Articles: general-anesthesia.
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Ned Tijdschr Geneeskd · Jun 2004
Review[Bispectral analysis of the electroencephalogram: a new method for recording the level of consciousness during anaesthesia].
Until recently, no measure was available that provided objective and reproducible information on the level of consciousness in patients under general anaesthesia. Several decades of research to find a reliable measure for determining the depth of anaesthesia has now led to the clinical introduction of the bispectral index scale (BIS), a parameter derived from the electroencephalogram. Implementation of the BIS-monitor in anaesthetic practice leads to a reduced use of hypnotic agents, a more rapid recovery phase and possibly a reduced incidence of awareness.
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In this review paper, the authors critically analyse the use of a number of depth of anaesthesia monitors in light of the most recent literature and their own clinical experience. There appears to be increasing evidence that anaesthesia depth monitors reduce the incidence of unexpected intraoperative awareness and also that they improve the quality of anaesthesia. ⋯ The information provided by anaesthesia depth monitors is detailed and relationships with clinical practice are established to provide the reader with key features for optimal use of those monitors and correct interpretation of data. Practitioners and patient's knowledge and expectations regarding this matter, as well as the cost-benefit relationship are also discussed.
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Intraoperative wakefulness ("awareness") is still a relevant problem. Different stages of wakefulness exist: conscious awareness with explicit recall of pain in 0.03% and with nonpainful explicit recall in 0.1-0.2% of all anesthesias; amnesic awareness or implicit recall may occur with unknown, even higher incidences. Sufficient analgesia minimizes possible painful perceptions. ⋯ The observation of clinical signs does not reliably detect intraoperative wakefulness in all cases; monitoring of end-tidal gas concentrations, EEG, or evoked potentials may help in prevention. Active information is recommended only for patients at higher risk. Complaints about recall of intraoperative events should be taken seriously; in cases of sustained symptoms psychological help may be necessary.
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All patients undergoing general anaesthetic are at risk of acid aspiration, particularly in emergency situations when they have not been starved preoperatively. To minimise the risk of acid aspiration, anaesthetists and anaesthetic nurses employ Rapid Sequence Induction of anaesthesia, cricoid pressure and endotracheal intubation. Knowledge of airway anatomy, airway management techniques, anaesthetic agents, muscle relaxant drugs, and Sellick's Manoeuvre help the anaesthetic nurse ensure the safety of the high risk patient.
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Reg Anesth Pain Med · May 2004
Review Comparative StudyPostoperative cognitive function as an outcome of regional anesthesia and analgesia.
It has been suggested that intraoperative neuraxial (spinal, epidural) anesthesia may decrease postoperative cognitive dysfunction when compared with general anesthesia, but the issue remains controversial. We systematically reviewed the data from published studies to determine the effect of intraoperative neuraxial anesthesia versus general anesthesia on postoperative cognitive dysfunction and delirium. ⋯ The use of intraoperative neuraxial anesthesia does not appear to decrease the incidence of postoperative cognitive dysfunction when compared with general anesthesia. There are methodologic and study-design issues present in many studies, and further elucidation of the pathophysiology of postoperative cognitive dysfunction may provide a direction for future studies.