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Background: Guidelines to treat iron deficiency recommend daily provision of oral iron, but this may decrease fractional iron absorption and increase side effects. Our objective was to compare consecutive-day versus alternate-day iron supplementation. Methods: In a double-masked, randomized, placebo-controlled trial, young Swiss women (n = 150; serum ferritin ≤30 µg/L) were assigned to: daily 100 mg iron for 90 d, followed by daily placebo for another 90 d (consecutive-day group) or the same daily dose of iron and placebo on alternate days for 180 d (alternate-day group). The study period was 24/11/2021-10/8/2022. Co-primary outcomes, at equal total iron doses, were serum ferritin and gastrointestinal side effects; secondary outcomes were iron deficiency and serum hepcidin. Compliance and side effects were recorded daily using a mobile application. Data were analysed using mixed models and longitudinal prevalence ratios (LPR). The trial was registered at ClinicalTrials.gov (NCT05105438). Findings: 75 women were assigned to each group and included in the intention-to-treat analysis. Capsule adherence and side effect reporting was >97% in both groups. At equal total iron doses, comparing consecutive-day and alternate-day groups, median serum ferritin was 43.8 µg/L (31.7-58.2) versus 44.8 µg/L (33.8-53.6) (P = 0.98), the LPR for gastrointestinal side effects on days of iron intake was 1.56 (95% CI: 1.38, 1.77; P < 0.0001), and median serum hepcidin was 3.0 nM (IQR 2.0-5.0) versus 1.9 nM (1.4-2.9) (P < 0.0001). Iron deficiency prevalence after 3 months was 5.5% versus 4.3% (P = 0.74) and after 6 months was 11.4% and 3.0% (P = 0.049). Interpretation: At equal total iron doses, compared to consecutive day dosing of iron, alternate day dosing did not result in higher serum ferritin but reduced iron deficiency at 6 months and triggered fewer gastrointestinal side effects. Funding: Swiss National Science Foundation, Bern, Switzerland.
RESUMO
OBJECTIVE: The Vigileo/FloTrac system (software version 1.01; Edwards Lifesciences, Irvine, CA) determines cardiac output, without calibration, by analysis of the arterial pulse wave. To assess the accuracy of the Vigileo/FloTrac system, it was compared with the pulmonary artery catheter bolus thermodilution method as the current standard method. The study design was prospective and observer blinded. SETTING: A single university hospital. PARTICIPANTS: Thirty elective coronary artery bypass graft surgery patients. No special interventions were done to the participants. MEASUREMENTS AND MAIN RESULTS: After approval by the ethics committee and with written informed consent, synchronized measurements using both methods were made at 7 predefined time points, intraoperatively and postoperatively, producing 192 data pairs for evaluation. The statistical evaluation was performed by using the Bland-Altman method of analysis. In addition, a +/-20% and +/-30% deviation from the pulmonary artery catheter were evaluated (20% criteria and 30% criteria). In total, 46% of measurements did not fulfill the 20% criteria; 26% were outside the 30% limits. The Bland-Altman analysis for all time points showed that 95% of all differences between both methods were within a range between -2.2 and +3.1 L/min. Regression analysis revealed low correlation values at all time points. CONCLUSION: The described deviation from the standard must be regarded according to the user's needs. Considering the 30% limits of agreement, the Vigileo system (version 1.01) seems sufficiently accurate; applying the 20% criteria, it is not.