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Hypoxia Challenge Testing in Neonates for Fitness to Fly

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Background: Preflight hypoxia challenge testing (HCT) in a body plethysmograph has previously been done only on infants >3 months of corrected gestational age (CGA). This study aims to determine the earliest fit-to-fly age by testing neonates <1 week old. Methods: A prospective observational study was carried out on 3 groups of infants: healthy term infants ≤7 days old, preterm infants (≥34 weeks CGA) 2 to 3 days before discharge, and preterm infants with bronchopulmonary dysplasia (BPD). HCT was conducted using a body plethysmograph with a 15% fraction of inspired oxygen. The oxygen saturation (Spo2) test fail point was <85%. Results: Twenty-four term (mean CGA 40 weeks), 62 preterm (37 weeks), and 23 preterm with BPD (39.5 weeks) infants were tested. One term infant (4.2%) and 12 preterm infants without BPD (19.4%) failed. Sixteen (69.3%) preterm infants with BPD failed (P < .001), with a median drop in Spo2 of 16%. At 39 weeks CGA, neither preterm infants without BPD nor term infants had an Spo2 <85%. However, 7 of 12 term infants with BPD failed the HCT. Conclusions: Term and preterm infants without BPD born at >39 weeks CGA do not appear to be likely to desaturate during a preflight HCT and so can be deemed fit to fly according to current British Thoracic Society Guidelines.
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ARTICLE
PEDIATRICS Volume 137 , number 3 , March 2016 :e 20152915
Hypoxia Challenge Testing in
Neonates for Fitness to Fly
Susanne Vetter-Laracy, PhD, MD,a Borja Osona, MD,b Jose Antonio Peña-
Zarza, MD,b Jose Antonio Gil, MD,b Joan Figuerola, PhD, MDb
abstract
BACKGROUND: Preflight hypoxia challenge testing (HCT) in a body plethysmograph has
previously been done only on infants >3 months of corrected gestational age (CGA). This
study aims to determine the earliest fit-to-fly age by testing neonates <1 week old.
METHODS: A prospective observational study was carried out on 3 groups of infants: healthy
term infants 7 days old, preterm infants (34 weeks CGA) 2 to 3 days before discharge,
and preterm infants with bronchopulmonary dysplasia (BPD). HCT was conducted using a
body plethysmograph with a 15% fraction of inspired oxygen. The oxygen saturation (SpO2)
test fail point was <85%.
RESULTS: Twenty-four term (mean CGA 40 weeks), 62 preterm (37 weeks), and 23 preterm
with BPD (39.5 weeks) infants were tested. One term infant (4.2%) and 12 preterm infants
without BPD (19.4%) failed. Sixteen (69.3%) preterm infants with BPD failed (P < .001),
with a median drop in SpO2 of 16%. At 39 weeks CGA, neither preterm infants without BPD
nor term infants had an SpO2 <85%. However, 7 of 12 term infants with BPD failed the HCT.
CONCLUSIONS: Term and preterm infants without BPD born at >39 weeks CGA do not appear to
be likely to desaturate during a preflight HCT and so can be deemed fit to fly according to
current British Thoracic Society Guidelines.
Divisions of aNeonatology and bPaediatric Respiratory Medicine, Department of Paediatrics, University Hospital
Son Espases, Palma de Mallorca, Spain
Drs Vetter-Laracy and Osona conceptualized and designed the study, carried out the initial
analysis and interpretation of data collection, and drafted the initial manuscript; Drs Peña-Zarza,
Gil, and Figuerola made substantial contributions to conception and design and reviewed and
revised the manuscript; and all authors coordinated and supervised data collection, approved
the fi nal manuscript as submitted, and agree to be accountable for all aspects of the work
in ensuring that questions related to the accuracy or integrity of any part of the work are
appropriately investigated and resolved.
DOI: 10.1542/peds.2015-2915
Accepted for publication Dec 2, 2015
Address correspondence to Susanne Vetter-Laracy, Department of Paediatrics, Division of
Neonatology, University Hospital Son Espases, Carretera Valldemossa 79, 07120 Palma de
Mallorca/Spain. E-mail: vettersusan@yahoo.com
PEDIATRICS (ISSN Numbers: Print, 0031-4005; Online, 1098-4275).
Copyright © 2016 by the American Academy of Pediatrics
FINANCIAL DISCLOSURE: The authors have indicated they have no fi nancial relationships relevant
to this article to disclose.
FUNDING: No external funding.
POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential confl icts of
interest to disclose.
To cite: Vetter-Laracy S, Osona B, Peña-Zarza JA, et al.
Hypoxia Challenge Testing in Neonates for Fitness to Fly.
Pediatrics. 2016;137(3):e20152915
WHAT’S KNOWN ON THIS SUBJECT: Preterm
infants ≥ 3 months of corrected gestational age
and without bronchopulmonary dysplasia are at no
greater risk of hypoxia compared with term infants
during a pre ight hypoxic challenge test in a body
plethysmograph thus can be considered fi t to fl y.
WHAT THIS STUDY ADDS: Preterm and term infants
without pulmonary problems from a corrected
gestational age of >39 weeks are not a t risk for
hypoxia during a prefl ight hypoxic challenge tes t in a
body plethysmograph.
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VETTER-LARACY et al
Commercial planes fly at 9000
to 13 000 m, requiring cabin
pressurization to 1530 to 2440 m.
