1. What is the Bladder Volume Formula?

The bladder volume formula estimates bladder volume from ultrasound measurements using the ellipsoid formula with a correction factor of 0.52. It provides a quick assessment of bladder volume without invasive procedures.

2. How Does the Calculator Work?

The calculator uses the MDCalc formula:

Where:

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

Explanation: The formula approximates the bladder as an ellipsoid and uses the correction factor to account for the irregular shape.

3. Importance of Bladder Volume Calculation

Details: Bladder volume estimation is crucial for assessing urinary retention, post-void residual volumes, and monitoring bladder function in various clinical settings.

4. Using the Calculator

Tips: Enter all three dimensions in centimeters from ultrasound measurements. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this formula?
A: The formula has about 90% accuracy compared to catheterized volumes when measurements are taken properly.

Q2: What are normal bladder volumes?
A: Normal bladder capacity is typically 300-500 mL, though this varies with age and individual factors.

Q3: When should bladder volume be measured?
A: Common indications include evaluation of urinary retention, post-void residuals, and pre-operative assessment.

Q4: Are there limitations to this formula?
A: Less accurate with irregularly shaped bladders, large diverticula, or when measurements aren't perpendicular.

Q5: What's the clinical significance of post-void residual?
A: Residuals >100-150 mL may indicate incomplete emptying and require further evaluation.