Anesthesiology
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Comparative Study
Incidence and risk factors for perioperative adverse respiratory events in children who are obese.
Consistent with the increasing prevalence of obesity in the United States and many countries worldwide, anesthesiologists are now presented with a greater number of adult and pediatric patients who are significantly overweight. This prospective study was designed to examine the relation between age-adjusted body mass index, preoperative comorbidities, and perioperative outcome in children. ⋯ These results suggest that children presenting for elective surgical procedures who are obese have a greater prevalence of preexisting comorbid medical conditions and an increased incidence of perioperative adverse respiratory events compared with normal-weight children. Identification and awareness of risk factors for perioperative complications will be important in optimizing the anesthetic management of these children.
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Metabolic syndrome represents a constellation of risk factors associated with increased incidence of cardiovascular disease and progression to diabetes mellitus. Insulin resistance, a state of decreased biologic response to physiologic concentrations of insulin, is a key component of this syndrome and seems to be the result of a primary defect at the skeletal muscle glucose transporter. Acute illness and the perioperative period are characterized by a state of insulin resistance that manifests as hyperglycemia and leads to various other metabolic and biochemical alterations that adversely affect end organ function. ⋯ Achieving euglycemia seems beneficial in certain clinical situations, but considerable disagreement exists regarding the target blood sugar levels, the duration of therapy, and the modality. Pharmacotherapy, exercise, and nutrition to improve insulin sensitivity seem promising but require further evaluation to confirm their efficacy for perioperative risk reduction. This review discusses the pathophysiology and the clinical implications of metabolic syndrome and insulin resistance in the acutely ill patient with an emphasis on perioperative modulation strategies.
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Randomized Controlled Trial Comparative Study
Quantitation of the effect of nitrous oxide on rocuronium infusion requirements using closed-loop feedback control.
Nitrous oxide has a minor effect on the effective dose 50% values of bolus doses of rocuronium. The authors have studied the effect of nitrous oxide on the infusion requirements of rocuronium using closed-loop feedback control of rocuronium infusion. ⋯ Nitrous oxide does not affect the infusion requirements of rocuronium to a clinically significant degree.
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Randomized Controlled Trial Comparative Study
Magnitude of the second gas effect on arterial sevoflurane partial pressure.
A number of studies have demonstrated a faster rate of increase in end-expired partial pressure as a fraction of inspired (Pa/Pi) for volatile agents in the presence of high concentrations of nitrous oxide, consistent with the second gas effect. However, no study has demonstrated a similar effect on arterial blood concentrations. ⋯ Nitrous oxide uptake exerts a significant second gas effect on arterial sevoflurane partial pressures. This effect is two to three times more powerful than the effect on end-expired partial pressures. The authors explain how this is due to the influence of ventilation-perfusion scatter on the distribution of blood flow and gas uptake in the lung.
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Volatile anesthetics are known to protect the heart against ischemia-reperfusion injury. The authors tested whether anesthetic preconditioning with isoflurane is mediated via activation of the transcription factor hypoxia inducible factor 1 (HIF-1) and evaluated the role of mammalian target of rapamycin signaling in this process. ⋯ The current results indicate that isoflurane-induced myocardial protection involves activation of the HIF-1 pathway that is mediated by the mammalian target of rapamycin.