Is bladder voiding in sleeping preterm infants accompanied by arousals?

doi:10.1016/j.sleep.2007.03.017

Sleep Medicine

Volume 9, Issue 2, January 2008, Pages 137-141

https://doi.org/10.1016/j.sleep.2007.03.017 Get rights and content

Abstract

Background

As it has been reported that bladder voiding in sleeping full-term infants is consistently accompanied by a cortical arousal, it was the aim of the present study to find out whether this could also hold true for preterm infants.

Methods

Polygraphic recordings were performed in 21 healthy preterm infants (10 female). The infants’ gestational age at birth was 31 ± 2.7 weeks and postnatal age at study entry was 26 ± 8 days (mean ± standard deviation). Bladder voiding was recorded by an adapted enuresis detector which was connected to the polygraphic computer unit. Arousals were defined as suggested by the International Paediatric Work Group on Arousals.

Results

Bladder voiding was recorded 50 ± 7 min after sleep onset and occurred during quiet sleep (QS) only. Heart rate (HR), respiratory frequency (RF) and electroencephalographic (EEG) frequency did not change during bladder voiding. Body movements were recorded in 52% of all preterm infants.

Conclusion

We found that bladder voiding was not accompanied by arousals, suggesting that the arousal process in preterm infants may be delayed due to immaturity.

Introduction

It was previously assumed that bladder voiding in infants is induced by a constant bladder-filling volume and that it is not influenced by the brain, and is, therefore, independent of behavioural state. Recently, however, it was shown that the neonatal brain is involved in the regulation of bladder function [1], [2].

Furthermore, it has been shown that bladder voiding in sleeping infants is consistently accompanied by a cortical arousal, reflected by body movements, increase in heart rate (HR) and an increase in electroencephalographic (EEG) frequency [3]. This arousal may be considered to be a short and incomplete change in behavioural state [4]. Arousal from sleep is an important protective response to a life-threatening event. One of the current leading hypotheses to explain sudden infant death syndrome (SIDS) is a failure of the infants to arouse [5]. Supporting this idea is the finding that one of the few indicators in prospective studies that distinguish infants who subsequently died of SIDS from healthy infants was the occurrence of fewer body movements during sleep in the SIDS infants, indicating fewer episodes of spontaneous arousal [6].

As cortical arousals during bladder voiding have been described in full-term infants at the age of one month and as the actual literature lacks any information about whether this could also hold true for preterm infants, it was the aim of this study to find out whether bladder voiding in sleeping preterm infants is accompanied by any arousal reaction.

Section snippets

Subjects

Polygraphic recordings were performed during undisturbed daytime naps in 21 healthy preterm infants (10 female, 11 male). The infants’ gestational age at birth was 31.6 ± 2.7 weeks and postnatal age at study entry was 26 ± 8 days; birth weight was 1698 ± 492 g and actual weight at study entry was 2062 ± 250 g (mean ± standard deviation). None of these preterm infants showed any neurological deficits at the time of polygraphic recording. Apgar scores 1, 5, and 10 min after delivery were 8.57 (±0.17), 9.90

Results

Mean polygraphic recording time was 2.5 (±0.1) h and mean time spent in AS, QS, and intermediate sleep (IS) was 42 ± 0.6%, 40 ± 0.8%, and 18 ± 1.2%, respectively. Bladder voiding was recorded at a mean time of 50 ± 7 min after sleep onset and occurred during QS only. When comparing EEG frequency, no significant difference in HR and RF before and after the onset of bladder voiding was found. This was true when comparing raw figures as well as percentage of modification (for details, see Table 1).

Bladder

Discussion

Our main finding was that bladder voiding in sleeping preterm infants was not accompanied by arousals.

Events such as body movements, changes in HR, EEG frequency, and RF occur during sleep in infants and are essential for cardiopulmonary homeostasis and normal development [11], [12]. These events indicate arousals and are defined by the International Paediatric Work Group on Arousals [10]. It has been shown that the characteristics of arousals change with age [13]. Therefore, the arousal