At this altitude, the reduced pO2 is
equivalent to breathing 15% oxygen
(fraction of inspired oxygen [FIO2]
0.15) at sea level. It is already well
known that pulse oxygen saturation
(SpO2) declines significantly in
healthy children and adults (4%,
down to 94.4%) during commercial
airline travel, but this is not
considered pathologic.1,2 Newborns
are particularly susceptible to
hypoxemic episodes in a hypoxic
environment because of factors
such as an increased tendency for
ventilation-perfusion mismatch and
a left shift of the oxygen dissociation
curve due to fetal hemoglobin in
the first months of life.3 Premature
infants have more apneic pauses
and periodic breathing when they
reach term than term infants, and
apneic pauses may be triggered by
chronic hypoxemia.4–6 Thus, studies
testing term infants and premature
infants during the first months of life
for fitness to fly have been ruled out
by most other researchers despite
the fact that the number of families
wanting to take their newborns on
flights shortly after delivery has
increased.7–11
The British Thoracic Society
(BTS) has published guidelines for
infants stating that term newborns
(>37 weeks) should wait 1 week
after birth term before traveling,
premature infants who have not
reached term should have in-flight
oxygen of 1 to 2 L/min (grade C
evidence), and premature infants
<1 year old with neonatal chronic
respiratory problems should undergo
hypoxia challenge testing (HCT).12,13
Son Espases neonatal unit is located
on Mallorca, the largest of the
Balearic Islands and a major tourism
hub in the Mediterranean Sea. An
average of 29 premature births to
nonresident mothers take place
annually. Approximately 9 premature
infants are born on the surrounding
islands each year and are transferred
to our center for follow-up. It is
therefore necessary to assess the
safety of flying for neonates of
mothers not residing on Mallorca.
No other fitness-to-fly testing
has been conducted in a body
plethysmograph on healthy term
infants in the first week of life and
premature infants at term age.
The objective of this study was to
determine the earliest fit-to-fly age
of preterm and term infants. This
was done by testing preterm infants
at term age, including those with
bronchopulmonary dysplasia (BPD),
and comparing the results with a
control group of healthy infants that
were 7 days old.
METHODS
This was a prospective observational
clinical study. Term infants (37
weeks gestational age [GA]) and
2 days and 7 days old were
recruited from the postnatal ward
of the University Hospital Son
Espases, Palma de Mallorca. Preterm
infants (<37 weeks GA and 34
weeks of corrected gestational
age [CGA]) were selected shortly
before discharge from the neonatal
unit. All parents of included infants
were planning a flight shortly after
discharge. Written informed consent
was given by all parents. Ethics
approval was granted by the Ethics
Committee of Clinical Investigation of
the Balearic Islands (IB 1231/09).
The condition for all included
infants was a baseline SpO2 of >94%.
Exclusion criteria were respiratory
infection 1 week before testing,
current oxygen requirement, and
cardiac, respiratory (other than BPD),
or metabolic disease. Birth history
and all clinical data were obtained
from patient reports.
The infants were divided in 3 groups:
Group 1, term infants; Group 2,
premature infants without BPD; and
Group 3, premature infants with
BPD. BPD was evaluated at 36 weeks
CGA and was defined as the need for
supplemental oxygen for 28 days,
per National Institute of Child Health
and Human Development criteria.12
Fitness-to-fly testing was performed
according to the testing protocol in
the Pediatric Pulmonary Function
Testing Laboratory, Pediatric
Respiratory Unit, University Hospital
of Son Espases, from September 2010
to May 2013.
The HCT was performed with the
infant on the caregiver’s lap sitting
inside a sealed body plethysmograph
(MasterScreen Body, Erich Jaeger).
To test all infants in the same
conditions, the infants needed to
remain awake and in a half-seated
position without flexing the neck and
without being fed.
SpO2 and pulse rate of the newborns
were measured continuously with a
Masimo SET Radical-7 Electron pulse
oximeter attached to the infant’s
hand or foot. Readings were taken
after a stable plateau was reached,
and baseline SpO2 and pulse rate in
room air were recorded. Nitrogen
was added into the chamber with
a flow of 50 L/min, gradually
reducing the FIO2 to a concentration
of 15% (O2 concentration was
measured by MiniOx3000, Medical
Products). FIO2, SpO2, and pulse
rate were continuously observed for
20 minutes, at which point timing
and any changes were also noted.
If SpO2 dropped to <85%, oxygen
was administered immediately in
a nasal cannula until the baseline
SpO2 was reached. The minimum
amount of supplemental oxygen
given was recorded. An SpO2 of <85%
was counted as a test fail, and the
newborn was deemed not fit to fly.
If the newborns failed the HCT it was
recommended supplemental oxygen
be given on board flights ,as outlined
in BTS guidelines.13,14 Parents were
then requested to repeat the test
every 2 months until obtaining fit-to-
fly status. For families living on the
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PEDIATRICS Volume 137 , number 3 , March 2016
surrounding islands, a ferry
trip home was recommended in all
cases.
After a power calculation, we
simulated the recruitment of 54
patients in the study with 18 patients
in each of the 3 groups. Descriptive
analysis was performed calculating
median and quartiles, or mean and
95% confidence interval (CI) if
variables were normally distributed.
To contrast the hypothesis, the test of
Mann–Whitney and Kruskal–Wallis,
or Student t test and analysis of
variance, were used. To describe
qualitative variables, proportions
and 95% CI were calculated. An
exploratory analysis using binary
logistic regression was used to
3
calculate the adjusted effect over
desaturation as a dependent variable
of several independent variables.
Odds ratios (ORs) are presented with
95% CIs and used for variables with
significant association. All statistical
tests were 2-tailed, and for differences
between groups, a Bonferroni-
corrected P value <.016 was
considered significant. IBM Statistics
SPSS 20.0 software was used.
