Clinical physiology and functional imaging
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Clin Physiol Funct Imaging · Nov 2016
Review Meta AnalysisNear infrared spectroscopy for frontal lobe oxygenation during non-vascular abdominal surgery.
Cerebral deoxygenation, as determined by near infrared spectroscopy (NIRS), seems to predict postoperative complications following cardiac surgery. We identify the type of non-vascular abdominal surgery associated with cerebral deoxygenation and/or hyperoxygenation, how such deviations affect patient outcome, and whether maintained cerebral oxygenation improves outcome. ⋯ NIRS seems important for predicting neurological complications associated with LTx. Also, surgery in reverse Trendelenburg's position and in other types of abdominal surgery about one-fourth of the patients are subjected to episodes of cerebral deoxygenation that seems to predict a poor outcome. Although there are currently only few studies available for patients going through abdominal surgery, the available evidence points to that it is an advantage to maintain the NIRS-determined cerebral oxygenation.
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Clin Physiol Funct Imaging · Nov 2016
Dynamic cerebral autoregulation to induced blood pressure changes in human experimental and clinical sepsis.
Previous studies have demonstrated that dynamic cerebral autoregulation to spontaneous fluctuations in blood pressure is enhanced following lipopolysaccharide (LPS) infusion, a human experimental model of early sepsis, whereas by contrast it is impaired in patients with severe sepsis or septic shock. In this study, we hypothesized that this pattern of response would be identical during induced changes in blood pressure. Dynamic cerebral autoregulation was assessed in nine healthy volunteers and six septic patients. ⋯ In healthy volunteers, thigh-cuff deflation caused a MAP reduction of 16 (13-20) % at baseline and 18 (16-20) % after LPS, while the MAP reduction was 12 (11-13) % in patients (P<0·05 versus volunteers at baseline; P<0·01 versus volunteers after LPS). The corresponding RoR values increased from 0·46 (0·31-0·49) s(-1) at baseline to 0·58 (0·36-0·74) s(-1) after LPS (P<0·05) in healthy volunteers, whereas they were similar to values observed in patients [0·43 (0·36-0·52) s(-1) ; P = 0·91 versus baseline; P = 0·14 versus LPS]. While our findings support the concept that dynamic cerebral autoregulation is enhanced during the very early stages of sepsis, they remain inconclusive with regard to more advanced stages of disease, because thigh-cuff deflation failed to induce sufficient MAP reductions in patients.