This study found an association between cumulative duration of low BIS and mortality in the setting of cardiac surgery. Notably, this association was independent of both volatile anesthetic concentration and duration of anesthesia, suggesting that intermediate-term mortality after cardiac surgery was not causally related to excessive anesthetic dose.
Background: Postoperative mortality has been associated with cumulative anesthetic duration below an arbitrary processed electroencephalographic threshold (bispectral index [BIS] Ͻ45). This substudy of the B-Unaware Trial tested whether cumulative duration of BIS values lower than 45, cumulative anesthetic dose, comorbidities, or intraoperative events were independently associated with postoperative mortality. Methods: The authors studied 1,473 patients (mean Ϯ SD age, 57.9 Ϯ 14.4 yr; 749 men) who underwent noncardiac surgery at Barnes-Jewish Hospital in St. Louis, Missouri. Multivariable Cox regression analysis was used to determine whether perioperative factors were independently associated with all-cause mortality. Results: A total of 358 patients (24.3%) died during a follow-up of 3.2 Ϯ 1.1 yr. There were statistically significant associations among various perioperative risk factors, including malignancy and intermediate-term mortality. BIS-monitored patients did not have lower mortality than unmonitored patients (24.9 vs. 23.7%; difference ϭ 1.2%, 95% CI, Ϫ3.3 to 5.6%). Cumulative duration of BIS values less than 45 was not associated with mortality (multivariable hazard
BackgroundExcessive intravenous fluid prescription may play a causal role in postoperative complications following major gastrointestinal resectional surgery. The aim of this study was to investigate whether fluid and salt restriction would decrease postoperative complications compared with a more modern controlled liberal regimen.MethodsIn this observer-blinded single-site randomized clinical trial consecutive patients undergoing major gastrointestinal resectional surgery were randomized to receive either a liberal control fluid regimen or a restricted fluid and salt regimen. The primary outcome was postoperative complications of grade II and above (moderate to severe).ResultsSome 240 patients (194 colorectal resections and 46 oesophagogastric resections) were enrolled in the study; 121 patients were randomized to the restricted regimen and 119 to the control (liberal) regimen. During surgery the control group received a median (interquartile range) fluid volume of 2033 (1576–2500) ml and sodium input of 282 (213–339) mmol, compared with 1000 (690–1500) ml and 142 (93–218) mmol respectively in the restricted group. There was no significant difference in major complication rate between groups (38·0 and 39·0 per cent respectively). Median (range) hospital stay was 8 (3–101) days in the controls and 8 (range 3–76) days among those who received restricted fluids. There were four in-hospital deaths in the control group and two in the restricted group. Substantial differences in weight change, serum sodium, osmolality and urine : serum osmolality ratio were observed between the groups.ConclusionThere were no significant differences in major complication rates, length of stay and in-hospital deaths when fluid restriction was used compared with a more liberal regimen. Registration number: ISRCTN39295230 (http://www.controlled-trials.com).
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