Elderly patients are more prone than younger patients to develop cerebral desaturation because of the reduced physiologic reserve that accompanies aging. To evaluate whether monitoring cerebral oxygen saturation (rSO(2)) minimizes intraoperative cerebral desaturation, we prospectively monitored rSO(2) in 122 elderly patients undergoing major abdominal surgery with general anesthesia. Patients were randomly allocated to an intervention group (the monitor was visible and rSO(2) was maintained at > or =75% of preinduction values; n = 56) or a control group (the monitor was blinded and anesthesia was managed routinely; n = 66). Cerebral desaturation (rSO(2) reduction <75% of baseline) was observed in 11 patients of the treatment group (20%) and 15 patients of the control group (23%) (P = 0.82). Mean (95% confidence intervals) values of mean rSO(2) were higher (66% [64%-68%]) and the area under the curve below 75% of baseline (AUCrSO2(2)< 75% of baseline) was lower (0.4 min% [0.1-0.8 min%]) in patients of the treatment group than in patients of the control group (61% [59%-63%] and 80 min% [2-144 min%], respectively; P = 0.002 and P = 0.017). When considering only patients developing intraoperative cerebral desaturation, a lower Mini Mental State Elimination (MMSE) score was observed at the seventh postoperative day in the control group (26 [25-30]) than in the treatment group (28 [26-30]) (P = 0.02), with a significant correlation between the AUCrSO(2) < 75% of baseline and postoperative decrease in MMSE score from preoperative values (r(2)= 0.25, P = 0.01). Patients of the control group with intraoperative cerebral desaturation also experienced a longer time to postanesthesia care unit (PACU) discharge (47 min [13-56 min]) and longer hospital stay (24 days [7-53] days) compared with patients of the treatment group (25 min [15-35 min] and 10 days [7-23 days], respectively; P = 0.01 and P = 0.007). Using rSO(2) monitoring to manage anesthesia in elderly patients undergoing major abdominal surgery reduces the potential exposure of the brain to hypoxia; this might be associated with decreased effects on cognitive function and shorter PACU and hospital stay.

No abstract

No abstract

X-ray photoelectron spectroscopy was applied to chracterize CuO-ZnO catalysts (Cu/Zn ataomic ratio ≥1) prepared by thermal decomposition at 350°C in air of hydroxycarbonate precursors obtained by the coprecipitation method at constant pH. For the precursors, the surface Cu/Zn atomic ratios have, within experimental error, the same values as that obtained by chemical analysis. This shows both a homogeneous dispersion of zinc in the zincian-malachite solid solutions for the samples Cu/Zn=92/8, 85/15 and 77/23, and a good interdispersion of the zincian-malachit and aurichalcite phases in the 67/33 and 50/50 samples. In our calcined samples we find a strong interaction between the small oxide particules but no evidence of Cu2+/ZnO and Zn2+/CuO solid solutions. In the catalysts with low zinc loading, the ZnO phase (amorphous or with particles of a size <40 angstrom) tends to cover the CuO particles. The catalysts with high zinc loading present the differential charging phenomenon due to the peculiar morphological situation of CuO and ZnO particles, as shown by the XPS measurements of samples supported on a biased sample holder. The reduction in situ underH2 at 135 and 200°C of these catalysts shows that Cu and Cu+ (Cu2O-like) species are formed