Postmicturition catheterization is the usual method for assessment of
postoperative residual urine volume. Ultrasonography, though noninvasive,
comfortable and safe compared with catheterization, is still accused
as being inaccurate. The present study attempted to revive the ultrasound
method by improving its accuracy through the usage of the
combined formulae for volume estimation of the ellipsoid utilizing the
most reliable measurement parameters. One hundred and fifty postoperative
female patients were investigated. The ultrasound-estimated volumes
were compared with the actual volumes measured following catheterization.
Nonsignificant differences were detected at volumes between 100
c.c. and 300 c.c. (P>0.05). Significant differences were detected at urine
volumes below 100 c.c. (P<0.01). Such error was not due to missing positive
cases (sensitivity 100% ), but was due to underestimation in 8.9% of
cases with urine volumes larger than 100 c.c. (specificity 91.1%) . Similarly,
though the sensitivity of ultrasound was 100 % at volumes above
300 c. c., significant differences were detected between ultrasonography
and catheterization (P <0.05) . This was due to overestimation in 2.1%
of cases with urine volumes less than 300 c.c. (specificity 57.9%).
Through the usage of the present calculation method, ultrasonography
may, therefore, be considered an accurate method of estimation of postoperative
residual urine volume. |
