Journal of anesthesia
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Journal of anesthesia · Mar 1996
Oral clonidine reduces thiamylal requirement for induction of anesthesia in adult patients.
Although preanesthetic clonidine, an α-2 agonist, is known to reduce anesthetic requirements, the effect of preanesthetic oral clonidine medication per se on the requirement of thiamylal in adult humans has not yet been examined. One hundred and sixty-one adult patients (14-78 years of age) were randomly assigned to groups that received oral clonidine (5μg·kg(-1) (n=51), 2.5μg·kg(-1) (n=55), or none (n=55)) in addition to 20mg oral famotidine 90min before anesthesia induction. ⋯ Thiamylal requirements were significantly less in both clonidine groups (2.95±0.09 and 3.14±0.10 mg·kg(-1) (mean±SE) for patients receiving 5μg·kg(-1) and 2.5μg·kg(-1) clonidine, respectively) than in the control group (3.81±0.11 mg·kg(-1),P<0.05); however, no difference was found between the two clonidine groups. Although mean blood pressure and heart rate during the study period were significantly lower in both clonidine groups than in the control group, no profound hypotension or marked bradycardia were noted in the clonidine groups.
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Journal of anesthesia · Mar 1996
Halothane anesthesia suppresses reflex tachycardia caused by calcitonin gene-related peptide in dogs.
Calcitonin gene-related peptide (CGRP) is known to produce vasodilation, hypotension, and tachycardia. To investigate the interaction between CGRP and anesthetics, the hemodynamic response to infusions of CGRP was studied in dogs anesthetized with halothane or pentobarbital. In halothane-anesthetized dogs given 0.4 μg·kg(-1) of CGRP, mean arterial pressure (MAP) did not change significantly. ⋯ The results show that the hemodynamic profiles induced by CGRP during halothane or pentobarbital anesthesia are a decrease in MAP accompanied by a reduction in SVR and no consistent alterations in CI. However, CGRP effects on HR showed in a different way. The results also show that HR response differs depending on the anesthetics used: HR increases during pentobarbital anesthesia, while it does not increase during halothane anesthesia.
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Journal of anesthesia · Mar 1996
Does increasing end-tidal carbon dioxide during laparoscopic cholecystectomy matter?
To examine the adverse effects of peritoneal carbon dioxide (CO2) insufflation during laparoscopic cholecystectomy, both hemodynamic and respiratory alterations were continously monitored in 17 adult patients using noninvasive Doppler ultrasonography and a continuous spirometric monitoring device. During the surgery, which was performed under inhalational general anesthesia, intraabdominal pressure was maintained automatically at 10mmHg by a CO2 insufflator, and a constant minute ventilation, initially set to 30-33 mmHg of end-tidal CO2 (ETCO2), was maintained. ⋯ The stress of 10mmHg pneumoperitoneum was a major cause of hemodynamic changes during laparoscopic cholecystectomy. Some clinical strategies such as deliberate intraabdominal insufflation at the initial phase might be required to minimize these hemodynamic changes.
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Journal of anesthesia · Mar 1996
Ketamine and its isomers have equipotent relaxant effects on tracheal smooth muscle contracted by tachykinins.
Recent studies indicate that not only inflammatory cells but also neural mechanisms by which tachykinins such as substance P (SP) and neurokinin A (NKA) are released from vagal afferent C-fiber contribute to asthma. Although ketamine (K) has been used in the anesthetic management of asthmatic patients, the mechanism by which K relaxes the airway smooth muscle is still uncertain, and no information exists on any differential effect of K and its isomers. We determined the spasmolytic effect of racemic [R(±)]K and its isomers S(+) K and R(-) K on SP and NKA-induced contraction of tracheal smooth muscle in guinea pigs. ⋯ R(±), R(-), or S(+) K (4.5-18.0×10(-4)M) was cumulatively administered into the bath. The calculated ED50 values (the concentration that relaxed the contraction by 50%) of R(±), R(-) and S(+) K were 7.6±0.5, 7.8±0.6, and 7.6±0.5 (10(-4)M), respectively, when the contraction was elicited with SP, and 8.0±1.0, 8.2±1.2, and 7.9±1.3 (10(-4)M), respectively, when NKA was used. We concluded that K and its isomers have equipotent spasmolytic effects on airway smooth muscle precontracted with tachykinins.
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Journal of anesthesia · Mar 1996
Alterations in the myocardial β-adrenergic system during experimental endotoxemia.
In this study to investigate whether β-adrenergic receptor systems in the heart are impaired during endotoxemia, we examined two models of septic shock in rats, each of which has a different time course for the shock state. Male Wistar rats were divided into two groups: (1) the LPS (lipopolysaccharide) iv group (Escherichia coli endotoxin 1.0 mg·kg(-1) iv bolus administration), and (2) the CLP (cecal ligation and puncture model) group. As a control group for each model, a 0.9% saline injection group and a sham-operated group were also prepared. ⋯ The alteration in hemodynamics of septic-shock rats observed in this study was linked to the change in heart β-receptor density rather than the change in plasma CA. These observations suggested that the alterations which occur in the β-receptor system during endotoxemia depend upon the model of animal sepsis that is employed, and the time course of the septic-shock state. These alterations in the β-adrenergic system are thought to cause myocardial dysfunction during endotoxemia.