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Question 6#

A male patient has a detrusor pressure at maximum flow rate of 70 cm H₂O, a maximum detrusor pressure of 80 cm H₂O and a maximum flow rate of 8 mL/sec. What is his bladder outflow obstruction index?

A. 54
B. 64
C. 72
D. 110
E. 120

Correct Answer is A

Comment:

Answer A

The bladder outlet obstruction index (BOOI) enables classification of patients’ voiding into obstructed, unobstructed or equivocal once calculated numerically and is commonly plotted on the International Continence Society nomogram. This replaces the Abrams-Griffiths number and nomogram.

The BOOI is calculated using the following formula: pdetQ_max –  (2*Q_max)

• pdetQ_max = detrusor pressure at maximum flow rate
• Q_max = maximum flow rate 
• Obstructed if BOOI is >40
• Equivocal if BOOI is 20–40
• Unobstructed if BOOI is <20

Bladder contractility index can also be calculated from these variables to determine ranges of contractility using the following formula: pdetQ_max +  (5*Q_max).

A bladder contractility index of <100 is weak, 100–150 is normal and >150 is strong contractility.