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Strokovni članek Zdrav Vestn | mesec – mesec 2017 | Letnik 86
id
1
 Unit of Cardiology, 
Division of Paediatrics, 
University Medical Centre 
Ljubljana, Ljubljana
2
 Division of Paediatrics, 
University Medical Centre 
Ljubljana, Ljubljana
Korespondenca/
Correspondence:
Samo Vesel,  
e: samo.vesel@mf.uni-lj.
si
Ključne besede:
prirojene srčne napake; 
epidemiologija; pulzna 
oksimetrija; pediatrija; 
kardiologija
Key words:
congenital heart defects; 
epidemiology; pulse 
oximetry; paediatrics; 
cardiology
Citirajte kot/Cite as:
Zdrav Vestn. 2017;  
86:276–85.
prispelo: 13. 9. 2016 
Sprejeto: 7. 5. 2017
Reprodukcija človeka izvirni znanstveni članek Zdrav Vestn | julij – avgust 2017 | Letnik 86
Congenital heart disease detection in 
Slovenia: Improvement potential of neonatal 
pulse oximetry screening
Diagnostika prirojenih srčnih napak v Sloveniji: Kaj bi lahko 
doprinesla uvedba presejanja s pulzno oksimetrijo
Zoltan Narancsik,
1
 Minca Mramor,
2
 Samo Vesel
1
Abstract
Introduction: Patients with major or critical congenital heart disease (CHD) require surgical treat-
ment or interventional cardiac catheterization during the first year or 28 days of life, respectively. 
Currently, the detection of CHD in Slovenia relies on the prenatal ultrasound screening and physical 
examination of the newborn.
Aims: 1) To determine the incidence of major/critical CHD in Slovenia; 2) to determine the pro-
portion of infants with late detection of major/critical CHD based on the existing clinical practice; 
and 3) to estimate the improvement in CHD detection with a nation-wide neonatal pulse oximetry 
screening programme.
Methods: We reviewed the documentation of all patients with major/critical CHD born in Slovenia 
in years 2007–2012. W e determined whether the heart condition was detected: 1) on time – prenatally 
or prior to discharge from maternity ward; or 2) late – after discharge or at autopsy.
Results: Among 128,839 live-born babies, 293 were diagnosed with a major CHD (2.27/1000 live 
births, 95 % confidence interval (CI): 2.0–2.5/1000) and of those 150 with a critical CHD (1.16/1000 
live births, 95 % CI: 1.0–1.4/1000). Late detection occurred in 17.7 % of patients with major and 10.9 % 
patients with critical CHD. Out of 15 late-detected patients with critical CHD, 14 had an obstructive 
left heart lesion. In 2 patients CHD was diagnosed after death.
Conclusions: Detection of CHD in Slovenia is satisfactory. However, in the observed period, 10.9 % 
of newborns with a critical CHD were discharged undiagnosed. A nation-wide pulse oximetry 
screening programme could improve pre-discharge CHD detection.
Izvleček
Uvod: Prirojene srčne napake (CHD) so najpogostejše prirojene napake organov in organskih siste-
mov. Pri polovici bolnikov so napake hemodinamsko pomembne, kar pomeni, da je potrebno kirur-
ško ali kardiološko intervencijsko zdravljenje v prvem letu življenja. Podskupino predstavljajo bolni-
ki s kritičnimi CHD, pri katerih je zdravljenje potrebno v prvih 28 dneh življenja. CHD ugotavljamo 
s kliničnim pregledom novorojenčka, pred rojstvom pa z ultrazvočnim pregledom plodovega srca. 
Kljub široki dostopnosti obeh preiskav ostane del bolnikov do odpusta iz porodnišnice neprepozna-
nih. Kot uspešna dopolnilna metoda za prepoznavanje novorojenčkov s CHD se je v zadnjih letih 
uveljavilo presejanje s pulzno oksimetrijo. 