RESULTS
Demographics
From September 2009 to May 2013,
109 infants were tested: 24 term,
62 preterm without BPD, and 23
preterm with BPD. All term infants
were healthy and had uneventful
deliveries. Complications suffered by
preterm infants during their hospital
stay were resolved by the time of
testing. Demographic and clinical
data for all newborns are listed in
Table 1.
Test Results, Predictors of Test
Failure, and Comparison Between
Groups
One 5-day-old healthy term infant
(38 weeks, 1 day GA) failed the test
(1 of 24, 4.2%). SpO2 dropped to 82%
and the infant needed 0.5 L/min of
oxygen to recover. Pulmonary or
cardiac diseases were excluded by
image studies in this infant. Twelve
of the 62 preterm infants (19.4%)
without BPD and 16 of 23 preterm
(69.3%) with BPD had SpO2 <85%
during the test. The test results are
listed in Table 2.
After a CGA of 39 weeks, none
of the preterm infants without
BPD and none of the term infants
desaturated <85%, but 7 of 12
infants >39 weeks with BPD failed
the test (Figs 1 and 2). BPD was
a strong predictor of failing the
HCT, with an OR of 17.2 (95% CI
4.8–60.9; P < .001).
TABLE 1 Demographic and Clinical Data of the Tested Groups
Characteristic Group 1, Term Group 2, Preterm Without
BPD
Group 3, Preterm With
BPD
n24 62 23
Mean GA, wksa39.6 (39.1–40) 32.5 (31.9–33) 28.2 (27–29.5)
Male, n (%) 12 (50) 36 (58) 10 (43)
Mean birth weight, kga3.3 (3–3.4) 1.8 (1.7–1.9) 0.9 (0.8–1)
Mean age, da3 (3–3.8) 27 (14.5–46.5) 78 (64.4–102.3)
Mean corrected age,
wksa
40 (39.6–40.5) 37 (36.5–37.6) 39.5 (38.1–40.9)
Days of oxygen therapyb 1 (0–4) 47 (44–73)
Days of mechanical
ventilationb
2 (1–5) 8 (1–11)
Days of CPAPb 0 (0–2) 12 (2–26)
Days without oxygen
therapyb
25 (12.3–42) 18 (13–36)
Data are a mean (95% CI) or b median (interquartile range).
TABLE 2 Test Results and Comparison of Groups
Characteristic Group 1, Term Group 2, Preterm Without
BPD
Group 3, Preterm With BPD P
Group 1 vs 2 Group 1 vs 3 Group 2 vs 3
n24 62 23
Baseline SpO2, % 99 (97–100) 99 (98–100) 99 (96.5–99.5) NS NS .015
Change in SpO29 (8–11) 8 (6–12) 16 (10–19) NS .001 <.001
Time to reach lowest test SpO2,
min
10 (10–15) 15 (10–18) 8 (5–12) NS NS .003
Lowest test SpO2, % 89 (88–90) 91 (87–94) 81 (80–88) NS .001 <.001
Time until failing test, min 20a10 (8–12) 8 (5–9) NS
Baseline pulse rate, beats per
min
138 (121–153) 159 (147–170) 158 (138–70) <.001 NS NS
Highest test pulse rate, beats
per min
152 (141–162) 169 (160–179) 163 (157–177) NS NS .015
Pulse rate during desaturation,
beats per min
127 148 (143–163) 158 (144–177) NS
Test failure SpO2 <85%, n (%) 1 (4.2) 12 (19.4) 16 (69.6) NS <.001 <.001
SpO2 <90% during test, n (%) 12 (50) 21 (33.9) 19 (82.6) NS NS <.001
Data are median (interquartile range). NS, not signifi cant.
a Only 1 term infant failed the test.
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VETTER-LARACY et al
As mentioned above, a significant
difference was observed between
preterm infants with BPD and
neonates without BPD. There was
a significant drop in SpO2 (P = .001)
during the test comparing infants
who were term or preterm without
BPD (median change 9 and 8,
respectively) versus preterm with
BPD (median change 16).
Minimum SpO2 during the test was
significantly lower in infants with
BPD (median 81%, interquartile
range 80%–88%, P < .001) compared
with the other 2 groups. The BPD
infants reached the minimum SpO2
earlier (8 minutes, P = .003) than
preterm infants without BPD (15
min).
The 16 BPD patients who failed the
test needed 0.5 to 1 L/min of oxygen
to recover, and the 12 preterm
infants without BPD needed 0.5 to
2 L/min (only 2 children needed 2
L/min). Twelve of the infants had
mild BPD, 9 moderate BPD, and 2
severe BPD.12 Unexpectedly, time
without supplementary O2 was not a
significant factor in passing the test
(Table 1).
The term infant who failed the HCT
did not repeat the test 2 months later
as advised. Only 2 of the preterm
infants without BPD repeated the
test, at 5 and 6 months CGA; both
passed the second time.
Seven of 16 preterm infants with
BPD repeated the test. Of these, 3
at 2 months and 2 at 6 months CGA
passed. One child with BPD was
retested at 6 months CGA and failed
again. Another preterm infant with
BPD born at 23 weeks GA was first
tested at 42 weeks CGA and was
retested at 7 and 17 months CGA, but
failed all HCTs.
DISCUSSION
SpO2 declines 4% in healthy
children and adults while in flight.1,2
Term and preterm infants without
BPD in our study had an important
drop in SpO2 during the preflight
test (9% and 8%, respectively).
Interestingly, we found that all
neonates >39 weeks CGA and those
without BPD passed the test.
Similar results to these were found in
previous studies conducted on older
infants, as in the studies of Bossley
et al,7 who tested term and preterm
infants of 3 and 6 months CGA, and
Martin et al,15 who tested healthy
term infants (13–221 weeks old)
and found that only 1 of 24 healthy
children desaturated.
