Chronic obstructive pulmonary disease * 11: fitness to fly with COPD

Cardiorespiratory Adaptation to Short-Term Exposure to Altitude vs. Normobaric Hypoxia in Patients with Pulmonary Hypertension

Prediction of adverse health effects at altitude or during air travel is relevant, particularly in pre-existing cardiopulmonary disease such as pulmonary arterial or chronic thromboembolic pulmonary hypertension (PAH/CTEPH, PH). A total of 21 stable PH-patients (64 ± 15 y, 10 female, 12/9 PAH/CTEPH) were examined by pulse oximetry, arterial blood gas analysis and echocardiography during exposure to normobaric hypoxia (NH) (FiO2 15% ≈ 2500 m simulated altitude, data partly published) at low altitude and, on a separate day, at hypobaric hypoxia (HH, 2500 m) within 20−30 min after arrival. We compared changes in blood oxygenation and estimated pulmonary artery pressure in lowlanders with PH during high altitude simulation testing (HAST, NH) with changes in response to HH. During NH, 4/21 desaturated to SpO2 < 85% corresponding to a positive HAST according to BTS-recommendations and 12 qualified for oxygen at altitude according to low SpO2 < 92% at baseline. At HH, 3/21 received oxygen due to safety criteria (SpO2 < 80% for >30 min), of which two were HAST-negative. During HH vs. NH, patients had a (mean ± SE) significantly lower PaCO2 4.4 ± 0.1 vs. 4.9 ± 0.1 kPa, mean difference (95% CI) −0.5 kPa (−0.7 to −0.3), PaO2 6.7 ± 0.2 vs. 8.1 ± 0.2 kPa, −1.3 kPa (−1.9 to −0.8) and higher tricuspid regurgitation pressure gradient 55 ± 4 vs. 45 ± 4 mmHg, 10 mmHg (3 to 17), all p < 0.05. No serious adverse events occurred. In patients with PH, short-term exposure to altitude of 2500 m induced more pronounced hypoxemia, hypocapnia and pulmonary hemodynamic changes compared to NH during HAST despite similar exposure times and PiO2. Therefore, the use of HAST to predict physiological changes at altitude remains questionable. (ClinicalTrials.gov: NCT03592927 and NCT03637153).

Impact of hypobaric flight simulation on walking distance and oxygenation in COPD patients

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a disease that compromises fitness to fly.

OBJECTIVE

To investigate, whether hypobaric mid-distance flight simulation limits exercise endurance in COPD patients.

METHODS

Patients with COPD GOLD stages 2-4 were challenged by hypobaric flight simulation. Patients completed 6-minute walking distances before and after the simulation test. Pulse oximetry and Borg dyspnea scale were measured every 30 min during the test.

RESULTS

Thirty-five patients were included in the study. The distance of the 6-min walking exercise decreased from 343 ± 93 m to 308 ± 101 m (p < 0.0001). The oxygen saturation nadir for the whole group was 72.2% ± 9.1%. The Borg-dypnea-score did not correlate with oxygen desaturation (R-square 0.009, p > 0.05).

CONCLUSIONS

A 3-h hypobaric flight simulation compromises exercise endurance by 35 m or 10%. Hypoxia was well tolerated and more liberal recommendations might by justifiable since hypoxemia appears to be unrelated to dyspnea perception.

Should I stay or should I go? COPD and air travel

Chronic obstructive pulmonary disease (COPD) is a challenging respiratory problem throughout the world. Although survival is prolonged with new therapies and better management, the magnitude of the burden resulting from moderate-to-severe disease is increasing. One of the major aims of the disease management is to try to break the vicious cycle of patients being homebound and to promote an active lifestyle. A fundamental component of active daily life is, of course, travelling. Today, the world is getting smaller with the option of travelling by air. Air travel is usually the most preferred choice as it is easy, time saving, and relatively inexpensive. Although it is a safe choice for many passengers, the environment inside the aeroplane may sometimes have adverse effects on health. Hypobaric hypoxaemia due to cabin altitude may cause health risks in COPD patients who have limited cardiopulmonary reserve. Addressing the potential risks of air travel, promoting proactive strategies including pre-flight assessment, and education of COPD patients about the "fitness to fly" concept are essential. Thus, in this narrative review, we evaluated the current evidence for potential risks of air travel in COPD and tried to give a perspective for how to plan safe air travel for COPD patients.

