More than 27 million Americans undergo noncardiac surgery annually. Cardiac complications can be a major source of morbidity and mortality in the perioperative period. Preoperative risk stratification, intraoperative ischemia monitoring and postoperative surveillance help to predict, identify and efficiently treat these adverse events. A renewed emphasis on preoperative evaluation has helped to identify patients at an increased risk for adverse cardiac events and thus, implement noninvasive or invasive cardio protective strategies in an attempt to minimize these complications. In this review we briefly describe the current evidence on perioperative management of patients presenting for noncardiac surgery. As the surgeon will remain one of the first to evaluate patients before noncardiac surgery it is essential he/she be well versed with this information.
Cerebral blood flow (CBF) and blood-brain barrier (BBB) permeability by arterial spin labeling (ASL)- and dynamic contrast enhanced (DCE)-magnetic resonance imaging (MRI), respectively were repeatedly measured under either halothane (N = 5) or isoflurane (N = 5) anesthesia in a rat stroke model of embolic occlusion of middle cerebral artery (MCA). Cerebral blood flow measurements were made after MCA embolization, following intravenous recombinant tissue plasminogen activator (rtPA) treatment at 3 hours post-ictus and again at 48 hours. Blood-brain barrier opening was examined after rtPA infusion and again at 48 hours. Data were analyzed using paired t-tests and significance considered at P < 0·05. The extent and magnitude of CBF reduction due to stroke did not differ between the two groups. Blood-to-brain forward rate constant, K(trans), a measure of BBB permeability, for an MRI contrast agent gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA), was elevated in the ipsilateral hemisphere in both cohorts. However, isoflurane-anesthetized rats exhibited a trend of lower K(trans) values at 48 hours (P = 0·06) indicating reduced BBB damage in the ipsilateral hemisphere. The area of BBB opening followed a similar trend with the isoflurane-anesthetized group exhibiting a smaller area of BBB damage acutely and at 48 hours compared to the halothane-anesthetized group.
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