist, and an alpha 2-adrenergic agonist) would blunt these responses. ⋯ Fentanyl, esmolol, and clonidine blunt the transient cardiovascular response to a rapid increase in desflurane concentration. Fentanyl may be the most clinically useful of these drugs because it blunts the increase in heart rate and blood pressure, has minimal cardiovascular depressant effects, and imposes little postanesthetic sedation.
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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.