Anesthesia and analgesia
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Anesthesia and analgesia · Mar 1996
Comparative StudyComparative electrophysiologic and hemodynamic effects of several amide local anesthetic drugs in anesthetized dogs.
Large and equipotent doses of several local anesthetics were administered in a cardiac electrophysiologic model on closed-chest dogs. Five groups of pentobarbital-anesthetized dogs were each given intravenously 16 mg/kg lidocaine, 12 mg/kg mepivacaine, 4 mg/kg or 8 mg/kg etidocaine, and 4 mg/kg bupivacaine. Lidocaine induced bradycardia, slowing of atrioventricular node conduction (AH), and marked hemodynamic depression, represented by a decrease in mean aortic pressure (MAoP), in the peak of first derivative of left ventricular pressure (LVdP/dt(max)) and by an increase in left ventricular end-diastolic pressure (LVEDP). ⋯ We conclude that mepivacaine induced moderate cardiotoxicity. In contrast, lidocaine induced dramatic hemodynamic depression while etidocaine and bupivacaine markedly impaired both electrophysiologic and hemodynamic variables. This double impairment could explain the great difficulty in resuscitating patients who have had cardiotoxic accidents induced by etidocaine or bupivacaine.
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Anesthesia and analgesia · Mar 1996
Simulated clinical evaluation of conventional and newer fluid-warming devices.
The purpose of the study was to evaluate the ability of five commercially available devices utilizing a variety of heat exchange technologies to deliver normothermic (37 degrees C) fluids. Conditions of slow (6.5 mL/ min), moderate (13-25 mL/min), and rapid (gravity and pressure driven flows, roller clamp wide open) infusion were simulated. Fluid temperatures were measured using rapid response thermistors after the fluid exited the heat exchanger (T outlet) and before delivery to the patient intravenously (IV) (T distal). ⋯ With gravity and pressure driven flows, T distal of crystalloid were 39.0 and 38.9 for H1000 at 42 degrees C, 38.7 and 38.4 degrees C for FW537 at 42 degrees C, 34.7 and 28.9 degrees C for Hotline at 42 degrees C, 29.2 and 24.2 degrees C for BairHugger, and 29.7 and 24.2 degrees C for Flotem. In conclusion, only the H1000 at 42 degrees C was effective at delivering normothermic fluids at all clinically relevant flow rates. The Hotline at 42 degrees C was effective at slow and moderate flow, whereas the FW537 was effective only at rapid flow.
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The anesthetist exerts axial force on the laryngoscope handle to expose the glottis. The anesthetist must also apply a perpendicular force to balance the torque on the laryngoscope. Several studies have measured axial force during direct laryngoscopy, but none has measured torque. ⋯ Peak force and torque demonstrated stress relaxation, a viscous property of biologic tissues. Force and torque decreased monoexponentially to approximately 70% of peak values with a half-time of 4 +/- 0.3 s. The phenomenon occurred in spite of administration of muscle relaxants, and was probably due to stress relaxation of pharyngeal tissues that are passively stretched during laryngoscopy.
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Anesthesia and analgesia · Mar 1996
The Amsterdam Preoperative Anxiety and Information Scale (APAIS)
The purpose of the present study was to assess patients' anxiety level and information requirement in the preoperative phase. During routine preoperative screening, 320 patients were asked to assess their anxiety and information requirement on a six-item questionnaire, the Amsterdam Preoperative Anxiety and Information Scale (APAIS). Two hundred patients also completed Spielberger's State-Trait Anxiety Inventory (STAI-State). ⋯ It emerged that 32% of the patients could be considered as "anxiety cases" and over 80% of patients have a positive attitude toward receiving information. Moreover, results demonstrated that 1) women were more anxious that men; 2) patients with a high information requirement also had a high level of anxiety; 3) patients who had never undergone an operation had a higher information requirement than those who had. The APAIS can provide anesthesiologists with a valid, reliable, and easily applicable instrument for assessing the level of patients' preoperative anxiety and the need for information.
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Anesthesia and analgesia · Mar 1996
The effects of neuromuscular block on peak airway pressure and abdominal elastance during pneumoperitoneum.
Administration of muscle relaxants is considered as necessary to prevent high intraabdominal and peak inspiratory pressures induced by pneumoperitoneum during laparoscopy. In the present study, we hypothesized that neuromuscular block does not alter pulmonary or abdominal elastic properties in pigs receiving general anesthesia. To test this hypothesis, changes in peak airway pressure and abdominal elastance during intraabdominal CO(2), insufflation from 0 to 15 mm Hg were recorded in anesthetized pigs, with or without muscle relaxants. ⋯ Abdominal pressure/volume relationships were independent of muscle relaxant administration (calculated elastance was 3.98 +/- 1.56 mm Hg/L without muscle relaxant vs 3.86 +/- 1.37 mmHg/L in the atracurium group). We conclude that high peak inspiratory airway pressures and intraabdominal pressures during laparoscopy are not affected by neuromuscular block. These findings also question the necessity of muscle relaxants in clinical anesthetic practice during laparoscopic surgery.