Acta Pædiatrica ISSN 0803-5253
REGULAR ARTICLE
Serious periventricular white matter injury has a significant effect on the voiding pattern of preterm infants Ya Lun Wang1, Jian Guo Wen2,3, Lu Xing2,3, Qian Zhang4, Yan Sha Zhang5, Yu Ming Xu ([email protected])1 1.Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou City, Henan Province, China 2.Pediatric Urodynamic Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou City, Henan Province, China 3.Institute of Clinical Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou City, Henan Province, China 4.Neonatal Intensive Care Unit, The First Affiliated Hospital of Zhengzhou University, Zhengzhou City, Henan Province, China 5.Department of Pediatrics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou City, Henan Province, China
Keywords Periventricular white matter injury, Preterm infants, Senior nerve centre, Voiding
ABSTRACT Aim: To evaluate the effect of serious periventricular white matter injury (PWMI) on the
Correspondence Yu Ming Xu, Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Jianshe East Road, Zhengzhou City, 450052 Henan Province, China. Tel: +86 13903711125 | Fax: +86 371 66970906 | Email: [email protected]
Methods: Free voiding was continuously observed for eight hours in 19 preterm infants
Received 11 August 2013; revised 20 November 2013; accepted 25 November 2013. DOI:10.1111/apa.12525
voiding patterns of preterm infants. with serious PWMI and 16 infants without PWMI. The infants had a gestational age of 32–35 weeks and a postnatal age of 9–15 days. Voiding frequency, voided volume, postvoid residual volume, empty voiding, awake voiding and interrupted voiding were recorded and compared between the two groups of infants. Results: The voiding frequency ((5.1 1.0) vs. (7.0 1.1)), awake voiding percentage ((23 11)% vs. (42 7)%) and empty voiding percentage (lower quartile = 16% vs. 28%, median = 20% vs. 33%, upper quartile = 28% vs. 40%) were significantly lower, while the voided volume ((19.9 6.6) mL vs.(15.9 5.3) mL)and postvoid residual volume (lower quartile = 1 mL. vs. 0 mL., median = 3 mL. vs. 2 mL., upper quartile = 3 mL. vs. 2 mL.) were significantly higher in the injured preterm infants, compared with the healthy infants (p < 0.05). Conclusion: Serious PWMI has a significant effect on the voiding pattern of preterm infants, and the senior nerve centre plays a role in the voiding reflex of preterm infants.
INTRODUCTION Periventricular white matter injury (PWMI) is the most common brain injury in preterm infants (1) and survival rates are increasing. This has led to a large amount of research on PWMI, but it has mostly been limited to pathogenesis and prognosis and very few studies have investigated the voiding pattern of preterm infants with PWMI. It has been reported that adults with PWMI experience obvious bladder dysfunction, indicating that periventricular white matter plays an important role in the micturition reflex (2). Research on the voiding patterns of preterm infants with PWMI is interesting and necessary and could help us to understand the role of the senior nerve centre in their micturition reflex. The aim of this study was to evaluate the effect of PWMI on the free voiding patterns of preterm infants with, and without, PWMI, for eight hours.
PATIENTS AND METHODS Patients This study included 35 preterm infants, with a gestational age of 32–35 weeks and a postnatal age of 9–15 days, who had been admitted to the neonatal intensive care unit at the
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First Affiliated Hospital of Zhengzhou University of China. Nineteen of the infants had serious PWMI and the other 16 did not have PWMI and formed the control group. Bedside cerebral sonography and comprehensive examinations were performed on all the infants in the first week after their birth. After this, the infants were examined every week using cerebral sonography to continuously evaluate their brain status. In practice, PWMIs are always found in the first week after birth, and the characteristic ultrasound presentation is bilateral periventricular echodensities (3). According to extent of the injury, PWMI can be categorised
Key notes
Periventricular white matter injury (PWMI) is the most common brain injury in preterm infants. This study found significant differences between the voiding patterns of 16 healthy preterm infants and 19 infants with serious PWMI. The findings indicate that serious PWMI has a significant effect on the voiding patterns of preterm infants and that the senior nerve centre plays a role in their voiding reflexes.
©2013 Foundation Acta Pædiatrica. Published by John Wiley & Sons Ltd 2014 103, pp. e106–e110
Wang et al.
as slight PWMI, defined as transient periventricular echodensities (14 days) or periventricular leucomalacia found using continuous cerebral sonography (4). All the PWMI infants in this study had serious injuries, with periventricular echodensities (>14 days) that were diagnosed in the first week after birth. The infants with transient periventricular echodensities ( 0.05 indicated normal distribution.
