Causes, risk factors and outcomes in neonates with respiratory failure

TẠP CHÍ Y - DƢỢC HỌC QUÂN SỰ SỐ CHUYÊN ĐỀ HÌNH THÁI HỌC-2017

CAUSES, RISK FACTORS AND OUTCOMES IN NEONATES
WITH RESPIRATORY FAILURE
Nguyen Thanh Nam*; Cao Thi Bich Hao*
Pham Van Dem**; Dong Khac Hung***; Nguyen Tien Dung*
Summary
Objectives: To determine some causes, risk factors and outcomes in neonates with
respiratory failure. Subjects and methods: A descriptive and prospective study on 139 neonates
who were diagnosed respiratory failure after birth (case group) and 278 neonates without
respiratory failure (control group) were admitted in Pediatric Department, Bachmai Hospital.
Results: Mortality rate in neonates was 15.1%. The average of gestational age in neonates with
respiratory failure was 34 weeks, significantly lower than the control group with 38 weeks (p <
0.001). The mean birth weight of case group (2,057 Gr) was significantly lower than control
group (2,893 Gr) (p < 0.001). The most causing respiratory failure was respiratory disease
38.9%, premature 30.9%. The relative risk in neonates without risk factor was 0.24. Cooperated with pediatrician in neonates with risk factor of case group (64.7%) was significantly
st
higher than control group (30.9%). Asphyxia rate at 1 mimute after birth of control group
(11.2%) was significantly lower than case group (69.1%) (p < 0.001). Respiratory distress in
st
newborn babies who have Apgar score at 1 minute ≤ 7 points was 17.8. Respiratory distress in
newborn babies who were delivered by elective cesarean section without labour was 40.3.
Respiratory distress in newborn babies whose mothers suffered from disease was 3.7.
Conclusion: The mortality was high in neonates with respiratory failure. The most causing
respiratory failure was respiratory disease. Premature, low birth weight increased respiratory
failure. In addition, asphyxia rate after birth, delivered by elective cesarean section without
labour and mother’s disease were common risk factors of respiratory distress in neonates.
Co-operation between obstetrician and pediatrician are very important.
* Keywords: Neonates; Respiratory failure; Causes; Risk factors.

INTRODUCTION

Respiratory failure is a common disease
in neonates and is a common cause of
treatment in neonatal intensive care unit.
There are many diseases such as hyaline
membrane disease; meconium aspiration
syndrome;
pneumonia;
pulmonary
hemorrhage, congenital heart defects [2]...
There are many factors that affect the rate

of neonates with respiratory failure such
as maternal disease, problems at delivery,
premature birth, cesarean delivery (CS),
especially CS without labour, neonatal
resuscitation [5, 7]... these factors can be
intervened to reduce the risk factors of
respiratory failure. The objectives of the
study is to: Find some causes, treatment
results and factors affecting in neonatal
respiratory failure.

* Bachmai Hospital
** Vietnam National University Hanoi
*** Vietnam Military Medical University
Corresponding author: Nguyen Thanh Nam ()
Date received: 30/07/2017
Date accepted: 09/09/2017

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TẠP CHÍ Y - DƢỢC HỌC QUÂN SỰ SỐ CHUYÊN ĐỀ HÌNH THÁI HỌC-2017

SUBJECTS AND METHODS
1. Subjects.
- Case group: 139 neonates who were
born at Department of Obstetrics - Bachmai
Hospital and were diagnosed as respiratory
failure, hospitalized and treated at Neonatal
Intensive Care room at Department of
Pediatrics, Bachmai Hospital from 1 - 2013
to 12 - 2015. Acute respiratory failure is
defined as lung dysfunction, causes failure
at gas exchange, oxygen is decreased
and carbon dioxide is increased, so the
lung is not able to hold on Pa02, PaC02
and pH in threshold criteria [2]. Diagnosis
of acute respiratory failure based on
clinical and paraclinical symptoms.
Clinical symptom of respiratory failure
[1, 2]: respiratory failure is defined as one
of the signals: respiratory distress:
tachypnoea > 60 breaths/min or slow
breathing < 40 breaths/min; chest wall
recessions, paradoxical movement of the
chest wall; nasal flaring; grunting or apnoea,
cyanosis; Apgar score after birth at
1 minute, 5 minutes based on heart rate,
respiratory effort, muscle tone, response

to stimulation and skin coloration (total
score: ≤ 3: severe asphyxia, 4 - 6 points:
moderate asphyxia, ≥ 7: normal). Subclinical

