1. What is Bladder Volume Calculation?

The bladder volume calculation estimates urine volume in the bladder using ultrasound measurements. It's commonly used in urology and emergency medicine to assess urinary retention or post-void residual volume.

2. How Does the Calculator Work?

The calculator uses the ellipsoid formula:

Where:

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

Explanation: The formula approximates bladder volume by treating it as an ellipsoid shape, with the correction factor accounting for the irregular shape.

3. Importance of Bladder Volume Measurement

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

4. Using the Calculator

Tips: Enter all three dimensions in centimeters as measured by ultrasound. Measurements should be taken with the bladder at maximal distension for most accurate results.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is ultrasound bladder volume measurement?
A: Generally within ±15-20% of actual volume when proper technique is used. Most accurate for volumes >100mL.

Q2: What is considered a normal bladder volume?
A: Normal capacity is typically 300-500mL in adults. Post-void residual should be <50mL in most cases.

Q3: When should bladder volume be measured?
A: When assessing for urinary retention, evaluating incomplete emptying, or before catheterization decisions.

Q4: Are there limitations to this calculation?
A: Less accurate for very small volumes, irregularly shaped bladders, or when measurements aren't taken at maximal distension.

Q5: What's the clinical significance of post-void residual?
A: Elevated post-void residual may indicate bladder outlet obstruction, neurogenic bladder, or detrusor underactivity.