British Thoracic Society Standards of Care Committee. Managing passengers with respiratory disease planning air travel: British Thoracic Society recommendations

Review Series: Lung function made easy: Assessing gas exchange

In clinical practice there are two sorts of measurements, a) arterial oxygen and carbon dioxide partial pressure (PaO2, PaCO2) or arterial oxygen saturation (SaO2), and b) the transfer capacity for carbon monoxide (TLCO). The former measures the output or performance of the lung as a gas exchanger, and the latter estimates the available surface area or potential for gas exchange. As gas exchange deteriorates (PaO2 falls and PaCO2 rises), the body compensates by increasing ventilation and lowering PaCO 2. Therefore, a high PaCO2 represents chronic respiratory or “compensation” failure, either chemo-insensitivity (“won't breathe”) or neuromuscular weakness/increased work of breathing (“cannot breathe”). Chronic respiratory failure may progress to acute failure in which PaCO2 falls and PaCO2 rises progressively, assisted ventilation is usually required. The TLCO is a laboratory test which measures the integrity of the blood-gas barrier, it is particularly useful in the assessment of emphysema, interstitial disease and pulmonary vascular disease. Chronic Respiratory Disease 2007; 4: 205—214

Going to High Altitude with a Newborn Infant

Fetal life conditions the responses of a newborn infant to high altitude. The fetal circulation is characterized by high pulmonary vascular resistance and low pulmonary blood flow, as well as intra and extracardiac shunts that serve to route blood to and from the placenta and around the fetal lungs. At birth, rapid changes occur in the pulmonary circulation under normoxia; pulmonary vascular resistance falls, pulmonary blood flow increases dramatically, and the fetal shunts close functionally, then anatomically. Under conditions of hypoxia, the changes of circulatory transition occur more slowly, and pronounced hypoxia can cause a reversion to fetal circulatory patterns, albeit without the placenta to serve as the organ of oxygenation. Underlying medical conditions of newborn infants that combine exaggerated hypoxemia in response to high altitude hypoxia with an underlying predisposition to pulmonary hypertension can increase the likelihood of problems at high altitude. Awareness of risk factors and clinical signs of hypoxemia in newborn infants, as well as measurement of arterial oxygen saturation by pulse oximetry, can aid health professionals and parents in recognizing and preventing altitude-associated illness.

A chronic pneumothorax and fitness to fly

According to Boyle's law, as the pressure falls, the volume of gas rises in an inversely proportional manner. This means that during an aircraft flight, the volume of trapped air in gas filled body chambers will increase. As a consequence, it is fairly well established that individuals with an untreated pneumothorax should not participate in commercial flying due to the risk of it enlarging and the possible development of tension. However, whether this also applies to individuals who have a long-standing, clinically stable pneumothorax is uncertain. The following article describes two adult patients each with a chronic pneumothorax who asked whether they would be fit to fly in an aircraft. We outline their histories and subsequent evaluation which consisted of clinical assessment, computed tomographic imaging, a hypoxic challenge test and exposure to a hypoxic hypobaric environment in a decompression chamber.

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.

Oxygen supplementation for chronic obstructive pulmonary disease patients during air travel

PURPOSE OF REVIEW

By 2008 it is projected that over two billion people will be travelling by commercial aircraft each year. With an ageing population and treatment improvements, many of these travellers will have lung disease, particularly chronic obstructive pulmonary disease. Current guidelines as to whether a patient requires supplemental oxygen during the flight are based on limited research evidence. Awareness of the increased risk has resulted in recent scientific interest in this area.

RECENT FINDINGS

Studies have demonstrated a lack of consistency in international guideline recommendations when performing assessments within the respiratory laboratory. This has led to more specific analysis of patients, including in-flight assessments, the inclusion of exercise stress and more interest in actual cabin pressure conditions.

SUMMARY

Commercial air travel is generally safe for patients with chronic obstructive pulmonary disease when their disease is stable. All current guidelines reflect the considerable uncertainty in relation to the clinical circumstances when oxygen prescription during flight is essential. Currently planned flight outcome studies will provide more precise risk quantification.

Intrapulmonary bronchogenic cyst and cerebral gas embolism in an aircraft flight passenger

Although it is estimated that > 1 billion passengers travel by air worldwide each year, the incidence of in-flight emergencies is low. However, due to nonstandardized reporting requirements for in-flight medical emergencies, the true incidence of pulmonary barotrauma in airplane passengers is unknown. We describe the case of a passenger with an asymptomatic intrapulmonary cyst in whom a severe case of cerebral gas embolism developed during an aircraft flight. The decrease in ambient pressure during the aircraft climb resulted in expansion of the cyst volume based on Boyle's law (pressure x volume = constant). Due to the cyst expansion, we believe tears in the wall led to the leakage of air into the surrounding vessels followed by brain gas emboli. Adult patients with intrapulmonary cysts should be strongly considered for cyst resection or should at least be advised to abstain from activities leading to considerable changes in ambient pressure.

[Medical aspects of commercial air travel]

A high proportion of commercial plane passengers are children: two million fly every year on Air-France airlines. In this field, the physician can be called upon to authorize or prohibit travelling. He could take measures or offer his services at the request of the cabin staff. The authors review flight physiology and stress, their potential effects on healthy children or those with medical conditions, and their fitness to fly.