Namen raziskave: 1) ugotoviti incidenco prirojenih srčnih napak v Sloveniji, 2) ugotoviti delež bol-
nikov, ki ostanejo neprepoznani do odpusta iz porodnišnice, in 3) oceniti potencial za izboljšanje 
prepoznave CHD ob morebitni uvedbi presejanja s pulzno oksimetrijo na nacionalni ravni.

congenital heart disease detection in Slovenia: improvement potential of neonatal pulse oximetry screening 277
iZViRNi ZNaNStVeNi čLaNek
Metode: V raziskavo smo vključili otroke s hemodinamsko pomembnimi/kritičnimi CHD, rojenimi 
v Sloveniji v obdobju 2007–2012. Podatke smo pridobili iz različnih podatkovnih baz in osebnih 
kartotek bolnikov, vodenih v sklopu Univerzitetnega kliničnega centra Ljubljana, edinega centra za 
kardiokirurško in kardiološko intervencijsko obravnavno otrok s prirojenimi srčnimi napakami v 
Sloveniji. Za vsakega posameznega bolnika smo opredelili, ali je bila CHD razpoznana pravočasno 
(pred rojstvom oz. pred odpustom iz porodnišnice) ali pozno (po odpustu iz porodnišnice oz. po 
smrti).
Rezultati: V obravnavanem obdobju je bilo v Sloveniji rojenih 128.839 otrok. Pri 293 otrocih 
(2,27/1000) smo ugotovili hemodinamsko pomembno CHD, pri 150 od njih (1,16/1000) smo napako 
opredelili kot kritično. Med bolniki s hemodinamsko pomembnimi CHD je bilo pozno razpoznanih 
17,7 %, med bolniki s kritičnimi CHD pa 10,8 % otrok. Od 15 bolnikov s pozno razpoznanimi kritič-
nimi CHD, jih je 14 imelo napake z obstrukcijo toka krvi v področju levostranskih srčnih struktur. 
Dva bolnika sta bila razpoznana šele po smrti.
Zaključki: Razpoznava novorojenčkov s hemodinamsko pomembnimi in kritičnimi CHD z usta-
ljenimi diagnostičnimi postopki, prenatalnim ultrazvočnim presejanjem in kliničnim pregledom 
novorojenčka je v Sloveniji dobra, še vedno pa ostaja ob odpustu iz porodnišnic približno desetina 
bolnikov s kritičnimi CHD neprepoznanih. Delež pozno razpoznanih bolnikov s kritičnimi CHD bi 
lahko zmanjšali z uvedbo presejalnega testiranja novorojenčkov s pulzno oksimetrijo.
1. Introduction
Congenital heart disease (CHD) is 
the most common group of congenital 
malformations and accounts for more 
than one third of major congenital ano-
malies diagnosed prenatally or in infan-
cy (1). The incidence of CHD is approxi-
mately 6–7/1000 newborns (2,3). Half 
of the patients have minor CHD that 
does not require treatment, or can be 
corrected later on in life. The remainder 
require cardiac surgery or interventional 
cardiac catheterization in the first year 
of life. Early diagnosis is particularly im-
portant in patients with duct-dependent 
lesions in which closure of the ductus 
arteriosus can result in acute cardiova-
scular collapse, acidosis, and death (4-6). 
Despite the improvement in diagnostics 
and treatment of CHD in the last few de-
cades, CHD still cause significant morbi-
dity and mortality, accounting for more 
than one third of deaths in children with 
congenital anomalies in the first year of 
life (7).
Screening strategies to detect CHD 
include prenatal ultrasound and physical 
examination of the newborns. However, 
using just these two diagnostic options, a 
sizeable proportion of patients remains 
undetected before discharge from the 
maternity units  (8-10). Neonatal pulse 
oximetry screening reduces this diagno-
stic gap and helps identify infants with 
critical CHD before they present with 
acute cardiovascular collapse (11–14).
The aims of our study were to: 1) de-
termine the incidence of major and cri-
tical CHD in Slovenia; 2) determine the 
proportion of infants with late detection 
of major/critical CHD based on existing 
clinical practice; and 3) estimate the im-
provement in CHD detection with a na-
tion-wide neonatal pulse oximetry scre-
ening programme.