©2013 Foundation Acta Pædiatrica. Published by John Wiley & Sons Ltd 2014 103, pp. e106–e110
e107
Periventricular white matter injury and voiding
Wang et al.
The voiding parameters between the control and injured groups – voiding frequency, voided volume, awake voiding percentage and bladder capacity – were compared by two independent sample t-tests (p > 0.05, Shapiro–Wilk W test). The other voiding parameters– the residual volume and empty voiding percentage were compared by Wilcoxon rank test, a nonparametric statistic. When it came to residual volume, neither group showed normal distribution (p < 0.01, Shapiro–Wilk W test), and, in the case of empty voiding percentage, the control group showed normal distribution (p = 0.21, Shapiro–Wilk W test), but the injured group did not (p = 0.02, Shapiro–Wilk W test). We compared the proportion of empty voids between the two groups using Pearson chi-square (total amount >40) and the proportion of interrupted voiding between two groups using Fisher’s exact probabilities (total amount 0.05, Shapiro–Wilk W test), and the gestational ages (the control group showed normal distribution (p = 0.06, Shapiro–Wilk W test) and injured group did not (p = 0.02, Shapiro–Wilk W test)) were compared by Wilcoxon rank test.
RESULTS In the control group, we recorded 112 voids, including 39 empty voids. In the injured group, we recorded 97 voids, including 21 empty voids. When they were compared with the control group, the preterm infants with serious PWMI showed significantly decreased voiding frequency ((5.1 1.0) vs. (7.0 1.1)), awake voiding percentage ((23 11)% vs. (42 7)%) and empty voiding percentage (lower quartile = 16% vs. 28%, median = 20% vs. 33%, upper quartile = 28% vs. 40%).
However, there were significant increases in the voided volume ((19.9 6.6 mL) vs. (15.9 5.3 mL)) and the postvoid residual volume (lower quartile = 1 mL. vs. 0 mL., median quartile =3 mL. vs 2 mL., upper quartile = 3 mL. vs. 2 mL.). The bladder capacity of the PWMI infants had an increased tendency towards bladder capacity than the control group ((24.5 6.7) mL vs. (20.5 5.4) mL). Detailed information is presented in Table 2 and (Fig. 1). The bladder capacity against postvoid residual volume was compared between the 16 healthy preterm infants and the 19 ones with serious PWMI. The detailed information is presented in (Fig. 2). The proportion of empty voids in the injured group was significantly lower than the control group (21/97 voids = 21% vs. 39/112 voids = 35%, v2 = 4.41, p = 0.03). The proportion of infants with interrupted voiding (10/19 voids = 52% vs. 7/16 voids = 44%, p = 0.74) showed no significant difference between the injured and control group.
DISCUSSION Periventricular white matter injuries have a significant effect on the neural development of preterm infants, as they are the most common brain injury in this age group (6). The pathogenesis mainly includes the lack of a robust blood supply to the periventricular white matter and the vulnerability of the oligodendrocytes (7). In practice, cerebral sonography is used to diagnose PWMI in the first postnatal week, and the characteristic ultrasound findings are bilateral periventricular echodensities (8). In addition, the periventricular echodensities are very different from each other in terms of intensity and duration. It has been demonstrated that the prognosis of PWMI is correlated with duration rather than intensity of periventricular echodensities. Infants with temporary periventricular
Table 2 The comparison of voiding parameters between PWMI and control group
Whole voiding frequency (range) (sample capacity) Empty voiding percentage,% (range) (sample capacity) Awake voiding percentage,% (range) (sample capacity) Voided volume, mL. (range) (sample capacity) Residual volume, mL. (range) (sample capacity) Bladder capacity, mL. (range) (sample capacity)
PWMI group
Control group
Statistics(t/Z)
p Value
5.1 1.0 (3–7) (n = 19) P25 = 16, P50 = 20 P75 = 28 (0–40) (n = 19) 23 11 (0–40) (n = 19) 19.9 6.6 (5–32) (n = 97) P25 = 1, P50 = 3 P75 = 3 (0–4) (n = 97) 24.5 6.7 (12–35) (n = 19)
7.0 1.1 (5–9) (n = 16) P25 = 28, P50 = 33 P75 = 40 (20–44) (n = 16) 42 7 (28–57) (n = 16) 15.9 5.3 (5–27) (n = 112) P25 = 0, P50 = 2 P75 = 2 (0–4) (n = 112) 20.5 5.4 (11–30) (n = 16)
t = 5.22
REGULAR ARTICLE