Pre-flight testing of preterm infants with neonatal lung disease: a retrospective review

BACKGROUND

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.

METHODS

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.

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).

CONCLUSIONS

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.

Recomendaciones al viajero en situaciones especiales

The increase in the hope and quality of life, along with the greater rapidity and comfort of the different means of transport have made possible that travellers with chronic diseases, pregnant and kids makes tourist trips to tropical or subtropical zones. On the other hand the increase of the international cooperation has caused the appearance of long stay travellers who live in conditions such as the local population. These travellers have special characteristics due to their physical training conditions, chronic treatments, or the way of life during the travel that them makes more susceptible to suffer problems of health during the travel. For this reason the usual recommendations for travellers are insufficient in these groups and is necessary to make an individualized travel advice that considers these factors. This revision shows the most important warnings that must be made in these groups of special travellers.

Adult domiciliary oxygen therapy. Position statement of the Thoracic Society of Australia and New Zealand

Patients with chronic obstructive pulmonary disease and a stable daytime PaO2 of < or = 55 mmHg (7.3 kPa) live longer and have a better quality of life if provided with long-term continuous oxygen therapy. It is reasonable to offer continuous oxygen therapy also to patients with other lung diseases that cause chronic hypoxaemia. Indications for supplemental oxygen therapy during exercise (ambulatory oxygen therapy) and sleep (nocturnal oxygen therapy) are less clear.

Respiratory diseases and high altitude

The aim of this paper is to review how preexisting pulmonary diseases can be affected by altitude exposure. Obstructive (asthma and chronic obstructive pulmonary disease or COPD) and restrictive (interstitial pulmonary fibrosis), as well as pulmonary vascular diseases, will be considered, and the goal will be to provide insight and tools to clinicians to optimize the medical condition and thus the life-style of these patients. The underlying pathophysiologies and the effect of hypobaric hypoxia on these diseases will be reviewed such that techniques to assess patients will be appropriate. Therapeutic interventions, including the use of supplemental oxygen, in light of the underlying pathologic processes, will also be discussed.

Health risks to air travelers

With focused pretravel counseling and intervention, travelers can be prepared to avoid many risks of in-flight problems. Travel medicine practitioners can include appropriate guidance for in-flight health and safety in discussions during pretravel visits.

Economy class stroke syndrome: case report and review of the literature

OBJECTIVES

Venous thromboembolism associated with travelling, or economy class syndrome, is increasingly recognised as a sequence of long haul flights and so paradoxical cerebral embolism through a patent foramen ovale. Materials and methods. We present a new case of economy class stroke syndrome and review of the literature using MEDLINE search.

RESULTS

Literature review identified 12 additional cases. In most of them, stroke occurred in close approximation with landing of the aircraft following a long-haul flight. Venous thromboembolism was present in 58%, while a patent foramen ovale was diagnosed with contrast echocardiography in all but one case. Our case presented with severe left hemispheric stroke, and significant delay, two days after a long-haul flight.

CONCLUSIONS

The small number of reported cases indicates either the rarity of this entity or unawareness of its existence. The true incidence of this condition remains unknown. However, because of treatment implications such as the need to treat venous thromboembolism or close the patent foramen ovale, clinicians should be aware of this entity.

[Analysis of logistical and organizational aspects of a cruise for patients with chronic respiratory insufficiency. The RESpIRA Expedition and the COPD Cruise]

Patients with chronic respiratory insufficiency who are receiving domiciliary oxygen therapy and mechanical ventilation report great difficulty in taking complex trips involving several destinations and prolonged stays away from home. Such patients share a common need for home equipment whose technology is relatively sophisticated, a condition that limits their freedom of movement. We are referring to systems for delivering oxygen therapy and mechanical respirators. Given that such patients have problems traveling by air, we hypothesized that a cruise would be an ideal alternative, given that travel would take place in the hotel itself. A cruise would facilitate the logistics of the journey, given that the equipment would have to be set up at only one setting. Working with these assumptions, we have thus far organized two cruises for chronic respiratory insufficiency patients: the "RESpIRA Expedition" and the "COPD Cruise". Our experience shows that the organizational problems to be coped with are patient recruitment, financing and choice of itinerary. With those aspects clear, organizers must then obtain the authorization of the cruise operator, including the approval of the medical and safety personnel on board. After obtaining permission for the cruise and as soon as the organizers know how many patients will travel, a list of oxygen therapy equipment (respirators and disposable supplies) must be compiled. Finally, equipment suppliers must be found. Afterwards, all that remains is to enjoy the trip. The participation of physicians responsible for domiciliary oxygen therapy and mechanical ventilation programs is essential for making patients feel safe and for assuring solutions for technical and medical problems that might arise.

The airline passenger: current medical issues

It is widely accepted that travel by air is unlikely to be a hazard to the vast majority of passengers. However, there are potentially adverse effects of cabin air of poor quality and of the reduced oxygen tension of the cabin environment. There is also the possibility of thrombosis related, at least in part, to the relative inactivity of a long journey. It may well be that the toxicity of the oil additives that are used in aircraft engines should be revisited, and that research should be carried out on the relative importance and potential interactions of the many risk factors for thrombosis that could be enhanced during a long flight. Formal guidelines need to be developed for passengers.