Inter-unit management of neonates with congenital heart diseases between NICU and PICU

doi:10.21203/rs.3.rs-2106470/v1

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Inter-unit management of neonates with congenital heart diseases between NICU and PICU

https://doi.org/10.21203/rs.3.rs-2106470/v1

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Background: Neonates undergoing cardiac surgeries require highly specialized perioperative care. However, limited information is currently available on the impact of the preoperative location of neonates undergoing cardiac surgeries on the management and outcomes. This was a retrospective observational study that compared management patterns, morbidity, and mortality among infants before and after the renovation of the neonatal intensive care unit (NICU) and pediatric intensive care unit (PICU) in a single university hospital.

Methods: We retrospectively reviewed the medical records of neonates admitted to the University of Tokyo Hospital NICU who underwent cardiac surgery and were treated in the PICU during hospitalization. We collected data on infants born in two different time periods (“Before”: in 2017 and 2018, and “After”: in 2020 and 2021). The “Before” group comprised patients managed in the previous ward, while the “After” group included patients managed in the new ward.

Results: Maternal age was higher and complicated cases were significantly more frequent in the “After” group (p<0.05). However, in-hospital mortality was similar between the two groups (p=0.98). Patients were exchanged between the NICU and PICU significantly more often in the “After” group (p<0.01). Patients in the “After” group left the PICU earlier after cardiac surgeries.

Conclusions: The results of this retrospective analysis of a single center showed that management plans for neonates with congenital heart defects may be changed depending on the ward arrangement. Patients were transferred between the NICU and PICU more frequently when adjacent to each other, which enabled an earlier discharge from the PICU.

Congenital heart defect

NICU

PICU

cardiac surgery

cohorting

Congenital heart defects (CHDs) are the most common congenital anomaly, occurring in approximately 6 to 10 infants per 1000 live births [1]. Approximately 25% of infants born with CHDs will require cardiac surgery or other immediate interventions to survive [2]. CHDs account for the highest percentage of hospitalizations (34%), have higher costs, and require longer hospital stays than any other congenital defects in neonates [3]. Neonates with CHDs require both neonatal intensive care and critical care. Therefore, neonates undergoing congenital heart surgery require highly specialized, resource-intensive perioperative care [4].

Adult and pediatric studies demonstrated that the cohorting of patients with specific conditions may improve outcomes. The specialization of care is associated with better outcomes [4–11]. Furthermore, fetal echocardiography has increased the frequency of diagnosis of prenatal CHDs, altered disease patterns observed in the neonatal intensive care unit (NICU), and resulted in better outcomes [12]. Cohorting and prenatal diagnosis may be the key to a better prognosis in infants with CHDs. Neonates who need surgical interventions are often cared for in both the NICU (specialized for neonates, mainly with prematurity) and pediatric intensive care unit (PICU, specialized for infants who need critical care). Limited information is available on the impact of the perioperative location on the outcomes of neonates undergoing cardiac surgery for CHDs. We speculate that the disposition of neonates in the NICU and PICU may affect management patterns as well as morbidity and mortality. This was a retrospective observational study to evaluate management patterns, morbidity, and mortality among infants before and after the renovation of the NICU and PICU in a single university hospital. The aim of the present study was to demonstrate that the preoperative location may affect the outcomes of infants undergoing surgical interventions for CHDs.

