www.elsevier.com/locate/jpedsurg

Journal of Pediatric Surgery (2011) 46, 814–816

Influence of location of delivery on outcome in neonateswith congenital diaphragmatic herniaAhmed Nasr 1, Jacob C. Langer 1,⁎for the Canadian Pediatric Surgery Network

Department of Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada M5G1X8

Received 24 January 2011; accepted 11 February 2011

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Key words:Congenital diaphragmatichernia;

CAPSnet;Perinatal center

AbstractBackground: Although it is often recommended that infants with antenatally diagnosed congenitaldiaphragmatichernia(CDH)bedeliveredinaperinatalcenter, thispracticehasnotbeenscientificallyvalidated.Methods:Data were obtained from The Canadian Pediatric Surgery Network, covering 16 pediatric surgicalcenters over a 4-year period. Inborn was defined as birth in a hospital with a neonatal intensive care unit orconnected to a neonatal intensive care unit by a bridge or tunnel.Outbornwas defined as requiring transfer byambulance or flight. Primary outcome variable was mortality.Results: Of 140 infants with antenatally diagnosed CDH, 75 were inborn and 65 were outborn. Univariateanalysis demonstrated no significant difference between groups with respect to gestational age, birth weight,days to surgery, primary repair, need for ventilation, use of pressors or extracorporealmembrane oxygenation,or incidence of comorbidities. Severity of illness, as reflected by the Score for Neonatal Acute Physiology II(SNAP II), was significantly higher among inborn infants (21 [interquartile range, 7-32] vs 5 [interquartilerange, 9-12];P= .0001). Logistic regression analysis, controlling for severity of illness, revealed that locationof delivery was a significant independent predictor formortality, with an odds ratio of dyingwhen outborn of2.8 (P = .04).Conclusions: Outborn delivery is a significant predictor of mortality for infants with antenatallydiagnosed CDH.© 2011 Elsevier Inc. All rights reserved.

The detection of many congenital anomalies has predict long-term outcome. Antenatal diagnosis facilitates

increased because of improved antenatal ultrasounddiagnosis. This enables fetal medicine specialists to lookfor other associated structural anomalies, test for geneticabnormalities, offer fetal therapy in selected cases, and

⁎ Corresponding author. Division of General and Thoracic Surgery, Theospital for Sick Children, Toronto, Ontario, Canada M5G1X8.E-mail address: jacob.langer@sickkids.ca (J.C. Langer).1 The Canadian Paediatric Surgery Network.

022-3468/$ – see front matter © 2011 Elsevier Inc. All rights reserved.oi:10.1016/j.jpedsurg.2011.02.007

parental counseling and allows preparation for a poten-tially complex postnatal course. In addition, it permitsparents and health providers to make appropriate choicesregarding location, timing, and mode of delivery for theaffected fetus [1,2].

There are no data in the literature discussing whetherinfants with a prenatal diagnosis of congenital diaphrag-matic hernia (CDH) should be delivered in a perinatalcenter with a level 3 neonatal intensive care unit (NICU)and surgical facilities (inborn) or if they could be safely

Table 1 Demographics and physiological parameters

Inborn (n = 75) Outborn (n = 65) P value

Gestation age 37.7 ± 1.9 37 ± 6.5 .3Birth weight 3079 ± 655 2959 ± 789 .3SNAP II 21 (IQR, 7-32) 5 (IQR, 9-12) .0001Need for pressors 49 (65%) 44 (67%) .9Ventilation 72 (96%) 60 (92%) .3ECMO 5 (6%) 10 (15%) .1

815Influence of location of delivery on outcome in CDH

delivered in a more local hospital and then transferred to aperinatal center (outborn). Theoretically, inborn deliveryshould result in better outcomes because of immediateaccess to high-level neonatal and surgical care, advancedtechnology such as extracorporeal membrane oxygenation(ECMO) and high-frequency oscillation, and the avoidanceof neonatal transport situations in which expertise orequipment may not be readily available. However, thisquestion has not been previously studied using population-based methodology. Our goal was to determine the impactof delivery site on outcomes for neonates diagnosedwith CDH.

Table 2 Primary and secondary outcomes

Inborn(n = 75)

Outborn(n = 65)

P value

Days to surgery 5 (IQR, 2-6) 6.5 (IQR, 2-15) .3Primary repair 37 (49%) 24 (37%) .6Complications 23 (30%) 30 (46%) .5Comorbidities 46 (61%) 50 (76%) .1Length of stay (d) 35.1

(IQR, 15-47)37.2(IQR, 14-46)

.7

% Discharged home 60% 60% .1Mortality 17 (20%) 21 (18%) .3

1. Methods

1.1. Study design

This was a retrospective cohort study.

1.2. Data source

Data were obtained from the Canadian Pediatric SurgeryNetwork (CAPSNet), a multidisciplinary group of Canadi-an health researchers covering 16 tertiary perinatal centersin Canada. In addition to pediatric surgeons, groupmembers extend to other disciplines including neonatology,maternal-fetal medicine specialists, and epidemiologists.All infants born with CDH and managed at one of theCAPSNet centers between 2005 and 2008 were surveyed.Only those in which an antenatal diagnosis was made wereincluded in this study.

