Anesthesia and analgesia
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Anesthesia and analgesia · Sep 1992
Comparative StudyBlood flow and tissue oxygen pressures of liver and pancreas in rats: effects of volatile anesthetics and of hemorrhage.
The object of this investigation was to compare the effects of volatile anesthetics and of hemorrhage at comparable arterial blood pressures on splanchnic blood flow (radioactive microspheres) and tissue oxygenation of the liver and pancreas (surface PO2 [PSO2] electrodes). In contrast to earlier studies, we did not use identical minimum alveolar anesthetic concentration multiples as a reference to compare volatile anesthetics; rather, we used the splanchnic perfusion pressure. Under general anesthesia (intravenous chloralose) and controlled ventilation, 12 Sprague-Dawley rats underwent laparotomy to allow access to abdominal organs. ⋯ Thus, volatile anesthetics preserved pancreatic but not hepatic blood flow and tissue oxygenation in this rat model. Despite comparable effects on perfusion, the PSO2 of the liver and pancreas was the least during hemorrhagic hypotension compared to that with the anesthetics. Because the volative anesthetic-induced hypotension has such a different effect on splanchnic tissue oxygenation compared with hemorrhagic-induced hypotension, the authors conclude that the method of inducing hypotension may have different effects on oxygenation of various tissues.
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Anesthesia and analgesia · Sep 1992
Should all children with suspected or confirmed malignant hyperthermia susceptibility be admitted after surgery? A 10-year review.
Children otherwise suitable for same-day discharge may be admitted to the hospital solely because they are known or suspected to be malignant hyperthermia-susceptible (MHS). To determine whether their hospitalization is necessary, the medical charts of 303 children labeled MHS who had undergone surgery with anesthesia free of malignant hyperthermia-triggering agents on 431 occasions between 1981 and 1990 were reviewed. Eighteen of these patients (25 cases) who were subsequently identified as biopsy-negative were excluded from the study. ⋯ These episodes were not considered to be malignant hyperthermia and were not treated with dantrolene. None of the remaining 275 patients exhibited any features of malignant hyperthermia, although one had an adverse reaction to radiologic contrast medium. On the basis of our retrospective analysis, postoperative admission to the hospital solely on the basis of the MHS label is not warranted.
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Anesthesia and analgesia · Sep 1992
Randomized Controlled Trial Comparative Study Clinical TrialEpidural test dose and intravascular injection in obstetrics: sensitivity, specificity, and lowest effective dose.
The authors studied the sensitivity and specificity of several epidural test doses as markers of intravascular injection in laboring patients in a prospective double-blind, randomized study. Fifty-nine parturients were assigned randomly to receive an intravenous injection of either normal saline solution (3 mL, NS group) or 1.5% lidocaine with epinephrine 1:200,000 (1 mL, EPI-5 group; 2 mL, EPI-10 group; or 3 mL, EPI-15 group). The EPI-5 and EPI-10 doses were diluted to 3 mL volume with normal saline solution. ⋯ In the other groups, the increase was 21 +/- 8 (EPI-5 group), 31.5 +/- 13 (EPI-10 group), and 29 +/- 9 beats/min (EPI-15 group). A baseline-to-peak criterion of greater than 10 beats/min identified all intravascular injections in the EPI-15 (by design) and EPI-10 groups (15 of 15 and 14 of 14, respectively) with a sensitivity of 100%. Specificity was 73% (11 of 15 true negatives).(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Sep 1992
Influence of volume on the spread of local anesthetic-methylene blue solution after injection for intercostal block.
The purpose of this study was to evaluate the influence of the volume of methylene blue-local anesthetic on the spread of the injectate along the costal pleura. Twenty patients undergoing elective thoracotomy were studied. Twelve patients received intercostal nerve injection with 10 mL of 0.5% bupivacaine with methylene blue (10-mL group), and eight patients received 5 mL of 0.5% bupivacaine with methylene blue (5-mL group). ⋯ In the 10-mL group, eight patients had bupivacaine-methylene blue spread to two intercostal spaces, three patients to three intercostal spaces, and one patient to four intercostal spaces. In the 5-mL group, seven patients had bupivacaine methylene blue spread confined to one intercostal space and one patient to two intercostal spaces. We conclude that a potential anatomic space exists between the costal pleura and the internal intercostal muscle and that the spread of local anesthetic after intercostal nerve block injection is volume dependent.
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Anesthesia and analgesia · Sep 1992
Interscalene brachial plexus block for shoulder surgery: a proximal paresthesia is effective.
This study was designed to determine whether the location of paresthesias is related to the success of interscalene blocks in providing anesthesia for shoulder surgery. Interscalene blocks were performed in 45 patients presenting for elective shoulder surgery. Interscalene injections of 33-55 mL of 1.5% mepivacaine with epinephrine were performed after the first elicited paresthesia to the shoulder, arm, forearm, or hand. ⋯ The time-course of onset of motor block as evaluated at the shoulder and elbow was not different between patients with shoulder paresthesias and those with more distal paresthesias. Handgrip strength was quantitatively evaluated with a dynamometer, and both paresthesia groups showed similar decrements in hand strength except at the end of the measurement period, when patients with distal paresthesias had a significantly weaker handgrip than patients with shoulder paresthesias. We recommend that paresthesias to the shoulder be accepted in performing interscalene blocks for patients undergoing shoulder surgery.