Facility Policy

The University of Tokyo Hospital is located in and covers the east Tokyo metropolitan area. In the NICU, as a perinatal medical center, we care for neonates with prematurity and/or a wide variety of disorders. Pregnant women with a fetal diagnosis of CHDs are referred to our hospital and we schedule the birth plan. If neonates diagnosed with CHDs after their birth need interventions during the neonatal period, we accept neonatal transport all day. As a perinatal medical center, approximately 1,200 infants are born each year in our hospital. Neonates diagnosed with CHDs are initially admitted to the NICU in our hospital. Our PICU functions as a tertiary center and we offer intensive care for critically ill patients and perioperative patients. Neonates with CHDs are treated in the PICU after cardiac surgery because critical care is indispensable for infants soon after cardiac surgery. Even before cardiac surgery, we predominantly dispose perioperative neonates who need critical procedures, including hypoxia therapy with nitrogen for high pulmonary blood flow, renal replacement therapy, and extracorporeal circulation, in the PICU. Some neonates with severe prematurity are treated in the NICU even with these procedures. After stabilized, neonates leave the PICU for the NICU or the Pediatric Ward to continue the postoperative care. The NICU and PICU were both renovated in 2019. The NICU and PICU were previously located on different floors. Therefore, it was often difficult to transfer perioperative patients safely between the NICU and PICU. In the renovation, we planned to locate these perioperative centers next to each unit to facilitate the exchange of patients in a timely manner when their conditions change.

Subjects

In the present study, we enrolled neonates admitted to the University of Tokyo Hospital NICU who underwent cardiac surgery and were treated in the PICU during hospitalization. Infants with a fetal diagnosis who were born as scheduled in our hospital and those who were diagnosed after birth and transferred to our hospital were included. We collected data on infants born in two different time periods (“Before”: between January 2017 and December 2018, and “After”: between January 2020 and December 2021). The “Before” group comprised patients managed in the previous ward, while the “After” group included patients managed in the new ward. We excluded patients in 2019 as a washout period because they were born in the transition between the “Before” and “After” time periods. Patients who continued to be hospitalized after January 2022 were also excluded.

Medical record review

To compare the clinical features of infants who underwent cardiac surgery during neonatal periods, we retrospectively investigated patients admitted to our hospital using their medical records. The diagnosis of CHD in each case was based on an echocardiographic evaluation by pediatric cardiologists, and corrected from the findings of invasive procedures and surgery if needed. Ligation or clipping for patent ductus arteriosus as an isolated cardiac defect in preterm infants was excluded because it had a different etiology from other CHDs and patients with patent ductus arteriosus were only cared for in the NICU in our hospital. We did not count catheter interventions, pacemaker placement, or re-operation soon after surgery (e.g. the adjustment of a Blalock-Taussig shunt).

We initially compared basic characteristics between the time periods. To clarify differences among infants admitted between the different time periods, we reviewed the following perinatal data via medical records: the number of cardiac surgeries during that period, maternal age, infertility treatment, sex, fetal diagnosis, birth place, delivery method, gestational age, preterm birth, birth weight, and Apgar scores at one and five minutes. We also reviewed the following neonatal data during hospitalization: chromosomal disorders, congenital anomalies, surgical interventions, the length of hospital stay, outcomes, the intravenous use of prostaglandin E1 (PGE1), the use of cardiopulmonary bypass during cardiac surgery, the number of times patients had moved between wards, the length of stay in the PICU after cardiac surgery, and the ward they had moved to when they left the PICU. These data were compared between the different time periods. To compare the severity of CHDs, we classified disease patterns according to Botto et al [13]. We also compared the complexity of the cardiac surgeries performed according to the Risk Adjustment for Congenital Heart Surgery (RACHS-1) method [14]. All data were collected without patient identification.

Infertility treatment included attempts of assisted ovulation, artificial insemination, or assisted reproductive technology; fertilization-embryo transfer, intracytoplasmic sperm injection, and the use of cryopreserved embryos. Small for gestational age was defined as a birth weight less than the 10th percentile of the neonatal growth curve of Japanese infants at birth [15]. Congenital anomalies in infants were defined as functional and/or structural abnormalities diagnosed and requiring treatment during their hospital stay. These anomalies included neurological diseases, gastrointestinal diseases, genitourinary anomalies, orthopedic and plastic surgical diseases, and other conditions. Chromosomal disorders included defects proven by G-banding and/or fluorescence in situ hybridization during the hospital stay. The primary outcomes for the present study were differences in the survival hospital discharge rate between the “Before” and “After” groups. We also planned to clarify changes in the disposition pattern of CHD infants.

Statistical analysis

Continuous data were compared between groups by the t-test. Categorical data were compared using the chi-square test. All statistical analyses were performed using EZR, a graphical user interface for R [16]. Two-sided P-values less than 0.05 were considered to be significant.

