Managing passengers with stable respiratory disease planning air travel: British Thoracic Society recommendations

Hypoxia Challenge Testing in Neonates for Fitness to Fly

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.

Fitness to fly in patients with lung disease

Patients with chronic lung disease may have mild hypoxemia at sea level. Some of these cases may go unrecognized, and even among those who are known to be hypoxemic, some do not use supplemental oxygen. During air travel in a hypobaric hypoxic environment, compensatory pulmonary mechanisms may be inadequate in patients with lung disease despite normal sea-level oxygen requirements. In addition, compensatory cardiovascular mechanisms may be less effective in some patients who are unable to increase cardiac output. Air travel also presents an increased risk of venous thromboembolism. Patients with cystic lung disease may also be at increased risk of pneumothorax. Although overall this risk appears to be relatively low, should a pneumothorax occur, it could present a significant challenge to the patient with chronic lung disease, particularly if hypoxemia is already present. As such, a thorough assessment of patients with chronic lung disease and cardiac disease who are contemplating air travel should be performed. The duration of the planned flight, the anticipated levels of activity, comorbid illnesses, and the presence of risk factors for venous thromboembolism are important considerations. Hypobaric hypoxic challenge testing reproduces an environment most similar to that encountered during actual air travel; however, it is not widely available. Assessment for hypoxia is otherwise best performed using a normobaric hypoxic challenge test. Patients in need of supplemental oxygen need to contact the airline and request this accommodation during flight. They should also be advised on arranging portable oxygen concentrators before air travel, and a discussion of the potential risks of travel should take place.

Profile of Travelers With Preexisting Medical Conditions Attending a Specialist Travel Medicine Clinic in Ireland

BACKGROUND

Patients with complex medical comorbidities travel for protracted periods to remote destinations, often with limited access to medical care. Few descriptions are available of their preexisting health burden. This study aimed to characterize preexisting medical conditions and medications of travelers seeking pre-travel health advice at a specialized travel medicine clinic.

METHODS

Records of travelers attending the Galway Tropical Medical Bureau clinic between 2008 and 2014 were examined and information relating to past medical history was entered into a database. Data were recorded only where the traveler had a documented medical history and/or was taking medications.

RESULTS

Of the 4,817 records available, 56% had a documented medical history and 24% listed medications. The majority of travelers with preexisting conditions were female. The mean age of the cohort was 31.68 years. The mean period remaining before the planned trip was 40 days. Southeast Asia was the most popular single destination, and 17% of travelers with medical conditions were traveling alone. The most frequently reported conditions were allergies (20%), insect bite sensitivity (15%), asthma (11%), psychiatric conditions (4%), and hypertension (3%). Of the 30 diabetic travelers, 14 required insulin; 4.5% of travelers were taking immunosuppressant drugs, including corticosteroids. Half of the female travelers were taking the oral contraceptive pill while 11 travelers were pregnant at the time of their pre-travel consultation.

CONCLUSIONS

This study provides an insight into the medical profile of travelers attending a travel health clinic. The diverse range of diseases reported highlights the importance of educating physicians and nurses about the specific travel health risks associated with particular conditions. Knowledge of the effects of travel on underlying medical conditions will inform the pre-travel health consultation.

Primary Care of the Patient with Asthma

Obstructive lung disease includes asthma and chronic obstructive pulmonary disease (COPD). Because a previous issue of Medical Clinics of North America (2012;96[4]) was devoted to COPD, this article focuses on asthma in adults, and addresses some topics about COPD not addressed previously. Asthma is a heterogeneous disease marked by variable airflow obstruction and bronchial hyperreactivity. Onset is most common in early childhood, although many people develop asthma later in life. Adult-onset asthma presents a particular challenge in the primary care clinic because of incomplete understanding of the disorder, underreporting of symptoms, underdiagnosis, inadequate treatment, and high rate of comorbidity.