Pre-flight evaluation of adult patients with cystic fibrosis: a cross-sectional study

BACKGROUND

Air travel may imply a health hazard for patients with cystic fibrosis (CF) due to hypobaric environment in the aircraft cabin. The objective was to identify pre-flight variables, which might predict severe hypoxaemia in adult CF patients during air travel.

METHODS

Thirty adult CF-patients underwent pre-flight evaluation with spirometry, arterial oxygen tension (PaO₂), pulse oximetry (SpO₂) and cardiopulmonary exercise testing (CPET) at sea level (SL). The results were related to the PaO₂ obtained during a hypoxia-altitude simulation test (HAST) in which a cabin altitude of 2438 m (8000 ft) was simulated by breathing 15.1% oxygen.

RESULTS

Four patients fulfilled the criteria for supplemental oxygen during air travel (PaO_{2 HAST} < 6.6 kPa). While walking slowly during HAST, another eleven patients dropped below PaO_{2 HAST} 6.6 kPa. Variables obtained during CPET (PaO_{2 CPET}, SpO_{2 CPET}, minute ventilation/carbon dioxide output, maximal oxygen uptake) showed the strongest correlation to PaO_{2 HAST}.

CONCLUSIONS

Exercise testing might be of value for predicting in-flight hypoxaemia and thus the need for supplemental oxygen during air travel in CF patients. Trial registration The study is retrospectively listed in the ClinicalTrials.gov Protocol Registration System: NCT01569880 (date; 30/3/2012).

Ouderen op reis

Ouderen reizen steeds meer, maar met de leeftijd neemt de kans toe om op reis te overlijden. De oorzaak hiervan is meestal een verergering van vooraf bestaande gezondheidsaandoeningen, eventueel uitgelokt door reisgerelateerde stress en vermoeidheid, infecties en hitte. Ook de hogere leeftijd zelf is echter verantwoordelijk voor een deel van de oversterfte, doordat de afweer afneemt met als gevolg meer kans op ernstige infecties. Daarnaast zijn ouderen gevoeliger voor diepveneuze trombose, dehydratie, temperatuurverschillen en jetlag. Een goede voorbereiding en rekening houden met de specifieke risico’s van een hogere leeftijd, zorgen ervoor dat ook ouderen in het algemeen veilig kunnen reizen.

[Physical exposure by travelling]

Approximately 40 million Germans travel abroad every year. Air travel is the most frequently used mean of transportation followed by the automobile. During airplane flights rheumatic patients are subjected to numerous physical, biological and climatic factors which can cause stress and adverse effects on general health. Therefore, preventive strategies are helpful to protect against health damage, provided that there is general fitness for air travel. The present article focuses on physical and biological stress as well as psychological aspects during air travel and reviews prophylactic measures.

Predicting the need for supplemental oxygen during airline flight in patients with chronic pulmonary disease: a comparison of predictive equations and altitude simulation

BACKGROUND

Patients with chronic pulmonary diseases are at increased risk of hypoxemia when travelling by air. Screening guidelines, predictive equations based on ground level measurements and altitude simulation laboratory procedures have been recommended for determining risk but have not been rigorously evaluated and compared.

OBJECTIVES

To determine the adequacy of screening recommendations that identify patients at risk of hypoxemia at altitude, to evaluate the specificity and sensitivity of published predictive equations, and to analyze other possible predictors of the need for in-flight oxygen.

