Early feasibility and usability study of a novel obstetric blood loss quantifying device

Abstract

Objective

To study the accuracy and usability of a novel obstetric blood loss quantifying tool in clinical settings.

Methods

A mixed-methods study was conducted in an Irish tertiary maternity unit. The accuracy of measuring the blood content (hemoglobin concentration) of elective Caesarean section birth waste with a novel obstetric blood loss quantifying device was compared, using Bland-Altman and correlation analysis, with staff volumetry and a reference hemoglobinometer. Hospital staff (nurses, midwives and doctors) opinion of the usability of the device was studied by an anonymous questionnaire which generated a System Usability Scale (SUS) score. SUS scores range from 0 to 100 with higher scores reflecting greater usability.

Results

The device was used by 19 different hospital staff members (nine nurses, four midwives and six doctors) in 19 elective Caesarean deliveries that had varying levels of PPH risk. Bland-Altman analysis produced mean biases of −0.7 ± 1.5 g/dL and 0.2 ± 1.2 g/dL for the device and staff measurements respectively. The width of the limits of agreement was narrower for device measurements than for staff measurements (4.5 g/dL and 5.7 g/dL respectively). The device’s measurements of hemoglobin content correlated more strongly with the hemoglobinometer rather than with hospital staff measurements (Spearman correlation coefficients of 0.9 and 0.6 respectively). This suggests that the device is more accurate in determining the blood content of the birth waste than hospital staff volumetric measurements. Hospital staff members assigned the device a mean SUS score of 82 which suggests that the device is highly usable.

Conclusion

An early feasibility study in clinical settings suggests that a novel device for quantifying obstetric blood loss was more accurate than volumetry in measuring the hemoglobin content of birth waste. Health professionals also found the device highly usable. This data suggests that there is much potential in transitioning from a “human-made” to a “machine-made” assessment of blood loss. Future studies will entail additional testing of the device to assess its impact on the morbidities associated with postpartum hemorrhage.