Abstract

Background: The aim of this study was to identify risk factors for lengthened ICU stay of VLBW (very low birth weight) neonates and analyze results as delayed discharge is a big problem for those neonates, not only for medical costs but also for their health. Methods: In total 71 consecutive VLBW ethnic Chinese neonates (body weight <1500 g) admitted to our neonatal intensive care unit (NICU) from Jan. 1, 2009 through Apr. 30, 2010 have entered this study. Their birth weights range from 605 to 1495 g (1160.4±244.7 g), gestational ages from 23 to 35 weeks (29.30±2.87weeks). Results: Significant differences were observed between length of ICU stay of VLBW neonates and their birth weights, p=0.01 (pearson correlation), suggesting that length of VLBW neonatal ICU stay increases with decreased birth weight. No significant differences were observed between ICU stays of VLBW neonates and PN (parenteral nutrition) use or beractant use, p=0.109 (t-test) and 0.129 (t-test), respectively, suggesting that neither malnutrition requiring PN use nor RDS requiring beractant use has an influential effect on length of ICU stay, yet bronchopulmonary dysplasia is a major cause of increased length of hospitalization among VLBW neonates which is mainly caused by RDS (respiratory distress syndrome) or PDA (patent ductus arteriosus). Conclusion: Significant PDA might be a contributing factor affecting on the length of ICU stay of VLBW neonates. Further studies are needed in non-Chinese neonates due to lack of racial varieties in this research.

Key Words: PDA, VLBW neonate, ICU stay

Introduction

Early neonatal intensive care unit (NICU) discharge has been suggested as this can prevent neonates from adverse environment of prolonged hospital stay and reduce costs of medical care. However, very low birth weight (VLBW) neonates (birth weight <1500 g) are more vulnerable to health problems,¹ such as nutrition condition,² some diseases, and compromised physical condition necessitating lots of medical interventions. Consequently, delayed discharge is a big problem for them, not only for medical costs but also for their health. Risk factors for delayed discharge are independently associated with bronchopulmonary dysplasia (BPD),³ decreasing birth weight,³ surgically treated necrotizing enterocolitis, ^3,4 intraventricular hemorrhage (IVH) grades 3-4, ³ congenital anomalies, ³ etc..

Advances in ICU health care within the recent decades have resulted in increased survival of preterm neonates. As a result, BPD, a chronic lung disorder, is usually seen in neonates with low birth weights or who were prematures. BPD is a major cause of increased length of hospitalization among VLBW neonates,^5,6 and this disorder is supposed to be suspected in extremely low birth weight neonates with early respiratory distress.^7,8 Preventive or therapeutic modalities, like early nasal continuous positive airway pressure or surfactant which reduces respiratory distress syndrome (RDS) at birth or shortly after, are required to reduce the incidence of BPD and even length of neonatal ICU stay.^5,9,10 Aside from RDS, patent ductus arteriosus (PDA), a congenital disorder in heart wherein a neonate's ductus arteriosus fails to close after birth, is the second leading cause to the development of BPD.⁸

Methods

Neonates born in Chang Gung Memorial Hospital at Kaohsiung (Taiwan) and admitted to our NICU, or born in other hospitals but sent to NICU of this hospital within the first 24 hours after birth from Jan. 1, 2009 through Apr. 30, 2010 were eligible to enter this study. Included neonates had to be ethnic Chinese (Taiwanese, aborigine, mainlander, Hakka) or mixed ethnic Chinese. Foreigners were excluded. Exclusion criteria were: surgically treated necrotizing enterocolitis, intraventricular hemorrhage grades 3-4, congenital anomalies, expiration or AAD (against advice discharge).

Pediatricians making the decisions to transfer the neonates out of NICU were not involved in the study, and the other members were blinded with respect to group. Statistical significance was defined as a p value <0.05.

Results

In total, 92 consecutive neonates with body weight <1,500 g (VLBW) admitted to our NICU during this period of time have entered this study. Nine neonates born in other hospital, two had IVH grades 3-4, three had congenital anomalies, one foreigner, six neonates died or AAD, leaving only 71 neonates included in this study shown in table 1. The birth weights of those 71 VLBW neonates range from 605 to 1495 g (1160.4±244.7 g), gestational ages (GA) from 23 to 35 weeks (29.30±2.87weeks). Length of neonatal ICU stay, TPN use or not, BW, GA, survanta use or not, indomethacin use or not are shown in table 2.

 

 

Significant differences were observed between length of ICU stay of VLBW neonates and their birth weights, p=0.01 (pearson correlation), suggesting that length of VLBW neonatal ICU stay increases with decreased birth weight. No significant differences were observed between the length of ICU stays of VLBW neonates and PN use or beractant use, p=0.109 (t-test) and 0.129 (t-test), respectively, suggesting that neither malnutrition requiring PN use nor RDS requiring beractant use has an influential effect on the length of ICU stay.

Discussion

In our NICU, neonates qualified to be transferred to a common neonatal ward are those who do not have any signs of infections, whose body weight is over 2000 g, those that are comfortable without the use of an oxygen hood or ventilator, and those with smooth feeding. Therefore, being able to be transferred to a common ward is equal to be generally healthy in this study so as to provide a relatively equal basis for comparison among VLBW neonates.

