Anesthesiology
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Randomized Controlled Trial Clinical Trial
The sedative and analgesic sparing effect of music.
To determine whether music influences intraoperative sedative and analgesic requirements, two randomized controlled trials were performed. ⋯ Use of intraoperative music in awake patients decreases patient-controlled sedative and analgesic requirements. It should be noted, however, that patients in the no-music group did not use a headset during operation. Thus, the decrease in sedative and analgesic requirements could be caused by elimination of ambient operating room noise and not by the effects of music.
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Comparative Study Clinical Trial
A comparison of left ventricular performance indices measured by transesophageal echocardiography with automated border detection.
Automated border detection (ABD) allows semiautomated measurement of left ventricular (LV) areas. They can be combined with left ventricular pressure signals to generate pressure-area loops and pressure-dimension indices of contractility. This study compared conventional indices of ventricular performance (fractional area change [FAC] and circumferential fiber shortening [Vcfc]) with pressure-dimension indices of contractility. A secondary aim was to compare the effects of volatile anesthetics on the indices. ⋯ The association between pressure-dimension indices and Vcfc or FAC was weak or nonexistent. A reduction in myocardial contractility induced by the administration of volatile anesthetic agents was detected by Ees and PRSF, but not by FAC, Vcfc, or dP/dtmax x EDA(-1). After myocardial revascularization, Ees and PRSF appear more sensitive than FAC or Vcfc for measuring changes in contractility.
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Sometimes a high intrapulmonary shunt occurs after cardiac surgery, and impairment of lung function and oxygenation can persist for 1 week after operation. Animal studies have shown that postoperative shunt can be explained by atelectasis. In this study the authors tried to determine if atelectasis can explain shunt in patients who have had cardiac surgery. ⋯ Large atelectasis in the dorsal part of the lungs was found on the first postoperative day after cardiac surgery. However, there was no clear correlation between atelectasis and measured shunt fraction.
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Clinical Trial
Quantitative EEG correlations with brain glucose metabolic rate during anesthesia in volunteers.
To help elucidate the relationship between anesthetic-induced changes in the electroencephalogram (EEG) and the concurrent cerebral metabolic changes caused by anesthesia, positron emission tomography data of cerebral metabolism obtained in volunteers during anesthesia were correlated retrospectively with various concurrently measured EEG descriptors. ⋯ Some EEG descriptors correlated linearly with the magnitude of the cerebral metabolic reduction caused by propofol and isoflurane anesthesia. These data suggest that a physiologic link exists between the EEG and cerebral metabolism during anesthesia that is mathematically quantifiable.
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Airway pressure-release ventilation provides ventilation comparable to controlled mechanical ventilation (CMV), but with lower peak airway pressures and less dead-space ventilation. To obtain these advantages for patients administered general anesthesia, the authors (1) designed a mode similar to airway pressure-release ventilation, intermittent continuous positive airway pressure (CPAPI), and compared its efficiency with that of CMV; and (2) assessed the accuracy of end-tidal carbon dioxide tension (PETCO2) as a monitor of the partial pressure of carbon dioxide in arterial blood (PaCO2) during CPAPI compared with during CMV. ⋯ During CPAPI, less ventilation was necessary to produce a PaCO2 comparable to that during CMV. This represents a significant reduction in dead-space ventilation, improved efficiency of ventilation, and a lower value for P(a-ET)CO2. Compared with CMV, CPAPI also improves the accuracy of PETCO2 as a monitor of PaCO2.