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Fitness to fly testing in term and ex-preterm babies without bronchopulmonary dysplasia
Abstract
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.
... [4][5][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][8][9][10][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. ...
... 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. ...
... 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][6][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. ...
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.
... For young infants, studies show that HAST by means of a face mask does not adequately rule out inflight desaturation [13]. Testing in a body plethysmograph is probably much more reliable, but to date, no study has included follow-up with measurements while flying [14]. If necessary, on-board oxygen can be safely administered by a portable oxygen concentrator (POC). ...
... Desaturation (SpO 2 < 85%) during HAST is rare in term neonates during the first week of life but more common in preterm neonates, especially when diagnosed with bronchopulmonary dysplasia (BPD). In the latter, around 70% of neonates desaturate during HAST [11,14,18]. The recommendations of the BTS are to refrain from air travel for 1 week after birth in term children. ...
Conclusion:
We present an overview of the most up to date recommendations to ensure the safety of children during flight. What is Known: • Around 65% of on-board medical emergencies are complications of underlying disease. • In children, the three most common emergencies during flight concern respiratory, neurological and infectious disease. What is New: • Although studies are scarce, some advices to ensure safe air travel can be given for most underlying medical conditions in children, based on physiology, studies in adults and expert opinions. • In former preterm infants without chronic lung disease, hypoxia altitude simulation testing to rule out in-flight desaturation is not recommended.
... 20 21 Beyond 3 months of age there is no evidence that ex-preterm infants, without bronchopulmonary dysplasia, are at significantly greater risk of desaturation during a HCT than term infants. 22 In addition to very young and ex-preterm infants, the children most at risk of hypoxia are those with anaemia, congenital heart disease with an actual or potential right to left shunt, 23 neuromuscular disorders or chronic or acute lung disease. Low humidity during air travel can also present a problem for children with respiratory conditions such as CF. ...
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.
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.
EquipmentGoals of Neonatal TransportOptimally, all infants requiring neonatal intensive care should be delivered at a facility capable of providing such services. Unfortunately, numerous circumstances may arise which prevent this, including geographical and economic constraints, and unexpected complications of labor, delivery, or the neonatal period. EquipmentGoals of Neonatal TransportOptimally, all infants requiring neonatal intensive care should be delivered at a facility capable of providing such services. Unfortunately, numerous circumstances may arise which prevent this, including geographical and economic constraints, and unexpected complications of labor, delivery, or the neonatal period. Goals of Neonatal TransportOptimally, all infants requiring neonatal intensive care should be delivered at a facility capable of providing such services. Unfortunately, numerous circumstances may arise which prevent this, including geographical and economic constraints, and unexpected complications of labor, delivery, or the neonatal period. Optimally, all infants requiring neonatal intensive care should be delivered at a facility capable of providing such services. Unfortunately, numerous circumstances may arise which prevent this, including geographical and economic constraints, and unexpected complications of labor, delivery, or the neonatal period.
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/
Objective
Commercial airplanes fly with an equivalent cabin fraction of inspired oxygen of 0.15, leading to reduced oxygen saturation (SpO2) in passengers. How this affects children with complex congenital heart disease (CHD) is unknown. We conducted Hypoxic Challenge Testing (HCT) to assess need for inflight supplemental oxygen.
Methods
Children aged <16 years had a standard HCT. They were grouped as (A) normal versus abnormal baseline SpO2 (≥95% vs <95%) and (B) absence versus presence of an actual/potential right-to-left (R–L) shunt. We measured SpO2, heart rate, QT interval corrected for heart rate and partial pressure of carbon dioxide measured transcutaneously (PtcCO2). A test failed when children with (1) normal baseline SpO2 desaturated to 85%, (2) baseline SpO285%–94% desaturated by 15% of baseline; and (3) baseline SpO275%–84% desaturated to 70%.
Results
There were 68 children, mean age 3.3 years (range 10 weeks–14.5 years). Children with normal (n=36) baseline SpO2 desaturated from median 99% to 91%, P<0.0001, and 3/36 (8%) failed the test. Those with abnormal baseline SpO2 (n=32) desaturated from median 84% to 76%, P<0.0001, and 5/32 (16%) failed (no significant difference between groups). Children with no R–L shunt (n=25) desaturated from median 99% to 93%, P<0.0001, but 0/25 failed. Those with an actual/potential R–L shunt (n=43) desaturated from median 87% to 78%, P<0.0001, and 8/43 (19%) failed (difference between groups P<0.02). PtcCO2, heart rate and QT interval corrected for heart rate were unaffected by the hypoxic state.