symptoms: blood gases are criteria for the
diagnosis of acute respiratory failure [2]:
Pa02 < 60 mmHg, and/or PaCO2 > 50
mmHg and pH < 7.1 - 7.2; chest X-ray [1]:
normally, bilateral lungs enlarge badly,
ground-glass opacity nodules, stagnant
air bronchograms.
- Control group: 278 neonates at
Department of Obstetrics who were moved
to the neonatal room at Department of
Pediatrics, Bachmai Hospital without
respiratory failure from 1 - 2013 to 12 - 2015.
2. Methods.
Descriptive and prospective study.
RESULTS
1. General characteristics of the groups.
From January, 2013 to December, 2015,
we evaluated 139 neonates with respiratory
failure and 278 neonates without respiratory
failure who were treated at Department of
Pediatrics. The average gestational age
of the case group (34 weeks) was
significantly lower than the control group
with 38 weeks (p < 0.001). The average
weight of the case group (2,057 Gr) was
significantly lower than the control group

with 2,893 Gr (p < 0.001).

Chart 1: Gestational age distribution in the study.
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TẠP CHÍ Y - DƢỢC HỌC QUÂN SỰ SỐ CHUYÊN ĐỀ HÌNH THÁI HỌC-2017

In 139 neonates with respiratory failure, 28% of the neonates were smaller than
32 weeks while in the control group, 0.4% of the neonates were smaller than 32 weeks.
Neonates without respiratory failure were primary as full term infants. So prematrure
infants had significantly higher risk of neonatal respiratory failure (p < 0.001).
Table 1: Some common causes of respiratory failure.
Respiratory failure

Causes
n

%

Hyaline membrane disease

15

10.8%

Asphyxia

22

15.8%

Transient tachypnoea of the newborn baby

14

10.1%

Pneumonia

3

2.2%

Patent ductus arteriosus

22

15.8%

Pulmonary arterial hypertension

5

3.6%

Sepsis

4

2.9%

Respiratory failure due to premature birth

43

30.9%

Brain hemorrhage

1

0.7%

Hypoglycemia

7

5%

Other congenital heart defects

1

0.7%

Other diseases

2

1.4%

139

100%

Total

In 139 neonates with respiratory failure who were required mechanical ventilation,
the cause of lung was 38.9% and asphyxia had the largest number. Congenital heart
defects were primary as patent ductus arteriosus, pulmonary arteria hypertension.
Premature infant was a cause which had high rate with 30.9 percent of neonates with
respiratory failure.

Chart 2: Results of treatment for respiratory failure.
In 139 neonates with respiratory failure, the discharged rate was 84.9%, the
mortality rate was 21 (15.1%).
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Table 2: Relationship between neonatal weight and respiratory failure.
Groups

Case group

Control group

OR

(95%CI)

Weight

n

%

n

%

Weight < 2,500 Gr

91

65.5%

73

26.3%

Weight  2,500 Gr

48

34.5%

205

73.7%

5.324
(3.429 - 8.267)

139

100%

278

100%

p < 0.001

Total

The lower neonatal weight was, the higher rate of respiratory failure was. In this
study, the rate of respiratory failure in the low birth weight group was 65.5%, while the
rate of low birth weight in the control group was significantly smaller than 26%
(p < 0.001). If neonatal weight is smaller than 2,500 Gr, neonates will have a risk of
respiratory failure is 5.324 (95%CI; 3.429 - 8.267).
Table 3: Role of co-operation with pediatrist in neonatal resuscitation.
Groups

Case group

Control group

OR

(95%CI)

Pediatrician

n

%

n

%

Neonate is not at risk

49

35.3%

192

69.1%

90

64.7%

86

30.9%

0.244
(0.158 - 0.375)

139

100%

278

100%

p < 0.001

Neonate has risk factors
Total

Neonates who were not at risk had a rate of respiratory failure (35.5%) was
significantly lower than control group (69.1%) (p < 0.001). Neonate was not at risk
whose risk of postpartum respiratory failure was only 0.244 (95%CI; 0.158 - 0.375).
Table 4: Apgar scores at the first minute and respiratory failure.
Groups

Case group

Apgar scores

n

%

Apgar ≤ 7

96

Apgar > 7

43
139

Total

Control group

OR
(95%CI)

n

%

69.1%

31

11.2%

30.9%

247

88.8%

17.888
(10.592 - 29.875)

