The Recognition of Excessive blood loss At ChildbirTh (REACT) Study: a two‐phase exploratory, sequential mixed methods inquiry using focus groups, interviews and a pilot, randomised crossover study

From Wiley via Jisc Publications RouterHistory: accepted 2021-04-16, pub-electronic 2021-05-27Article version: VoRPublication status: PublishedFunder: Research Trainees Coordinating Centre; Id: http://dx.doi.org/10.13039/501100000659; Grant(s): DRF‐2012‐05‐140Objectives: To explore how childbirth‐related blood loss is evaluated and excessive bleeding recognised; and to develop and test a theory of postpartum haemorrhage (PPH) diagnosis. Design: Two‐phase, exploratory, sequential mixed methods design using focus groups, interviews and a pilot, randomised crossover study. Setting: Two hospitals in North West England. Sample: Women (following vaginal birth with and without PPH), birth partners, midwives and obstetricians. Methods: Phase 1 (qualitative): 8 focus groups and 20 one‐to‐one, semi‐structured interviews were conducted with 15 women, 5 birth partners, 11 obstetricians, 1 obstetric anaesthetist and 19 midwives (n = 51). Phase 2 (quantitative): 11 obstetricians and ten midwives (n = 21) completed two simulations of fast and slow blood loss using a high‐fidelity childbirth simulator. Results: Responses to blood loss were described as automatic, intuitive reactions to the speed, nature and visibility of blood flow. Health professionals reported that quantifying volume was most useful after a PPH diagnosis, to validate intuitive decisions and guide ongoing management. During simulations, PPH treatment was initiated at volumes at or below 200 ml (fast mean blood loss 79.6 ml, SD 41.1; slow mean blood loss 62.6 ml, SD 27.7). All participants treated fast, visible blood loss, but only half treated slow blood loss, despite there being no difference in volumes (difference 18.2 ml, 95% CI −5.6 to 42.2 ml, P = 0.124). Conclusions: Experience and intuition, rather than blood loss volume, inform recognition of excessive blood loss after birth. Women and birth partners want more information and open communication about blood loss. Further research exploring clinical decision‐making and how to support it is required. Tweetable abstract: During a PPH, clinical decision‐making is intuitive with clinicians treating as soon as excessive loss is recognised

Measuring every particle's size from three-dimensional imaging experiments

Often experimentalists study colloidal suspensions that are nominally monodisperse. In reality these samples have a polydispersity of 4-10%. At the level of an individual particle, the consequences of this polydispersity are unknown as it is difficult to measure an individual particle size from microscopy. We propose a general method to estimate individual particle radii within a moderately concentrated colloidal suspension observed with confocal microscopy. We confirm the validity of our method by numerical simulations of four major systems: random close packing, colloidal gels, nominally monodisperse dense samples, and nominally binary dense samples. We then apply our method to experimental data, and demonstrate the utility of this method with results from four case studies. In the first, we demonstrate that we can recover the full particle size distribution {\it in situ}. In the second, we show that accounting for particle size leads to more accurate structural information in a random close packed sample. In the third, we show that crystal nucleation occurs in locally monodisperse regions. In the fourth, we show that particle mobility in a dense sample is correlated to the local volume fraction.Comment: 7 pages, 5 figure