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The 11 studies included cross sectional and qualitative research designs. The age of the participants from the included literature ranged between newborn [8,13–19] and 4 years [20]. The number of subjects varied between 4 [15] and 286 [21].
An early start of toilet training, which is related to a younger age of acquiring full bladder control, can generate important health advantages. Children display different ‘elimination signals' related to voiding or defaecation. The aim of this systematic review is to map these ‘elimination signals’ in young, healthy children aged 0–4 years.
The systematic literature search was performed in two databases and was conducted using the preferred reporting items for systematic reviews and meta-analyses (PRISMA statement).
Two main distinctions in elimination signals were made. The first could be classified as visual, auditory and tactile, most frequently involving a change in facial expression, often combined with body movements and verbal expressions such as a short cry or grunting. Secondly significant changes in heart rate, respiratory frequency or EEG frequency could be defined as ‘clinically assessed elimination signals'.
Different ‘elimination signals' could be detected in healthy children while voiding or defaecating and should be observed when initiating toilet training.
Detection of noticeable visual, auditory and tactile signals will facilitate and shorten this process.
Relationship between brain activity and voiding patterns in healthy preterm neonates
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There were no significant differences in EEG frequency during the 5-second period before voiding onset, voiding, and after voiding onset (P > 0.05; Table 1) or among all urination states in any group (P > 0.05; Fig. 1; Table 2). According to the traditional concept, neonatal voiding is entirely induced by a constant bladder volume and without influence from the brain, as observed in full-term neonates with immature bladder function [6]. However, some findings have indicated brain involvement in the regulation of bladder function from as early as the full-term neonatal period [16], as suggested by examples of small infants waking or demonstrating signs of arousal (e.g. body movements) when voiding [3–5,14,17,18].
It remains controversial as to whether the brain affects voiding control in preterm newborns. Constant bladder volume has previously been thought to induce bladder voiding in neonates, with no influence from the brain. Lately, there has been distinct evidence for an existing connection between the central nervous system and bladder voiding in preterm infants, as the voiding reflex arouses neonatal children. Video electroencephalography (EEG) is useful for recording bioelectrical activity of the cerebral cortex and exploring its relationship with voiding patterns in preterm neonates.
The objective was to investigate the relationship between voiding patterns and brain activity in healthy preterm neonates by using video-EEG.
Forty-seven healthy preterm neonates (16 females) with a mean postconceptional age (PCA) of 34.1 ± 1.8 weeks were divided according to PCA into three groups: Group I (31–33 weeks, n = 13); Group II (33–35 weeks, n = 14); and Group III (35–37 weeks, n = 20). Video-EEG data from eight cortical regions were recorded from 08:00–12:00, along with 4-hour free voiding patterns and status at voiding (awake/sleep).
In Group I, the voiding frequency (VF) was significantly higher and the voiding volume (VV) was significantly lower than in the other groups. There were no significant differences in bladder capacity (BC), bladder capacity/birth weight (BC/BW), postvoiding residual/bladder capacity (PVR/BC), or urinary flow rate (UFR) among the three groups. The Fp1-T3 and Fp2-T4 lead amplitudes significantly differed in Group I and Group II at 5 s before (pre-5), during, and after voiding (post-5). The Fp2-C4 total and theta band lead amplitudes significantly differed across all urination states among the groups. There were no significant differences in electroencephalography frequency among the groups in any urination state.
There were no significant differences in BC, BC/BW, PVR/BC, or UFR among the three groups, indicating slow bladder function development in preterm neonates. In this study, the EEG amplitude changed in certain pairs of electrodes. These changes might indicate the degree of bladder sensor maturation along with an increasing PCA. This study further suggests that the brain changes in preterm neonates during quiet sleep voiding prominently occur in the right prefrontal cortex and central region.
In preterm neonates, bladder voiding during quiet sleep was accompanied by cortical arousal that might have emanated from a lower center.
Relationship between arousal response in newborn infants before micturition and bed-wetting from 5 to 7years of age
2013, Early Human Development
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The cases in which an arousal response was not seen before micturition may have a neurologic abnormality or developmental delay in relation to the arousal system. Hence, the absence of an arousal response before micturition may become a predictive factor of diseases involving the arousal mechanism, such as sudden infant death syndrome (SIDS) and bed-wetting [12]. These conclusions are limited by the small study size and necessitate additional prospective studies.
Arousal from sleep pathways are affected by the prone sleeping position and preterm birth. preterm birth, prone sleeping and arousal from sleep.
2013, Early Human Development