Our data are not in accordance with
the results of Udomittipong et al,16
who found that a high proportion
(38 of 47) of preterm infants with a
median corrected age of 1.4 months
are at a high risk of in-flight hypoxia.
The discrepancy in results with
Udomittipong et al may be due to the
different test methods used. We used
a whole-body plethysmograph during
the test, which is recommended in
the BTS guidelines. Udomittingpong
et al16 and other studies on infants
of a similar age used high-flow (15
L/min) 14% oxygen in nitrogen
via a non-rebreathing facemask
incorporating a 1-valve assembly.
This method may not be reliable
when used with infants, as has been
suggested by other authors.15
Neonates >39 weeks CGA without
BPD who reach term age have a test
behavior similar to that of older
infants, so the necessity for an HCT
could be eliminated for this group.
In-flight oxygen may not be necessary
either.
BPD was highly associated with test
failure, with an OR of 17.2. Infants
with BPD also suffered a median
drop in SpO2 of 16% (P = .001), and
69.6% of BPD infants failed the HCT
and thus were deemed unfit to fly. In
2004, Buchdahl et al17 performed a
retrospective review of test results in
infants with BPD and discovered that
8 of 20 patients desaturated during
4
FIGURE 1
Individual test results of premature and term infants. SpO2 of infants tested after 39 weeks CGA (16
term and 12 preterm) did not fall below 85%.
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PEDIATRICS Volume 137 , number 3 , March 2016
the HCT, whereas Udomittipong
et al in 200616 found that 23 of 32
preterm infants with BPD failed the
HCT.
The improvement of failure rates
in our study observed in term and
preterm infants without BPD when
they reached >39 weeks CGA was not
evident among the infants with BPD
(Fig 2). It has to be mentioned that
infants with BPD had a considerably
lower GA (28.2 vs 32.5 weeks); thus
extreme prematurity might have an
influence on the test result.
The strengths of this study include
the relatively large number of
patients tested and their young
age; infants so young have not been
tested before. Also, the infants were
tested in a body plethysmograph, the
recommended method in the BTS
guidelines. Limitations include the
time of testing and the conditions of
testing (awake without feeding), and
that accuracy of HCT results was not
confirmed by comparison with actual
inflight SpO2 in the tested infants.
It is possible that the testing time of
20 minutes may not be long enough
and thus not generate sufficient
data to predict safety limits for long-
distance flights, as SpO2 usually
decreases in proportion to the
duration of hypoxemia.1,9 Most of our
test patients who failed desaturated
in 8 to 10 minutes; however, the only
term child who failed did not drop
to <85% until the end of the testing
period.
The HCT was carried out with the
infant awake without feeding and
without decubitus position. The
authors are aware that all those
factors and others (duration of the
test, humidity, infections of the upper
airways, noise, etc) vary greatly
during flight. It is true that active
sleep, changes of position (which
can influence the obstruction of the
upper airway), and feeding may have
an impact on oxygen saturation.5–7
Therefore, we decided to standardize
conditions as much as possible and
tried to avoid introducing variables.
The BTS guidelines do not establish
recommendations in reference to
the mentioned conditions even
though they can have an important
impact on the results. Further studies
are needed that analyze similar
populations for the significance of
sleep or change of body position.
Many studies have proved the HCT to
be equivalent to in-flight conditions
and hypobaric chamber results
in adults and children.18–21 Two
studies were recently conducted by
an Australian group to assess HCT
accuracy by using a non-rebreathing
mask on infants. They published data
of 46 preterm (35.8 weeks) and 24
term infants >2 weeks old, finding
false-positive and false-negative
HCT results compared with in-flight
SpO2.10,22
The studies that concluded that the
HCT is unreliable in infants both
used facemasks to do the testing,
and this is thought to be a flaw,
as false-positive results due to
immediate exposure to FIO2 of 14%
or crying or false-negative results
due to insufficient sealing of the mask
and air room entrainment can be
responsible for the discrepancy of
test and in-flight results.15,22,23
In the first study, done on preterm
infants, the range of time between
HCT and flight was 1 to 15 days.10
A delay of 2 weeks might change
the condition of a premature infant
considerably and could explain the
differences between the results. In
the study done on term infants, the
inflight SpO2 nadir was 5% lower
than the HCT nadir. Flight duration
may also play a role, as 3 children
had SpO2 both below and above
85% on different flights. Sitting in
a sealed chamber in 15% oxygen is
presently the best method available
for simulation of in-flight conditions,
5
FIGURE 2
Individual test results of premature infants with BPD. Seven of 12 infants >39 weeks CGA failed the
HCT.
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VETTER-LARACY et al
but further studies are needed to
prove the accuracy of the HCT in a
plethysmograph in term and preterm
infants.
In another recent study from
Australia, SpO2 of infants <6 months
old was monitored during aircraft
transport, and no difference in the
incidence of desaturation was found
between children <6 and >6 weeks
old.24 This could support our data
that young infants are able to fly. The
cutoff limit in the study was 94%,
which explains the high incidence
of desaturations in all age groups
(one-third). In 2011, the cutoff limit
of the HCT was changed in the BTS
guidelines from SpO2 90% to 85%.14
If it is set to 90%, the probability to
fail the test increases in all groups,
especially in healthy infants (Table
2).15,25 An explanation for the high
failure rate of term infants in our
study if SpO2 is set to <90% in
comparison with preterm infants
could be the younger chronological
age of term infants and a shorter
adaptation period to extrauterine
life (eg, higher amount of fetal
hemoglobin in term infants). If a
temporal SpO2 of 85% to 90% has
any negative impact on infants, it is
still not clear.8
The HCT via body plethysmograph
represents a reasonable
approximation of the physiologic
changes infants undergo in a hypoxic
environment and is useful for
advising a family about the risk of
commercial air travel and the need
for oxygen during a flight.
