Obstetric blood loss quantification

Lutfi, Ahmed

Obstetric blood loss quantification

dc.check.chapterOfThesis	Chapter 3 (p 49-62), Chapter 5 (p 73-80), Chapter 6 (81-97)	en
dc.contributor.advisor	Greene, Richard A.
dc.contributor.advisor	Higgins, John R.
dc.contributor.author	Lutfi, Ahmed	en
dc.contributor.funder	Stryker
dc.date.accessioned	2025-05-22T14:16:02Z
dc.date.available	2025-05-22T14:16:02Z
dc.date.issued	2024	en
dc.date.submitted	2024
dc.description.abstract	Background The research undertaken for this thesis focuses on the quantification of obstetric blood loss. Obstetric haemorrhage contributes to rising worldwide maternal morbidity and mortality rates. In Ireland, obstetric haemorrhage is the leading cause of Severe Maternal Morbidity (SMM). Accurate and rapid assessment of maternal bleeding status is essential to the diagnosis of obstetric haemorrhage. Obstetric blood loss quantification needs to be standardised as a varying approach to measuring maternal blood loss may lead to a missed or delayed diagnosis. It is possible that currently utilised quantitative methods, namely volumetry and gravimetry, produce inconsistent measurements of maternal blood loss and that an alternative method may be more reliable. The aim of this research was to identify the limitations of currently utilised quantitative methods and to explore novel blood loss quantifying technology. We also aimed to identify the cost of obstetric haemorrhage to aid in future cost-effectiveness studies on novel blood loss quantifying technology. Methods We used a mixed methods approach, utilizing both qualitative and quantitative research methods, to provide a deeper understanding of the cost of obstetric haemorrhage and to study obstetric blood loss quantification. Micro-costing, a research methodology from the social sciences, was used to estimate the cost of obstetric haemorrhage and the cost contribution of blood transfusions used in the management of obstetric haemorrhage in Ireland. In this study, we used a dataset generated from a nationwide cross-sectional study of obstetric haemorrhage from the National Perinatal Epidemiology Centre (NPEC) in Ireland. An observational study of Caesarean births was performed to assess current blood loss quantification practices in Cork University Maternity Hospital (CUMH), which is a tertiary maternity hospital. Through laboratory testing, we compared the blood detecting accuracy of a novel blood loss quantifying device (the Stryker (R) System), developed by Stryker Instruments Innovation Centre, against a reference haematology analyser. In this study, unwanted human whole blood provided by the Irish Blood Transfusion Service was diluted with normal saline to simulate birth waste. We transitioned to clinical testing of the device in Caesarean section patients delivering in CUMH where we compared the device against standard volumetry performed by hospital staff members. The haemoglobin content of the birth waste as measured by a haemoglobinometer was assigned as the standard for the purpose of comparison. Hospital staff feedback of the device was gathered to guide future device modifications and improvements. Results A cost-analysis of obstetric haemorrhage in Ireland estimates that obstetric haemorrhage adds an additional 140% to maternity care costs with blood transfusions contributing to one third to half of this additional cost. We identified that assessments of maternal blood loss following Caesarean birth varied with hospital staff members applying both subjective and objective methods (a hybrid approach) in the majority of cases (84%). Patients classified as high risk of haemorrhage had more objective methods utilized (40%) when compared to patients classified as low or medium risk (19% and 7% respectively). A pilot study evaluating the accuracy the Stryker (R) System against a reference haematology analyser showed that the device is accurate in measuring haemoglobin concentrations (g/dL) of fluid mixtures. Bland-Altman analysis in this study demonstrated 95% limits of agreement of –0.96 to 1.03 g/dL. An early feasibility study of the Stryker (R) System’s performance in Caesarean section births showed that the device offered more accurate measurements of maternal blood loss when compared with volumetry done by hospital staff. Bland-Altman analysis produced mean biases of 0.236 +/- 1.213 g/dL and -0.661 +/- 1.458 g/dL for the device and staff measurements respectively when compared against the haemoglobinometer. The width of the limits of agreement at 95% confidence was narrower for device measurements than staff measurements (4.519 g/dL and 5.715 g/dL respectively). The device’s measurements of haemoglobin content correlated more strongly with the haemoglobinometer rather than hospital staff measurements (Spearman correlation coefficients of 0.881 and 0.635 respectively). This suggests that the device is more accurate in determining the blood content of the birth waste than hospital staff volumetric measurements. Lastly, a mean System Usability Scale (SUS) score of 82 +/- 13 suggests that the device is highly usable. Conclusion This thesis sheds light on the critical issue of obstetric blood loss quantification. The research highlights the financial burden of obstetric haemorrhage on the healthcare system. Furthermore, it reveals the current inconsistencies and subjectivity in assessing maternal blood loss. This research underscores the necessity for standardized, accurate, and rapid quantification methods to ensure timely diagnosis and management of obstetric haemorrhage. It sets the stage for future advancements in obstetric care, emphasizing the importance of incorporating novel technologies to enhance patient outcomes and mitigate the global affliction of obstetric haemorrhage.	en
dc.description.status	Not peer reviewed	en
dc.description.version	Accepted Version	en
dc.format.mimetype	application/pdf	en
dc.identifier.citation	Lutfi, A. 2024. Obstetric blood loss quantification. MD Thesis, University College Cork.
dc.identifier.endpage	134
dc.identifier.uri	https://hdl.handle.net/10468/17567
dc.language.iso	en	en
dc.publisher	University College Cork	en
dc.rights	© 2024, Ahmed Lutfi.
dc.rights.uri	https://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject	Obstetric haemorrhage	en
dc.subject	Blood loss quantification	en
dc.subject	Cost analysis	en
dc.subject	Medical device	en
dc.title	Obstetric blood loss quantification
dc.type	Doctoral thesis	en
dc.type.qualificationlevel	Doctoral	en
dc.type.qualificationname	MD - Doctor of Medicine	en