Anesthesiology
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Clinical Trial
Influence of erythrocyte concentrate storage time on postsurgical morbidity in cardiac surgery patients.
The transfusion of erythrocytes that have been stored for long periods of time can produce visceral ischemia and favor the acquisition of postsurgical infections. To estimate the role of the duration of storage of erythrocytes on morbidity in cardiac surgery, we performed an observational study. ⋯ Prolonged storage of erythrocytes does not increase morbidity in cardiac surgery. However, storage for longer than 28 days could be a risk factor for the acquisition of nosocomial pneumonia.
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Randomized Controlled Trial Clinical Trial
Simultaneous assessment of drug interactions with low- and high-extraction opioids: application to parecoxib effects on the pharmacokinetics and pharmacodynamics of fentanyl and alfentanil.
Parecoxib is a parenteral cyclooxygenase-2 (COX-2) inhibitor intended for perioperative analgesia. It is an inactive prodrug hydrolyzed in vivo to the active inhibitor valdecoxib, a substrate for hepatic cytochrome P450 3A4 (CYP3A4); hence, a potential exists for metabolic interactions with other CYP3A substrates. This study determined the effects of parecoxib on the pharmacokinetics and pharmacodynamics of the CYP3A substrates fentanyl and alfentanil compared with the CYP3A inhibitor troleandomycin. Alfentanil is a low-extraction drug with a clearance that is highly susceptible to drug interactions; fentanyl is a high-extraction drug and, thus, is theoretically less vulnerable. We therefore also tested the hypothesis that the extraction ratio influences the consequence of altered hepatic metabolism of these opioids. ⋯ Single-dose parecoxib does not alter fentanyl or alfentanil disposition or clinical effects and does not appear to cause significant CYP3A drug interactions. CYP3A inhibition decreases alfentanil clearance more than fentanyl clearance, confirming that the extraction ratio influences the consequence of altered hepatic drug metabolism. Modified cassette, or "cocktail," dosing is useful for assessing drug interactions in humans.
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A patient underwent repair of a thoracoabdominal aortic aneurysm. Epidural morphine, 4 mg, was given for pain relief. After anesthesia, the patient displayed lower extremity paraparesis. This effect was reversed by naloxone. The authors sought to confirm these observations using a rat spinal ischemia model to define the effects of intrathecal morphine administered at various times after reflow on behavior and spinal histopathology. ⋯ These data indicate that during the immediate reflow following a noninjurious interval of spinal ischemia, intrathecal morphine potentiates motor dysfunction. Reversal by naloxone suggests that this effect results from an opioid receptor-mediated potentiation of a transient block of inhibitory neurons initiated by spinal ischemia.
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Randomized Controlled Trial Clinical Trial
Noninvasive cardiac output measurement using partial carbon dioxide rebreathing is less accurate at settings of reduced minute ventilation and when spontaneous breathing is present.
Although evaluation of cardiac output by the partial carbon dioxide rebreathing technique is as accurate as thermodilution techniques under controlled mechanical ventilation, it is less accurate at low tidal volume. It is not clear whether reduced accuracy is due to low tidal volume or low minute ventilation. The effect of spontaneous breathing on the accuracy of partial carbon dioxide rebreathing measurement has not been fully investigated. The objectives of the current study were to investigate whether tidal volume or minute ventilation is the dominant factor for the accuracy, and the accuracy of the technique when spontaneous breathing effort is present. ⋯ During controlled mechanical ventilation, minute ventilation rather than tidal volume affected the accuracy of cardiac output measurement using the partial carbon dioxide rebreathing technique. When spontaneous breathing is present, the carbon dioxide rebreathing technique is less accurate and increases spontaneous tidal volume and respiratory rate.
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Women are at higher risk for stroke after cardiac surgery than men. Prior analysis of risk profiles for perioperative stroke that have mostly combined data from women and men may fail to identify gender-specific risks. The purpose of this study was to evaluate whether patient gender impacts adjusted risk for stroke after cardiac surgery. ⋯ These data show that prior stroke before surgery is strongly and independently associated with susceptibility for stroke after cardiac surgery, particularly for men. Other risk factors for perioperative stroke, though, do not appear to be influenced by patient gender.