Are conventional pressure-flow measurements dependent upon filled volume?

Objective: To determine, in a prospective study, whether detrusor pressure (p(det.Qmax)) and maximum urinary flow rate (Q(max)) measurements obtained after filling to maximum cystometric capacity (MCC) differ from those obtained with filling restricted to average voided volume (V(void)), as standard protocols for pressure flow studies (PFS) mandate bladder filling until the subject has a strong desire to void, which aids standardization but further divorces the test from real-life experience.

Patients And Methods: After calculating the appropriate sample size, 84 patients attending for PFS with an adequately completed 3-day frequency-volume chart were recruited.

Can bladder outflow obstruction be diagnosed from pressure flow analysis of voiding initiated by involuntary detrusor overactivity?

Purpose: We investigated whether a diagnosis of bladder outflow obstruction could be established from pressure flow analysis of a void initiated by involuntary detrusor overactivity.

Materials And Methods: A total of 79 men with lower urinary tract symptoms were identified prospectively. In each subject 2 sequential pressure flow studies were performed during the same session.