Anesthesiology
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Multicenter Study Observational Study
End-tidal to Arterial Gradients and Alveolar Deadspace for Anesthetic Agents.
According to the "three-compartment" model of ventilation-perfusion ((Equation is included in full-text article.)) inequality, increased (Equation is included in full-text article.)scatter in the lung under general anesthesia is reflected in increased alveolar deadspace fraction (VDA/VA) customarily measured using end-tidal to arterial (A-a) partial pressure gradients for carbon dioxide. A-a gradients for anesthetic agents such as isoflurane are also significant but have been shown to be inconsistent with those for carbon dioxide under the three-compartment theory. The authors hypothesized that three-compartment VDA/VA calculated using partial pressures of four inhalational agents (VDA/VAG) is different from that calculated using carbon dioxide (VDA/VACO2) measurements, but similar to predictions from multicompartment models of physiologically realistic "log-normal" (Equation is included in full-text article.)distributions. ⋯ Alveolar deadspace for anesthetic agents is much larger than for carbon dioxide and related to blood solubility. Unlike the three-compartment model, multicompartment (Equation is included in full-text article.)scatter models explain this from physiologically realistic gas uptake distributions, but suggest a residual factor other than solubility, potentially diffusion limitation, contributes to deadspace.
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Randomized Controlled Trial
Magnesium and Bladder Discomfort after Transurethral Resection of Bladder Tumor.
Catheter-related bladder discomfort occurs because of involuntary contractions of the bladder smooth muscle after urinary catheterization. Magnesium is associated with smooth muscle relaxation. This study hypothesized that among patients having transurethral resection of bladder tumor, magnesium will reduce the incidence of postoperative moderate-to-severe catheter-related bladder discomfort. ⋯ Magnesium reduced the incidence of catheter-related bladder discomfort above a moderate grade and increased patient satisfaction among patients having transurethral resection of bladder tumor.
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The recent demonstration of the significant reduction in mortality in patients with septic shock treated with adjunctive glucocorticoids combined with fludrocortisone and the effectiveness of angiotensin II in treating vasodilatory shock have renewed interest in the role of the mineralocorticoid axis in critical illness. Glucocorticoids have variable interactions at the mineralocorticoid receptor. ⋯ The suggestion is that there is a defect at the level of the adrenal zona glomerulosa associated with a high mortality rate that may represent an adaptive response aimed at increasing cortisol levels. Furthermore, cross-talk exists between angiotensin II and aldosterone, which needs to be considered when employing therapeutic strategies.
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Multicenter Study
Risk Factors for Failure to Rescue in Myocardial Infarction after Noncardiac Surgery: A Cohort Study.
Compared to other perioperative complications, failure to rescue (i.e., death after suffering a complication) is highest after perioperative myocardial infarction (a myocardial infarction that occurs intraoperatively or within 30 days after surgery). The purpose of this study was to identify patient and surgical risk factors for failure to rescue in patients who have had a perioperative myocardial infarction. ⋯ Routinely identified patient and surgical factors predict risk of failure to rescue after perioperative myocardial infarction.
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Acute kidney injury (AKI) is a frequent and deadly complication after cardiac surgery. In the absence of effective therapies, a focus on risk factor identification and modification has been the mainstay of management. The authors sought to determine the impact of intraoperative hypotension on de novo postoperative renal replacement therapy in patients undergoing cardiac surgery, hypothesizing that prolonged periods of hypotension during and after cardiopulmonary bypass (CPB) were associated with an increased risk of renal replacement therapy. ⋯ MAP less than 65 mmHg for 10 min or more post-CPB is associated with an increased risk of de novo postoperative renal replacement therapy. The association between intraoperative hypotension and AKI was weaker in comparison to factors such as renal insufficiency, heart failure, obesity, anemia, complex or emergent surgery, and new-onset postoperative atrial fibrillation. Nonetheless, post-CPB hypotension is a potentially easier modifiable risk factor that warrants further investigation.