Increased PN use in lower birth weight neonates were observed in this study, yet complications from PN remain problematic and include catheter-related bloodstream infections, cholestatic jaundice, ¹¹ hypophosphataemia, ¹¹ elevated serum transaminase and bilirubin levels,¹² oxidants from TPNs while neonates are receiving phototherapy, ¹³ and calcium-phosphate incompatibility, etc. These complications are responsible for some morbidities and mortalities, and malnutrition requiring PN use does not correlate with length of ICU stay which might be ambivalent to some speculation. Therefore, it is essential to evaluate if PN use is needed for VLBW neonates within several days after birth.

VLBW neonates with surgically treated necrotizing enterocolitis, intraventricular hemorrhage grades 3-4, and congenital anomalies are supposed to stay in the ICU for longer time according to former studies, ^3,4 that is why those neonates were excluded from this study to avoid confounding factors.

BPD is a major cause of increased length of hospitalization among VLBW neonates, ⁵ and RDS is a contributing factor leading to the development of BPD, ^6,7 That is why VLBW neonates with RDS requiring surfactant therapy or not are also being studied. In this study, length of ICU stay of VLBW neonates correlated well with birth weight. However, no significant differences were found between length of ICU stay and neonates with RDS requiring surfactant (beractant) therapy which is contradictory to former studies, ^6,7 suggesting that either some of those not receiving beractant were supposed to have RDS and they were undertreated, or significant PDA might be an important factor which is supposed to have led to the development of BPD causing lengthened ICU stay of VLBW neonates. ⁸ However, only 5 VLBW neonates were treated with indomethacin for significant PDA in this study, making it hard to make conclusion statistically.

Neonatalogists in this ICU have the same standards for the use of PN for malnutrition, ¹⁴ beractant for RDS, ¹⁰ and indomethacin for PDA. ¹⁵ These standards are based on the criteria, so the assumption of neonates being undertreated for significant RDS is not likely.

Conclusion

Significant PDA requiring indomethacin treatment might be a contributing factor affecting on lengthened ICU stay of VLBW neonates. Further studies are needed in non-Chinese neonates due to lack of racial varieties in this research.

References:

1. Tronchin DM, Tsunechiro MA: Very low-weight preterm infants: from birth until the first year of age. Revista Gaucha de Enfermagem 2007; 28(1): 79-88.

2. Bober OK, Kornacka MK: Effects of glutamine supplemented parenteral nutrition on the incidence of necrotizing enterocolitis, nosocomial sepsis and length of hospital stay in very low birth weight infants. Medycyna Wieku Rozwojowego 2005; 9(3): 325-333.

3. Klinger G, Reichman B, Sirota L, et al: Risk factors for delayed discharge home in very-low-birthweight infants:-a population-based study. Acta Paediatrica 2005; 94(11): 1674-1679.

4. Samanta M, Sarkar M, Ghosh P, et al: Prophylactic probiotics for prevention of necrotizing enterocolitis in very low birth weight newborns. Journal of Tropical Pediatrics 2009; 55(2): 128-131.

5. Klinger G, Sirota L, Lusky A, et al: Bronchopulmonary dysplasia in very low birth weight infants is associated with prolonged hospital stay. Journal of perinatology 2006; 26(10): 640-644.

6. Aly H, Massaro AN, El-Mohandes AA: Can delivery room management impact the length of hospital stay in premature infants. Journal of Perinatology 2006; 26(10): 593-596.

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8. Demirel N, Bas AY, Zenciroglu A: Bronchopulmonary dysplasia in very low birth weight infants. Indian Journal of Pediatrics 2009; 76(7): 695-698.

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13. Mohamed RB, Hala A, Hesham AH, et al: A randomized controlled trial on parenteral nutrition, oxidative stress, and chronic lung diseases in preterm infants. Journal of Pediatric Gastroenterology and Nutrition 2009; 48: 363-369.

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摘要

延長住院對非常低出生體重（VLBW）新生兒不僅是增加醫療費用且影響其身體健康，本研究之目的是要瞭解延長這些新生兒住加護病房（NICU）的危險因子及分析其結果。

從2009年1月1日至2010年4月30日，總共連續71個VLBW華人新生兒(體重<1500克)曾住在我們的NICU且進入此研究。這些新生兒體重605-1495克（1160.4±244.7克），母親懷孕週數23 to 35週（29.30±2.87週）。

VLBW新生兒住ICU的天數與其體重呈有意義相關，p=0.01（pearson correlation），此意含VLBW新生兒住ICU的天數隨著出生體重下降而增加。而與靜脈營養(PN)使用及beractant使用的統計結果分別是p=0.109（t-test）及0.129（t-test），無顯著的相關，意含不論是嚴重到需使用PN之營養不良症或嚴重到需使用beractant來治療之呼吸窘迫症，對於其住ICU天數均無明顯的影響。然而，肺支氣管發育不良是VLBW新生兒住ICU天數延長之主因，而此症主要是由出生時有呼吸窘迫症及開放性動脈導管所致。

有意義的開放性動脈導管可能是VLBW新生兒住ICU天數延長之主因；外國人新生兒由於缺乏資料，還需再進一步研究。

作者

高雄長庚紀念醫院藥劑科藥師 李榮明、
吳秋瑩、李炳鈺

行政院衛生署屏東醫院藥劑科藥師 江吉文