Supplemental oxygen and surgical-site infections: an alternating intervention controlled trial.

BACKGROUND: The main defence against bacterial infection is oxidative killing by neutrophils, which requires molecular oxygen in wounded tissues. High inspired-oxygen fractions increase tissue oxygenation. But, whether improving tissue oxygenation actually reduces surgical-site infection (SSI) remains controversial. We therefore tested the primary hypothesis that supplemental oxygen (80% vs 30%) reduces the risk of a 30-day composite of deep tissue or organ-space SSI, healing-related wound complications, and mortality. METHODS: In an isolated suite of operating rooms, the inspired-oxygen concentration was alternated between 30% and 80% at 2-week intervals for 39 months. The analysis was restricted to patients who had major intestinal surgery lasting at least 2 h. Qualifying operations (5749) were analysed, including 2843 (49%) colorectal resections, 1866 (32%) lower gastrointestinal therapeutic procedures, 373 (6%) small-bowel resections, and 667 (13%) other colorectal procedures. RESULTS: The 80% and 30% oxygen groups were well balanced on all of the demographic, baseline, and procedural variables. The oxygen intervention had no effect on the composite primary outcome or any of its components. The overall observed incidence of the composite outcome was 10.8% (314/2896) in the 80% oxygen group and 11.0% (314/2853) in the 30% group. The estimated relative risk was 0.99 (95% CI: 0.85, 1.14) for 80% vs 30%, P=0.85. CONCLUSIONS: Supplemental oxygen does not prevent major infection and healing-related complications after major intestinal surgery. CLINICAL TRIAL REGISTRATION: NCT01777568.

Double-blind treatment of major depression with dehydroepiandrosterone.

OBJECTIVE: This study was designed to assess possible antidepressant effects of dehydroepiandrosterone (DHEA), an abundant adrenocortical hormone in humans. METHOD: Twenty-two patients with major depression, either medication-free or on stabilized antidepressant regimens, received either DHEA (maximum dose = 90 mg/day) or placebo for 6 weeks in a double-blind manner and were rated at baseline and at the end of the 6 weeks with the Hamilton Depression Rating Scale. Patients previously stabilized with antidepressants had the study medication added to that regimen; others received DHEA or placebo alone. RESULTS: DHEA was associated with a significantly greater decrease in Hamilton depression scale ratings than was placebo. Five of the 11 patients treated with DHEA, compared with none of the 11 given placebo, showed a 50% decrease or greater in depressive symptoms. CONCLUSIONS: These results suggest that DHEA treatment may have significant antidepressant effects in some patients with major depression. Further, larger-scale trials are warranted.