Conclusions
This is the first evidence to help guide which children with CHD need a preflight HCT. We suggest all children with an actual or potential R–L shunt should be tested.
During airflight, cabins are pressurised to 8000 ft (2438 m) leading to an effective FiO2 of 0.15. This leads to a fall in oxygen saturation in all passengers, and especially those with underlying lung disease. The hypoxic challenge test using a body plethysmograph can predict a need for supplemental oxygen during airflight, and the process is described.
Most children will experience a small, clinically insignificant drop in oxygen saturation during air travel due to the effects of altitude. Clinically significant hypoxia may occur in individuals with an underlying cardio-respiratory condition, in particular young infants born prematurely or with chronic lung disease of prematurity and in children with neuromuscular disorders. To date there is very little in-flight data available in these clinical populations to allow the development of evidence based guidelines for pre-flight assessment of the risk of hypoxia in-flight. The hypoxia flight simulation test is considered the gold standard for assessing the risk of in-flight hypoxia in adults and existing clinical guidelines for pre-flight assessment are largely based on data extrapolated from adults. The hypoxia challenge test has not been validated in infants and children and there are data to suggest that the test may not be accurate in neonates. We recommend high risk paediatric patients are assessed on a case by case basis by a respiratory paediatrician, with consideration of a hypoxia flight simulation test in certain circumstances.
Airplanes are widely used by families and their children and pediatricians are increasingly asked to answer questions on this subject. The main purpose of this study was to evaluate the knowledge of pediatricians in this field except for medical transportation. Pediatricians belonging to the AFPA, the SFP, the SNPEH, or the SP2A were emailed a questionnaire on the physiological particularities of airborne transportation, contraindications to flight related to diseases (infections, diabetes, sickle-cell anemia, respiratory diseases, etc.) and the possible medication intake on board. Among the 232 responders, 82.3% had an exclusive hospital practice and 65% were specialized in more than one area of medicine. Regarding contraindications to flying, the rate of correct answers varied from 14 to 84% with divided opinions regarding respiratory and hematological pathologies. However, contraindications related to infections were well known. Items related to oxygen therapy raised questions as 35–68% of pediatricians stated that they could not answer. On the whole, this work demonstrated very fragmented knowledge on this topic.
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.
Airplanes are widely used by families and their children and pediatricians are increasingly asked to answer questions on this subject. The main purpose of this study was to evaluate the knowledge of pediatricians in this field except for medical transportation. Pediatricians belonging to the AFPA, the SFP, the SNPEH, or the SP2A were emailed a questionnaire on the physiological particularities of airborne transportation, contraindications to flight related to diseases (infections, diabetes, sickle-cell anemia, respiratory diseases, etc.) and the possible medication intake on board. Among the 232 responders, 82.3% had an exclusive hospital practice and 65% were specialized in more than one area of medicine. Regarding contraindications to flying, the rate of correct answers varied from 14 to 84% with divided opinions regarding respiratory and hematological pathologies. However, contraindications related to infections were well known. Items related to oxygen therapy raised questions as 35-68% of pediatricians stated that they could not answer. On the whole, this work demonstrated very fragmented knowledge on this topic.
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.
The aim of this study was to simulate an in flight environment at sea level with a fractional inspired concentration of oxygen (FiO2) of 0.15 to determine how much supplemental oxygen was needed to restore a subject's oxygen saturation (SaO2) to 90% or to the level previously attained when breathing room air (FiO2 of 0.21).
Three groups were selected with normal, obstructive, and restrictive lung function. Using a sealed body plethysmograph an environment with an FiO2 of 0.15 was created and mass spectrometry was used to monitor the FiO2. Supplemental oxygen was administered to the patient by nasal cannulae. SaO2 was continuously monitored and recorded at an FiO2 of 0.21, 0.15, and 0.15 + supplemental oxygen.
When given 2 l/m of supplemental oxygen all patients in the 15% environment returned to a similar SaO2 value as that obtained using the 21% oxygen environment. One patient with airways obstruction needed 3 l/m of supplemental oxygen to raise his SaO2 above 90%.
This technique, which simulates an aircraft environment, enables an accurate assessment to be made of supplemental oxygen requirements.
