Anesthesiology
-
Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
A randomized controlled trial comparing the cuffed oropharyngeal airway and the laryngeal mask airway in spontaneously breathing anesthetized adults.
The cuffed oropharyngeal airway (COPA), a modified Guedel airway, was compared with the laryngeal mask airway (LMA) during spontaneous breathing anesthesia. Specifically examined were ease of use, physiologic tolerance, and the frequency of problems. ⋯ Although the COPA and LMA are equivalent devices in terms of physiologic alterations and overall clinical problems associated with their use, the LMA was associated with a higher first-time insertion rate and fewer manipulations, suggesting that it is easier to use. The COPA was associated with less blood on the device and fewer sore throats, suggesting it may cause less pharyngeal trauma. Ultimately, both devices were similar in establishing a safe and effective airway for spontaneously breathing anesthetized adults.
-
Randomized Controlled Trial Clinical Trial
Epidural anesthesia reduces the gain and maximum intensity of shivering.
Shivering can be characterized by its threshold (triggering core temperature), gain (incremental intensity increase), and maximum intensity. The gain of shivering might be preserved during epidural or spinal anesthesia if control mechanisms compensate for lower-body paralysis by augmenting the activity of upper-body muscles. Conversely, gain will be reduced approximately by half if the thermoregulatory system fails to compensate. Similarly, appropriate regulatory feedback might maintain maximum shivering intensity during regional anesthesia. Accordingly, the gain and maximum intensity of shivering during epidural anesthesia were determined. ⋯ These results confirm that regional anesthesia reduces the shivering threshold. Epidural anesthesia reduced the gain of shivering by 63% because upper-body muscles failed to compensate for lower-body paralysis. The thermoregulatory system thus fails to recognize that regional anesthesia reduces metabolic heat production, instead responding as if lower-body muscular activity remained intact.
-
Comparative Study Clinical Trial Controlled Clinical Trial
Awakening propofol concentration with and without blood-effect site equilibration after short-term and long-term administration of propofol and fentanyl anesthesia.
The propofol awakening concentration can vary. However, the effect site awakening propofol concentration will be a fixed value. The purpose of this study was to determine the awakening propofol concentrations obtained from infusion Schede using abrupt discontinuation of propofol (half-maximal effective concentration [EC50]) or a descending decrease in concentration to allow blood-effect site equilibration (EC50eq). ⋯ The EC50eq was independent of propofol infusion length, compared with the EC50. Thus the potential for hysteresis during emergence from propofol anesthesia was confirmed.
-
Comparative Study Clinical Trial
Changing from isoflurane to desflurane toward the end of anesthesia does not accelerate recovery in humans.
In an attempt to combine the advantage of the lower solubilities of new inhaled anesthetics with the lesser cost of older anesthetics, some clinicians substitute the former for the latter toward the end of anesthesia. The authors tried to determine whether substituting desflurane for isoflurane in the last 30 min of a 120-min anesthetic would accelerate recovery. ⋯ Substituting desflurane for isoflurane during the latter part of anesthesia does not improve recovery, in part because partial rebreathing through a semiclosed circuit limits elimination of isoflurane during the crossover period. Although higher fresh gas flow during the crossover period would speed isoflurane elimination, the amount of desflurane used and, therefore, the cost would increase.
-
Comparative Study Clinical Trial
Correlation of regional cerebral blood flow with ischemic electroencephalographic changes during sevoflurane-nitrous oxide anesthesia for carotid endarterectomy.
Carotid endarterectomy necessitates temporary unilateral carotid artery occlusion. Critical regional cerebral blood flow (rCBF) has been defined as the rCBF below which electroencephalographic (EEG) changes of ischemia occur. This study determined the rCBF50, the rCBF value at which 50% of patients will not demonstrate EEG evidence of cerebral ischemia with carotid cross-clamping. ⋯ The rCBF50 of 0.6-1.2% sevoflurane in 50% N2O, as determined using logistic regression analysis, is 11.5 +/- 1.4 ml 100 g(-1) x min(-1). Further, in patients anesthetized in this manner, ischemic EEG changes due to carotid occlusion were accurately and rapidly detected.