Articles: general-anesthesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
Neuroleptanesthesia versus thoracic epidural anesthesia for abdominal aortic surgery.
The hemodynamic consequences of abdominal aortic surgery with infrarenal cross-clamping were studied in 21 patients randomized in two groups. In Group I (11 patients), neuroleptanesthesia was utilized, while Group II (10 patients) received thoracic epidural anesthesia at the T8-9 level. ⋯ Nevertheless, in the two groups of patients, it is suggested that cardiac function was unfitted to the tissue oxygen demand after unclamping of the aortic prosthesis because the saturation in oxygen of the mixed venous blood and an increase in arteriovenous difference in oxygen were documented. These results point out that, whatever the anesthesia technique, the critical period in abdominal surgery could be aortic unclamping.
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Current alarms protect the manufactures of medical equipment from liability but do little to improve the quality of patient care. Existing alarms are so intrusive that the response of the anesthesiologist and others in the operating room is to want the offensive noise to go away, rather than to address potentially life-threatening situations. Alarms need to be refined so that only those whose attention is required (e.g., the anesthesiologist) are disturbed. It should always be immediately clear which particular variable is outside accepted limits, and alarms for different variables should operate independently so that if one alarm fails, others will still work.
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The administration of anesthesia may be viewed as a closed-loop control system consisting of three major components: the anesthesia system, the patient, and the system operator. A monitoring and alarm system during anesthesia should not be limited to only one of the three major components but must include monitoring of the patient, the performance of the anesthesia system, and the action of the system operator. ⋯ The authors describe the characteristics of a structured alarm system that maximizes the time available to correct a potential problem before injury begins, that clearly identifies the cause of the problem, and that prioritizes alarms according to the urgency of the required response. Alarms should be easy to temporarily silence, have built-in alarm default settings to prevent the inadvertant use of settings meant for a previous patient, and have a graphic display that enables the operator to detect problems or trends before an alarm sounds.
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Respiratory oxygen, carbon dioxide, and nitrous oxide concentrations were recorded in 20 patients breath-by-breath during general anesthesia and early recovery, using the Cardiocap multiparameter monitor. Several approved maneuvers were performed to demonstrate the usefulness of endtidal oxygen measurement. "Oxygrams" provided by the fast paramagnetic oxygen sensor confirmed the capnometric information in the diagnosis of hypoventilation, apnea, and disconnections. In one patient, the alarm for inspiratory oxygen concentration, set at 18%, appeared to prevent alveolar hypoxia and low arterial saturation from occurring when oxygen instead of nitrous oxide was turned off. ⋯ Changes in nitrous oxide concentration often complemented oxygen-related information obtained in our observations. In the recovery room, a decrease in end-tidal oxygen concentration preceded low pulse oximetry readings. Therefore, it is suggested that all three gases should be monitored continuously to prevent mishaps related to insufficient ventilation and inappropriate gas concentrations during anesthesia and immediate recovery.