RESUMEN
BACKGROUND AND OBJECTIVES: Postpartum anaemia is a prevalent health problem. We aimed to determine the compliance rate for red blood cell (RBC) transfusion indication among postpartum women in a single tertiary care centre in Quebec, Canada. MATERIALS AND METHODS: Retrospective cohort study including all women ≥6 h postpartum who received ≥1 RBC transfusion during their delivery hospitalization between January 2005 and February 2022. We determined our centre's compliance rate by indication as compared to current society guidelines, all published after 2015 (Network for the Advancement of Patient Blood Management, Haemostasis and Thrombosis [NATA], Royal College of Obstetricians and Gynaecologists [RCOG], American College of Obstetricians and Gynecologists [ACOG]). We then explored predictors of guideline non-compliance and described transfusion practices in our centre. RESULTS: A total of 171 women were included. Our centre's compliance rate was 79.5% (95% confidence interval [CI] 72.7-84.8). Predictors of guideline non-compliance were maternal medical comorbidity or abnormal placentation, both limited by large CIs (odds ratio [OR] 2.26, CI 1.02-4.94, p = 0.04; OR 4.00, CI 1.31-12.06, p = 0.01, respectively). Postpartum haemorrhage was diagnosed among 68% of the cohort, mostly due to uterine atony (73.3%). Mean baseline and nadir haemoglobin were 111 g/L (±18) and 62 g/L (±7.7), respectively. Multiple unit initial transfusion was found in a majority of patients (63.7%). Iron therapy was administered to 51.5% of women in-hospital and 81.9% received an oral iron prescription at discharge. There were no differences in primary or secondary outcomes subsequent to relevant guideline publication. CONCLUSION: Our centre's compliance rate for RBC transfusion indication meets current practice guidelines. Areas for improvement include single-unit initial transfusion protocols and adjuvant iron treatment. Antenatal optimization of haemoglobin and ferritin stores may limit postpartum transfusions.
RESUMEN
Recently, a step-flow growth mode has been proposed to break the inherent molybdenum disulfide (MoS2) crystal domain bimodality and yield a single-crystalline MoS2 monolayer on commonly employed sapphire substrates. This work reveals an alternative growth mechanism during the metal-organic chemical vapor deposition (MOCVD) of a single-crystalline MoS2 monolayer through anisotropic 2D crystal growth. During early growth stages, the epitaxial symmetry and commensurability of sapphire terraces rather than the sapphire step inclination ultimately govern the MoS2 crystal orientation. Strikingly, as the MoS2 crystals continue to grow laterally, the sapphire steps transform the MoS2 crystal geometry into diamond-shaped domains presumably by anisotropic diffusion of ad-species and facet development. Even though these MoS2 domains nucleate on sapphire with predominantly bimodal 0 and 60° azimuthal rotation, the individual domains reach lateral dimensions of up to 200 nm before merging seamlessly into a single-crystalline MoS2 monolayer upon coalescence. Plan-view transmission electron microscopy reveals the single-crystalline nature across 50 µm by 50 µm inspection areas. As a result, the median carrier mobility of MoS2 monolayers peaks at 25 cm2 V-1 s-1 with the highest value reaching 28 cm2 V-1 s-1. This work details synthesis-structure correlations and the possibilities to tune the structure and material properties through substrate topography toward various applications in nanoelectronics, catalysis, and nanotechnology. Moreover, shape modulation through anisotropic growth phenomena on stepped surfaces can provide opportunities for nanopatterning for a wide range of materials.