Articles: general-anesthesia.
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Minerva anestesiologica · Mar 1994
[Monitoring of cuff pressure in double-lumen endotracheal tubes during anesthesia for thoracic surgery].
It is well known that cuff overinflation in endotracheal tubes may cause serious damage to the tracheal mucosa. Cuff overinflation is also related to the diffusion of nitrous oxide across the cuff membrane, thus giving way to a progressive volume/pressure increase up to overcoming, critical capillaric perfusion pressure. The kinetics of hi-lo cuff-pressure in single-lumen endotracheal tubes during general anesthesia using nitrous oxide has been well documented. ⋯ In ten of these case, special equipment was used in order to keep the cuff-pressures steady and at the lowest sealing level. The pressure shows the same trend in both cuffs but, depending on the medium calibre of the main left bronchus and the volume/pressure relations of the endobronchial cuffs, the pressure in the latter increases faster. The investigation was performed using an original equipment developed by the authors; such equipment is able not only to monitor the cuff-pressures, but also to maintain them at steady controlled levels (below 20 cm water seal), by means of counterregulating all the volume variations due either to anesthetic requirements, or to the diffusion of nitrous oxide.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
Changes in haemodynamic variables during transurethral resection of the prostate: comparison of general and spinal anaesthesia.
We have compared changes in haemodynamic variables before and during transurethral resection of the prostate in 22 patients under general or spinal anaesthesia. In the general anaesthetic group there was a significant decrease in cardiac output (mean 32% (SEM 5%)) and mean arterial pressure (14% (3%)) after induction of anaesthesia and a significant decrease (27% (3%)) in heart rate before the start of resection. ⋯ We conclude that with both these anaesthetic techniques the greatest changes in haemodynamic variables occurred shortly after induction, and that these changes were greater during general than spinal anaesthesia. The resection period was not associated with significant haemodynamic changes.
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Randomized Controlled Trial Comparative Study Clinical Trial
Midlatency auditory evoked potentials and explicit and implicit memory in patients undergoing cardiac surgery.
A high incidence of intraoperative awareness during cardiac surgery has been reported. Midlatency auditory evoked potentials (MLAEP) have been used recently as an indicator of awareness. In the current study, memory for information presented during anesthesia was investigated using MLAEP as one experimental indicator in 45 patients scheduled for elective cardiac surgery. ⋯ When the early cortical potentials of MLAEP are preserved during general anesthesia, auditory information may be processed and remembered postoperatively by an implicit memory task.
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Rev Esp Anestesiol Reanim · Mar 1994
Comment Randomized Controlled Trial Comparative Study Clinical Trial[Oral premedication with clonidine in patients undergoing coronary revascularization surgery].
To analyze the effect of premedication with clonidine on level of sedation, anesthetic requirements and hemodynamic repercussions in patients undergoing coronary revascularization. ⋯ Use of clonidine in the type of patient studied does not improve the level of sedation over that achieved with lorazepam. Fentanyl requirements decreased with clonidine. With respect to hemodynamic profile, systemic vascular resistance fell in the clonidine group after removal of ECC, and thus this drug offers no advantages for routine premedication.
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Impaired gas exchange is a major complication after cardiac surgery with the use of extracorporeal circulation. Blood gas analysis gives little information on underlying mechanisms, in particular if the impairment is multifactorial. In the current study we used the multiple inert gas technique with recordings of hemodynamics to analyze the separate effects of intrapulmonary shunt (QS/QT), ventilation-perfusion (VA/Q) mismatch, and low mixed venous oxygen tension on arterial oxygenation during cardiac surgery. ⋯ QS/QT is a major component of impaired gas exchange before, during, and after cardiac surgery. QS/QT increases after induction of general anesthesia, probably because of development of atelectasis. After separation from extracorporeal circulation, accumulation of extravascular lung water or further collapse of lung tissue may aggravate QS/QT. Postoperatively, oxygenation improves, possibly because of recruitment of previously nonventilated alveoli or resolution of extravascular lung water. During spontaneous breathing, additional mechanisms such as altered mechanics of the chest, perfusion of low-VA/Q regions, and decreased mixed venous oxygen tension may contribute to impaired gas exchange.