We have previously suggested that it is possible to predict oxygen desaturation during flight in children with cystic fibrosis and chronic lung disease by non-invasive measurement of oxygen saturation following inhalation of 15% oxygen--the pre-flight hypoxic challenge. This study reports on the results of measurements over 5 years.
The study comprised a pre-flight hypoxic challenge measuring oxygen saturation by finger tip pulse oximetry (SpO(2)) during tidal breathing of 15% oxygen in nitrogen and spirometric testing 1 month before the flight followed by SpO(2) measurements during intercontinental flights to and from holidays abroad with children in wake and sleep states.
Pre-flight tests were completed on 87 children with cystic fibrosis. Desaturation of <90% occurred in 10 children at some stage during the flight, three of whom received supplementary oxygen. Using a cut off SpO(2) of 90%, the pre-flight hypoxic challenge correctly predicted desaturation in only two of these children. The sensitivity and specificity of the pre-flight hypoxic challenge were 20% and 99%, respectively, compared with 70% and 96% for spirometric tests (using a cut off for forced expiratory volume in 1 second (FEV(1)) of <50% predicted). Overall, pre-flight spirometric tests were a better predictor of desaturation during flight with the area under the Receiver Operating Characteristic (ROC) curve of 0.89 compared with 0.73 for the hypoxic challenge test.
In this group of subjects pre-flight spirometric testing was a better predictor of desaturation during flight than the pre-flight hypoxic challenge.
Modern aircraft flying at high altitude are cabin pressurised to an atmospheric partial pressure of up to 8000 feet (2348 metres), equivalent to breathing approximately 15% oxygen. This may expose individuals with cardiorespiratory disease to the risk of developing hypoxia. In 2002 the British Thoracic Society (BTS) issued recommendations for passengers with respiratory diseases who are planning to fly.1 These recommendations included the use of a hypoxic challenge test in children with a history of respiratory disease too young to undergo conventional lung function tests. While pre-flight hypoxic challenge tests have been evaluated in older children2 and adults3 with respiratory disease, there are few data on hypoxic responses in infants and young children with respiratory disease although one study has observed profound desaturation in a small number of healthy infants while asleep.4
In the last 6 years we have tested …
The low oxygen environment during air travel may result in hypoxia in patients with respiratory disease. However, little information exists on the oxygen requirements of infants with respiratory disease planning to fly. A study was undertaken to identify the clinical factors predictive of an in-flight oxygen requirement from a retrospective review of hypoxia challenge tests (inhalation of 14-15% oxygen for 20 minutes) in infants referred for fitness to fly assessment.
Data from 47 infants (median corrected age 1.4 months) with a history of neonatal lung disease but not receiving supplemental oxygen at the time of hypoxia testing are reported. The neonatal and current clinical information of the infants were analysed in terms of their ability to predict the hypoxia test results.
Thirty eight infants (81%) desaturated below 85% and warranted prescription of supplemental in-flight oxygen. Baseline oxygen saturation was >95% in all infants. Age at the time of the hypoxia test, either postmenstrual or corrected, significantly predicted the outcome of the hypoxia test (odds ratio 0.82; 95% confidence intervals 0.62 to 0.95; p = 0.005). Children passing the hypoxia test were significantly older than those requiring in-flight oxygen (median corrected age (10-90th centiles) 12.7 (3.0-43.4) v 0 (-0.9-10.9) months; p < 0.0001).
A high proportion of ex-preterm infants not currently requiring supplemental oxygen referred for fitness-to-fly assessment and less than 12 months corrected age are at a high risk of requiring in-flight oxygen. Referral of this patient group for fitness to fly assessment including a hypoxia test may be indicated.
Commercial aircrafts cruise between 9150 and 13000 m above sea level, with a cabin pressure equivalent to 1530–2440 m at which passengers breathe the equivalent of 15–17% of fractional inspired oxygen (FiO2) at sea level.
British Thoracic Society recommendations for passengers with chronic respiratory disorders planning air travel1 suggest that infants and young children unable to perform spirometry, with a history of neonatal respiratory disease consult a paediatrician and a hypoxia test be considered. The recommended hypoxia test method in young children is to place the child in a body plethysmograph while seated on the parent’s lap and introduce nitrogen until FiO2 equals 15%. This method relies on equipment not readily available outside the tertiary hospital setting. We have reported a review of hypoxia testing in …
Preterm infants with bronchopulmonary dysplasia often demonstrate sucking difficulties. The aim of this study was to determine whether the severity of bronchopulmonary dysplasia affects not only coordination among suck-swallow-respiration but also sucking endurance and performance itself.