100%

278

100%

p < 0.001

Apgar score at the first minute  7 in the control group had higher rate than in the
case group (69.1% vs. 11.2%) (p < 0.001). Children with Apgar score at the first minute
 7 had a risk of respiratory failure (17.888) (95%CI; 10.592 - 29.875). As a result, the
baby's appearance of asphyxia immediately after birth (the first minute) warns the risk
of respiratory failure in the next hours.
Table 5: CS without labor and the rate of respiratory failure.
Groups

Case group

Control group

OR
(95%CI)

CS without labour

n

%

Yes

59

42.4%

5

1.8%

No

80

57.6%

273

98.2%

40.268
(15.631 - 103.736)

139

100%

278

100%

p < 0.001

Total

n

%

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TẠP CHÍ Y - DƢỢC HỌC QUÂN SỰ SỐ CHUYÊN ĐỀ HÌNH THÁI HỌC-2017

Cesarean delivery without labour had a significant effect on the risk of postpartum
respiratory failure (p < 0.001). The risk of neonatal respiratory failure was 40.268
(95%CI; 15.631 - 103.736) CS without labour.
Table 6: The effect of maternal factors on the postpartum respiratory failure.
Groups
Maternal factors

Case group

Control group

n

%

n

%

Abnormal

38

27.3%

52

18.7%

Normal

101

72.7%

226

81.3%

Maternal disease
during pregnancy

Yes

73

52.5%

121

43.5%

No

66

47.5%

157

56.5%

Maternal problem at
delivery

Yes

95

68.3%

102

36.7%

No

44

31.7%

176

63.3%

History of maternal
pregnancy

p

OR
(95%CI)

0.043

1.635
(1.012 - 2.641)

0.083

1.435
(0.954 - 2.16)

<
0.001

3.725
(2.417 - 5.743)

History of maternal pregnancy was associated with postpartum respiratory failure
(p = 0.043). The risk of postpartum respiratory failure was 1.635 (95%CI; 1.012 - 2.641)
times when the mother had a history of abnormal pregnancy. Maternal disease during
pregnancy was not associated with postpartum respiratory failure (p = 0.083). Maternal
problem during labor had an effect on the incidence of postpartum respiratory failure
(p < 0.001). The risk of pediatric respiratory failure was 3.725 (95%CI: 2.417 - 5.743)
times when mothers had medical diseases during labor.
DISCUSSION
The study was carried out from 1 - 2013
to 12 - 2015, 139 neonates who were
diagnosed as respiratory failure were
transferred from the Department of
Obstetrics to the Neonatal Intensive Care
Unit room at Department of Pediatrics,
Bachmai Hospital for treatment. During
the admission process, we evaluated and
exploited the maternal history and recorded
the factors related to the pregnancy and
childbirth to find out some causes and risk
factors related to the possibility of being
respiratory failure of the baby after birth.
In 139 neonates who were diagnosed
as respiratory failure hospitalized, the causes

of the disease varies from lung and respiratory
diseases (hyaline membrane disease,
asphyxia, meconium aspiration syndrome,
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pneumonia...), cardiovascular disease (patient
ductus arteriosus, pulmonary hypertension...),
respiratory failure in premature birth....
However, the rate of lung disease, respiratory
disease and respiratory failure in premature
birth was still high, 38.9% and 30.9%
respectively. These pathologies are potentially
preventable and treatable if the prognosis
of the risk factors that affects the respiratory
status of the postnatal children to timely
therapeutic intervention, limiting the negative
impact on the respiratory function of children
when they begin to adapt to life outside
uterus. This is the role of management of
pregnancy and childbirth in the per partum
and postpartum period, especially in the
per partum period, which directly affect
infant’s status. In our study, the obstetric
history of the mother (giving birth prematurely,
miscarriage, fetal death, etc.) had an effect


TẠP CHÍ Y - DƢỢC HỌC QUÂN SỰ SỐ CHUYÊN ĐỀ HÌNH THÁI HỌC-2017

on neonatal respiratory failure risk (p = 0.043),

risk of neonatal respiratory failure was
OR = 1.635 (95%CI; 1.012 - 2.641) when
the mother has a history of abnormal
pregnancy. Huynh Thi Duy Huong had
detail risk factor of respiratory distress
such as: fetal death… [2]. The common
complications during CS were hypertension,
cardiovascular disease, renal failure,
systemic disease (lupus), pregnancy toxicity,
preeclampsia, HELLP syndrome… If these
conditions were detected and controlled, it
would reduce the risk of postpartum
respiratory failure. Maternal health factors
as risks for postnatal child were also reported
by foreign authors such as Khairy et al who
found that pregnant women with congenital
heart had risk factors that directly affected
their health and their infants, in which
giving birth prematurely and respiratory
distress accounted for a high proportion of
neonates receiving postpartum support [4].
Gelfand et al presented risk factors for
meconium aspiration in infants including
hypertension, gestational diabetes,
preeclampsia, chronic heart disease [3].
Prematures and low birthweight are risk
factors that increase rate of respiratory
distress after birth. We evaluated 139
neonates with respiratory failure and 278
neonates without respiratory failure who

