Assessing the inter-rater reliability of (Uscan) bladder scanner during pregnancy and following childbirth

Mary Steen, Belinda Lovell, Adrian Esterman

Research output: Contribution to journalArticlepeer-review


tudy background. Evidence suggests that bladder-scanner findings used for maternity care can be inaccurate. Therefore, to address the inaccuracies reported, a newly designed scanner (Uscan) with real-time ultrasound and editing functions has been developed. This article will describe and discuss the inter-rater reliability of this bladder scanner during late pregnancy and the early postnatal period. It is essential to assess its accuracy, reliability and usability as there are potential benefits to women, such as a reduction in the number of urinary catheters inserted and then the avoidance of the negative sequela that often follows. Research to test the latest technology in bladder scanners and scanning is urgently required. Objective. To assess inter-rater reliability of a bladder scanner (Uscan) during late pregnancy and the early postnatal period. Method. Following ethical approval, inter-rater reliability testing of the (Uscan) bladder scanner commenced at the Women’s and Children’s hospital in Adelaide, South Australia. It took place in July 2016 (antenatal), January 2017 (postnatal) and June 2017 (antenatal). The testing involved two midwives scanning pregnant and newly birthed women to compare urine volumes measured using the Uscan bladder scanner. The results were compared for inter-rater reliability between two midwives/assessors. Findings. Initially, the inter-rater reliability testing was conducted on 12 pregnant women, and these preliminary results demonstrated that the (Uscan) bladder scanner was unreliable. This instigated further technology development and technicians altered the algorithms and improved the editing function to combat the problems identified. The bladder scanner was then re-tested on pregnant women and the results showed an intraclass correlation coefficient (ICC) of 0.98 (95% CI 0.94-0.99). The bladder scanner was then tested for inter-rater reliability on 12 newly birthed mothers and results demonstrated that the scanner was also reliable for use postnatally. The ICC between two raters was found to be 0.97 (95% confidence interval 0.833-1.00). Conclusion. A high inter-rater reliability score was achieved both antenatally and postnatally after learning from initial reliability testing of the (Uscan) bladder scanner, which prompted further development work that involved altered algorithms and improved editing functions. There is potential to use the (Uscan) bladder scanner in midwifery clinical practice to assess bladder volume. Using the scanner may lead to a decrease in the number of urinary catheters used during the childbirth continuum. A decrease in use of urinary catheters will reduce the associated risk of urinary tract infections (UTIs), urethral trauma, uncomfortable sensation and embarrassment for women, which collectively has an impact upon healthcare costs, length of hospital stay and family separation. Further research is indicated to assess the impact of utilising the Uscan bladder scanner in a clinical trial.
Original languageEnglish
Article number4
Pages (from-to)113-120
Number of pages8
JournalEvidence Based Midwifery
Issue number4
Publication statusPublished - 2019


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