2. Methods
The study group consisted of all live-
-born infants with major/critical CHD 
in Slovenia from January 1, 2007 , through 
December 31, 2012. Patients were iden-
tified by reviewing and cross-checking 
data from four different databases: 1) pa-
tients referred for surgical treatment of 

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CHD; 2) patients referred for interven-
tional cardiac catheterization for CHD; 
3) patients with prenatally diagnosed 
CHD; and 4) Death Registry of the Nati-
onal Institute of Public Health.
Major and critical CHD were defi-
ned as requiring surgical treatment or 
interventional cardiac catheterization 
or causing death during the first year or 
first four weeks of life, respectively. Data 
were obtained from labour and delivery 
records and personal medical records at 
the University Medical Centre Ljublja-
na (UMCL). All patients, except those 
who died before referral to UMCL, un-
derwent a detailed echocardiographic 
examination with the assessment of 
cardiac morphology and function at 
UMCL, a single tertiary referral centre 
for children with CHD serving a popu-
lation of 2 million in Slovenia. The echo-
cardiograms were performed using the 
Aloka Prosound SSD-5500, Aloka α 10 
and Aloka α 7 ultrasound systems (Alo-
ka Co. Ltd., Tokyo, Japan). Congenital 
heart defects were classified according 
to the standard anatomic nomenclature 
that assigns priority to morphological-
ly dominant traits. Patients with isola-
ted patent ductus arteriosus (PDA) that 
was a consequence of prematurity were 
excluded from the study.
By reviewing the documentation, we 
additionally determined whether the 
diagnosis of CHD for each patient was 
established: 1) prenatally; 2) prior to di-
scharge from the maternity ward; 3) after 
discharge from the maternity ward; and 
4) at autopsy. We considered patients 
that were diagnosed prenatally or prior 
to discharge from the maternity ward as 
detected on time, while those diagnosed 
after discharge or at autopsy as detected 
late.
To objectively estimate the potential 
improvement in on-time detection of 
CHD with a nation-wide neonatal pul-
se oximetry screening programme, we 
excluded the following patients from 
further analyses: 1) with recognized or 
strongly suspected chromosomal aber-
rations at the first neonatal examination 
(25 patients); 2) with oesophageal atresia 
or diaphragmatic hernia (5 patients); 3) 
admitted to the neonatal intensive care 
unit due to prematurity (born at 33 ge-
stational weeks or less, 7 patients); and/
or 4) born at home (1 patient). We as-
sumed that these patients would not 
be eligible for neonatal pulse oximetry 
screening since they would have had a 
detailed clinical examination and possi-
bly echocardiography done solely on the 
basis of their primary condition. For ob-
vious reasons, the patient that was born 
at home would also not be screened by 
pulse oximetry.
Statistical analyses were performed 
using MedCalc for Windows, version 
16.4.3 (MedCalc Software, Ostend, Bel-
gium). The confidence intervals for the 
incidence rates were calculated as sugge-
sted by Sahai and Khurshid (15). W e used 
chi-square test to compare data with ca-
tegorical outcomes.
3. Results
During the 6-year study period, the-
re were 128,839 live-born babies in Slo-
venia (16). 293 were diagnosed with a 
major CHD, and among these 150 had 
critical CHD. Therefore, the incidence 
of major CHD in Slovenia was 2.27/1000 
live births (95 % CI: 2.0–2.6/1000) and 
1.16/1000 live births (95 % CI: 1.0–
1.4/1000) for critical CHD. The inciden-
ce of specific major forms of CHD is 
presented in Table 1.
