Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2011
Comparative StudyEquivalence and noninferiority testing in regression models and repeated-measures designs.
Equivalence and noninferiority designs are useful when the superiority of one intervention over another is neither expected nor required. Equivalence trials test whether a difference between groups falls within a prespecified equivalence region, whereas noninferiority trials test whether a preferred intervention is either better or at least not worse than the comparator, with worse being defined a priori. Special designs and analyses are needed because neither of these conclusions can be reached from a nonsignificant test for superiority. ⋯ We then show how the analogous hypotheses can be tested in a repeated-measures setting in which there are multiple outcomes per subject. We especially address interactions between the repeated factor, usually time, and treatment. Although we focus on the analysis of continuous outcomes, extensions to other data types as well as sample size consideration are discussed.
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Anesthesia and analgesia · Mar 2011
Comparative StudyDoes anesthetic additivity imply a similar molecular mechanism of anesthetic action at N-methyl-D-aspartate receptors?
Isoflurane and carbon dioxide (CO(2)) negatively modulate N-methyl-d-aspartate (NMDA) receptors, but via different mechanisms. Isoflurane is a competitive antagonist at the NMDA receptor glycine binding site, whereas CO(2) inhibits NMDA receptor current through extracellular acidification. Isoflurane and CO(2) exhibit additive minimum alveolar concentration effects in rats, but we hypothesized that they would not additively inhibit NMDA receptor currents in vitro because they act at different molecular sites. ⋯ In contrast to our hypothesis, NMDA receptor inhibition by CO(2) and isoflurane is additive. Possibly, CO(2) acidification modulates a pH-sensitive loop on the NMDA receptor that in turn alters glycine binding affinity on the GluN1 subunit. However, ketamine plus either CO(2) or H(+) synergistically inhibits NMDA receptor currents. Drugs acting via different mechanisms can thus exhibit additive or synergistic receptor effects. Additivity may not robustly indicate commonality between molecular anesthetic mechanisms.
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Anesthesia and analgesia · Mar 2011
Comparative StudyHemodynamic changes during a combined psoas compartment-sciatic nerve block for elective orthopedic surgery.
Hemodynamic variables can theoretically be influenced by a combined psoas compartment-sciatic nerve block (CPCSNB) owing to a relatively high systemic absorption of local anesthetics and extended vasodilatation in the anesthetized limb (hemisympatectomy). In this study we assessed and documented hemodynamic changes during CPCSNB for elective orthopedic surgery. ⋯ CPCSNB did not affect cardiac index. Changes in arterial blood pressure and heart rate, although statistically significant, remained within an acceptable clinical range (<10% variation). CPCSNB does not appear to induce clinically significant hemodynamic changes in this group of patients.
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Anesthesia and analgesia · Mar 2011
Comparative StudyPublication misrepresentation among anesthesiology residency applicants.
Publication misrepresentation has been documented among applicants for residency positions in several specialties. However, these data are not available for anesthesiology applicants. Our purpose in this study was to document the prevalence of publication misrepresentation among applicants to a single anesthesiology residency, to compare anesthesiology publication misrepresentation data with similar data in other specialties, and to determine how often publication misrepresentation leads to an unfair competitive advantage in the application process. ⋯ Misrepresented publications were fairly common among anesthesiology residency applicants. However, only a small percentage of applicants listed misrepresented publications that were clearly fraudulent or contained a citation error that conferred a competitive advantage. Identification of fraudulent publications on Electronic Residency Application Service applications is important to maintain the integrity of the application process.
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Anesthesia and analgesia · Mar 2011
Comparative StudyTransplantation of endothelial progenitor cells improves pulmonary endothelial function and gas exchange in rabbits with endotoxin-induced acute lung injury.
Circulating endothelial progenitor cells (EPCs) have been therapeutically applied to aid vascular repair and myocardial regeneration. The number of circulating EPCs also provides invaluable outcome prediction for fatal diseases such as acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). However, evidence for the therapeutic potential of EPCs in subjects with ALI/ADRS is limited. ⋯ Transplantation of EPCs restored pulmonary endothelial function, preserved integrity of the alveolocapillary barrier and suppressed the lung inflammatory response, thereby improving pulmonary gas exchange in rabbits with intratracheal lipopolysaccharide-induced ALI. Transplantation of EPCs can be a novel cell-based, endothelium-targeted therapeutic strategy for prevention and treatment of ALI/ARDS.