Anesthesiology
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Intraoperative hypotension (IOH) is frequently associated with adverse outcome such as 1-yr mortality. However, there is no consensus on the correct definition of IOH. The authors studied a number of different definitions of IOH, based on blood pressure thresholds and minimal episode durations, and their association with 1-yr mortality after noncardiac surgery. ⋯ This observational study showed no causal relation between IOH and 1-yr mortality after noncardiac surgery for any of the definitions of IOH. Nevertheless, additional analysis suggested that for elderly patients, the mortality risk increases when the duration of IOH becomes long enough. The length of this duration depends on the designated blood pressure threshold, suggesting that lower blood pressures are tolerated for shorter durations. The effect of IOH on 1-yr mortality remains debatable, and no firm conclusions on the lowest acceptable intraoperative blood pressures can be drawn from this study.
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Ischemic preconditioning (IPC) and anesthetic-induced preconditioning against myocardial infarction are mediated via protein kinase B. Pim-1 kinase acts downstream of protein kinase B and was recently shown to regulate cardiomyocyte survival. The authors tested the hypothesis that IPC and anesthetic-induced preconditioning are mediated by Pim-1 kinase. ⋯ These data suggest that Pim-1 kinase mediates at least in part desflurane-induced preconditioning and IPC against myocardial infarction in mice.
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Thoracic epidural anesthesia (TEA) protects the intestinal microcirculation and improves perioperative outcomes. TEA also reduces mortality in acute experimental pancreatitis. Its impact on hepatic microcirculation, however, in health and critical illness is unknown. Therefore, the authors studied the effect of TEA on the liver in healthy rats and in experimental severe acute pancreatitis. ⋯ TEA reduces liver injury in necrotizing acute pancreatitis. This could be related to a regional sympathetic block. TEA could thus preserve liver function in systemic inflammatory disorders such as acute pancreatitis.
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Remifentanil anesthesia enhances postoperative pain in animals and humans. The authors evaluated the impact of the dose (microg x kg(-1) x min(-1)) and duration of remifentanil infusion, and the effects of a second surgery on postoperative pain sensitization. ⋯ In this model of incisional pain, remifentanil induces pronociceptive effects, which are dose dependent but unaltered by the duration of administration. A second surgery performed on the same site and experimental conditions induces greater postoperative hyperalgesia that is enhanced when remifentanil is used as an anesthetic.