In our series, major CHD were more 
common in males than females. In ye-
ars 2007–2012, 66,282 boys were born in 
Slovenia, of which 172 were diagnosed 
with major CHD (2.5/1000 live births, 

congenital heart disease detection in Slovenia: improvement potential of neonatal pulse oximetry screening 279
iZViRNi ZNaNStVeNi čLaNek
95 % CI: 2.2–3.0/1000). In the same time 
period, 62,557 girls were born, of which 
121 had major CHD (1.9/1000, 95 % CI: 
1.6–2.3/1000 live births). The difference 
is statistically significant (p = 0.01).
Chromosomal and genetic aberrati-
ons were detected in 41 patients (14.3 %) 
with major CHD. The type of the gene-
tic defect and the form of CHD are pre-
sented in Table 2. One fifth of patients 
in our series were born prematurely, at 
a gestational age ≤ 37 weeks. The propor -
tion of multiple birth pregnancies in pa-
tients with major CHD was significantly 
higher than in the general population 
(6.14 % vs. 3.49 %, p = 0.01).
T able 1: the incidence of specific forms of major and critical cHd in Slovenia from 2007–2012.
Live births n = 128839
Major CHD Critical CHD only
Defect type* n n/10000 (95 % CI) n % of major CHD
all 293 22.7 (20.2–25.5) 150 51.2
co a o 59 4.5 (3.5–5.9) 48 81.4
VSd 58 4.5 (3.4–5.8) 1 1.7
d-t Ga 32 2.5 (1.7–3.5) 32 100
to F 26 2.0 (1.3–3.0) 5 19.2
aVSd 22 1.7 (1.1–2.6) 3 13.7
HLHS 19 1.4 (0.9–2.3) 19 100
aoSt 17 1.4 (0.8–2.1) 13 5.9
pa-VSd 9 0.7 (0.3–1.3) 6 66.7
puSt 8 0.6 (0.3–1.2) 4 50
doRV 6 0.5 (0.2–1.0) 3 50
iaa 6 0.5 (0.2–1.0) 6 100
truncus arteriosus 5 0.4 (0.1–0.9) 0 0
univentricular Heart 3 0.2 (0.05–0.7) 2 66.7
pa-iVS 3 0.2 (0.05–0.7) 3 100
pda 3 0.2 (0.05–0.7) 0 0
tapVd 3 0.2 (0.05–0.7) 2 66.7
other
†
14 1.1 (0.6–1.8) 3 21.4
*CoAo – coarctation of the aorta; VSD – ventricular septal defect; d-TGA – d-transposition of the great 
arteries; T oF – tetralogy of Fallot; AVSD – atrioventricular septal defect; HLHS – hypoplastic left heart 
syndrome; AoSt – aortic stenosis; PA-VSD – pulmonary atresia with ventricular septal defect; PuSt – 
pulmonary stenosis; DORV – double outlet right ventricle; IAA – interruption of the aortic arch; PA-IVS 
– pulmonary atresia with intact ventricular septum; PDA – patent ductus arteriosus; TAPVD – total 
anomalous pulmonary venous drainage
†
Absent pulmonary valve syndrome; anomalous left coronary artery originating from pulmonary artery 
(ALCAPA); aorto-left ventricular tunnel; aorto-pulmonary window; atrial septal defect type primum; 
atrial septal defect type secundum; congenitally corrected transposition of great arteries; double aortic 
arch; pulmonary veins stenoses; tricuspid valve atresia.

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As described in the Methods chapter 
of this article, we included 255 patients 
in the second part of the study, where 
we analysed the timing of detection of 
major/critical CHD. The general results 
are summarised in Table 3 and the spe-
cific results based on the major forms of 
CHD are presented in Table 4. The dia-
gnosis of a major CHD was established 
after discharge or at autopsy for 45 of the 
255 patients (17.5 %). Among 138 neona-
tes with critical CHD 15 patients (10.9 %) 
were detected late, 13 of them after di -
scharge from the maternity ward and the 
remaining two at autopsy (Table 5).
4. Discussion
To our knowledge, this is the first 
study that investigated the incidence of 
major and critical CHD in the Sloveni-
an population. The reported incidence is 
in agreement with previously published 
series (11,13,17). The incidence would be 
approximately 21 % higher if all women 
in whom CHD had been detected pre-
natally would have decided to continue 
pregnancy (unpublished data).