Basic characteristics

Overall patient data are summarized in Table 1. A total of 135 neonates with CHDs underwent cardiac surgery during the two time periods. Twenty-five patients were excluded because they were preterm infants and only underwent ligation or clipping for patent ductus arteriosus. Thirteen patients were excluded because they were not discharged before January 31st, 2022. The total number in Table 1 was equal to the number of patients admitted to the NICU and PICU who matched the inclusion criteria. Fifty-three cardiac surgeries were performed on 48 patients in the “Before” period, and 56 on 49 patients in the “After” period.

Maternal age was significantly higher in the “After” group than in the “Before” group (p < 0.01). No significant differences were observed in infertility treatment, sex, fetal diagnosis, outborn patients, Caesarean section, gestational age, preterm birth, birth weight, low birth weight and very low birth weight infants, SGA infants, Apgar scores at one and five minutes, congenital anomalies, surgical interventions, the use of PGE1 medication, or the use of cardio-pulmonary bypass (CPB) during cardiac surgery. We classified infants with coexisting illnesses (chromosomal disorders, congenital anomalies, and/or surgical interventions) together as “complicated” cases to clarify the severity of noncardiac problems. Complicated cases were significantly more frequent in the “After” group than in the “Before” group.

Table 1 Basic characteristics of patients in different time periods
	Before (n = 48)	After (n = 49)	P value
Total number of cardiac surgeries	53	56
Maternal age (SD)	33.1 (4.6)	35.2 (5.0)	< 0.05
Infertility treatment (%)	3 (6.3)	8 (16.3)	0.21
Male (%)	25 (52.1)	23 (47.0)	0.76
Fetal diagnosis (%)	33 (68.8)	34 (69.4)	1.0
Outborn (%)	16 (33.3)	19 (38.8)	0.73
Caesarean section (%)	17 (35.4)	18 (36.7)	1.0
Gestational age	38/0	38/2	0.52
Preterm (%)	8 (16.7)	9 (18.4)	1.0
Birth weight, gram (SD)	2661.3 (673.5)	2875.3 (606.6)	0.1
Low birth weight (%)	12 (25.0)	10 (20.4)	0.77
Very low birth weight (%)	5 (10.4)	1 (2.0)	0.2
SGA (%)	11 (22.9)	9 (18.4)	0.76
Apgar 1 min (SD)	7.4 (1.1)	7.4 (1.4)	0.91
Apgar 5 min (SD)	8.2 (0.9)	8.1 (1.1)	0.83
Chromosomal disorder (%)	6 (12.5)	13 (26.5)	0.14
Congenital anomaly (%)	5 (10.4)	10 (20.4)	0.28
Surgical intervention (%)	5 (10.4)	8 (16.3)	0.58
PGE1 (%)	33 (68.8)	30 (61.2)	0.57
CPB (%)	31 (58.5)	35 (62.5)	0.92
Complicated (%)	10 (20.8)	20 (40.8)	< 0.05
Data represent the mean standard deviation (SD) or a number (%)
SGA: Small for Gestational Age
PGE1: Prostaglandin 1, CPB: Cardio-pulmonary bypass

Types of CHDs

The classification and analysis of CHDs in etiologic studies are challenging because of the diversity of cardiac phenotypes. We used two methods to clarify the phenotype and severity of neonatal CHDs. One method involves the categorization of CHDs by the classification proposed by Botto et al [13]. They classified CHDs into eight groups (conotruncal, atrioventricular septal defect: AVSD, anomalous pulmonary venous return: APVR, heterotaxy, complex, left ventricular outflow tract obstruction; LVOTO, septal, right ventricular outflow tract obstruction: RVOTO) according to the heart defect type, heart defect complexity, and overall pattern of malformations. The results obtained are shown in Fig. 1. We then classified congenital heart surgeries into six risk categories (Risk categories 1–6) according to the RACHS-1 method (Fig. 2) [14]. We did not perform statistical processing for the classification of CHDs because the sample size was too small to detect differences among the categories.

