Comparing suprapubic urine aspiration under real-time ultrasound guidance with conventional blind aspiration

To determine the optimal method of suprapubic aspiration (SPA), the success rates of real-time ultrasound-guided SPA were compared with those of conventional SPA, and factors associated with success were studied. Thirty infants were randomly allocated to group A (for real-time ultrasound-guided SPA) and 30 infants to group B (for blind SPA with a prehydration protocol). The results showed that the overall success rates for all attempts were similar (26/30 or 87% in group A vs 24/30 or 80% in group B, p > 0.05). The first attempts in both groups were equally successful (both 18/30 or 60%). In comparison with failed attempts, successful ultrasound SPA attempts were associated with a greater bladder depth (mean +/- SD: 28 +/- 11 vs 21 +/- 5 mm, p < 0.01), length (32 +/- 12 vs 23 +/- 9 mm, p < 0.05) and volume (17 +/- 13 vs 8 +/- 6 ml, p < 0.01), but similar width (33 +/- 9 vs 29 +/- 5 mm, p > 0.05). In blind SPA, successful attempts were associated with the presence of bladder dullness on percussion (odds ratio 29).

This study confirms that ultrasound-guided SPA has a high success rate. Blind SPA could also be equally successful with appropriate preparation. Ultrasound-guided SPA is recommended when the bladder depth exceeds 3 cm, or the bladder length exceeds 3.7 cm. If an ultrasound machine is not available, blind SPA may be an alternative, with attention being paid to prehydration and the demonstration of bladder dullness by percussion.