Concordancia entre la estimación visual y la medición del volumen recolectado en una bolsa del sangrado intraparto en mujeres con parto normal en Bogotá, Colombia, 2006

Objective: to establish agreement between visual estimation and volume of blood collected in a bag during normal delivery according to the different observer characteristics in a medium complexity teaching hospital and the correlation between the collected volume and mean change in haemoglobin and haematocrite. Methods: a concordance study was carried out, comparing visual estimation by simultaneous observers having various degrees of education and experience to the objective measurement of the volume collected in a sterilised bag during and until the first hour post partum. The study included 168 pregnant women who underwent normal vaginal delivery. Concordance was evaluated by concordance correlation coefficient (CCC Lin), 95% limits of agreement and Pearson's correlation coefficient for changes in haemoglobin concentration and haematocrite with measured collected volume. Results: median collected volume during normal delivery was 494 millilitres (mL) (p5 = 110, p95 = 1320), median change of haematocrite 3,8% and haemoglobin 1,2 g/dL. Global concordance was acceptable [CCC = 0.72 (IC95%: 0.67-0.76)] with an average visual underestimation of 110,2 mL (limits of agreement: -562.1 mL, to 341.8 mL). Underestimation and loss of reliability increased with the greater volumes collected for all of the observers' categories. Correlations between collected volume and change in haemoglobin and haematocrite were 0.55 and 0.53 respectively. Conclusions: the reliability of visual estimation was acceptable for the small volumes collected and decreased as collected volume increased. Introducing measuring instruments and continued education is necessary for improving visual estimation reliability to prevent post partum haemorrhage.