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Archives of Disease in Childhood, 1975, 50, 449.
Pneumothorax in the newborn
Changing pattern
V. Y. H. YU, S. W. LIEW, and N. R. C. ROBERTON*
From the Department of Paediatrics, University of Oxford, John Radcliffe Hospital
Yu, V. Y. H., Liew, S. W., and Roberton, N. R. C. (1975). Archives of Disease in
Childhood, 50, 449. Pneumothorax in the newborn: changing pattern. The
clinical course of pneumothorax and its allied conditions was studied in 34 newborn
infants who presented over a 2a-year period. We found an overall incidence of 3/
live births. 11 term infants without obvious pulmonary pathology presented early (
within minutes of birth); 6 of these had aspirated meconium or blood. The remaining 23
were preterm infants with hyaline membrane disease (HMD) and accounted for 68 % of
the infants in this series. In contrast, they presented late (mean 45 hours) and 16 were
on continuous distending pressure (CDP) or intermittent positive pressure ventilation
(IPPV) at the onset of pneumothorax. 15 % of all infants with HMD who required CDP/
IPPV developed pneumothorax; this increased incidence was most evident in infants
who received CDP only.
All except 2 of the 11 term infants in the first group were managed conservatively and
all survived. When pneumothorax occurred as a complication of HMD in preterm
infants, 14 of the 16 infants required intrapleural drainage. Persistence or recurrence of
pneumothorax occurred in 9 infants, 7 of whom were receiving CDP/IPPV at the time.
Lung expansion was affected only after replacement with a patent chest drain through
the same incision or insertion of a second drain on the same side of the chest.
All 5 deaths occurred in the group of preterm infants with HMD. 3 resulted direct-
ly from respiratory failure due to severe HMD complicated by pneumothorax. We
emphasize the increasing importance of pneumothorax as a complication of HMD in
preterm infants, particularly in those receiving CDP. Successful management depends
on prompt diagnosis and treatment of pneumothorax, which may occur as unexplained
sudden deterioration at any time during the course of illness in this group of high risk
infants.
Pneumothorax may be associated with severe
respiratory distress, and^ particularly in^ the^ presence
of hyaline membrane disease (HMD) it is a frequent
cause of sudden deterioration or collapse. Never-
theless, it is one of the few pulmonary diseases in
the newborn period in which prompt treatment can be life saving. Detection in newborn infants depends as much on a high degree of awareness of
its possibility as on the knowledge of its predispos-
ing factors^ and^ cincial^ features.^ We present our
experience of this condition over the last 2A years and emphasize the increasing importance of its
Received 11 November 1974. *Present address: Department of Paediatrics, Addenbrooke's Hospital, Cambridge.
occurrence in low birthweight infants with HMD
during intermittent positive pressure ventilation
(IPPV) and continuous distending pressure (CDP). Pneumomediastinum and^ pneumopericardium are included in the (^) analysis as (^) they are (^) probably a variant of the same underlying pathology.
Clinical observations
The clinical course of pneumothorax and^ pneumo-
mediastinum was^ studied^ in^34 newborn infants.^ These
patients represent all^ recognized cases^ of^ pneumothoraces
and allied conditions (^) occurring in the (^) special care
nursery during a 2A year period, January 1972 to July
1974, with the exception of^2 for^ which^ case^ notes were
incomplete. 3 infants^ were^ referred^ from^ other^ hospitals
on the first day of life.
Yu, Liew, and Roberton
The overall incidence of pneumothoraces and (^) allied conditions was 3/1000 live births. This study includes 26 infants with pneumothoraces all of whom were symptomatic and in whom deterioration in respiratory symptoms had led to chest x-ray. 6 out of the 26 had coexisting pneumomediastinum (23%) and one had coexisting pneumopericardium. 6 other infants had isolated pneumomediastinum and 2 had severe pul- monary interstitial emphysema with lung cysts; these 8 were asymptomatic and were diagnosed on routine x-rays. Males were more than twice as common as females (24: 10). Pneumothoraces were found nearly twice as frequently on the right as on the left (R:L = 14:8) and 4 patients (15%) had bilateral pneumothoraces. The (^) infants studied can be separated into two distinct groups depending on whether there (^) was associated idiopathic respiratory distress syndrome-presumably HMD (Table I). The first group, that (^) of infants
TABLE I
Clinical data of infants with pneumothoraces and
allied conditions
Infants' without HMD Infants with HMD
No. 11 23 Gestation (w) 40 (38-41) 34 (27-38) Birthweight (g) 3453 (2710-4130) 2307 (990-3510) Age of onset (h) Birih 45 (12-140) (2 at 14 h) Apgar score at birth 4 or less 4 7 Endotracheal intubation and IPPV at birth 4 8 Aspiration of meconium or blood 6 0 CDP or IPPV at onset of (^) pneumothorax - (^16)
HMD, hyaline membrane disease; CDP, continuous (^) distending pressure; IPPV, intermittent positive pressure ventilation.