Serious periventricular white matter injury has a significant effect on the voiding pattern of preterm infants Ya Lun Wang1, Jian Guo Wen2,3, Lu Xing2,3, Qian Zhang4, Yan Sha Zhang5, Yu Ming Xu ([email protected])1 1.Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou City, Henan Province, China 2.Pediatric Urodynamic Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou City, Henan Province, China 3.Institute of Clinical Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou City, Henan Province, China 4.Neonatal Intensive Care Unit, The First Affiliated Hospital of Zhengzhou University, Zhengzhou City, Henan Province, China 5.Department of Pediatrics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou City, Henan Province, China
Keywords Periventricular white matter injury, Preterm infants, Senior nerve centre, Voiding
ABSTRACT Aim: To evaluate the effect of serious periventricular white matter injury (PWMI) on the
Correspondence Yu Ming Xu, Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Jianshe East Road, Zhengzhou City, 450052 Henan Province, China. Tel: +86 13903711125 | Fax: +86 371 66970906 | Email: [email protected]
Methods: Free voiding was continuously observed for eight hours in 19 preterm infants
Received 11 August 2013; revised 20 November 2013; accepted 25 November 2013. DOI:10.1111/apa.12525
voiding patterns of preterm infants. with serious PWMI and 16 infants without PWMI. The infants had a gestational age of 32–35 weeks and a postnatal age of 9–15 days. Voiding frequency, voided volume, postvoid residual volume, empty voiding, awake voiding and interrupted voiding were recorded and compared between the two groups of infants. Results: The voiding frequency ((5.1 1.0) vs. (7.0 1.1)), awake voiding percentage ((23 11)% vs. (42 7)%) and empty voiding percentage (lower quartile = 16% vs. 28%, median = 20% vs. 33%, upper quartile = 28% vs. 40%) were significantly lower, while the voided volume ((19.9 6.6) mL vs.(15.9 5.3) mL)and postvoid residual volume (lower quartile = 1 mL. vs. 0 mL., median = 3 mL. vs. 2 mL., upper quartile = 3 mL. vs. 2 mL.) were significantly higher in the injured preterm infants, compared with the healthy infants (p < 0.05). Conclusion: Serious PWMI has a significant effect on the voiding pattern of preterm infants, and the senior nerve centre plays a role in the voiding reflex of preterm infants.
INTRODUCTION Periventricular white matter injury (PWMI) is the most common brain injury in preterm infants (1) and survival rates are increasing. This has led to a large amount of research on PWMI, but it has mostly been limited to pathogenesis and prognosis and very few studies have investigated the voiding pattern of preterm infants with PWMI. It has been reported that adults with PWMI experience obvious bladder dysfunction, indicating that periventricular white matter plays an important role in the micturition reflex (2). Research on the voiding patterns of preterm infants with PWMI is interesting and necessary and could help us to understand the role of the senior nerve centre in their micturition reflex. The aim of this study was to evaluate the effect of PWMI on the free voiding patterns of preterm infants with, and without, PWMI, for eight hours.
PATIENTS AND METHODS Patients This study included 35 preterm infants, with a gestational age of 32–35 weeks and a postnatal age of 9–15 days, who had been admitted to the neonatal intensive care unit at the
e106
First Affiliated Hospital of Zhengzhou University of China. Nineteen of the infants had serious PWMI and the other 16 did not have PWMI and formed the control group. Bedside cerebral sonography and comprehensive examinations were performed on all the infants in the first week after their birth. After this, the infants were examined every week using cerebral sonography to continuously evaluate their brain status. In practice, PWMIs are always found in the first week after birth, and the characteristic ultrasound presentation is bilateral periventricular echodensities (3). According to extent of the injury, PWMI can be categorised
Key notes
Periventricular white matter injury (PWMI) is the most common brain injury in preterm infants. This study found significant differences between the voiding patterns of 16 healthy preterm infants and 19 infants with serious PWMI. The findings indicate that serious PWMI has a significant effect on the voiding patterns of preterm infants and that the senior nerve centre plays a role in their voiding reflexes.
©2013 Foundation Acta Pædiatrica. Published by John Wiley & Sons Ltd 2014 103, pp. e106–e110
Wang et al.
as slight PWMI, defined as transient periventricular echodensities (14 days) or periventricular leucomalacia found using continuous cerebral sonography (4). All the PWMI infants in this study had serious injuries, with periventricular echodensities (>14 days) that were diagnosed in the first week after birth. The infants with transient periventricular echodensities ( 0.05 indicated normal distribution.
