Chernov A. Optimizing the measurement and assessment of blood loss in third stage of labor and postpartum period.

The thesis is devoted to solving current challenge of contemporary obstetrics -development of effective approach to early recognition of abnormal postpartum blood loss, improving the accuracy of its volume measurement and individualized assessment of its hemodynamic significance. The rate of PPH diagnosis directly depended on method of blood loss estimation is used: direct measurement - 14.3%, gravimetric method - 11.9% and visual estimation - 2.4%. Using direct measurement as a gold standard visualy estimated blood loss had 16.6% sensitivity and 81.1% accuracy and gravimetric method had 83.3% sensitivity and 97.6% accuracy in detecting PPH. Thorough collection of blood within 2 hours after vaginal birth showed that total blood loss of ? 500 ml and ? 1000 ml had 23.8% and 4.8% women respectively. Among the reasons of PPH factor "Trauma" was found in the majority of cases - 83.3%. However the biggest average volume of blood loss was associated with factors "Tone" (1000±200 ml) and "Tissue" (812.5±82.6 ml). Women lost ?500 ml of blood within 2 hours postpartum had hemodynamic deterioration (58.3%) only if >10% of calculated pregnancy blood volume or/and >0.8% of body mass was lost. Visual estimation was shown to be the most prevalent method of postpartum blood loss assessment after vaginal birth. Reporting of blood loss had a stereotype format. Traditional visual estimation (TVE) is used in a "quantitative" style and grossly underestimates postpartum blood loss. An accuracy of the estimate decreased with an increase in blood volume. Sensitivity of TVE was high for volumes?300 ml (53% - 92%) and low for clinically sufficient blood volumes ?500 ml (?18%). A proposed new "semi-quantitative" method of visual blood loss estimation (SQVE) demonstrated high accuracy of estimates for both low and high blood volumes (60% - 100%). The results of SQVE could be significantly improved by simulation training (р<0,001). Early recognition and timeliness of clinical response to abnormal postpartum blood loss was provided in 83%, 33% and 60% cases of PPH by direct measurement, TVE and SQVE respectively. New classification of postpartum blood loss and algorithm of measurement and assessment of blood loss in third stage of labor and postpartum period were proposed.