Anesthesiology
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Randomized Controlled Trial Clinical Trial
Placental transfer and neonatal effects of epidural sufentanil and fentanyl administered with bupivacaine during labor.
This randomized double-blind investigation was designed to study the placental transfer and neonatal effects of epidural sufentanil and fentanyl infused with bupivacaine for labor analgesia. ⋯ Although the degree of placental transfer of sufentanil appeared greater than that of fentanyl, lower MV sufentanil concentrations resulted in less fetal exposure to sufentanil. The lower NACS at 24 h in group B-F may reflect the continued presence of fentanyl in the neonate.
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Randomized Controlled Trial Clinical Trial
Effects of exogenous intravenous glucose on plasma glucose and lipid homeostasis in anesthetized infants.
Whether intravenous glucose administration to infants during anesthesia is necessary remains to be resolved. The current study was designed to investigate the effect of exogenous glucose infusion on plasma glucose and lipid homeostasis in infants undergoing minor surgery. ⋯ These data indicate that, in otherwise healthy infants undergoing minor surgery, intravenous infusion of 2% glucose may be sufficient to maintain plasma glucose concentrations within physiologic ranges and to prevent a compensatory increase in lipid mobilization (lipolysis) when fluids are infused at a rate of 6 ml.kg-1.h-1. However, there are limitations in extrapolating the results to neonates.
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Hypothermia is common in surgical patients and victims of major trauma; it also results from environmental exposure and drug abuse. In most cases, hypothermia results largely from drug-induced inhibition of normal thermoregulatory control. Although opioids are given to a variety of patients, the thermoregulatory effects of opioids in humans remain unknown. Accordingly, the hypothesis that opioid administration impairs thermoregulatory control was tested. ⋯ The observed pattern of thermoregulatory impairment is similar to that produced by most general anesthetics: a slight increase in the sweating threshold and a substantial, linear decrease in the vasoconstriction and shivering thresholds.
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Pulmonary administration of fentanyl solution can provide satisfactory but brief postoperative pain relief. Liposomes are microscopic phospholipid vesicles that can entrap drug molecules. Liposomal delivery of fentanyl has the potential to control the uptake of fentanyl by the lungs and thus provide sustained drug release. To demonstrate that inhalation of a mixture of free and liposome-encapsulated fentanyl can provide a rapid increase and sustained plasma fentanyl concentrations (CfenS), this study determined the pharmacokinetic profiles after the inhalation of free and liposome-encapsulated fentanyl in healthy volunteers. ⋯ The data suggest that this analgesic method offers a simple and noninvasive route of administration with a rapid increase of Cfen and a prolonged therapeutic fentanyl concentration. Future studies are required to determine the optimal liposome composition that would produce a sustained stable Cfen within analgesic therapeutic concentrations.
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Systemic vascular resistance (the ratio of mean aortic pressure [AP] and mean aortic blood flow [AQ]) does not completely describe left ventricular (LV) afterload because of the phasic nature of pressure and blood flow. Aortic input impedance (Zin) is an established experimental description of LV afterload that incorporates the frequency-dependent characteristics and viscoelastic properties of the arterial system. Zin is most often interpreted through an analytical model known as the three-element Windkessel. This investigation examined the effects of isoflurane, halothane, and sodium nitroprusside (SNP) on Zin. Changes in Zin were quantified using three variables derived from the Windkessel: characteristic aortic impedance (Zc), total arterial compliance (C), and total arterial resistance (R). ⋯ The major difference between the effects of isoflurane and halothane on LV afterload derived from the Windkessel model of Zin was related to R, a property of arteriolar resistance vessels, and not to Zc or C, the mechanical characteristics of the aorta. No changes in arterial wave reflection patterns determined from Zin spectra occurred with isoflurane and halothane. These results indicate that isoflurane and halothane have no effect on frequency-dependent arterial properties.