Anesthesiology
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Randomized Controlled Trial Clinical Trial
Effects of fentanyl versus sufentanil in equianesthetic doses on middle cerebral artery blood flow velocity.
Sufentanil has been reported to increase cerebral blood flow in comparison with fentanyl. However, because of the use of animal models, supraclinical doses and/or background anesthetic agents, the clinical applicability of these studies remains difficult to assess. Therefore, transcranial Doppler ultrasonography was used to determine the cerebral hemodynamic effects of equianesthetic doses of fentanyl and sufentanil on middle cerebral artery (MCA) blood flow velocity in patients without intracranial pathologic conditions. ⋯ These data suggest that, at clinically relevant doses in the absence of other drugs, cerebral blood flow velocity is increased by both fentanyl and sufentanil. Furthermore, there appears to be no significant differences in the cerebral hemodynamic profiles of the two drugs, as assessed by transcranial Doppler ultrasonography.
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Randomized Controlled Trial Multicenter Study Clinical Trial
Randomized evaluation of pulse oximetry in 20,802 patients: II. Perioperative events and postoperative complications.
The authors describe the effect of pulse oximetry monitoring on the frequency of unanticipated perioperative events, changes in patient care, and the rate of postoperative complications in a prospective randomized study. ⋯ This study demonstrated that pulse oximetry can improve the anesthesiologist's ability to detect hypoxemia and related events in the OR and PACU and that the use of the oximeter was associated with a significant decrease in the rate of myocardial ischemia. Although monitoring with pulse oximetry prompted a number of changes in patient care, a reduction in the overall rate of postoperative complications was not observed.
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The N1 and P3 waves of the auditory event-related potential provide information on consciousness and cortical function. The N1 wave is reduced during states of low vigilance. The P3 wave occurs only for stimuli that somehow capture the subject's attention. There are two types of P3:P3a and P3b. The P3a predominates frontally and probably occurs when the subject simply notices the stimulus. The P3b predominates parietally and indicates conscious awareness of the evoking stimulus. The N1 and P3 were recorded in 12 patients during cardiac surgery under sufentanil anesthesia to search for unintentional awareness. The study was limited to the period before cardiopulmonary bypass. ⋯ The attenuation of N1 from induction onward reflects a decrease in the level of arousal caused by sufentanil. A P3a during postintubation and precardiopulmonary bypass indicates that pitch discrimination at the cortical level occurs but does not prove that conscious awareness has occurred. Whether or not the P3a reflects the regaining of consciousness is not known.
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The effects of propofol on uterine blood flow are not understood well. This is a relatively new agent that is finding increased use for nonobstetric surgical procedures during pregnancy and induction of anesthesia for cesarean section. ⋯ Assuming the applicability of ovine data to humans, these findings suggest that induction and maintenance of anesthesia with propofol and 50% nitrous oxide in oxygen has no adverse fetal effects but warrants caution because of the potential risk of severe maternal bradycardia during induction of anesthesia using the combination of propofol and succinylcholine.