were treated at Department of Pediatrics.
The average gestational age of the case
group (34 weeks) was significantly lower
than the control group with 38 weeks
(p < 0.001). The average weight of the
case group (2,057 Gr) was significantly
lower than the control group (2,893 Gr)
(p < 0.001). The rate of respiratory failure
in the low birth weight < 2,500 Gr (65.5%)
in case group was significantly higher than

that in the control group (26%) (p < 0.001).
If neonatal weight is smaller than 2,500 Gr,
neonates will have a risk of respiratory
failure 5.324 (95%CI; 3.429 - 8.267). Mahoney
reported that the rate of respiratory distress
of late preterm was 28.9% and term was
5.3%, the early term infants (35 weeks) risk
of respiratory distress was 9 times compared
with term baby (38 - 40 weeks) [6].
Cesarean delivery on maternal request
is also one of neonatal respiratory distress
risk factors. According to our study, the
respiratory distress rate was 42.4% in CS
on maternal request group and was only 1%
in the rest. This difference has statistical
significance (p < 0.05). This problem was
investigated by Ray et al in women with
no indication of labor at 34 - 37 gestation
weeks, suggesting that more than 25% of

neonates have severe respiratory failure
after delivery [7]. According to a study by
Liu et al (2005), full-term infants undergoing
CS on maternal request increased the risk
of respiratory distress [5]. It is an issue for
gynecologists to do more research to have
more concrete evidence in choosing a safe
birth route for both mother and newborn baby.
Obstetrical-neonatal care co-operation
module is important and effective in reducing
the rate of respiratory distress and asphyxia
in the delivery room especially in the case
of preterm as well as full-term infants
whose mothers have chronically diseases,
contributes to restrict postpartum morbidity,
particularly in cases of respiratory failure,
preterm infants. In our study, pediatric
resuscitation during childbirth was essential
for children with respiratory failure at birth
(64.7%), while 30.9% of children in the control
group needed support of the pediatric
resuscitation. Pediatric patients, who did
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not have any risk, needed for coordination
of pediatric resuscitation (OR = 0.244;
95%CI: 0.158 - 0.375; p < 0.001). This

combination is highly appreciated in the
world and is being implemented in obstetrics
and pediatrics hospitals. It is especially
valuable in general hospitals because of
the proportion of mothers with medical
conditions that need to be intervened had
increased more and more, it is necessary
to have other support from the fields of
internal medicine, cardiology combined
with obstetrics and pediatrics to treat both
mother and child properly.

- There are many factors that influence
the rate of neonatal respiratory failure related
to maternal pregnancy, maternal morbidity
during labor, CS without labour, effective
postpartum resuscitation and premature
labor, low weight... These factors can be
intervened to reduce the rate of respiratory
failure, asphyxia when pregnancy is managed
strictly, proper diagnosis and treatment of
maternal disease, holding on relationship
between Department of Obstetrics and
Department of Pediatrics in caring for
neonates after birth.

The Apgar score provides an accepted
and convenient method for reporting the
status of the newborn infant immediately
after birth and the response to resuscitation

if needed. According to our observation,
Apgar score  7 at the first minute at risk
for respiratory distress was OR = 17.888
(95%CI; 10.592 - 29.875; p < 0.001). Thus,
neonatal resuscitation after birth will have
reduced the rate of neonatal respiratory
distress. Pediatric and obstetrics combination
actually plays an important role in reducing
the risk of neonatal respiratory distress.

REFERENCES

CONCLUSION
- The mortality rate from respiratory
failure is high: 15.1% of neonates with
respiratory failure.
- Common causes of neonatal respiratory
failure are causes of lung or pulmonary
diseases such as asphyxia, hyaline
membrane disease, pneumonia, transient
tachypnoea of the newborn baby...,
congenital heart defects such as patent
ductus arteriosus, pulmonary arterial
hypertension... and respiratory failure in
premature birth, all of them can be intervened.
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