METHODS

The charts of 27 consecutive eligible patients referred for hypoxia altitude simulation testing before flight were reviewed. Patients breathed a fraction of inspired oxygen of 0.15 for 20 min. This patient population was compared with the screening recommendations made by six official bodies and compared the partial pressure of arterial oxygen (PaO(2)) obtained during altitude simulation with the PaO(2) predicted by 16 published predictive equations.

RESULTS

Of the 27 subjects, 25% to 33% who were predicted to maintain adequate oxygenation in flight by the British Thoracic Society, Aerospace Medical Association or American Thoracic Society guidelines became hypoxemic during altitude simulation. The 16 predictive equations were markedly inaccurate in predicting the PaO(2) measured during altitude simulation; only one had a positive predictive value of greater than 30%. Regression analysis identified PaO(2) at ground level (r=0.50; P=0.009), diffusion capacity (r=0.56; P=0.05) and per cent forced expiratory volume in 1 s (r=0.57; P=0.009) as having predictive value for hypoxia at altitude.

CONCLUSIONS

Current screening recommendations for determining which patients require formal assessment of oxygen during flight are inadequate. Predictive equations based on sea level variables provide poor estimates of PaO(2) measured during altitude simulation.

High altitude cognitive performance and COPD interaction

INTRODUCTION

Thousands of people work and perform everyday in high altitude environment, either as pilots, or shift workers, or mountaineers.The problem is that most of the accidents in this environment have been attributed to human error. The objective of this study was to assess complex cognitive performance as it interacts with respiratory insufficiency at altitudes of 8000 feet and identify the potential effect of hypoxia on safe performance.

METHODS

Twenty subjects participated in the study, divided in two groups: Group I with mild asymptomatic chronic obstructive pulmonary disease (COPD), and Group II with normal respiratory function. Altitude was simulated at 8000 ft. using gas mixtures.

RESULTS

Individuals with mild COPD experienced notable hypoxemia with significant performance decrements and increased number of errors at cabin altitude, compared to normal subjects, whereas their blood pressure significantly increased.

Definition of Cutoff Values for the Hypoxia Test Used for Preflight Testing in Young Children With Neonatal Chronic Lung Disease

BACKGROUND

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).

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Air travel in women with lymphangioleiomyomatosis

BACKGROUND AND OBJECTIVE

The safety of air travel in patients with pneumothorax-prone pulmonary diseases, such as lymphangioleiomyomatosis (LAM), has not been studied to any great extent. A questionnaire-based evaluation of air travel in patients with LAM was conducted to determine experiences aboard commercial aircraft.

METHODS

A survey was sent to women listed in the US LAM Foundation registry (n = 389) and the UK LAM Action registry (n = 59) to assess air travel, including problems occurring during flight. Women reporting a pneumothorax in flight were followed up to ascertain further details about the incident.

RESULTS

327 (73%) women completed the survey. 308 women answered the travel section, of whom 276 (90%) had "ever" travelled by aeroplane for a total of 454 flights. 95 (35%) women had been advised by their doctor to avoid air travel. Adverse events reported included shortness of breath (14%), pneumothorax (2%, 8/10 confirmed by chest radiograph), nausea or dizziness (8%), chest pain (12%), unusual fatigue (11%), oxygen desaturation (8%), headache (9%), blue hands (2%), haemoptysis (0.4%) and anxiety (22%). 5 of 10 patients with pneumothorax had symptoms that began before the flight: 2 occurred during cruising altitude, 2 soon after landing and 1 not known. The main symptoms were severe chest pain and shortness of breath.

DISCUSSION AND CONCLUSION

Adverse effects occurred during air travel in patients with LAM, particularly dyspnoea and chest pain. Hypoxaemia and pneumothorax were reported. The decision to travel should be individualised; patients with unexplained shortness of breath or chest pain before scheduled flights should not board. Patients with borderline oxygen saturations on the ground should be evaluated for supplemental oxygen therapy during flight. Although many women had been advised not to travel by air, most travelled without the occurrence of serious adverse effects.