Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2002
Evaluating the relationship between arterial blood pressure changes and indices of pulse oximetric plethysmography.
The finger plethysmographic waveform of pulse oximeters is a qualitative indicator of fingertip perfusion. This waveform has been used to assess the depth of anesthesia. Its cyclical changes associated with mechanical ventilation have also been used to detect changes in blood volume under normotensive conditions and has revealed that minimal normotensive hypovolemia can cause a significant increase in the delta-down component of this waveform. Hypovolemia may be associated with hypotension; the latter may be due to causes other than hypovolemia. Because the effects of the hypotension on plethysmographic waveform have not been evaluated, it may be difficult to detect hypovolemia in these conditions by inspecting a plethysmogram. Therefore, we performed this study to evaluate the effect of normovolemic hypotension on characteristics of plethysmographic waveform in 33 adult patients undergoing general anesthesia with controlled hypotension. The delta-down and ventilatory systolic variation components were increased significantly with decreases in systolic blood pressure. The result of this study shows that the effect of pharmacologic hypotension on the plethysmographic waveform of pulse oximeter is similar to that of minimal hypovolemia. Therefore, blood volume may be inaccurately assessed by the inspection of ventilatory-induced cyclical changes of pulse oximetric waveform in the presence of hypotension. ⋯ The cyclical respiratory-induced changes in the amplitude of the pulse oximeter waveform can be used to detect normotensive hypovolemia. This study shows that hypotension produces the same effect. Therefore, in hypotensive conditions, we cannot determine the presence of hypovolemia.
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Anesthesia and analgesia · Dec 2002
Interactions of volatile anesthetics with cholinergic, tachykinin, and leukotriene mechanisms in isolated Guinea pig bronchial smooth muscle.
We studied relaxation of airway smooth muscle by sevoflurane, desflurane, and halothane in isolated guinea pig bronchi. Ring preparations were mounted in tissue baths filled with physiological salt solution and continuously aerated with 5% CO(2) in oxygen. Electrical field stimulation induced contractions sensitive to tetrodotoxin, indicating nerve-mediated responses. These consisted of an atropine-sensitive cholinergic phase and a nonadrenergic noncholinergic (NANC) phase sensitive to SR48968, a neurokinin-2 receptor antagonist. Anesthetics were added to the gas aerating the tissue baths. Sevoflurane and desflurane at 1.0 minimum alveolar anesthetic concentration and halothane at 1.0-2.0 minimum alveolar anesthetic concentrations inhibited both cholinergic and NANC contractions to electrical field stimulation. None of the anesthetics affected responses to exogenously applied neurokinin A, a likely mediator of NANC contractions, suggesting prejunctional inhibition of NANC neurotransmission. The anesthetics did not affect the initiation of contractile responses to leukotriene C(4) (LTC(4)), a mediator of asthmatic bronchoconstriction. However, sevoflurane and desflurane both relaxed bronchi in a steady-state contraction achieved by LTC(4). Surprisingly, halothane did not relax LTC(4) contractions. Concerning LTC(4)-elicited bronchoconstriction, sevoflurane and desflurane were more potent airway smooth muscle relaxants in vitro. ⋯ Halothane, sevoflurane, and desflurane attenuated airway smooth muscle tone via inhibition of cholinergic and nonadrenergic noncholinergic neurotransmission. Sevoflurane and desflurane reduced leukotriene C(4)-induced bronchoconstriction, whereas halothane did not. This indicates a beneficial role for sevoflurane and desflurane in asthmatics.
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Anesthesia and analgesia · Dec 2002
Case ReportsContinuous sacral nerve root block in the management of neuropathic cancer pain.
Neuropathic cancer pain caused by tumor infiltration in the sacral plexus is primarily treated by nonsteroidal antiinflammatory drugs, antidepressants, anticonvulsants, and opioids. In one patient with severe pain despite pharmacotherapy, a catheter for the continuous administration of local anesthetics was inserted along the first sacral root, resulting in markedly improved analgesia.
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Anesthesia and analgesia · Dec 2002
Central venous access: the effects of approach, position, and head rotation on internal jugular vein cross-sectional area.
We investigated the effects of approach (lateral versus anterior), position (supine versus Trendelenburg), and head rotation (0 degrees, 20 degrees, and maximum) during central venous catheterization on the area of the right internal jugular vein. Twenty-four patients were placed in supine position, followed by 25 degrees of Trendelenburg position. In each position, measurement of the anterior and lateral right internal jugular vein cross-sectional areas was obtained by using planimetry with the patient's head oriented at 0 degrees, 20 degrees, and maximum rotation. The largest cross-sectional areas were achieved in the lateral approach with the Trendelenburg position. In this position, no differences were detected among head rotation conditions. Data suggest that for those patients who tolerate the Trendelenburg position, the lateral access approach yields the statistically largest target area regardless of head rotation. When the Trendelenburg position is contraindicated, the results of this study suggest other approaches, e.g., the anterior approach, for central venous catheter placement that maximize the internal jugular vein area. ⋯ Central venous catheter insertion is commonly performed in the neck by using the right internal jugular vein. This study assesses factors affecting the cross-sectional area of this vein during central venous catheterization.
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Anesthesia and analgesia · Dec 2002
Introducing a balanced scorecard management system in a university anesthesiology department.
The study goal was to show how Balanced Scorecard, a modern management tool based on score numbers, can efficiently be applied to a university anesthesiology department. Nineteen score numbers were established in four perspectives. Meaningful results were obtained with limited resources to support a process of innovation and improvement.