Anesthesiology
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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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Comparative Study
Gabapentin prevents delayed and long-lasting hyperalgesia induced by fentanyl in rats.
Opioid-induced hyperalgesia can develop rapidly after opioid exposure. Neuropathic pain and opioid-induced hyperalgesia share common pathophysiologic mechanisms. Gabapentin is effective for the management of neuropathic pain and may therefore prevent opioid-induced hyperalgesia. This study tested the effectiveness of gabapentin for prevention of long-lasting hyperalgesia induced by acute systemic fentanyl in uninjured rats. Involvement of the alpha2delta auxiliary subunits of voltage-gated calcium channels in the prevention of opioid-induced hyperalgesia by gabapentin also was assessed. ⋯ Intraperitoneal and intrathecal gabapentin prevents the development of hyperalgesia induced by acute systemic exposure to opioids. This prevention may result, at least in part, from binding of gabapentin to the alpha2delta auxiliary subunits of voltage-gated calcium channels.
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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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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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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.