Bed control and Outcomes

We compared differences in disposition patterns and clinical outcomes between the “Before” and “After” groups in Table 2. Patients were exchanged between the NICU and PICU significantly more frequently in the “After” group than in the “Before” group. Patients in the “After” group left the PICU for the NICU more often and also left the PICU earlier after cardiac surgeries than those in the “Before” group. No significant differences were detected in survival hospital discharge rates between the groups.

Table 2 Bed control and outcomes
	Before (n = 48)	After (n = 49)	P value
Exchange between the NICU and PICU (total number)	78	122		< 0.01
Exchange between the NICU and PICU (per person)	1.6	2.5		< 0.01
Discharged from the NICU (%)	32 (60.3)	51 (91.1)		< 0.01
Discharged from the Pediatric Ward (%)	19 (35.8)	3 (5.4)		< 0.01
Mean length of stay in the PICU after surgery (SD)	13.1 (15.8)	8.5 (5.7)		< 0.01
Mean length of hospital stay (SD)	47.6 (40.4)	85.4 (57.6)		< 0.01
Hospital discharge (%)	45 (93.7)	47 (95.9)		0.98
Data represent the mean standard deviation (SD) or a number (%)
NICU: neonatal intensive care unit, PICU: pediatric intensive care unit

Neonates with CHDs have the characteristics of both neonates and patients with heart defects. We herein conducted a retrospective analysis to compare clinical management before and after the renovation of the NICU and PICU in a single center. Patients were exchanged more frequently in the “After” group than in the “Before” group because ward renovation enabled the easy transport of patients. The number of complicated cases was higher, the length of hospital stay was longer, and the length of stay in the PICU was shorter in the “After” group.

Limited information is available on the relationship between ward renovations and patient outcomes in neonatal settings. This was an observational study, a significant feature of which lies in the original perspective that the renovation of wards may improve the clinical outcomes of neonates with CHDs. Many of the basic maternal and neonatal characteristics did not significantly differ between the groups, which indicated that the severity of infant conditions as neonates did not markedly differ between the groups. However, maternal age was older and the number of complicated cases was significantly higher in the “After” group. An older maternal age was concordant with the national trend of late childbearing [17]. More complicated cases were admitted to our hospital after the renovation of the wards. The presence of a major noncardiac structural anomaly and major chromosomal abnormality increases the risk of an in-hospital death [14]. Even with the complexity of noncardiac anomalies, in-hospital mortality was similar between the “Before” and “After” groups. The length of hospital stay was longer in the “After” group, which may be partly due to the complexity of noncardiac anomalies.

As evident from the findings of previous studies, heart defects are anatomically, clinically, epidemiologically, and developmentally heterogeneous [13]. Although the classification of CHDs is challenging, we attempted to compare the severity of CHDs between the groups from several viewpoints. The frequency of the intravenous use of PGE-1 did not significantly differ between the groups, which indicates that the prevalence of CHDs dependent on ductus arteriosus circulation was similar. The classification of CHDs and cardiac surgery also implied few differences between the groups. We did not observe marked differences in the types of CHDs between the groups. RACHS-1 was designated to develop a consensus-based method of risk adjustments for in-hospital mortality among children younger than 18 years after surgery for CHDs. The classification of CHDs according to severity is also challenging. From a surgical point of view, the use of CPB during cardiac surgery indicated intracardiac surgeries, which are often more complex. The frequency of CPB was similar between the groups, implying that the complexity of cardiac surgeries was similar between the groups. In comparisons of the two groups, few differences were detected in maternal and neonatal characteristics, the severity of CHDs, and the complexity of cardiac surgeries.