without obvious pulmonary disease, used to be the most
common: (^) they were (^) usually diagnosed in the first (^) hour of life, being mainly term or post-term infants presenting
with respiratory difficulty at delivery. There was often
a history of fetal distress, difficult delivery, or over-
zealous resuscitation, and evidence of aspiration of meconium, blood, or^ mucus. This group of 11 infants accounted for only 32% of pneumothoraces in Oxford. Their mean gestational age was 40 weeks (range 38 to (^41) w) and mean birthweight 3453 g (range 2710-4130 g). In 9 infants the signs were evident at delivery, while (^) in the remaining 2 pneumothorax was not obvious until 14 and 15 hours of age, respectively. There was a strong possibility of aspiration of meconium or blood as a predisposing event^ in^6 out of the 11 infants and the possible aspiration ofmucus could not be ruled out in (^) any infant. 4 ofthe pneumothoraces occurred in resuscitated infants, but it is not possible to ascertain to what extent overzealous resuscitative efforts or the underlying cause
of apnoea is responsible for the pneumothoraces.
3 infants in this group had coexisting pneumomediasti- num. In the second group, pneumothorax and pneumo- mediastinum occurred as a complication of HMD in 23 infants, and these accounted for 68% of the infants in this series. The types of air leak developing in the 23
cases are shown in Table II. Their mean gestational
TABLE II
Types of pneumothoraces and allied conditions
Infants without Infants with HMD (11) HMD (23)
Pneumothorax alone 7 12 Pneumothorax with pneumomediastinum 3 3 Pneumothorax with pneumopericardium 0 1 Pneumomediastinum alone 1 5 Severe pulmonary interstital emphysema 0 2 with lung cysts
age was 34 weeks (range 27-38 w) and mean birthweight was 2307 g (range 990-3510 g). All suffered from respi- ratory distress syndrome presumably due^ to^ HMD. Initial x-rays were (^) compatible with HMD and did not show (^) pneumothoraces. Onset of (^) pneumothorax was later than in the first group and occurred at a mean of 45 hours (^) postnatally (range 12 to (^140) h). The (^) diagnosis was strongly suspected in all 16 infants with (^) pneumo- thorax in this group before x-ray confirmation. 4 infants presented with acute collapse and 12 with un- explained but more gradual clinical deterioration during the course of the respiratory distress syndrome so that repeat chest x-rays were taken to detect possible pneu- mothorax. The remaining 7 infants, 5 of whom had pneumomediastinum without pneumothorax and 2 with severe pulmonary interstitial emphysema and lung cysts were^ detected^ by routine^ chest^ x-ray without antecedent clincial (^) suspicion. 12 of the 16 infants with pneumothorax were on either CDP (8 cases, mean duration 30 h, range 2-70 h) or IPPV (4 (^) cases, mean duration 23 h, range 2-120 h) at the time of onset of pneumothorax. All infants received a maximum CDP of 10 cm H20 except one early case in whom 15 cm H was (^) applied for a (^) period of 9 hours. The 4 infants (^) who developed pneumothorax (^) during IPPV were (^) being ventilated at a pressure of 40 cm H20. Only one infant was subjected to IPPV in association with positive end-expiratory pressure and this was discontinued 20 hours before the onset of (^) pneumothorax. The overall incidence of pneumothorax and allied conditions occurring in infants with HMD was 11% (23 out of 216). 15% of infants with HMD on CDP or IPPV developed these (^) complications (16 out of 106). This increased incidence was most evident in infants who had (^) received CDP alone and was lqwer in infants on IPPV (Table III).
