Articles: anesthetics.
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J Cardiothorac Anesth · Jun 1988
Randomized Controlled Trial Comparative StudyLocal anesthesia for radial artery cannulation: a comparison of a lidocaine-prilocaine emulsion and lidocaine infiltration.
A topical anesthetic emulsion consisting of a mixture of lidocaine and prilocaine (EMLA) was used in an attempt to reduce the pain associated with radial artery cannulation. Three groups were compared: (1) EMLA applied at least 90 minutes prior to cannulation (EMLA 90); (2) EMLA applied 60 minutes prior to cannulation (EMLA 60); and (3) lidocaine 2% infiltration performed immediately prior to the procedure (infiltration). ⋯ There was no statistically significant difference in pain scores between the EMLA 60 and infiltration groups. Local side-effects of EMLA were negligible.
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J Cardiothorac Anesth · Jun 1988
Clinical TrialThe effects of cardiopulmonary bypass on plasma concentrations and protein binding of methohexital and thiopental.
The effects of cardiopulmonary bypass (CPB) on plasma concentrations and protein binding of methohexital and thiopental were studied during continuous infusions in two groups of ten cardiac surgical patients. Patients were administered an infusion regimen designed to produce a stable total plasma concentration at 5 mg/L for methohexital and 10 mg/L for thiopental. Prior to the commencement of CPB the mean (+/-SD) total plasma methohexital concentration was 5.00 +/- 0.69 mg/L. ⋯ The unbound concentration (1.51 +/- 0.21 mg/L) was again unchanged by the onset of CPB, being 1.71 +/- 0.29 mg/L at 75 minutes. Plasma protein binding of both drugs correlated strongly with plasma albumin concentration, which decreased by 40% during CPB. It is concluded that hemodilution caused the reduction in total drug concentration and protein binding at the onset of CPB, but that the decrease in protein binding counteracted the dilution of unbound drug, resulting in a stable unbound concentration throughout CPB, and that this effect may be common for barbiturates.
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Comparative Study
Effects of anesthetics on cardiovascular responses of the marmot Marmota flaviventris.
The effects of pentobarbital (30 mg/kg), urethan (2 g/kg), chloralose/urethan (50 mg/kg, 500 mg/kg), and thiobutabarbital (Inactin, 100 mg/kg) on the mean arterial pressure (BP) and heart period (HP) of Marmota flaviventris were examined. Anesthesia significantly decreased BP by 22-27 mm Hg and HP by 123-151 msec. In a series of paired studies with eight marmots it was found that pentobarbital increased the BP response to phenylephrine and almost abolished the baroreflex HP responses to phenylephrine and nitroglycerin. ⋯ Chloralose/urethan, urethan, or Inactin reduced the reflex BP response to unilateral carotid occlusion by 50% and the HP response by 96%. It was concluded that the anesthetic agents investigated depress baroreflex responses significantly by influencing efferent sympathetic and parasympathetic reflex responses. They, therefore, are not appropriate for cardiovascular studies in acute, anesthetized preparations of the marmot and, perhaps, other hibernating species.
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Randomized Controlled Trial Clinical Trial
Obtunding the sympathetic response to intubation. Experience at 2 minutes after administration of the test agent in patients with cerebral aneurysms.
The sympathetic response to laryngoscopy and intubation was studied in 39 patients who were to undergo surgical clipping of a cerebral aneurysm. Intravascular radial artery pressure and ECG monitoring for ST-segment changes or dysrhythmias were used. Ward blood pressures were controlled on bed rest and labetalol. ⋯ Intubation produced an immediate increase in blood pressure and pulse rate, maximal at 30-60 seconds, falling rapidly towards normal within 2-3 minutes. Alfentanil was very effective in obtunding this response with stable cardiovascular parameters; fentanyl produced a more variable response; and intravenous lignocaine was less satisfactory. Lignocaine spray was ineffective.