Articles: general-anesthesia.
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Acta Anaesthesiol Scand · Oct 1989
ReviewLung function during anesthesia and respiratory insufficiency in the postoperative period: physiological and clinical implications.
This review covers the physiological and clinical implications of lung function during anesthesia and respiratory insufficiency in the postoperative period. We have divided it into 3 main sections: 1) lung function changes induced by anesthesia and surgery, in which the impact on pulmonary mechanics, ventilation/perfusion changes and gas exchange are examined; 2) physiological implications of postoperative respiratory function secondary to decreased alveolar ventilation, development of atelectasis, and interstitial lung edema; and 3) clinical implications of postoperative respiratory failure. In this last section we analyze the current therapeutic modalities available to reduce the incidence of postoperative respiratory failure, as well as related morbidity and mortality.
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The need to incorporate alarms in monitoring systems is related to the growing complexity of monitoring and the large number of variables. For sophisticated alarms, information about the inputs to the patient is of importance; for example, clinical interventions such as drug administration and ventilation readjustment need to be known to the monitoring system. Alarms are triggered by signals or signal features that exceed thresholds. ⋯ Approaches to determine such levels automatically are discussed in this article. Most promising seems the multiple signal approach using an expert system. It seems reasonable to expect that information concerning alarm limits, needed for the operation of knowledge-based alarm systems, may come from integrated departmental data bases.
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Review Case Reports
Massive intraoperative atelectasis secondary to untreated mediastinal Hodgkin's disease: report of the hazard and review of the literature.
Mediastinal adenopathy in Hodgkin's disease has been known to cause relative airway compromise, particularly in the more vulnerable left mainstem bronchus. This has been infrequently reported to occur during general anesthesia and to cause respiratory embarrassment, representing a significant hazard. The possibility of its occurrence should be recognized. Preoperative evaluation of the airway by chest films and tomography, followed by radiation therapy in those patients at risk, is recommended to minimize the chances of respiratory complications during general anesthesia.
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Apneic, anesthetized patients frequently develop airway obstruction or may be disconnected from ventilatory support. The rate of PaCO2 rise is usually assumed to be equal to that of anesthetized humans who are receiving apneic oxygenation. Apneic oxygenation may eliminate CO2 because it requires a continuous O2 flow. ⋯ Piecewise linear approximation yielded a PaCO2 increase of 12 mmHg during the first minute of apnea, and 3.4 mmHg/minute thereafter. These values should be employed when estimating the duration of apnea from PaCO2 change for anesthetized patients who lack ventilatory support. In addition, it appears that the flows of O2 that most earlier investigators used when delivering apneic oxygenation probably did not eliminate significant CO2 quantities.