Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2003
Case ReportsRight ventricular exclusion surgery for arrhythmogenic right ventricular dysplasia with cardiomyopathy.
The authors describe the management of a patient with arrhythmogenic right ventricular dysplasia treated with right ventricular exclusion surgery.
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Anesthesia and analgesia · Jun 2003
Case ReportsPostdural puncture headache: an imaging-guided management protocol.
We propose an imaging-based algorithm for the management of headache caused by the inadvertent puncture of dura that occurs sporadically during epidural analgesia. Its implementation can identify those postdural puncture headache cases that cannot benefit from epidural blood patches, and their unnecessary application can consequently be avoided.
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Anesthesia and analgesia · Jun 2003
Knowledge and practice regarding prophylactic perioperative beta blockade in patients undergoing noncardiac surgery: a survey of Canadian anesthesiologists.
A lack of awareness of the "best" current practice is frequently cited as a major barrier to the practice of evidence-based medicine. The purpose of this study was to survey Canadian anesthesiologists to determine their knowledge and practices associated with prophylactic perioperative beta blockade, a therapy that has been widely discussed in the literature and has the potential for a significant positive impact on patient outcomes. We sent questionnaires to 1234 members of the Canadian Anesthesiologists' Society. The overall response rate was 54%. Ninety-five percent of respondents were aware of the perioperative beta blocker literature, and of these, 93% agreed that beta blockers were beneficial in patients with known coronary artery disease (CAD). Fifty-seven percent reported always or usually administering prophylactic beta blockers in patients with known CAD, and 34% of these regular users continued therapy beyond the early postoperative period. Only 9% of respondents reported that a formal protocol existed at their facility. This study suggests that barriers to the translation of research to practice were not related to a lack of awareness of the current best evidence. With respect to perioperative beta blockers, controversies within the literature as well as practical considerations may be greater barriers to implementation of best evidence. ⋯ This survey found that anesthesiologists were aware of and supported the use of prophylactic perioperative beta blockers in patients with risk factors or known coronary artery disease; however, only 57% frequently prescribed perioperative beta blockers. A lack of awareness of the current "best" evidence was not a barrier to use.
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Anesthesia and analgesia · Jun 2003
Comparative StudyThe effects of enflurane, isoflurane, and intravenous anesthetics on rat diaphragmatic function and fatigability.
We examined the effect of isoflurane, enflurane, midazolam, ketamine, propofol, and thiopental on diaphragmatic functions under unfatigued and fatigued conditions in 228 rat isolated muscle strips. Diaphragmatic twitch characteristics and tetanic contractions were measured before and after muscle fatigue, which was induced by repetitive tetanic contraction with or without exposure to one of the anesthetics at clinically relevant plasma concentrations, and at 10 and 100 times this concentration, or at 1, 2, and 3 minimum alveolar anesthetic concentration (MAC). Isoflurane, midazolam, ketamine, propofol, and thiopental did not induce a direct inotropic or lusitropic effect under unfatigued and fatigued conditions. Enflurane did not change contraction or relaxation in fresh isolated diaphragm, but enflurane at 2-3 MAC enhanced diaphragmatic fatigability itself and fatigue-induced impairment of twitch characteristics and tetanic tensions. These effects were greater at 3 MAC than at 2 MAC. Our findings suggest that the reduction of diaphragm function previously reported in in vivo experiments using propofol, midazolam, and isoflurane is not related to a direct effect on intrinsic diaphragmatic contractility. Our results also indicate that large concentrations of enflurane may impair the diaphragmatic function at sites other than excitation-contraction coupling. ⋯ Enflurane did not change contraction or relaxation in fresh isolated rat diaphragm, but enhanced diaphragmatic fatigability itself and fatigue-induced impairment of twitch characteristics and tetanic tensions. Isoflurane, midazolam, ketamine, propofol, and thiopental had no direct effects on diaphragmatic functions under unfatigued and fatigued conditions. Isoflurane and these i.v. anesthetics may be advantageous over enflurane to anesthetize and/or sedate patients who are predisposed to diaphragmatic fatigue.
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Anesthesia and analgesia · Jun 2003
Olprinone for the treatment, but not prevention, of fatigue-induced changes in guinea-pig diaphragmatic contractility.
Olprinone, a phosphodiesterase III inhibitor, improves the contractility in fatigued diaphragm in vivo, but no data are available for the treatment and prevention of fatigue-induced changes in vitro. We therefore examined the efficacy of Olprinone for the treatment and prevention of fatigue-induced changes in guinea-pig diaphragmatic contractility. The guinea-pig diaphragm strips were randomly allocated according to dose of Olprinone (0, 10(-6), 10(-5), and 10(-4) M) (n = 7 each) and were stimulated directly in an organ bath. Diaphragmatic contractility was measured by assessing twitch tension and force at 20-Hz and 100-Hz stimulation. Diaphragmatic fatigue was induced by generating rhythmic, repetitive contractions produced by 20-Hz stimulation for 5 min. In the first experiment, after the fatigue-producing period, Olprinone was administered to the organ bath for 5 min. In the second experiment, Olprinone was pretreated for 5 min, and then diaphragmatic fatigue was produced. In Experiment 1, after a fatigue-producing period, tetanic force to each stimulus decreased from baseline values (P < 0.05). Olprinone 10(-5)-10(-4) M caused an increase in force at both stimuli from fatigued values (P < 0.05). In Experiment 2, no change in tetanic force was observed by pretreatment with Olprinone (0-10(-4) M). After producing fatigue, tetanic force to each stimulus decreased from baseline values (P < 0.05). These results suggest that Olprinone 10(-5)-10(-4) M improves the fatigue-induced changes in guinea-pig diaphragmatic contractility and that pretreatment with Olprinone does not prevent diaphragmatic fatigability. ⋯ Olprinone is effective for the treatment, but not prevention, of fatigue-induced changes in guinea-pig diaphragmatic contractility.