Use of a portable ultrasound device to measure post-void residual volume among incontinent nursing home residents.

Objective: To determine the accuracy of a portable ultrasound device for the assessment of post-void residual (PVR) volume among incontinent nursing home (NH) residents.

Design: Prospective, clinical series.

Setting: Seven community-based nursing homes.

Study Population: Two hundred one consecutively assessed incontinent NH residents who were participating in a larger clinical trial.

Measurements: PVR volumes measured by trained research associates using a portable ultrasound device and by in-and-out catheterization were compared. The accuracy of the ultrasound was calculated using the volume obtained by catheterization as the gold standard.

Results: The ultrasound demonstrated excellent test-retest and interrater reliability. For low PVRs, the device was highly sensitive (.90) for PVR < 50 mL and .95 for PVR < 100 mL) and moderately specific (.71 for PVR < 50 mL and .63 for PVR < 100 mL). For PVRs of more than 200 mL (n = 26), the ultrasound had a sensitivity of .69 and a specificity of .99.

Conclusion: The portable ultrasound we used was reliable and reasonably accurate for assessing PVR in a representative sample of incontinent NH residents. Because the sensitivity for clinically significant urinary retention (PVR > 200 mL) was only .69, repeated measurements may be necessary to exclude high PVR in individual NH residents. Recent changes in ultrasound design should improve its ease of use and accuracy. Although measuring PVR by ultrasound is much easier and more comfortable than catheterization for both NH residents and staff, the cost of the device may be a barrier to its widespread use in the NH setting.