Preterm infants exhibit depressed arousability from sleep when compared with term infants. As the final cortical element of the arousal process may be the most critical for survival, we hypothesized that the increased vulnerability of preterm infants to the Sudden Infant Death Syndrome (SIDS) could be explained by depressed cortical arousal (CA) responses. We evaluated the effects of preterm birth on stimulus-induced arousal processes in both the prone and supine sleeping positions.
10 healthy preterm infants were studied with daytime polysomnography, in both supine and prone sleeping positions, at 36 weeks gestational age, 2–4 weeks, 2–3 months and 5–6 months post-term corrected age. Sub-cortical activations and cortical arousals (CA) were expressed as proportions of total arousal responses. Preterm data were compared with data from 13 healthy term infants studied at the same corrected ages.
In preterm infants increased CAs were observed in the prone position at all ages studied. Compared to term infants, preterm infants had significantly fewer CAs in QS when prone at 2–3 months of age and more CAs when prone at 2–4 weeks in AS. There were no differences in either sleep state when infants slept supine.
Prone sleeping promoted CA responses in healthy preterm infants throughout the first six months of post-term age. We have previously suggested that in term infants enhanced CA represents a critical protection against a potentially harmful situation; we speculate that for preterm-born infants the need for this protection is greater than in term infants.
Arousal from sleep mechanisms in infants
2010, Sleep Medicine
Arousals from sleep allow sleep to continue in the face of stimuli that normally elicit responses during wakefulness and also permit awakening. Such an adaptive mechanism implies that any malfunction may have clinical importance. Inadequate control of arousal in infants and children is associated with a variety of sleep-related problems. An excessive propensity to arouse from sleep favors the development of repeated sleep disruptions and insomnia, with impairment of daytime alertness and performance. A lack of an adequate arousal response to a noxious nocturnal stimulus reduces an infant’s chances of autoresuscitation, and thus survival, increasing the risk for Sudden Infant Death Syndrome (SIDS). The study of arousability is complicated by many factors including the definition of an arousal; the scoring methodology; the techniques used (spontaneous arousability versus arousal responses to endogenous or exogenous stimuli); and the confounding factors that complicate the determination of arousal thresholds by changing the sleeper’s responses to a given stimulus such as prenatal drug, alcohol, or cigarette use. Infant age and previous sleep deprivation also modify thresholds. Other confounding factors include time of night, sleep stages, the sleeper’s body position, and sleeping conditions. In this paper, we will review these different aspects for the study of arousals in infants and also report the importance of these studies for the understanding of the pathophysiology of some clinical conditions, particularly SIDS.
Urinary Flow Patterns in Premature Males
2010, Journal of Urology
We sought to assess urinary flow patterns in premature males using ultrasound flow probes.
Specifically customized ultrasound flow probes connected to a flowmeter were mounted on the penis of 29 premature males (median gestational age 31.3 weeks). Flow data were sampled to a personal computer and flow curves were assessed with regard to configuration, maximum flow rate and voided volume. Examinations were performed at the neonatal unit within the ambient environment of the incubators and under the surveillance of a study nurse for a period of 4 hours.
Data from 25 boys (98 voids) were applicable for analysis. Flow curve configuration was bell shaped in 48% of patients, interrupted in 44%, staccato in 6% and plateau in 2%. Overall 59% of flows were dyscoordinated, and no patient with more than 1 assessable void had exclusively coordinated flows. Median voided volume was 3.9 ml (range 0.6 to 25.2), median maximum flow rate was 1.0 ml per second (0.3 to 10.0) and median number of voids per hour was 1.0 (0.2 to 3.6). No correlation was found between flow curve configuration and maximum flow rate (p = 0.32). However, plateau shaped curves were associated with larger voided volumes (p = 0.05).
Urinary flow pattern assessment in preterm males is possible and reveals a high degree of dyscoordination. There is a tendency toward a mixture of coordinated and dyscoordinated flow patterns in the same individual.

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Original articleIs bladder voiding in sleeping preterm infants accompanied by arousals?

Abstract

Background

Methods

Results

Conclusion

Introduction

Section snippets

Subjects

Results

Discussion

Clin Perinatol

Pediatr Respir Rev

Early Hum Dev

Early Hum Dev

Electroencephalogr Clin Neurophysiol

Bladder function in preterm and full-term infants – free voidings during four-hour voiding observation

Scand J Urol Nephrol

Some new insights into bladder function in infancy

Br J Urol

Bladder voiding in sleeping infants is consistently accompanied by a cortical arousal

J Sleep Res

Does bladder voiding during sleep and wakefulness change the behavioural state of infants?

Acta Paed

Sleep and cardiorespiratory characteristics of infant victims of sudden death: a prospective case-control study

Sleep

A manual of standardized terminology, technique and criteria for scoring of states of sleep and wakefulness in newborn infants

Between sleep states transitions in premature babies

J Sleep Res

The scoring of arousals in healthy term infants (between the ages of 1 and 6 months)

J Sleep Res

Habituation of the infant arousal response

Sleep

Dynamic changes in arousal threshold during sleep in the human infant

Pediatr Res

Original article
Is bladder voiding in sleeping preterm infants accompanied by arousals?