CONCLUSIONS
This study shows that over a period
of 20 minutes in a controlled
environment with an FIO2 of 15%,
SpO2 levels remain within safe limits
for healthy term infants >39 weeks
CGA and also for preterm infants
>39 weeks CGA without BPD. The
majority of infants with BPD do not
maintain safe levels of SpO2 even in
a simulated in-flight environment,
and therefore testing at this early
age might not be useful. It is
recommended to delay the test until
the infant is 1 year old.
ACKNOWLEDGMENTS
We thank the nurses of the Paediatric
Functional Testing Laboratory who
gave careful technical effort to the
study. Thanks also to the medical
staff of the maternity ward and to
the families of the participating
infants. Particular thanks to Gerard
Laracy for his extensive effort and
commitment to the editing and
proofreading of this manuscript.
ABBREVIATIONS
BPD:  bronchopulmonary
dysplasia
BTS:  British Thoracic Society
CGA:  corrected gestational age
CI:  confidence interval
FIO2:  fraction of inspired oxygen
GA:  gestational age
HCT:  hypoxia challenge testing
OR:  odds ratio
SpO2:  pulse oxygen saturation
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Susanne Vetter-Laracy, Borja Osona, Jose Antonio Peña-Zarza, Jose Antonio Gil and
Hypoxia Challenge Testing in Neonates for Fitness to Fly
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... This is regulated by the European and North American authorities for normal operating conditions (4). The barometric pressure at a cruising altitude leads to a lower partial pressure of inspired oxygen equivalent to 15.2% ambient oxygen, resulting in lower transcutaneous oxygen saturation (SpO 2 ) in healthy children and adults down to 94.4% (5,6) and 88%-94% in term and preterm infants (7). Partial oxygen pressure (pO 2 ) is the major regulator of pulmonary vascular tone and a fall in alveolar pO 2 is the main stimulus for hypoxic pulmonary vasoconstriction (HPV). ...
... To assess the risk for patients with relevant underlying diseases before they board an aircraft, hypoxic challenge tests (HCT) have been established. By breathing oxygen-depleted air (15.2%) for a period of 5-20 min (7,(11)(12)(13), usually sitting in an upright position in a body plethysmograph (11) or breathing via a face mask (5), an approximate similar inspired pO 2 to breathing air at cruising altitude can be simulated under safe conditions. The British Thoracic Society (BTS) already recommends HCT for specific constellations to determine whether supplemental inflight oxygen is necessary or medical clearance can be given (4). ...
... He described lower baseline SpO 2 in Fontan patients and a significant reduction of SpO 2 after ascent and, more importantly, during cruise after 1 h compared to healthy controls (15). This shows that not only for children and adolescents with a Fontan circulation but also ex-preterm babies with or without bronchopulmonary dysplasia, adults with cyanotic congenital heart disease, passengers with cardiovascular disease, or patients with pulmonary hypertension, fitness to fly investigation is an issue of great importance (5,7,12,(16)(17)(18) and may be superior to HCT testing. ...
Article
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Introduction At cruising altitude, the cabin pressure of passenger aircraft needs to be adjusted and, therefore, the oxygen content is equivalent to ambient air at 2,500 masl, causing mild desaturation and a rising pulmonary vascular resistance (PVR) in healthy subjects. For Fontan patients with passive pulmonary perfusion, a rising PVR can cause serious medical problems. The purpose of this fitness to fly investigation (FTF) is to assess the risk of air travel for children and adolescents after Fontan palliation. Methods We investigated 21 Fontan patients [3–14y] in a normobaric hypoxic chamber at a simulated altitude of 2,500 m for 3 h. Oxygen saturation, heart rate, and regional tissue saturation in the forehead (NIRS) were measured continuously. Before entering the chamber, after 90 and 180 min in the hypoxic environment, blood gas analysis and echocardiography were performed. Results Heart rate and blood pressure did not show significant intraindividual changes. Capillary oxygen saturation (SaO 2 ) decreased significantly after 90 min by a mean of 5.6 ± 2.87% without further decline. Lactate, pH, base excess, and tissue saturation in the frontal brain did not reach any critical values. In the case of open fenestration between the tunnel and the atrium delta, P did not increase, indicating stable pulmonary artery pressure. Conclusion All 21 children finished the investigation successfully without any adverse events, so flying short distance seems to be safe for most Fontan patients with good current health status. As the baseline oxygen saturation does not allow prediction of the maximum extent of desaturation and adaption to a hypoxic environment takes up to 180 min, the so-called hypoxic challenge test is not sufficient for these patients. Performing an FTF examination over a period of 180 min allows for risk assessment and provides safety to the patients and their families, as well as the airline companies.
... Developing objective criteria and best practices for weaning premature infants from oxygen support has been attempted previously with varying degrees of success [13][14][15][16][17][18]. However, no standard of care presently exists, and the majority of prior studies have suffered from small sample sizes, retrospective design, and limited generalizability. ...
Article
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Objective We aim to identify potential risk factors associated with longer duration of supplemental oxygen use in preterm infants at risk for bronchopulmonary dysplasia (BPD) to better inform families and weaning protocols. Study design This is a retrospective study of infants with a birth gestational age (GA) < 32 0/7 weeks admitted to the neonatal intensive care unit (NICU) between October 2017 and September 2019. Results A total of 172 infants met criteria for inclusion and analysis, of which 69 (40.1%) infants required LFNC. Risk factors for longer duration included lower birth GA or birth weight, increased ventilator days, and diagnosis of a patent ductus arteriosus (PDA). BPD was diagnosed in 69.6% who required LFNC, of which 47.8% were discharged on home oxygen. Conclusion Younger birth GA, lower birth weight, increased ventilator days, and presence of a PDA were identified as risk factors for longer LFNC duration.