©2013 Foundation Acta Pædiatrica. Published by John Wiley & Sons Ltd 2014 103, pp. e106–e110
e107
Periventricular white matter injury and voiding
Wang et al.
The voiding parameters between the control and injured groups – voiding frequency, voided volume, awake voiding percentage and bladder capacity – were compared by two independent sample t-tests (p > 0.05, Shapiro–Wilk W test). The other voiding parameters– the residual volume and empty voiding percentage were compared by Wilcoxon rank test, a nonparametric statistic. When it came to residual volume, neither group showed normal distribution (p < 0.01, Shapiro–Wilk W test), and, in the case of empty voiding percentage, the control group showed normal distribution (p = 0.21, Shapiro–Wilk W test), but the injured group did not (p = 0.02, Shapiro–Wilk W test). We compared the proportion of empty voids between the two groups using Pearson chi-square (total amount >40) and the proportion of interrupted voiding between two groups using Fisher’s exact probabilities (total amount 0.05, Shapiro–Wilk W test), and the gestational ages (the control group showed normal distribution (p = 0.06, Shapiro–Wilk W test) and injured group did not (p = 0.02, Shapiro–Wilk W test)) were compared by Wilcoxon rank test.
RESULTS In the control group, we recorded 112 voids, including 39 empty voids. In the injured group, we recorded 97 voids, including 21 empty voids. When they were compared with the control group, the preterm infants with serious PWMI showed significantly decreased voiding frequency ((5.1 1.0) vs. (7.0 1.1)), awake voiding percentage ((23 11)% vs. (42 7)%) and empty voiding percentage (lower quartile = 16% vs. 28%, median = 20% vs. 33%, upper quartile = 28% vs. 40%).
However, there were significant increases in the voided volume ((19.9 6.6 mL) vs. (15.9 5.3 mL)) and the postvoid residual volume (lower quartile = 1 mL. vs. 0 mL., median quartile =3 mL. vs 2 mL., upper quartile = 3 mL. vs. 2 mL.). The bladder capacity of the PWMI infants had an increased tendency towards bladder capacity than the control group ((24.5 6.7) mL vs. (20.5 5.4) mL). Detailed information is presented in Table 2 and (Fig. 1). The bladder capacity against postvoid residual volume was compared between the 16 healthy preterm infants and the 19 ones with serious PWMI. The detailed information is presented in (Fig. 2). The proportion of empty voids in the injured group was significantly lower than the control group (21/97 voids = 21% vs. 39/112 voids = 35%, v2 = 4.41, p = 0.03). The proportion of infants with interrupted voiding (10/19 voids = 52% vs. 7/16 voids = 44%, p = 0.74) showed no significant difference between the injured and control group.
DISCUSSION Periventricular white matter injuries have a significant effect on the neural development of preterm infants, as they are the most common brain injury in this age group (6). The pathogenesis mainly includes the lack of a robust blood supply to the periventricular white matter and the vulnerability of the oligodendrocytes (7). In practice, cerebral sonography is used to diagnose PWMI in the first postnatal week, and the characteristic ultrasound findings are bilateral periventricular echodensities (8). In addition, the periventricular echodensities are very different from each other in terms of intensity and duration. It has been demonstrated that the prognosis of PWMI is correlated with duration rather than intensity of periventricular echodensities. Infants with temporary periventricular
Table 2 The comparison of voiding parameters between PWMI and control group
Whole voiding frequency (range) (sample capacity) Empty voiding percentage,% (range) (sample capacity) Awake voiding percentage,% (range) (sample capacity) Voided volume, mL. (range) (sample capacity) Residual volume, mL. (range) (sample capacity) Bladder capacity, mL. (range) (sample capacity)
PWMI group
Control group
Statistics(t/Z)
p Value
5.1 1.0 (3–7) (n = 19) P25 = 16, P50 = 20 P75 = 28 (0–40) (n = 19) 23 11 (0–40) (n = 19) 19.9 6.6 (5–32) (n = 97) P25 = 1, P50 = 3 P75 = 3 (0–4) (n = 97) 24.5 6.7 (12–35) (n = 19)
7.0 1.1 (5–9) (n = 16) P25 = 28, P50 = 33 P75 = 40 (20–44) (n = 16) 42 7 (28–57) (n = 16) 15.9 5.3 (5–27) (n = 112) P25 = 0, P50 = 2 P75 = 2 (0–4) (n = 112) 20.5 5.4 (11–30) (n = 16)
t = 5.22