The definition of major/critical CHD 
may exclude occasional patients with 
well-balanced complex CHD who mi-
ght not need surgical treatment before 
one year of age and/or inappropriate-
ly includes patients with simple lesions 
who have had heart surgery performed 
within the first year of life. However, we 
believe that our definition allows satis-
factory identification of those patients 
who could benefit most if their heart 
condition is detected on time. Not all 
heart defects are equally important and 
not all need to be treated during the first 
month/year of life. Atrial septal defects, 
for example, very rarely cause any clini-
cal problems before adulthood and are 
most commonly scheduled for closure at 
the age of 4 to 6 years, even if detected in 
T able 2: chromosomal and genetic aberrations in patients with major cHd .
Aberration T otal (N) Cardiac Defect T ype* n
trisomy 21 24 aVSd 18
VSd 6
deletion 22q11.2 8 absent p uV syndrome* 1
iaa 1
pa-VSd 2
to F 2
truncus arteriosus 1
VSd 1
klinefelter Syndrome 2 pa-iVS 1
co a o 1
trisomy 18 1 VSd 1
turner Syndrome 1 co a o 1
triple X Syndrome 1 doRV 1
charge Syndrome. 1 puSt 1
opitz Syndrome 1 VSd 1
kabuki Syndrome 1 VSd 1
Subtelomeric deletion 1 VSd 1
all 41
*AVSD – atrioventricular septal defect; VSD – ventricular septal defect; absent 
PuV syndrome – absent pulmonary valve syndrome; IAA – interruption of the 
aortic arch; PA-VSD – pulmonary atresia with ventricular septal defect; T oF
– tetralogy of Fallot; PA-IVS – pulmonary atresia with intact ventricular 
septum; CoAo – coarctation of the aorta; DORV – double outlet right ventricle; 
PuSt – pulmonary stenosis
T able 3: timing of detection of major and critical cHd .
Major CHD n (%) Critical CHD only n (%)
prenatally 40 (15.7 %) 28 (20.3 %)
prior to discharge 170 (66.6 %) 95 (68.8 %)
after discharge 43 (16.9 %) 13 (9.4 %)
post mortem 2 (0.8 %) 2 (1.5 %)
All 255 138

congenital heart disease detection in Slovenia: improvement potential of neonatal pulse oximetry screening 281
iZViRNi ZNaNStVeNi čLaNek
neonates. Another example is bicuspid 
aortic valve which might be only mildly 
stenotic at birth and does not need any 
intervention until a significant stenosis 
or regurgitation of the valve develops, 
which is usually well beyond infancy 
and childhood. Some minor defects even 
close spontaneously or never need any 
medical attention. Based on our data, 
approximately 50 babies per year need 
cardiac surgery or interventional cardi-
ac catheterization during the first year of 
life in Slovenia, half of them during the 
first month.
Currently, the detection of CHD in 
Slovenia relies primarily on the prena-
tal mid-trimester ultrasound cardiac 
screening performed by gynaecologists 
and the neonatal clinical examination 
performed by paediatricians. The latter 
T able 4: timing of detection of major cHd by specific defect type.
