Articles: general-anesthesia.
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Lung densities (atelectasis) and pulmonary gas exchange were studied in 13 supine patients with no apparent lung disease, the former by transverse computerized tomography (CT) and the latter by a multiple inert gas elimination technique for assessment of the distribution of ventilation/perfusion ratios. In the awake state no patient had clear signs of atelectasis on the CT scan. Lung ventilation and perfusion were well matched in most of the patients. ⋯ Both the density area and the shunt increased after muscle paralysis. PEEP reduced the density area in all patients but did not consistently alter the shunt. It is concluded that the development of atelectasis in dependent lung regions is a major cause of gas exchange impairment during halothane anesthesia, during both spontaneous breathing and mechanical ventilation, and that PEEP diminishes the atelectasis, but not necessarily the shunt.
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Anesthesia and analgesia · Feb 1987
Low-dose enflurane as adjunct to high-dose fentanyl in patients undergoing coronary artery surgery: stable hemodynamics and maintained myocardial oxygen balance.
The effects of enflurane (end-tidal concentration 0.7%) on central and coronary hemodynamics and myocardial oxygenation were studied during steady state, high-dose fentanyl anesthesia in ten patients undergoing coronary artery bypass grafting operations. Compared with the response in ten patients receiving the same fentanyl anesthesia (100 micrograms/kg) without enflurane supplementation, enflurane caused a moderate reduction in mean arterial pressure, systemic vascular resistance, and left ventricular stroke work index. No patient showed signs of myocardial ischemia, and mean coronary sinus flow and calculated coronary resistance remained unchanged. ⋯ Myocardial oxygen extraction decreased in the enflurane supplemented group although it increased in the fentanyl group after surgical stimulation. Three fentanyl group patients and one enflurane-fentanyl group patient had a low myocardial lactate extraction as a sign of myocardial ischemia during surgery. We conclude that a 0.7% enflurane supplementation of 100 micrograms/kg fentanyl anesthesia does not endanger myocardial oxygenation and effectively prevents central and coronary hemodynamic responses to skin incision and sternotomy in patients undergoing coronary artery surgery.
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By the year 1990, it is projected that 50 per cent of all surgery in the United States will be performed on an outpatient basis. Both surgeons and anesthesiologists must understand patient and procedure prerequisites for outpatient surgery. ⋯ Patients must meet established clinical criteria prior to discharge and must be examined by a physician at the time these criteria have been met. The physician's clinical judgment is the single most important factor in determining the patient's home readiness.
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A simulator of general anesthesia is described. It consists of an integrated set of physiologic computer models and a graphics display. The model predicts many of the physiologic and pharmacodynamic changes associated with general anesthesia. ⋯ Both intravenous and inhalation agents are included. Examples of its capabilities are presented, including pharmacokinetic changes associated with thiopental administration to a hypovolemic subject, administration of oxygen in several pulmonary pathologic conditions, and a simulation of an induction using fentanyl or thiopental. The model, combined with the graphics interface, becomes a real-time simulator useful for training students and residents.
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Randomized Controlled Trial Comparative Study Clinical Trial
Randomised trial of fentanyl anaesthesia in preterm babies undergoing surgery: effects on the stress response.
In a randomised controlled trial, preterm babies undergoing ligation of a patent ductus arteriosus were given nitrous oxide and d-tubocurarine, with (n = 8) or without (n = 8) the addition of fentanyl (10 micrograms/kg intravenously) to the anaesthetic regimen. Major hormonal responses to surgery, as indicated by changes in plasma adrenaline, noradrenaline, glucagon, aldosterone, corticosterone, 11-deoxycorticosterone, and 11-deoxycortisol levels, in the insulin/glucagon, molar ratio, and in blood glucose, lactate, and pyruvate concentrations were significantly greater in the non-fentanyl than in the fentanyl group. ⋯ Compared with the fentanyl group, the non-fentanyl group had circulatory and metabolic complications postoperatively. The findings indicate that preterm babies mount a substantial stress response to surgery under anaesthesia with nitrous oxide and curare and that prevention of this response by fentanyl anaesthesia may be associated with an improved postoperative outcome.