Use of ultrasound bladder monitoring in children after caudal anaesthesia

Ultrasonographic Assessment of Bladder Volumes in Children Undergoing Penile Surgery: Does the Type of Anesthesia Matter?

BACKGROUND

There are scant data reporting postoperative ultrasonographically measured bladder volumes in children undergoing penile surgery.

STUDY QUESTION

We studied the effect of various anesthesia techniques on return of micturition after penile surgery in children, using ultrasonographically measured bladder volumes.

DATA SOURCES

Ultrasonographically measured postvoiding residual bladder volumes indexed to age-appropriate capacity, and time elapsed between the end of surgery and spontaneous voiding after pediatric circumcision, distal hypospadias repair, or repair of urethrocutaneous fistula, were studied.

STUDY DESIGN

Children between 4 months and 12 years were randomized to caudal block, intravenous (IV) fentanyl or penile block, in association with inhaled general anesthesia. Bladder volumes were measured before surgery and immediately after voiding for the first time. Time to first postsurgery void was also recorded.

RESULTS

Thirty-one children completed all assessments; 12 underwent caudal block, 9 IV fentanyl anesthesia, and 7 were given penile block. The mean first postvoid bladder residual volumes were highest in the caudal and lowest in the penile block children (27.5 vs. 17.3 mL, P = 0.003). The time elapsing between the end of surgery and first voiding was the longest in the fentanyl group compared with caudal and penile blocks (232, 178, 150 minutes, respectively, P = 0.02).

CONCLUSIONS

None of the anesthetic techniques provoked postoperative urinary retention after minor penile surgery in children. The penile block appears superior to caudal block or to IV fentanyl-based anesthesia with regard to postoperative recovery of normal micturition.

Monitoring urinary bladder volume and detecting post-operative urinary retention in children with an ultrasound scanner

BACKGROUND

Post-operative urinary retention (PUR) is associated with a risk of over-distension and permanent detrusor damage. The prevention of PUR by routine catheterization may increase the risk of urinary tract infection. Post-operative monitoring of the bladder volume is a reliable method in adults, but has not been evaluated for reliability in children.

METHODS

Forty-eight patients who, according to current clinical guidelines, required urinary bladder emptying were scanned before catheterization using the Bladderscan. Volumes estimated with ultrasound were compared with volumes measured after emptying the bladder with a catheter. Bladder emptying was controlled by concomitant fluoroscopy in 20 children.

RESULTS

The mean difference between the ultrasound estimates and the catheter-emptied urine volumes was 4 ml [standard deviation (SD) = 25 ml] in 26 children above the age of 3 years and -18 ml (SD = 19 ml) in 22 younger children. In the subpopulation in whom complete bladder emptying could be confirmed by fluoroscopy (14 children; median age, 3 years; range, 1-11 years), the mean difference between the ultrasound estimates and the catheter-emptied volumes was -11 ml (SD = 24 ml).

CONCLUSIONS

This study confirms agreement between the ultrasound scanner estimates of urinary bladder volume and the urine volume measured by emptying the bladder. Reliability was good in children above the age of 3 years. The volume was underestimated in younger children. Thus, routine monitoring of urinary bladder volume with an ultrasound scanner is a non-invasive, pain-free and reliable way of preventing over-distension of the urinary bladder in children after surgery and other procedures under general anaesthesia.