Major CHD
On-time Detection Late Detection T otal
Defect type* n (%) n (%) N
co a 39 (72.2 %) 15 (27.8 %) 54
VSd – a ll t ypes 39 (78 %) 11 (22 %) 50
d-t Ga 32 (100 %) - 32
to F 22 (91.7 %) 2 (8.3 %) 24
HLHS 15 (83.3 %) 3 (16.7 %) 18
aoSt 14 (87.5 %) 2 (12.5 %) 16
puSt 7 (87.5 %) 1 (12.5 %) 8
pa-VSd 6 (85.7 %) 1 (14.3 %) 7
doRV 6 (100 %) - 6
aVSd 5 (100 %) - 5
iaa 5 (100 %) - 5
truncus arteriosus 4 (80 %) 1 (20 %) 5
univentricular Heart 3 (100 %) - 3
tapVd 2 (66.7 %) 1 (33.3 %) 3
pda 2 (66.7 %) 1 (33.3 %) 3
other† 9 (56.3 %) 7 (43.7 %) 16
T otal 210 (82.3 %) 45 (17.7 %) 255
*CoAo – coarctation of the aorta; VSD – ventricular septal defect; d-TGA – d- transposition of great 
arteries; T oF – tetralogy of Fallot; HLHS – hypoplastic left heart syndrome; AoSt – aortic stenosis; PuSt – 
pulmonary stenosis; PA-VSD – pulmonary atresia with ventricular septal defect; DORV – double outlet 
right ventricle; AVSD – atrioventricular septal defect; IAA – interruption of the aortic arch; TAPVD – total 
anomalous pulmonary venous drainage; PDA – patent ductus arteriosus
†Absent pulmonary valve syndrome; anomalous left coronary artery originating from pulmonary artery 
(ALCAPA); aorto-left ventricular tunnel; aorto-pulmonary window; atrial septal defect type primum; 
atrial septal defect type secundum; congenitally corrected transposition of the great arteries; double 
aortic arch; pulmonary atresia with intact ventricular septum; pulmonary veins stenoses; tricuspid valve 
atresia.

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includes the assessment of heart sounds 
and femoral pulses as well as inspection 
for cyanosis. If CHD is suspected, pati-
ents are referred to a foetal/paediatric 
cardiologist for further cardiac evaluati-
on . Of particular importance is timely 
detection of critical, duct-dependent le-
sions in which closure of the ductus arte-
riosus may result in acute cardiovascular 
collapse and death  (4,5,18). Our study 
demonstrates that currently 90 % of pa-
tients with critical CHD in Slovenia are 
detected either in utero or shortly after 
birth, before being discharged from the 
maternity ward. The pre-discharge de-
tection rate in our series was higher than 
previously reported in UK, Sweden and 
USA, where it ranged from 70–82 % (8-
11). This might be at least partly explai-
ned by longer average length of stay in 
the maternity ward. In 2010, the average 
length of stay in the maternity ward after 
normal delivery in Slovenia was 4.0 days 
while in Sweden, UK and USA it was 
substantially shorter, 2.3, 1.8 and 2.1 days, 
respectively (19). With longer postnatal 
hospital stay, the chance that a clinical 
deterioration due to duct closure occurs 
before discharge is higher.
Even if the current pre-discharge de-
tection rate of critical CHD in Slovenia 
seems satisfactory, one out of ten new-
borns with such a condition still leaves 
the maternity ward undetected. The 
proportion of undetected babies may 
increase in the future, if the trend to-
wards earlier discharge continues. The 
vast majority of undetected patients in 
our series, 14 out of 15, had left heart ob-
structive lesions, most of them coarcta-
T able 5: timing of detection of critical cHd by specific defect type.
Critical CHD
On-time Detection Late Detection T otal
Defect type* n (%) n (%) N
co a o 34 (79.1 %) 9 (20.9 %) 43
d-t Ga 32 (100 %) - 32
HLHS 15 (83.3 %) 3 (16.7 %) 18
aoSt 10 (83.3 %) 2 (16.7 %) 12
iaa 5 (100 %) - 5
pa-VSd 4 (100 %) - 4
to F 4 (80 %) 1 (20 %) 5
puSt 4 (100 %) - 4
doRV 3 (100 %) - 3
other† 12 (100 %) - 12
T otal 123 (89.1 %) 15 (10.9 %) 138
*CoAo – coarctation of the aorta; d-TGA – d-transposition of great arteries; HLHS – hypoplastic left heart 
syndrome; AoSt – aortic stenosis; IAA – interruption of the aortic arch; PA-VSD – pulmonary atresia with 
ventricular septal defect; T oF – tetralogy of Fallot; PuSt – pulmonary stenosis; DORV – double outlet right 
ventricle
†Aorto-left ventricular tunnel; atrioventricular septal defect; congenitally corrected transposition of 
great arteries; pulmonary atresia with intact ventricular septum; total anomalous pulmonary venous 
drainage, tricuspid valve atresia; univentricular heart.

