Intra-operative blood loss during elective lower segment caesarean section

Abstract

Objective: To measure intra-operative blood loss at elective lower segment caesarean section and to compare estimated wtih measured blood loss. Design: Prospective observational study. Blood loss was measured in patients who underwent lower segment caesarean section in the course of routine hospital activity. Setting: Tsan Yuk Hospital (Hong Kong), which is affiliated to the University of Hong Kong, 1990-1991. Subjects: Forty women (mean age 29 years) with singleton pregnancies (mean gestation 38 weeks) delivered by elective lower segment caesarean section under general anaesthesia (mean birth weight 3177 g). Main ontcome measure: Intra-operative blood loss measured by the alkaline haematin method (intra-assay co-efficient of variation 2.2%). Results: The mean measured blood loss was 487 ml (SE 40, range 164-1438). The mean estimated blood loss was 425 ml (SE 31) range 100-1300; mode 400). Observer error in estimating blood loss was higher if measured blood loss > 600 ml. One patient received a blood transfusion and another had a post-operative haemoglobin level < 10.0 g/dl. Conclusion: Blood loss at elective lower segment caesarean section was usually < 500 ml and was estimated with reasonable accuracy. However, there was a tendency to under-estimate blood loss when the measured loss exceeded 600 ml.