Poster
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Infants who travel by air are often exposed to unique physiologic challenges that can increase their risk of morbidity and mortality (1,2). This is especially true for premature infants. • This is especially true for premature infants. We present the case of a premature infant who developed severe respiratory distress during a commercial flight due to the lack of compensatory mechanisms to adjust to in-flight physiology as a call for protective guidelines (3). • The acute clinical decompensation experienced by our preterm patient are in keeping with physiologic changes associated with a combination of his lower baseline SpO 2 and limited compensatory mechanisms to respond to the drop in FiO 2 during his flight. • This supposition is supported by a clinical improvement with supplemental oxygen (Figure 1). • This case highlights the impact of in-flight decrease in FiO2 on infant respiratory physiology. While most children and adults tolerate this decrease 3 , preterm infants and individuals prone to hypoxia can experience desaturation and clinical decompensation 4,6. • Preterm and newborn infants have the additional effects of fetal hemoglobin, less efficient compensatory mechanisms and a tendency toward pulmonary hypertension. • Commercial air travel is usually at altitudes of 9150-13,000 m but pressurized to an equivalent of 1530-2440 m to avoid hypoxia However, the atmospheric partial pressure of oxygen at 2440 meters is equivalent to 15-16% FiO2, which can lead to hypoxemia. • Infants are particularly vulnerable due to their increased airway resistance, their potential for developing pulmonary hypertension and apneic episodes, and a shift in the oxygen dissociation curve due to fetal hemoglobin.
Article
Background and objectives: Former premature infants with bronchopulmonary dysplasia (BPD) are at risk for hypoxemia during air travel, but it is unclear until what age. We aimed to determine pass rates for high altitude simulation testing (HAST) by age in children with BPD and identify risks for failure. Methods: Retrospective, observational analysis of HAST in children with BPD at Boston Children's Hospital, using interval censoring to estimate the time-to-event curve of first pass. Curves were stratified by neonatal risk factors. Pass was considered lowest Spo2 ≥ 90%, or ≥94% for subjects with ongoing pulmonary hypertension (PH). Results: Ninety four HAST studies were analyzed from 63 BPD subjects; 59 studies (63%) were passed. At 3 months corrected gestational age (CGA), 50% of subjects had passed; at 6 months CGA, 67% has passed; at 12 and 18 months CGA, 72% had passed; and at 24 months CGA, 85% had passed. Neonatal factors associated with delayed time-to-pass included postnatal corticosteroid use, respiratory support at NICU discharge, and tracheostomy. BPD infants who did not require respiratory support at 36 weeks were likely to pass (91%) at 6 months CGA. At 24 months, children least likely to pass included those with a history of PH (63%) and those discharged from the NICU with oxygen or respiratory support (71%). Conclusions: Children with BPD on respiratory support at 36 weeks should be considered for preflight hypoxemia challenges through at least 24 months CGA, and longer if they had PH or went home from NICU on respiratory support.
Chapter
The revised and updated second edition covers practical approaches to caring for healthy and high-risk infants. https://shop.aap.org/neonatalogy-for-primary-care-2nd-edition-paperback/
Article
Healthy children may present acute mountain sickness (AMS) within a few hours after arrival at high altitudes. In few cases, serious complications may occur, including high-altitude pulmonary edema and rarely high-altitude cerebral edema. Those with preexisting conditions especially involving hypoxia and pulmonary hypertension shall not risk travelling to high altitudes. Newborn from low altitude mothers may have prolonged time to complete postnatal adaptation. The number of children and adolescents traveling on commercial aircrafts is growing, and this poses a need for their treating physicians to be aware of the potential risks of hypoxia while air traveling.
Article
Background: Children travel with their families, including children with chronic illness. We know that adults with chronic illness who travel are more likely than their healthy peers to become sick while traveling. A review of the literature was undertaken to identify what is known about traveling with children with special health care needs and to identify gaps in our knowledge. Methods: An Online search of the PubMed, CINAHL and Google databases of English language literature was conducted June 2016, October 2017, June 2018 and April 2019 using the terms children and travel, air travel, travel health, disabled child, children with special healthcare needs, parents of disabled children, vacations, recreation, international, wheelchairs, planning techniques, asthma, diabetes, altitude, cystic fibrosis, inflammatory bowel disease, sickle cell disease, depression, food allergies, Attention Deficit Hyperactivity Disorder (ADHD), and seizures. The search was limited to years 2000-2019. A secondary search of relevant articles was conducted using the reference sections of articles identified in the primary search. Results: 185 papers were examined for travel health related outcomes for children and adults with chronic diseases. Articles were excluded if they addressed the educational needs of students with disabilities traveling abroad, did not directly address travel health (e.g travel skills, travel itineraries), contained outdated policy statements, or were case reports of a single patient. The remaining 84 papers were organized and reviewed by organ systems. The articles were primarily descriptive and did not lend themselves to a systematic review. Conclusion: Children traveling with chronic and complex health conditions are a heterogeneous group of vulnerable travelers. Closing the knowledge gap about how to best help these travelers requires a multipronged approach. Research is urgently needed to identify best practices for five of the most common chronic childhood diseases: asthma, depression, ADHD, food allergies and autism. For less common illnesses, ones typically cared for in specialty clinics, expert consensus opinion and multi-center studies are needed. Families and disease advocacy societies should be included in the research as they may have already identified the most pressing travel-related health concerns and solutions for these problems.
