The calculation and comparison of the Detrusor Contractility Parameter and Watts Factor
Andrew Gammie1, Darryl Kitney2, Marcus Drake1
1Bristol Urological Institute, Southmead Hospital, Bristol, UK.
Aims:
To test the significance of association between a validated index of detrusor contractility, vCE , the Watts Factor, and the Detrusor Contractility Parameter, t20-80 ; and to test whether t20-80 depends on outflow tract resistance as indicated by Bladder Outlet Obstruction Index (BOOI).
Methods:
Thirty-seven pressure-flow traces from 20 male and 17 female patients were analyzed and forms of the Watts Factor, t20-80 and BOOI were compared with vCE .
Results:
The Detrusor Contractility Parameter, t20-80 , is significantly associated with vCE for both women and men without a high degree of bladder outlet obstruction. The Watts Factor only had a significant association with vCE at the point of maximum flow in women.
Conclusions:
The Detrusor Contractility Parameter (DCP) (t20-80 ), can be measured easily from the pressure flow curves of a urodynamic test. The Watts Factor at maximum urine flow, WFQmax , can be readily calculated, but is only applicable to women. In both women and men without a high degree of bladder outlet obstruction, DCP is better associated with true detrusor contractility than any Watts Factor analysis.
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