Twelve-hour daytime observation of voiding pattern in newborns less than four weeks of age, "Beyond the Abstract," by Jian Guo Wen, Yrjö T. Konttinen, and Yan Chen

BERKELEY, CA (UroToday.com) - The newborn is located in a very early period of voiding pattern development, and this period marks the transition from the fetal bladder contraction phase to voluntary infant urination. However, the voiding patterns and urodynamics parameters in newborns less than 4 weeks of age are still rarely studied.

bta iian guo wenThe non-invasive method to assess voiding function in infants is widely applied, and 4-hour voiding observation period has been most popular in the investigation of infants suspected to have bladder dysfunction.[1] It is unclear whether such a short observation period is really suitable for neonates. To obtain a more comprehensive idea of voiding patterns, we followed healthy neonates from birth to their 28th day of life using 12-h daytime observations. And at last, our results indicated that to obtain reliable data, it is necessary to use 12-h periods in newborns <1 day old. It was found that voids were not evenly distributed, sometimes neonates voided once or twice per hour, but the had over 4-h long pauses in voiding. As newborns are fed less at night, the relative frequency of nocturnal urination is probably lower than that of the daytime urination. In our study setting, the observation period ran from 9 a.m. to 9 p.m., mainly to be compatible with the care and feeding schedule, and also so as to not disturb the normal night sleep.

Precise recording of the voiding pattern in the newborn is not easy. Feeding, i.v. fluid supply, etc. may affect the voiding frequency (VF), voiding volume (VV) and voiding pattern in general. In our study, we used the same environments, same feeding and ⁄ or i.v. fluid supply protocol to minimize their effects on the voiding pattern recording.

In our research of the voiding parameters, VV was measured as the change of diapers weight before and after voiding by a microelectronic balance (accuracy 0.1 g) (LD1102; Dragon, Shenyang, China; PRV was measured (diameter x width x thickness x 0.5) by B ultrasound (accuracy 0.3 mm; LOGIQ400; GE, Fairfield, CT, USA); awake voiding (AV) was defined as movements like opening of the eyes, body movement, crying, and facial expression changes at voiding or peri-voiding.

In our research, we found that VV of the full-term neonates increased at two occasions, at day 4 and at day 28, while in preterm neonates it increased only once, at day 28. This observation is consistent with earlier report that VV increased significantly with age, but the temporal profile of the maturation of the voiding pattern has not been described before.[2] VV was higher in the full-term than in preterm newborns at days 4, 7, 14 and 28. This may relate to the weight and development of the neonates. VF was increased in the full terms and preterms from day 4 to 7, and logically, the interval between voidings was shortened from 2 to 1.5 h. These results are seemingly at odds with earlier reports on voiding once per hour. However, the use of 12-h observation periods disclosed that the voids are not evenly distributed over the observation period. Sometimes, voiding was reported once or twice an hour, followed by a longer period without voiding. At day 28, VF was lower in full terms than in preterms. Apparently, the full-term neonates have reached a more developed and controlled phase in their bladder development than the preterm neonates.

Voiding pattern of preterm vs. full-term subjects is characterized by an increased number of interrupted voids, further indicating immature detrusor–sphincter coordination. The changing PRV values over time in the full-term neonates indicate that their bladder is developing more quickly than in the preterms. PRV increased when the capacity of the bladder increased rapidly. The subsequent PRV reduction may reflect voiding maturation. Finally, PRV increased again in the late newborn stage and indicates a second increase in the bladder volume upon bladder maturation. Such statistically significant fluctuations lacked in the preterm neonates, probably because they are less developed, and changes in bladder volume are not so prominent. Bladder empty percentage was higher in the full terms at day 28 coincident with less frequent intermittent voiding, which confirms the more rapid voiding pattern development in the full-term than in the preterm neonates.

The meaning of the state of the consciousness at voiding, asleep or awake, is an everlasting controversy. We defined awake voiding (AV) as movements like opening of the eyes, body movement, crying and facial expression changes at voiding or peri-voiding. This approach is convenient and useful to the clinical practice. But in our on-going research, we apply the electroencephalogram (EEG) to define asleep or awake status more clearly.

Using this convenient approach, AV was observed in 30% of pre-terms, while the corresponding value was nearly 60% in full-terms. This indicates that the central nervous system is to some degree already involved in the control of urination early during human development but not that voiding in neonates would be a conscious or voluntary act, only that the voiding reflex also affects cortical events.

Based on the present limited number of cases, the 12-h recording seems necessary for evaluation of voiding function in newborns.

References:

  1. Holmdahl G, Hanson E, Hanson M, Hellstrom AL, Hjalmas K, Sillen U. Four-hour voiding observation in healthy infants. J Urol 1996; 156: 1809–12.
  2. Duong TH, Jansson UB, Holmdahl G, Sille´n U, Hellstrom AL. Development of bladder control in the first year of life in children who are potty trained early. J Pediatr Urol 2010; 6: 501–5.

 


Written by:

Jian Guo Wen,a, * Yrjö T. Konttinen,b and Yan Chena as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

a Pediatric Urodynamic Center, Department of Urology, Institute of Clinical Medicine, First Affiliated Hospital of Zhengzhou University, China

bDepartment of Medicine, Institute of Clinical Medicine Helsinki University, Finland 

*Jian Guo Wen, MD(CHN), PhD(DK)
Prof.of Pediatric Urology/incontinence
Chairman of Institute of Clinical Research
Head of Urodynamic Center
The First Affiliated Hospital of Zhengzhou University
Zhengzhou City, 450052
China


 

Twelve-hour daytime observation of voiding pattern in newborns less than four weeks of age - Abstract

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