Anesthesia and analgesia
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Anesthesia and analgesia · May 2002
Pre-ictal bispectral index has a positive correlation with seizure duration during electroconvulsive therapy.
Propofol anesthesia increases the seizure threshold of patients receiving electroconvulsive therapy. Excessive neuronal suppression could result in an unacceptably short seizure. We sought to identify the correlation between the pre-ictal bispectral index (BIS) score and seizure duration in patients receiving electroconvulsive therapy under propofol anesthesia. BIS was monitored in 38 psychotically depressed patients. Anesthesia was induced by a bolus injection of 1 mg/kg of propofol. The duration of muscular and electroencephalographic seizure was measured during the therapy. The BIS immediately before the electrical shock was 54 +/- 13. Both muscular and electroencephalographic seizure durations had a positive correlation with pre-ictal BIS (r = 0.68 and 0.73, respectively; P < 0.01). After the electrically induced seizure, BIS decreased to 30 +/- 8, reflecting post-ictal suppression. BIS scores when the patients had awakened after the seizure had a wide variation (range, 29-81; mean, 45; SD, 13). In conclusion, seizure duration has a positive correlation with BIS immediately before electrical shock; however, BIS may not be an accurate predictor of awakening after electrical shock. ⋯ Pre-ictal bispectral index had a positive correlation with seizure duration and could be useful to prevent an unacceptably short seizure in electroconvulsive therapy under propofol anesthesia.
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Anesthesia and analgesia · May 2002
Induction of anesthesia and insertion of a laryngeal mask airway in the prone position for minor surgery.
The use of the prone position for surgery presents potential obstacles to rapid tracking of patients during ambulatory anesthesia. We describe a prospective audit of 73 patients who placed themselves in the prone position; anesthesia was induced in this position and a laryngeal mask airway (LMA) was used to maintain the airway. Additional increments of propofol were given to one patient who had laryngospasm and to nine who required deepening of anesthesia before the LMA could be inserted. Of four cases with LMA malpositioning, the LMA was adjusted easily in three, but in one patient who was edentulous, it was necessary to hold the LMA for the duration of the procedure. Manual ventilation of the lungs via the LMA was required because of arterial oxygen desaturation and hypoventilation in four patients. Blood was noted outside the nostrils in two patients, presumably caused by soft tissue trauma after insertion of the LMA, and bradycardia occurred in five patients. In the postoperative period, hoarseness and sore throat were observed in one and six patients, respectively. With experience and appropriate patient selection, it is possible to induce and maintain anesthesia using a LMA in patients in the prone position for ambulatory surgery. ⋯ With experience and appropriate patient selection, it is possible to induce and maintain anesthesia using a laryngeal mask airway in patients in the prone position for ambulatory surgery.
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Anesthesia and analgesia · May 2002
Practice Guideline GuidelineACC/AHA Guideline Update for Perioperative Cardiovascular Evaluation for Noncardiac Surgery--Executive Summary. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1996 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery).
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Anesthesia and analgesia · May 2002
The association of complication type with mortality and prolonged stay after cardiac surgery with cardiopulmonary bypass.
Outcome after cardiac surgery varies depending on complication type. We therefore sought to determine the association between complication type, mortality, and length of stay in a large series of patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Multivariate logistic regression was used to test for differences between complication types in mortality and prolonged length of stay (>10 days) while controlling for preoperative and intraoperative risk factors. In 2609 consecutive cardiac surgical patients requiring CPB, the mortality rate was 3.6%; 36.5% had one or more complications, and 15.7% experienced an adverse outcome (death or prolonged length of stay). Multivariate logistic regression demonstrated that complication type was significantly associated with adverse outcome (P < 0.001) independent of Parsonnet score and CPB time (c-index = 0.80). The development of noncardiac complications only (Group NC) and cardiac complications with other organ involvement (Group B) significantly increased mortality and hospital and intensive care unit length of stay (P < 0.001) when compared with cardiac complications only (Group C). The incidences of adverse outcome in Groups C, NC, and B were 15%, 43%, and 67%, respectively; the mortality rates were 3%, 7%, and 20%, respectively. All these intergroup comparisons were significantly different (adjusted P < 0.05). Complications involving organs other than the heart appear to be more deleterious than cardiac complications alone, underscoring the need for strategies to reduce noncardiac complications. ⋯ Complications, particularly when they involve organs other than just the heart, increase mortality and prolong the length of hospital stay after heart surgery, independent of a patient's preoperative risk factors and the duration of cardiopulmonary bypass. Strategies aimed at preventing damage to other organs during cardiac surgery need to be improved.
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Anesthesia and analgesia · May 2002
The neuropathologic effects in rats and neurometabolic effects in humans of large-dose remifentanil.
Given in clinically relevant large doses to rats, mu-opioids produce limbic system hypermetabolism and histopathology. This investigation extends these observations, in both rats and humans, for the short-acting drug remifentanil, which allows more precise control and assessment of the effects of duration of opioid exposure. We performed two series of experiments: one in rats for neuropathologic effects and the second in humans for neurometabolic effects. Fifty mechanically ventilated rats received saline solution or remifentanil 20-160 microg x kg(-1) x min(-1) for 3 h, followed by neuropathologic evaluation 7 days later. Four volunteers underwent induction of anesthesia and endotracheal intubation with propofol and rocuronium administration followed by remifentanil infusion at 1-3 microg x kg(-1) x min(-1) with positron emission tomography evaluation of cerebral metabolic rate for glucose. In rats, dose-related electroencephalogram activation was evident and 19 of 40 remifentanil-treated rats showed brain damage, primarily in the limbic system (P < 0.01). In humans, cerebral metabolic rate for glucose in the temporal lobe increased from 6.29 +/- 0.32 to 7.68 +/- 1.05 mg x 100 g(-1) x min(-1) (P < 0.05). These data indicate that prolonged large-dose remifentanil infusion is neurotoxic in rats with congruent metabolic effects with brief infusion in humans and suggest that some adverse effects reported in rats may be clinically relevant. ⋯ This study demonstrates dose-related remifentanil neurotoxicity in physiologically controlled rats with congruent brain metabolic effects in four humans undergoing positron emission tomography evaluation during brief large-dose remifentanil anesthesia. These data suggest that some adverse effects reported in rats may be clinically relevant.