The survival discharge rate was similar between the groups, and the renovation of the wards in itself did not improve the mortality rate. The exchange of patients between the NICU and PICU occurred more frequently in the “After” group, and patients in the “After” group left the PICU for the NICU more often than those in the “Before” group. The length of stay in the PICU after cardiac surgery was significantly shorter in the “After” group, which enabled the more effective use of medical resources. They were archived by renovating the NICU and PICU adjacent to each other. Ward renovation may change the clinical management of infants with CHDs. In several adult and pediatric studies, the cohorting of patients with specific diseases improved outcomes. In the adult field, access to a neurosurgical ICU resulted in better clinical outcomes for patients with stroke and intracerebral hemorrhage [5, 6]. Furthermore, the specialty-specific admission of patients with gastroenterology-related illnesses was associated with better clinical outcomes [7]. In the pediatric population, infants with cancer had a significantly higher survival rate when managed in a pediatric cancer center [8, 9]. Moreover, there have been several studies on the cohorting of neonates. Lui et al. demonstrated that statewide coordinated strategies to reduce nontertiary hospital births and optimize the transport of outborn infants to perinatal centers markedly improved the outcomes of extremely premature infants [10]. Chung et al. showed that fetal echocardiography increased the frequency of a prenatal CHD diagnosis, altered disease patterns in the NICU, and resulted in better 1-year outcomes [12]. Gupta et al. indicated that the preoperative location affected the outcomes of children undergoing surgery for CHDs [11]. In the present study, the renovation of the NICU and PICU next to each other appeared to change disposition plans and clinical outcomes. Further investigations are warranted to clarify the influence of the ward design on the long-term outcomes of patients.

Since this was a retrospective descriptive study to investigate whether ward renovations influence patient management policies, there were several limitations. The results obtained cannot be generalized because of the bias in sampling and data being from a single center. Criteria for admission and management plans may have slightly differed between the groups. However, since there was only a 3-year time difference between the groups, overall policies did not markedly change. Patient exchange plans between the wards were decided by the attending physicians; therefore, differences in the disposition plans of the patients were the soft endpoint of this study.

Management plans for neonates with CHDs may be changed depending on the ward arrangement. The placement of the NICU and PICU adjacent to each other may be an important strategy to improve the outcomes of neonates with CHDs. Further studies that include a cost analysis and examine changes in the long-term prognosis of patients are needed.

Ethics approval This research study was conducted retrospectively with the approval of the Certified Clinical Research Review Board at The University of Tokyo Hospital (No. 2701-(5)).

Informed consent Informed consent was waived because of the retrospective nature of the study in accordance with the research ethics committee at the University of Tokyo Hospital.

Conflict of interest The authors have no relevant financial or non-financial interests to disclose.

Author contributions Kyosuke Ibi and Naoto Takahashi contributed to the study conception and design. Kyosuke Ibi performed material preparation, data collection and analysis, wrote the first draft of the manuscript. Naoto Takahashi commented on previous versions of the manuscript. Kyosuke Ibi and Naoto Takahashi read and approved the final manuscript.

