Comparison of pain during two methods of urine collection in preterm infants

Suprapubic aspiration (SPA) and urine catheterization (UC) are performed frequently in preterm neonates to rule out urinary tract infection; however, a comparison of the pain caused by both procedures has not been made previously.

To compare pain responses in preterm infants who are undergoing urine collection by using SPA versus UC.

Prospective, single-blind, randomized clinical trial was conducted in 2 NICUs. Preterm infants who required urine samples for microbiologic analysis were randomly assigned to undergo either SPA or UC. The infants' facial and physiologic responses were videotaped during the procedure and later scored by a research assistant who was blind to the method of urine collection. The primary outcome measure was facial-grimacing during the procedure, which was assessed by measuring the percentage of time the infants displayed brow-bulging. Secondary outcomes included changes in heart rate (beats per minute), oxygen saturation (%), and procedural success rate.

Forty-eight preterm infants participated. Characteristics did not differ (P > .05) between groups. The mean (SD) percent brow-bulging score was higher in the SPA group than in the UC group (67% [34] vs 42% [38]; P = .02). Heart rate and oxygen saturation did not differ (P = .50 and .74, respectively). The procedure-success rate, although lower in the SPA group, was not statistically different (60% vs 78%; P = .17).

SPA was more painful than UC, as assessed by brow-bulging, and had a tendency to be associated with a higher rate of procedure failure. These findings should be taken into consideration when choosing between these 2 procedures for preterm infants who undergo urine sampling.