Anesthesiology
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The "single-needle" celiac plexus block is becoming a popular technique. Despite different approaches and methods used to place the needle, the success of the block depends on adequate spread of the injectate in the celiac area. In the present retrospective study, the influence of needle tip position in relation to the celiac artery on injectate spread was evaluated. ⋯ These findings suggest that, when the celiac area is free from anatomic distortions, and the single-needle neurolytic celiac plexus block technique is used, the needle tip should be positioned cephalad to the celiac artery to achieve a wider neurolytic spread. It also appears that only a complete (four quadrants) neurolytic spread in the celiac area can guarantee long-lasting analgesia.
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The potential adverse effects of ketamine in neurosurgical anesthesia have been well established and involve increased intracranial pressure (ICP) and cerebral blood flow. However, reexamination of ketamine is warranted because data regarding the effects of ketamine on cerebral hemodynamics are conflicting. ⋯ These results suggest that ketamine may not adversely alter cerebral hemodynamics of mechanically ventilated head-trauma patients sedated with propofol. These encouraging results should be confirmed in larger groups of similar patients.
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Comparative Study
Comparison of pre- versus post-incision administration of intrathecal bupivacaine and intrathecal morphine in a rat model of postoperative pain.
Preclinical studies in experimental animals suggest that preemptive analgesia may improve postoperative pain management. The beneficial effects of preemptive analgesia appear less remarkable clinically. The purpose of this study is to examine the effect of pre- and post-incision administration of intrathecal bupivacaine and intrathecal morphine in a rat model for postoperative pain. ⋯ Early reduction in pain behaviors either by pre- or postincision management had no impact on subsequent measures of hyperalgesia in this model. These results agree with a number of clinical studies and suggest that incisional pain may be initiated and maintained differently than pain in other models.
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The aims of the study were to verify the effects of ketamine on ventricular conduction velocity and on the ventricular effective refractory period, to determine its effects on anisotropy and on homogeneity of refractoriness, and to use wavelength to determine whether ketamine has antiarrhythmic or arrhythmogenic properties. ⋯ Ketamine slowed ventricular conduction and prolonged refractoriness without changing anisotropy or increasing dispersion of refractoriness. Although these effects should result in significant antiarrhythmic effects of ketamine, this should not be construed to suggest a protective effect in ischemic or other abnormal myocardium.
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Propofol, a highly lipophilic anesthetic, is formulated in a lipid emulsion for intravenous use. Propofol has brisk onset and offset of effect after rapid administration and retains rapid offset characteristics after long-term administration. The authors tried to determine whether the emulsion vehicle is requisite for propofol's evanescent effect-time profile. ⋯ The incorporation of propofol in emulsion reduces dose requirements and produces rapid onset and recovery of anesthetic effect.