1.3. Definitions

The following definitions were used to identify outborn/inborn:

Inborn: infant born in the same building as the NICU or in adifferent building connected by a tunnel or bridge to the NICU.A prenatal diagnosis is made, and the delivery site plan is met.Outborn: infant born in a different building from the NICU,requiring transport in an ambulance or other form of transporta-tion. A prenatal diagnosis is made, and delivery site plan is met.Outborn may also include infants delivered in a hospital differentfrom the one intended in which a prenatal diagnosis is made butdelivery site plan is not met (ie, precipitous labor).

1.4. Statistical analysis

The Student t test was used to compare differences inmeans between groups, and χ2 was used to assess thedifferences in proportions between groups. Continuousoutcome variables exhibiting a skewed distribution weretransformed, using natural logarithms, before t tests wereconducted to satisfy the prerequisite assumptions ofnormality. Logistic/linear regression was used to adjust

for possible confounding variables between both groups(inborn/outborn).

2. Results

Of a total of 212 infants with CDH in the CAPSNetdatabase over this period, 140 infants were antenatallydiagnosed and were included in this study. There were75 inborn infants and 65 outborn infants. There were nodifferences between groups with regard to gestational age(37.7 ± 1.9 and 37 ± 6.5 weeks, respectively; P = .3) or birthweight (3079 ± 655 and 2959 ± 789 g; P = .3). The inborngroup was significantly sicker when compared with theoutborn group, as measured by the SNAP II score(21 [interquartile range {IQR}, 7-32] vs 5 [IQR, 9-12]; P =.0001) (Table 1) [3].

There was no significant difference between groups withregard to the need for ECMO, vasopressor medications, orventilation. Furthermore, there were no differences betweengroups with regard to the time between birth and surgery, andthe need for a patch repair (Table 2).

2.1. Univariate analysis

There was no difference in the mortality rate betweengroups in a univariate analysis (20% for the inborn infantsand 18% for the outborn infants; P = .3.) (Table 2). Therewere also no differences between the inborn and the outborninfants with regard to complications, comorbidities, length ofhospital stay, and percentage discharged home (Table 2).

816 A. Nasr et al.

2.2. Multivariate analysis

Logistic regression for mortality revealed that the locationof delivery was a significant independent predictor formortality, as were the SNAP II score (P = .005),comorbidities (P = .07), and the need for vasopressormedications (P = .05) and ECMO (P = .004). The odds ratioof dying when outborn was 2.8 (P = .04).

3. Discussion

Infants with CDH usually have some element ofpulmonary hypoplasia, which causes respiratory distress atthe time of delivery. In addition, many infants with CDHquickly develop pulmonary hypertension, which may lead todeath even in children with sufficient pulmonary parenchy-ma to support life. In recent years, improved survival in CDHbabies has resulted from a combination of new approaches,including stabilization before surgery, the utilization ofECMO and high-frequency oscillation, and the use of gentleventilation to minimize lung damage during the early stagesof resuscitation [4,5]. Because these interventions require ahigh level of sophisticated expertise and experience, as wellas technological resources, it has been widely believed thatthese infants should always be delivered at a perinatal center.However, this philosophy has not been proven in apopulation-based manner; and there are some infants forwhom delivery at a perinatal center is difficult (if notimpossible) because of resource or geographical obstacles.

In this study, we used the CAPSNet database, whichincludes all infants with CDHmanaged in a Canadian pediatricsurgical center, to answer this question. We found that thelocation of delivery, in addition to SNAP II score, comorbid-ities, and the need for vasopressor medications and ECMO,was a significant predictor for mortality. In Canada, pediatricsurgery centers are all tertiary children's hospitals. This maynot be true in the United States where a children's hospitalmay be a floor within a bigger hospital. Several of these placesdo not have the resources that exist in this study group.

The most likely explanation for our finding is the issue oflocal expertise in the delivery room and in the first few hoursafter delivery. The immediate management of a neonate withCDH consists of respiratory monitoring, insertion of anasogastric tube for bowel decompression, establishment of

intravenous access, and application of oxygen through anendotracheal tube. The use of noninvasive positive-pressurerespiratory support (ie, nasal or bag-mask continuouspositive airway pressure) should be avoided because itleads to further gaseous distension of the herniated viscera,which may further exacerbate cardiorespiratory compromise[5-7]. ‘‘Gentle ventilation’’ techniques, the early use ofECMO in appropriately selected infants, and the use ofpulmonary vasodilator therapy with nitric oxide are likelyonly available in experienced perinatal centers.

One potential weakness of our study is the possibility thatthe inborn and outborn groups were not equivalent. Althoughthe 2 groups were similar with respect to gestational age atdelivery and birth weight, it is possible that prenatal factorssuch as lung-head ratio, polyhydramnios, gestational age atdiagnosis, or the presence of other anomalies might have ledto purposeful inborn delivery of higher-risk patients andoutborn delivery of those fetuses that were felt to be of lowerrisk. This possibility is supported by the higher SNAP IIscores in the inborn group. However, this bias would beexpected to increase mortality in the inborn group; and infact, the mortality was lower in this group despite the worseprognosis predicted by the SNAP II scores.

In summary, our data suggest that outborn delivery is asignificant predictor of mortality for infants with antenatallydiagnosed CDH. Whenever possible, these infants should bedelivered in a perinatal center.

References

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