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These investigators report oxygen saturation measured during the transport of critically ill newborns in fixed-wing or rotary-wing aircraft.
Article
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This article summarises the key points from the 2011 British Thoracic Society (BTS) recommendations on managing passengers with respiratory disease planning air travel. The guidance aims to provide practical advice for respiratory specialists in secondary care and serves as a valuable reference for other healthcare professionals managing these patients. A greater awareness of the challenges posed by air travel will allow improved clinical assessment and practical advice to encourage patients to fly safely wherever possible.
Article
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To assess the response of healthy infants to airway hypoxia (15% oxygen in nitrogen). Interventional study. Infants' homes and paediatric ward. 34 healthy infants (20 boys) born at term; mean age at study 3.1 months. 13 of the infants had siblings whose deaths had been ascribed to the sudden infant death syndrome. Respiratory variables were measured in room air (pre-challenge), while infants were exposed to 15% oxygen (challenge), and after infants were returned to room air (post-challenge). Baseline oxygen saturation as measured by pulse oximetry, frequency of isolated and periodic apnoea, and frequency of desaturation (oxygen saturation < or = 80% for > or = 4 s). Exposure to 15% oxygen was terminated if oxygen saturation fell to < or = 80% for > or = 1 min. Mean duration of exposure to 15% oxygen was 6.3 (SD 2.9) hours. Baseline oxygen saturation fell from a median of 97.6% (range 94.0% to 100%) in room air to 92.8% (84.7% to 100%) in 15% oxygen. There was no correlation between baseline oxygen saturation in room air and the extent of the fall in baseline oxygen saturation on exposure to 15% oxygen. During exposure to 15% oxygen there was a reduction in the proportion of time spent in regular breathing pattern and a 3.5-fold increase in the proportion of time spent in periodic apnoea (P < 0.001). There was an increase in the frequency of desaturation from 0 episodes per hour (range 0 to 0.2) to 0.4 episodes per hour (0 to 35) (P < 0.001). In 4 infants exposure to hypoxic conditions was ended early because of prolonged and severe falls in oxygen saturation. A proportion of infants had episodes of prolonged (< or = 80% for > or = 1 min) or recurrent shorter (< or = 80% for > or = 4 s) desaturation, or both, when exposed to airway hypoxia. The quality and quantity of this response was unpredictable. These findings may explain why some infants with airway hypoxia caused by respiratory infection develop more severe hypoxaemia than others. Exposure to airway hypoxia similar to that experienced during air travel or on holiday at high altitude may be harmful to some infants.
Article
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To assess the effect of altitude and acclimatisation on cardiorespiratory function and well-being in healthy children. A daily symptom diary, serial measurements of spirometry, end-tidal carbon dioxide (etCO(2)) and daytime and overnight pulse oximetry (SpO(2)), were undertaken at sea level and altitudes up to 3500 m in healthy children during a trekking holiday. SpO(2) at altitude was compared with that in flight and during acute hypoxic challenge (breathing 15% oxygen) at sea level. Measurements were obtained in nine children aged 6-13 years (median 8). SpO(2) decreased significantly during the hypoxic challenge (difference -5%, 95% CI -6 to -3%, p<0.01) but remained above 90% in all children. There was a significant fall in daytime and overnight SpO(2) (95% CI -11.9 to -7.5% and -12 to -8, respectively) and etCO(2) (-8.5 to -4.5 mm Hg) as the children ascended to 3500 m. There was a significant increase in SpO(2) (95% CI 1.1 to 4.9%) and a further drop in etCO(2) (-5.9 to -0.8 mm Hg) after a week at altitude, etCO(2) being negatively correlated with SpO(2). There was no correlation between SpO(2) during hypoxic challenge, in flight or at altitude. Lung function remained within 7% of baseline in all but two children, in whom reductions of up to 23% in FVC and 16% FEV(1) were observed at altitude. The children generally remained well, but the Lake Louise scoring system was unreliable in this age group. A wide range of physiological responses to altitude are evident in healthy children. This study should inform future larger studies in children to improve understanding of responses to hypoxia in health and disease.
Article
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Overnight 12 hour tape recordings of arterial oxygen saturation (SaO2, pulse oximeter in the beat to beat mode), breathing movements, and airflow were made on 66 preterm infants (median gestational age 34 weeks, range 25-36) who had reached term (37 weeks) and were ready for discharge from the special care baby unit. No infant was given additional inspired oxygen during the study. The median baseline SaO2 was 99.4% (range 88.9-100%). Eight infants had baseline SaO2 values below 97%, the lowest value observed in a study on full term infants. All but one infant had short-lived falls in SaO2 to less than or equal to 80% (desaturations), which were more frequent (5.4 compared with 0.9/hour) and longer (mean duration 1.5 compared with 1.2 seconds) than in full term infants. There was no evidence that gestational age at birth influenced the frequency or duration of desaturations among the preterm infants. The frequency of relatively prolonged episodes of desaturation (SaO2 less than or equal to 80% for greater than or equal to 4 seconds), however, decreased significantly with increasing gestational age (0.5, 0.4, 0.2, and 0.1 episodes/hour in infants at less than or equal to 32, 33-34, 35, and 36 weeks' gestational age, respectively). Analysis of the respiratory patterns associated with such episodes showed that 5% occurred despite both continued breathing movements and continuous airflow. Five infants had outlying recordings: three had baseline SaO2 values of less than 95% (88.9, 92.7, and 93.8%), and two had many prolonged desaturations (14 and 92/hour; median for total group 0.2, 95th centile 2.3). None of these five infants had been considered clinically to have dis order of oxygenation. Although these data are insufficient to provide information about outcome, we conclude that reference data on arterial oxygenation in preterm infants are important to enable the identification of otherwise unrecognized hypoxaemia.
