1. What is Bladder Volume Calculation?

The bladder volume calculation estimates urine volume in the bladder using ultrasound measurements of length, width, and height. It's commonly used in urology and nephrology to assess urinary retention or post-void residual volume.

2. How Does the Calculator Work?

The calculator uses the bladder volume formula:

Where:

• \( Length \) — Longest dimension of bladder (cm)
• \( Width \) — Perpendicular to length (cm)
• \( Height \) — Anteroposterior measurement (cm)
• \( 0.52 \) — Correction factor for ellipsoid shape

Explanation: The formula approximates the bladder as an ellipsoid and applies a correction factor (0.52) to account for its actual shape.

3. Importance of Bladder Volume Measurement

Details: Accurate bladder volume measurement helps diagnose urinary retention, assess post-void residual, evaluate bladder function, and guide catheterization decisions.

4. Using the Calculator

Tips: Enter measurements in centimeters from ultrasound imaging. All values must be positive numbers. For best accuracy, measurements should be taken when the bladder is moderately full.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this calculation?
A: The formula has about 85-90% accuracy compared to actual catheterized volumes in most patients.

Q2: What is a normal bladder volume?
A: Normal capacity is typically 300-500 mL, but varies by individual. Post-void residual >100 mL may indicate retention.

Q3: When should bladder volume be measured?
A: Common indications include evaluation of urinary retention, monitoring post-void residual, or assessing bladder capacity.

Q4: Are there limitations to this calculation?
A: Less accurate with irregularly shaped bladders, very large volumes (>1000 mL), or when measurements are not taken at right angles.

Q5: Can this be used for pediatric patients?
A: Yes, but normal volumes are much smaller in children (approximately 30 mL + (age in years × 30) for expected capacity).