The validity of Visual Blood Loss Estimation in Postpartum Hemorrhage in Shanghai Hospitals: A Web-based Survey (Preprint)
BACKGROUND Postpartum Hemorrhage has been recognized as the most fatal factor in maternal death. Yet midwives can barely distinguish whether the blood loss has reached a life-threatening amount without precise measurement, particularly during a slow hemorrhage. Also, understaffed midwives in mainland China adds to the difficulty of timely accurate measurement of blood loss. OBJECTIVE To evaluate the accuracy of visual estimated blood loss in postpartum hemorrhage by clinical midwives, as well as the reproducibility of the visual estimation and influencing factors on accuracy. METHODS With a modified on-line visual estimation questionnaire of blood loss, a cross-sectional multicenter study was conducted among voluntary midwives or obstetrical nurses engaged in clinical practice in secondary and tertiary hospitals in Shanghai. A descriptive analysis was performed with demographic features and the rate of accurate responses. The Kappa coefficient was employed to determine the reproducibility of the agreement of visual estimation. The correlations between demographics and items of the questionnaire were conducted with Chi-square test and Spearman correlation analysis. RESULTS A total of 281 midwives and nurses participated in the survey. The finding showed relatively low accuracy and reproducibility of visual estimation, with 25.6% and 17.8% subjects in Shanghai hospitals distinguishing the postpartum hemorrhage (500ml) and the severe postpartum hemorrhage (1000ml), respectively. The Kappa coefficients were slight to moderate (0.062~0.450). The institutional routine for blood loss calculation turned out to be relevant to the accuracy of visual estimation. CONCLUSIONS Visual estimation cannot provide sound validity for blood loss evaluation in postpartum hemorrhage in China, especially when the amount exceeds 500ml. Institutions should make routines on how blood loss can be reckoned with the sterile drapes and gauzes they use, and provide regular training for midwives and nurses.