Yu, Liew, and Roberton
have shown pneumothorax in 1 to 2% of all new-
born infants (Davis and Stevens, 1930; Solis-
Cohen and Bruck, 1934; Steele et al., 1971) and
the incidence of symptomatic cases was reported
to be 0 05-0 (^) 07% (Harris and Steinberg, 1954;
Howie and Weed, 1957; Chernick and Avery,
1963; Malan and de V. Heese, 1966). In some of
these earlier reports on 'spontaneous' pneumo-
thorax in the newborn, infants who had received
oxygen under positive pressure (Chernick and
Avery, 1963; Malan and de V. Heese, 1966) or who
had underlying HMD (Malan and de V. Heese,
1966) were excluded. Reports of pneumomediasti-
num and pulmonary interstitial emphysema, when
unaccompanied by pneumothorax were also not
included in these case summaries (Harris and
Steinberg, 1954; Howie and Weed, 1957), though
they are^ probably related (Ovenfors, 1964; Cald- well, Powell, and^ Mullooly, 1970; Thibeault et al., 1973). In this series, a (^0 3) % incidence of pneumo-
thorax and its allied conditions is reported. Low
birthweight infants with HMD accounted for 68%
of our cases. Previous studies have suggested that
the term infant is most at risk (Peterson and
Pendleton, 1955; Emery, 1956; Chernick and Avery,
1963), and it has even been suggested that in
preterm infants HMD is not a common predis-
posing factor (Kirschner and Strauss, 1964;
Grosfeld, Clatworthy, and Frye, 1970). More
recently it^ has^ been^ recognized that HMD^ signifi-
cantly increases the incidence of pulmonary inter-
stitial emphysema and pneumothorax (Thibeault
et al., 1973). With the increasing use of CDP
or IPPV in infants with HMD, pneumothorax has
become even more frequent (Lancet, 1973; Baum
and Roberton, 1974). Signs of air leak develop in
as many as 30% of infants on positive pressure
ventilation plus positive end-expiratory pressure
(Blake et al., 1973). In this series, 15% of infants
with HMD requiring CDP and/or IPPV developed
this complication and 24% of those treated with
CDP alone. The detection of pneumothorax in
this group of infants depended on a high degree of
awareness that the diagnosis must always be
considered when such infants have sudden or
unexpected deterioration at any time during CDP
or IPPV. Radiological confirmation may be
difficult as an anteroposterior x-ray may not be
sufficient. A horizontal beam, lateral ('cross- table') view of the chest with the patient in the supine position should always be done (Roberton,
1975). Pneumomediastinum as well as intra-
pleural air collecting at the top of the thoracic
cavity can be seen better in such a view.
Pneumothorax as a result of overzealous positive
pressure resuscitation of the apnoeic newborn
(Chernick and Reed, 1970; Chernick and Avery,
1963) is^ a^ less^ frequent occurrence, and in 7 of^ our
11 early pneumothoraces no IPPV had been given.
Neonatal resuscitation is safer today than in the
past. It is known that the water manometer
system in resuscitation apparatus can be unreliable
when used with excessively applied oxygen flow
(Mathias, 1966) and modification of such systems
by the addition of a deadweight relief valve (Hey
and Lenney, 1973) had been carried out in our
delivery rooms.
Breathing 100% oxygen accelerates the resorption
of a pneumothorax (Chernick and Avery, 1963;
Northfield, 1971). This form of^ therapy has
generally been successful in our group of infants
without HMD who had only moderately severe
respiratory difficulty from pneumothorax or who
had a pneumomediastinum alone. In contrast,
most of the infants in this series with underlying
HMD who developed pneumothorax did require
insertion of a chest drain. A continued air leak
into the pleural space, particularly in conjunction
with CDP or IPPV required application of suction
to prevent reaccumulation of air. But, in spite of
this, over half in this group had persistence or
recurrence of pneumothorax: 5 of these 7 were on
CDP or IPPV at the time. Such complications
often occurred in situations where the chest drain
became blocked or was clamped too soon. We
found it useful to replace a new drain through the
same incision or to insert a second one on the same
side of the chest under such circumstances. We
have maintained a policy of leaving the chest drain
in situ during the period in which the infant was
still receiving CDP or IPPV.
Overall mortality rate for pneumothorax in this series was 0 04 % (5 in 11 169 live births). The
prognosis for pneumothorax occurring in infants
without HMD was uniformly good and all the
deaths occurred in the preterm infants with HMD.
Mortality rate^ in^ the infants with HMD developing
pneumothorax was 31% (5 of 16), compared with a
mortality rate of 14% in cases of HMD without
pneumothorax (27 of 200). This difference is not
statistically significant (^) (X2 =^ 3X15, P > 0 05) and
clearly pneumothorax is likely to be more common
in infants with severe HMD since pulmonary
interstitial emphysema is more likely to occur and
higher inflation pressures with IPPV are necessary.
Thus the deaths in cases complicated by pneumo-
thorax, when promptly and (^) adequately treated, may
be more indicative of the severity of the HMD than
of the consequence of this complication.
452
Pneumothorax in^ the newborn^453
We thank Professor^ J. P. M. Tizard^ for advice^ and
help in the preparation of the manuscript.
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Correspondence to Dr. V. Y. H. Yu, Department of
Paediatrics, John Radcliffe Hospital, Headington,
Oxford OX3 9DU.