Article
Full-text available
Overnight 12 hour tape recordings were made of arterial oxygen saturation (SaO2, pulse oximeter in the beat to beat mode) and abdominal wall breathing movement on 67 healthy, full term infants between the ages of 29 and 54 (median 39) days. The median baseline SaO2 during regular breathing was 99.8% (range 97.0-100%). Fifty four infants (81%) had shortlived episodes during which SaO2 fell to 80% or less (desaturation); the median rate was 0.9 desaturations/hour, and the median duration of each desaturation was 1.2 seconds. The 97th centile value for the duration of all episodes in which SaO2 fell to less than or equal to 80% was 4.0 seconds. The frequency of desaturations was significantly higher, and their duration significantly longer, when the breathing pattern was non-regular rather than regular. The percentage of apnoeic pauses (greater than or equal to 4 seconds in duration) followed by a desaturation was higher during non-regular than regular breathing; it was particularly high during periodic breathing. A knowledge of normal variability of baseline measurements of oxygenation and of the relationship between oxygenation and breathing patterns in infants is essential to the use of pulse oximetry in clinical practice.
Article
Up to a third of ex-preterm infants flying near term exhibit pulse oxygen saturation (SpO2) of less than 85% during air travel. A hypoxia challenge test (HCT) is recommended to evaluate the requirement for in-flight supplemental O2. The validity of the HCT in healthy, term infants has not been reported. This study aimed to characterise the in-flight hypoxia response and the accuracy of the HCT to predict this response in healthy, term infants in the first year of life. Infants (n=24: (15 male)) underwent a HCT prior to commercial air travel during which parents monitored SpO2. Thirty-two flights were undertaken with six infants completing multiple flights. The median in-flight SpO2 nadir was 87% and significantly lower than the HCT SpO2 nadir (92%: p<0.001). Infants on seven flights recorded SpO2<85% with one infant recording a HCT with a SpO2 less than 85%. There was marked variability in the in-flight SpO2 in the six infants who undertook multiple flights, and for three of these infants, the SpO2 nadir was both above and below 85%. We report that in healthy term infants an in-flight SpO2 below 85% is common and can vary considerably between flights and that the HCT poorly predicts the risk of in-flight hypoxia (SpO2<85%). As it is common for healthy term infants to have SpO2 less than 85% during air travel further research is needed to clarify whether this is an appropriate cut-off in this age group.
Article
Commercial aircraft are pressurised to ∼2438 m (8000 ft) above sea level that equates breathing 15% oxygen at sea level. A preflight hypoxic challenge test (HCT) is therefore recommended for children with cystic fibrosis or other chronic lung diseases and inflight oxygen is advised if pulse oximetric saturation (SpO2) decreases <90%. Study responses to a modified HCT, encompassing various body positions and light physical activity, reflecting relevant activities of children during flight, with a view to challenge the evidence of the current cut-off. Oxygenation, heart rate and ventilation were observed in 34 healthy schoolchildren (17 boys) undergoing a modified HCT, alternating between breathing room air and 15% oxygen in nitrogen while seated, supine, standing and walking at 3 km/h and 5 km/h. Nadir SpO2 <90%, median (range), occurred in 9 subjects sitting, 89% (78-89%); 6 supine, 88.5% (87-89%); 9 standing, 89% (85-89%); 23 walking 3 km/h, 87% (74-89%); and 21 walking 5 km/h, 86% (74-89%). Total time <90% for these subjects in seconds was 20 (10-80) sitting, 30 (10-190) supine, 50 (10-150) standing, 80 (10-260) walking 3 km/h and 125 (10-300) walking 5 km/h. Light exercise in general led to lower SpO2: 91% (77-96%), p<0.0001. A modified HCT led to moments of desaturation below 90% in various body positions at rest and during light physical activity in healthy schoolchildren. It is questionable whether the international recommended cut-off of 90% for children with chronic lung disease reflects clinical oxygen dependence during flights.
Article
During air flight, cabin pressurisation produces an effective fraction of inspired oxygen (FiO(2)) of 0.15. This can cause hypoxia in predisposed individuals, including infants with bronchopulmonary dysplasia (BPD), but the effect on ex-preterm babies without BPD was uncertain. The consequences of feeding a baby during the hypoxia challenge were also unknown. Ex-preterm (without BPD) and term infants had fitness to fly tests (including a period of feeding) at 3 or 6 months corrected gestational age (CGA) in a body plethysmograph with an FiO(2) of 0.15 for 20 min. A 'failed' test was defined as oxygen saturation (SpO(2)) <90% for at least 2 min. 41 term and 30 ex-preterm babies (mean gestational age 39.8 and 33.1 weeks, respectively) exhibited a significant median drop in SpO(2) (median -6%, p<0.0001); there was no difference between term versus ex-preterm babies, or 3 versus 6 months. Two term (5%) and two ex-preterm (7%) babies failed the challenge. The SpO(2) dropped further during feeding (median -4% in term and -2% in ex-preterm, p<0.0001), with transient desaturation (up to 30 s) <90% seen in 8/36 (22%) term and 9/28 (32%) ex-preterm infants; the ex-preterm babies desaturated more quickly (median 1 vs 3 min, p=0.002). Ex-preterm babies without BPD and who are at least 3 months CGA do not appear to be a particularly at-risk group for air travel, and routine preflight testing is not indicated. Feeding babies in an FiO(2) of 0.15 leads to a further fall in SpO(2), which is significant but transient.