Twenty very low birth weight infants were studied. Infants with anomalies or intraventricular hemorrhage were excluded from the evaluation. Subjects were divided into 3 groups: no bronchopulmonary dysplasia (7 infants), bronchopulmonary dysplasia without home oxygen therapy (7 infants), and bronchopulmonary dysplasia with home oxygen therapy (6 infants). In addition to sucking efficiency, pressure, frequency, duration, and duration of sucking burst, length of deglutition apnea, number of swallows per burst, and respiratory rate were also measured during bottle-feeding at 40 weeks' postmenstrual age. In addition, PCO2 and oxygen saturation were measured at rest and during bottle-feeding.
Infants with severe bronchopulmonary dysplasia demonstrated not only the lowest sucking pressure and sucking frequency, shortest sucking burst duration, and lowest feeding efficiency but also the lowest frequency of swallows during the run and the longest deglutition apnea. The respiratory rate was highest, and the decrease in oxygen saturation was largest, in infants with severe bronchopulmonary dysplasia.
Feeding problems depend on the severity of bronchopulmonary dysplasia. Infants with bronchopulmonary dysplasia demonstrated not only poor feeding coordination but also poor feeding endurance and performance.
Oral feeding has been reported to compromise breathing among preterm infants with bronchopulmonary dysplasia (BPD) during hospitalization or shortly after discharge. However, limited information was available concerning whether preterm infants with BPD remain vulnerable to feeding and growth insufficiency after a longer term of follow-up. The purpose of this study was therefore to examine the effect of severity of BPD on pulse oxygen saturation (SpO2) during feeding and growth in very low birth weight (VLBW) preterm infants during infancy. Seventy-two preterm infants with VLBW and 15 term infants were prospectively examined their growth and SpO2 during feeding at 2, 4, and 6 months of corrected age. The severity of BPD was graded in VLBW infants according to the American National Institutes of Health consensus definition. In comparison to VLBW infants with mild BPD and term infants, VLBW infants with severe BPD showed significantly lower mean levels of SpO2 during feeding at 2–6 months corrected age (P < 0.05). Those with severe BPD further exhibited higher rates of growth delay (weight < 10th percentile) throughout the study period. Among VLBW infants, severe BPD had an adverse relation with subsequent weight measures after adjustment for medical and demographic confounding variables (β = −904 g, P = 0.03). The consensus BPD definition is useful to identify those preterm infants who are at greater risk of feeding desaturation and growth delay during infancy and close monitoring of SpO2 during feeding should be advised. Pediatr Pulmonol. 2010; 45:165–173. © 2010 Wiley-Liss, Inc.
We examined 55 infants on 119 occasions, from birth to 6 months, to obtain normal data and to establish guidelines for the management of oxygen-dependent infants with chronic lung disease. Transcutaneous oxygen tension (tcPo2) and saturation (tcSao2) were monitored during four states: awake, feeding, quiet sleep, and active sleep. Lowest values (mean +/- SD) for tcSao2 were recorded in all states during the first week of life: awake 96.2% +/- 2.6%, feeding 91.2% +/- 3.7%, quiet sleep 93.2% +/- 2.9%, and active sleep 92.1% +/- 2.9%. After the first week the results were affected by state rather than age, with differences observed between awake and feeding (P less than 0.0001), awake and asleep (P less than 0.00001), and quiet sleep and active sleep (P less than 0.001). The findings for tcPo2 were less consistent and probably affected by the characteristics of skin. In the first week, values were as follows: awake 83.5 +/- 10.1 mm Hg, feeding 73.4 +/- 10.1 mm Hg, quiet sleep 78.5 +/- 10.9 mm Hg, and active sleep 73.4 +/- 11.4 mm Hg. Subsequently, only the state effect remained, and significant differences existed between awake and feeding (P less than 0.0001) and awake and asleep (P less than 0.00001). We conclude that transcutaneous blood gas measurements are affected by state of the infant.
To assess the usefulness of a hypoxic challenge in a laboratory at sea level in predicting acute desaturation at altitude in children with lung disease.
Comparison of responses to hypoxic challenge in different settings.
22 children (12 boys) aged 11 to 16 years with cystic fibrosis in whom the mean forced expiratory volume in one second was 64% (range 24-100%).
