Anesthesia and analgesia
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Anesthesia and analgesia · Jul 1989
Comparative StudyHemodynamic and cardiodynamic effects of propofol and etomidate: negative inotropic properties of propofol.
The hemodynamic effects of an induction dose of propofol, 2.5 mg/kg, or etomidate, 0.3 mg/kg, were studied in eight dogs. In addition, cardiodynamic changes were measured using a left ventricular catheter and needle force probes. Propofol was associated with significant decreases in systolic (19.9%) and diastolic (25.3%) arterial pressures associated with a 17.3% decrease in cardiac output (CO) and a 11.6% reduction in systemic vascular resistance (SVR) without change in pulmonary capillary wedge pressure (PCWP). ⋯ Signals generated by the force probes in the left ventricular myocardium showed a significant reduction (16.3%) in left ventricular force (LVF) and a decrease in early systolic rates of increase in force (dF/dt max) by 23.5% associated with propofol. In the presence of an unchanged preload, an unchanged HR, and a decreased SVR, the reduction in CO suggests that propofol has a negative inotropic effect. This negative inotropic effect was confirmed by a reduction in LVF and dF/dt max.
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A technique for blocking the dorsal nerves of the penis was designed after reevaluation of the gross anatomy of the subpubic space and penis in children. The technique consists of inserting a short bevel needle in the two compartments of the subpubic space, where the nerves run before entering the base of the penis, and of injecting a small volume (0.1 mL/kg of body weight) of local anesthetic. This two-puncture procedure was prospectively evaluated in 100 children undergoing surgery of the penis under light general anesthesia. ⋯ No complications occurred and anesthesia was satisfactory for completion of surgery. The duration of postoperative pain relief was significantly longer in patients given bupivacaine than in those given lidocaine. It is concluded that the subpubic approach to the dorsal nerves of the penis is easy, safe, and reliable, and that 0.5% plain bupivacaine provides long-lasting postoperative pain relief.
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Anesthesia and analgesia · Jul 1989
Effects of enflurane on contractile response of canine trachealis muscle.
The effect of enflurane anesthesia on bronchomotor tone was studied in 15 dogs, using isolated tracheal segments in situ. In six animals, the changes of tracheal tension in response to changing enflurane concentration were continuously measured while keeping tidal volume, respiratory frequency, and end-tidal PCO2 constant. In nine other dogs, the contractile response to a brief period of apnea was assessed in three planes of anesthesia, namely 0% (baseline anesthesia with pentobarbital), 1%, and 2% of inspired enflurane concentration. ⋯ Furthermore, the magnitude of contraction elicited by electrical stimulation of the recurrent laryngeal nerve (RLN) was determined at each depth of anesthesia in six animals. Increasing enflurane concentrations invariably decreased resting tracheal tension as well as the magnitude of contraction in response to apnea and RLN stimulation in a dose-dependent manner. These data suggest that enflurane not only decreases unstimulated canine bronchomotor tone but also inhibits contraction produced by various stimuli used in the present experiments.
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Anesthesia and analgesia · Jul 1989
Comparative StudyComparison of viscoelastic measures of coagulation after cardiopulmonary bypass.
Postoperative hemorrhage remains a major cause of morbidity after cardiopulmonary bypass (CPB). Treatment remains empiric because of the need for immediate correction and the lack of availability of rapid intraoperative coagulation monitoring (except for ACT) at most institutions. Thrombelastography (TEG) and Sonoclot analysis (SCT) are measures of viscoelastic properties of blood which allow rapid intraoperative evaluation of coagulation factor and platelet activity as well as overall clot integrity from a single blood sample. ⋯ After CPB, mean values for RCT were normal, but there were abnormalities in TEG and SCT parameters that reflect platelet-fibrin interaction. Both TEG and SCT were 100% accurate in predicting bleeding in these nine patients and, overall, both tests were significantly better predictors of postoperative hemorrhage than RCT. We conclude that viscoelastic determinants of clot strength may be abnormal after CPB and that SCT and TEG are, therefore, more useful than RCT for the detection and management of coagulation defects associated with CPB.