congenital heart disease detection in Slovenia: improvement potential of neonatal pulse oximetry screening 283
iZViRNi ZNaNStVeNi čLaNek
tion of the aorta. This is not surprising, 
as coarctation of the aorta may develop 
and progress in days after birth and is 
not always duct-dependent. Critical left 
heart obstructive lesions are occasional-
ly difficult to detect timely even in ne-
onates additionally screened by pulse 
oximetry (11,12). Nevertheless, we belie-
ve that implementation of a nation-wide 
neonatal pulse oximetry screening as an 
adjunct to the prenatal cardiac ultraso-
und and the clinical examination of the 
newborn would further increase the pre-
-discharge detection rate of major CHD. 
It is important to emphasize that pulse 
oximetry screening cannot replace a 
thorough physical examination that in-
cludes assessing for signs of heart failure 
and comparative pulse palpation.
Pulse oximetry is a well-established, 
inexpensive, non-invasive and accurate 
diagnostic test to objectively quantify 
oxygen saturation and thereby identify 
the clinically undetectable hypoxemia 
that might occur in newborns with cri-
tical CHD (20,21). It has been assessed 
as an accurate screening method for cri-
tical CHD in numerous studies (11,12,22-
25). In 2012, the US Secretary of Health 
and Human Services recommended to 
add it to the uniform neonatal screening 
panel, which was also endorsed by the 
American Academy of Pediatrics  (26). 
A meta-analysis of 13 screening studies, 
including almost 230,000 infants, repor -
ted a sensitivity of 76.5 %, specificity of 
99.9 % and a false positive rate of 0.14 % 
with no difference in accuracy reported 
when pre-ductal and post-ductal mea-
surements were performed versus only 
post-ductal measurements  (14,27). It 
has been demonstrated that referral of 
all cases with positive pulse oximetry 
for echocardiography does not increase 
substantially the burden for paediatric 
cardiologists as only 2.3 echocardio-
grams with normal cardiac findings were 
needed for every true positive case of 
duct-dependent circulation (11). In addi-
tion, more than 50 % of babies with “fal-
se positive” screening for critical CHD 
had some other relevant pathology, most 
commonly unrecognised pulmonary 
pathology or sepsis (28,29). Pulse oxime-
try screening should therefore be seen as 
a test of neonatal well-being rather than 
just a test to detect critical CHD.
During the study period, screening 
strategies to detect CHD in Slovenia 
based predominantly on prenatal ultra-
sound and physical examination of the 
newborns. A short survey among neo-
natologists from all Slovenian materni-
ty units revealed that since completion 
of the study, pulse oximetry had been 
gradually implemented as an additional 
method for detection of CHD in all Slo-
venian maternity units. However, diffe-
rent maternity units use different proto-
cols and no data exist whether the results 
of institutional screening had elsewhere 
been validated.
In conclusion, current pre-discharge 
detection rate of critical CHD in Slovenia 
is satisfactory. However, one tenth of the 
affected babies still leave the maternity 
ward undetected. The proportion of un-
detected babies may increase in the futu-
re if the trend towards earlier discharge is 
to be continued. The high pre-discharge 
detection rate could be further improved 
by a nation-wide neonatal pulse oximet-
ry screening programme. In addition to 
critical CHD, pulse oximetry screening 
could detect other potentially dangerous 
neonatal conditions.
5. Acknowledgment
We thank Tanja Železnik for helping 
with the organizational aspect of data re-
trieval.

284 Zdrav Vestn | julij – avgust 2017 | Letnik 86
RepRodukcija čL oVeka
6. Ethical approval
The study design was approved by the 
National Medical Ethics Committee of 
the Republic of Slovenia (no.35/10/14).
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