Lung function laboratory, the Alps, and aboard commercial jet aircraft.
Spirometric lung function at sea level and finger probe oximetry with air and 15% oxygen. Oximetry during high altitude flight and on a mountain at altitude of 1800 m.
Significant desaturation (range 0 to 12%) occurred with all hypoxic challenges (P < 0.002). The best predictor of hypoxic response from a single reading was the laboratory test (r2 = 76% for flight and r2 = 47% for mountain altitude), but the mean errors of prediction were not clinically significantly different. In six children who showed the greatest desaturation the laboratory test overestimated desaturation, but other predictors underestimated desaturation in three by up to 5%.
The laboratory hypoxic challenge directly predicted the worst case of desaturation during flight and at equivalent high altitude. Spirometry and baseline oxygen saturations may underestimate individual hypoxic response. The test may have wider applications to other patients with stable chronic lung diseases, particularly in determining who needs supplementary oxygen during air travel and who should be advised against holidays at high altitude.
The hypoxia test can be performed to identify potential hypoxia that might occur in an at-risk individual during air travel. In 2004, the British Thoracic Society increased the hypoxia test cutoff guideline from 85 to 90% in young children. The aim of this study was to investigate how well the cutoff values of 85% and 90% discriminated between healthy children and those with neonatal chronic lung disease (nCLD).
We performed a prospective, interventional study in young children with nCLD who no longer required supplemental oxygen and healthy control subjects. A hypoxia test (involving the administration of 14% oxygen for 20 min) was performed in all children, and the nadir in pulse oximetric saturation (Spo(2)) recorded.
Hypoxia test results were obtained in 34 healthy children and 35 children with a history of nCLD. Baseline Spo(2) in room air was unable to predict which children would "fail" the hypoxia test. In those children < 2 years of age, applying a cutoff value of 90% resulted in 12 of 24 healthy children and 14 of 23 nCLD children failing the hypoxia test (p = 0.56), whereas a cutoff value of 85% was more discriminating, with only 1 of 24 healthy children and 6 of 23 nCLD children failing the hypoxia test (p = 0.048).
In the present study, using a hypoxia test limit of 90% did not discriminate between healthy children and those with nCLD. A cutoff value of 85% may be more appropriate in this patient group. The clinical relevance of fitness to fly testing in young children remains to be determined.
During air flight, cabin pressurisation results in a reduced fraction of inspired oxygen to 0.15. Healthy children desaturate by around 4% and remain asymptomatic. However children under the age of 1 year are more susceptible to hypoxia, especially if they were born preterm, and even more so if they are survivors of chronic neonatal lung disease. Pre-flight testing with a 'fitness to fly' test is available in some tertiary respiratory centres. The British Thoracic Society 2004 guideline currently recommends supplemental oxygen be given if the child's oxygen saturation falls below 90% during the test, although 85% may be a more appropriate cut off level.
Air travel may pose risks to ex-preterm neonates due to the low oxygen environment encountered during flights. We aimed to study the utility of the preflight hypoxia challenge test (HCT) to detect in-flight hypoxia in such infants.
Ex-preterm (gestation < or = 35 completed weeks) infants ready for air transfer from the intensive/special care nursery to regional hospitals were studied. A pretransfer HCT was performed by exposing infants to 14% oxygen for 20 min. Failure was defined as a sustained fall in pulse oxygen saturation (Spo(2)) < or = 85%. A nurse blinded to the test result monitored the in-flight oxygen saturations in each infant. If Spo(2) fell to < or = 85%, oxygen was administered.
Forty-six infants with median gestation of 32.2 weeks (range, 24 to 35.6 weeks) and birth weight of 1,667 g (range, 655 to 2,815 g) were recruited. No infants were receiving supplemental oxygen at the time of transfer. The HCT was performed at a median corrected age of 35.8 weeks (range, 33.1 to 43 weeks). Thirty-five infants (76%) passed the test, and the remainder failed. During the flight, 16 infants met the criteria for in-flight oxygen, but 12 of these infants (75%) had passed the preflight HCT. Of the 11 infants who failed the HCT, only 4 infants (36%) required in-flight oxygen. The HCT incorrectly predicted in-flight responses in 42% (19 of 46 infants).
A significant percentage of ex-preterm neonates require in-flight oxygen supplementation. The HCT is not accurate for identifying which infants are at risk for in-flight hypoxia.