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References

1. Sullivan R, Baston CM. When Not to Trust the Bladder Scanner. The Use of Point-of-Care Ultrasound to Estimate Urinary Bladder Volume. Ann Am Thorac Soc. 2019 Dec;16(12):1582–4.
2. Taus PJ, Manivannan S, Dancel R. Bedside Assessment of the Kidneys and Bladder Using Point of Care Ultrasound. POCUS J. 2022 Feb 1;7(Kidney):94–104.
3. Dessie A, Steele D, Liu AR, Amanullah S, Constantine E. Point-of-Care Ultrasound Assessment of Bladder Fullness for Female Patients Awaiting Radiology-Performed Transabdominal Pelvic Ultrasound in a Pediatric Emergency Department: A Randomized Controlled Trial. Annals of Emergency Medicine. 2018;72(5):571-580. doi:1016/j.annemergmed.2018.04.010
4. O’Brian RA, Firan A, Sheridan MJ, Kou M, Place RC, Chung CH. Bladder Point-of-Care Ultrasound: A Time Saver in the Pediatric Emergency Department. The Journal of Emergency Medicine. 2021;61(3):e32-e39. doi:1016/j.jemermed.2021.04.010
5. Ho-Gotshall S, Wilson C, Jacks E, Kashyap R. Handheld Ultrasound Bladder Volume Assessment Compared to Standard Technique. Cureus [Internet]. 2024 Jul 16 [cited 2025 Apr 10]; Available from: https://www.cureus.com/articles/180394-handheld-ultrasound-bladder-volume-assessment-compared-to-standard-technique
6. Medical Advisory Secretariat. Portable bladder ultrasound: an evidence-based analysis. OntarioHealth TechnologyAssessmentSeries 2006; 6(11)
7. Akca Caglar A, Tekeli A, Karacan CD, Tuygun N. Point-of-Care Ultrasound-Guided Versus Conventional Bladder Catheterization for Urine Sampling in Children Aged 0 to 24 Months. Pediatr Emerg Care. 2021 Aug;37(8):413–6.
8. Chen L, Hsiao AL, Moore CL, Dziura JD, Santucci KA. Utility of Bedside Bladder Ultrasound Before Urethral Catheterization in Young Children. Pediatrics. 2005 Jan 1;115(1):108–11.
9. Marzuillo P, Guarino S, Capalbo D, et al. Interrater reliability of bladder ultrasound measurements in children. Journal of Pediatric Urology. 2020;16(2):219.e1-219.e7. doi:10.1016/j.jpurol.2019.12.015
10. Ma J, Mateer J. Ma and Mateer’s Emergency Ultrasound. 4e ed. USA: McGraw Hill; 2021
11. Jade Deschamps, Vi Dinh. Bladder Ultrasound Made Easy: Step-By-Step Guide [Internet]. POCUS 101. Available from: https://www.pocus101.com/bladder-ultrasound-made-easy-step-by-step-guide/
12. Lim LY, Chang SJ, Yang SSD. Age- and gender-specific normal post void residual urine volume in healthy adolescents. J Pediatr Urol. 2023 Aug;19(4):367.e1-367.e6.
13. Chang S, Chiang I, Hsieh C, Lin C, Yang SS. Age‐ and gender‐specific nomograms for single and dual post‐void residual urine in healthy children. Neurourol Urodyn. 2013 Sep;32(7):1014–8.
14. Chang SJ, Yang SSD. Variability, Related Factors and Normal Reference Value of Post-Void Residual Urine in Healthy Kindergarteners. J Urol. 2009;182(4S):1933-1938. doi:10.1016/j.juro.2009.02.086

Summary

> The bladder appearance and position vary depending on fullness

> The bladder is an anechoic structure. It should be evaluated in both the transverse and longitudinal orientation.

> Bladder volume calculation requires three unique measurements

>> Length – sagittal plane

>> Depth (height) – sagittal or transverse plane

>> Width – transverse plane

> PVR greater than 10% of the pre-void bladder volume estimated bladder capacity is generally considered abnormal

Pitfalls & Challenges

• Inadequately distended bladders can be difficult to visualize
• The variety of bladder shapes leave volume measures as estimates rather than an absolute calculation
• Difficulty visualizing the Foley catheter: If the catheter is mispositioned, it can be challenging to visualize its proper placement via POCUS
• Bladder injury or rupture following trauma can be difficult to assess with PoCUS, as subtle injuries may not be easily detected, and the bladder may be challenging to visualize if there is significant free fluid accumulation or if the bladder shape is disrupted.

Elevated Post-Void Residual

Bladder capacity and PVR volumes increase with age and can vary by gender [12,13]. As such, no single cutoff defines an elevated PVR in all pediatric patients. However, a PVR greater than 10% of the pre-void bladder volume estimated bladder capacity is generally considered abnormal and warrants further investigation [14]. Clinical judgment remains essential, as acceptable PVR values may vary depending on the child’s age, gender, bladder capacity and individual clinical context. Always refer to your institution’s local guidelines for specific reference ranges.

 

Debris

Debris within the bladder lumen in non-catheterized patients is not considered normal and may indicate an underlying issue. Additionally, dense debris (seen as echogenic masses or clumps within the bladder) in catheterized patients is also not considered normal and may suggest complications such as infection, bladder stone formation, or catheter-related obstruction.

 

Residual bladder fullness post catheterization

If the bladder remains distended after catheter drainage, it may indicate that the Foley catheter is either obstructed or mispositioned, preventing complete drainage (Figure 15).

*Residual fluid within the bladder would only be normal if the catheter has been intentionally clamped for bladder filling.

 

Foley balloon mispositioning

If the Foley catheter is not visualized within the bladder lumen, it may be mispositioned outside the bladder, in the urethra, or in adjacent structures, which could interfere with proper drainage and function (Figure 16).

 

Figure 15: Distended bladder despite Foley catheter in situ, suggesting the catheter is clamped or obstructed. Video courtesy of Dr. Dave Kirschner, used with permission.

 

Figure 16: Sagittal image of the bladder with foley catheter in the urethra. Image courtesy of Dave Kirschner, used with permission.