Chu PY, Li JS, Kosinski AS, Hornik CP, Hill KD (2017) Congenital Heart Disease in Premature Infants 25–32 Weeks' Gestational Age. J Pediatr 181:37–41. https://doi.org/10.1016/j.jpeds.2016.10.033
McElhinney DB, Wernovsky G (2001) Outcomes of neonates with congenital heart disease. Curr Opin Pediatr 13:104–110. https://doi.org/10.1097/00008480-200104000-00003
Johnson JT, Tani LY, Puchalski MD, Bardsley TR, Byrne JL, Minich LL, Pinto NM (2014) Admission to a dedicated cardiac intensive care unit is associated with decreased resource use for infants with prenatally diagnosed congenital heart disease. Pediatr Cardiol 35:1370–1378. https://doi.org/10.1007/s00246-014-0939-x
Johnson JT, Sullivan KL, Nelson RE, Sheng X, Greene TH, Bailly DK, Eckhauser AW, Marino BS, Minich LL, Pinto NM (2020) Factors That Contribute to Cost Differences Based on ICU of Admission in Neonates Undergoing Congenital Heart Surgery: A Novel Decomposition Analysis. Pediatr Crit Care Med 21:e842-e847. https://doi.org/10.1097/pcc.0000000000002507
Cadilhac DA, Pearce DC, Levi CR, Donnan GA; Greater Metropolitan Clinical Taskforce and New South Wales Stroke Services Coordinating Committee (2008) Improvements in the quality of care and health outcomes with new stroke care units following implementation of a clinician-led, health system redesign programme in New South Wales, Australia. Qual Saf Health Care 17:329–333. https://doi.org/10.1136/qshc.2007.024604
Diringer MN, Edwards DF (2001) Admission to a neurologic/neurosurgical intensive care unit is associated with reduced mortality rate after intracerebral hemorrhage. Crit Care Med 29:635–640. https://doi.org/10.1097/00003246-200103000-00031
Slattery E, Harewood GC (2012) Specialty-specific admission: a cost-effective intervention? Ir J Med Sci 181:87–91. https://doi.org/10.1007/s11845-011-0758-5
Kramer S, Meadows AT, Pastore G, Jarrett P, Bruce D (1984) Influence of place of treatment on diagnosis, treatment, and survival in three pediatric solid tumors. J Clin Oncol 2:917–923. https://doi.org/10.1200/jco.1984.2.8.917
Stiller CA (1988) Centralisation of treatment and survival rates for cancer. Arch Dis Child 63:23–30. https://doi.org/10.1136/adc.63.1.23
Lui K, Abdel-Latif ME, Allgood CL, Bajuk B, Oei J, Berry A, Henderson-Smart D; New South Wales and Australian Capital Territory Neonatal Intensive Care Unit Study Group (2006) Improved outcomes of extremely premature outborn infants: effects of strategic changes in perinatal and retrieval services. Pediatrics 118:2076–2083. https://doi.org/10.1542/peds.2006-1540
Gupta P, Beam BW, Noel TR, Dvorchik I, Yin H, Simsic JM, Tobias JD (2014) Impact of preoperative location on outcomes in congenital heart surgery. Ann Thorac Surg 98:896–903. https://doi.org/10.1016/j.athoracsur.2014.04.123
Chung ML, Lee BS, Kim EA, Kim KS, Pi SY, Oh YM, Park IS, Seo DM, Won HS (2010) Impact of fetal echocardiography on trends in disease patterns and outcomes of congenital heart disease in a neonatal intensive care unit. Neonatology 98:41–46. https://doi.org/10.1159/000264673
Botto LD, Lin AE, Riehle-Colarusso T, Malik S, Correa A; National Birth Defects Prevention Study (2007) Seeking causes: Classifying and evaluating congenital heart defects in etiologic studies. Birth Defects Res A Clin Mol Teratol 79:714–727. https://doi.org/10.1002/bdra.20403
Jenkins KJ, Gauvreau K, Newburger JW, Spray TL, Moller JH, Iezzoni LI (2002) Consensus-based method for risk adjustment for surgery for congenital heart disease. J Thorac Cardiovasc Surg 123:110–118. https://doi.org/10.1067/mtc.2002.119064
Itabashi K, Fujimura M, Kusuda S, Tamura M, Hayashi T, Takahashi T et al; Committee of Neonatal Medicine of Japan Pediatric Society (2010) Introduction of new gestational age-specific standards for birth size. J Jpn Pediatr Soc 114:1271–93 (in Japanese).
Kanda Y (2013) Investigation of the freely available easy-to-use software 'EZR' for medical statistics. Bone Marrow Transplant 48:452–458. https://doi.org/10.1038/bmt.2012.244
Vital, Health and Social Statistics Office (2022) VITAL STATISTICS OF JAPAN 2019. Ministry of Health, Labor, and Welfare. https://www.mhlw.go.jp/english/database/db-hw/vs01.html. Accessed 27 September 2022

No competing interests reported.

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Inter-unit management of neonates with congenital heart diseases between NICU and PICU

Status:

Version 1

Abstract

Figures

Introduction

Materials And Methods

Facility Policy

Subjects

Medical record review

Statistical analysis

Results

Basic characteristics

Types of CHDs

Bed control and Outcomes

Discussion

Conclusion

Declarations

References

Additional Declarations

Status:

Version 1