ERS task force statement: diagnosis and treatment of primary spontaneous pneumothorax

Primary spontaneous pneumothorax (PSP) affects young healthy people with a significant recurrence rate. Recent advances in treatment have been variably implemented in clinical practice. This statement reviews the latest developments and concepts to improve clinical management and stimulate further research.The European Respiratory Society's Scientific Committee established a multidisciplinary team of pulmonologists and surgeons to produce a comprehensive review of available scientific evidence.Smoking remains the main risk factor of PSP. Routine smoking cessation is advised. More prospective data are required to better define the PSP population and incidence of recurrence. In first episodes of PSP, treatment approach is driven by symptoms rather than PSP size. The role of bullae rupture as the cause of air leakage remains unclear, implying that any treatment of PSP recurrence includes pleurodesis. Talc poudrage pleurodesis by thoracoscopy is safe, provided calibrated talc is available. Video-assisted thoracic surgery is preferred to thoracotomy as a surgical approach.In first episodes of PSP, aspiration is required only in symptomatic patients. After a persistent or recurrent PSP, definitive treatment including pleurodesis is undertaken. Future randomised controlled trials comparing different strategies are required.

An Official American Thoracic Society/European Respiratory Society Statement: Research questions in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity, mortality, and resource use worldwide. The goal of this Official American Thoracic Society (ATS)/European Respiratory Society (ERS) Research Statement is to describe evidence related to diagnosis, assessment, and management; identify gaps in knowledge; and make recommendations for future research. It is not intended to provide clinical practice recommendations on COPD diagnosis and management.

METHODS

Clinicians, researchers, and patient advocates with expertise in COPD were invited to participate. A literature search of Medline was performed, and studies deemed relevant were selected. The search was not a systematic review of the evidence. Existing evidence was appraised and summarized, and then salient knowledge gaps were identified.

RESULTS

Recommendations for research that addresses important gaps in the evidence in all areas of COPD were formulated via discussion and consensus.

CONCLUSIONS

Great strides have been made in the diagnosis, assessment, and management of COPD as well as understanding its pathogenesis. Despite this, many important questions remain unanswered. This ATS/ERS Research Statement highlights the types of research that leading clinicians, researchers, and patient advocates believe will have the greatest impact on patient-centered outcomes.

An official American Thoracic Society/European Respiratory Society statement: research questions in COPD

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity, mortality, and resource use worldwide. The goal of this official American Thoracic Society (ATS)/European Respiratory Society (ERS) research statement is to describe evidence related to diagnosis, assessment and management; identify gaps in knowledge; and make recommendations for future research. It is not intended to provide clinical practice recommendations on COPD diagnosis and management.

Clinicians, researchers, and patient advocates with expertise in COPD were invited to participate. A literature search of Medline was performed, and studies deemed relevant were selected. The search was not a systematic review of the evidence. Existing evidence was appraised and summarised, and then salient knowledge gaps were identified.

Recommendations for research that addresses important gaps in the evidence in all areas of COPD were formulatedviadiscussion and consensus.

Great strides have been made in the diagnosis, assessment and management of COPD, as well as understanding its pathogenesis. Despite this, many important questions remain unanswered. This ATS/ERS research statement highlights the types of research that leading clinicians, researchers, and patient advocates believe will have the greatest impact on patient-centred outcomes.

Cleared for takeoff: The effects of hypobaric conditions on traumatic pneumothoraces

BACKGROUND

Current guidelines suggest that traumatic pneumothorax (tPTX) is a contraindication to commercial airline travel, and patients should wait at least 2 weeks after radiographic resolution of tPTX to fly. This recommendation is not based on prospective, physiologic study. We hypothesized that despite having a radiographic increase in pneumothorax size while at simulated altitude, patients with a recently treated tPTX would not exhibit any adverse physiologic changes and would not report any symptoms of cardiorespiratory compromise.

METHODS

This is a prospective, observational study of 20 patients (10 in Phase 1, 10 in Phase 2) with tPTX that has been treated by chest tube (CT) or high flow oxygen therapy. CT must have been removed within 48 hours of entering the study. Subjects were exposed to 2 hours of hypobaria (554 mm Hg in Phase 1, 471 mm Hg in Phase 2) in a chamber in Salt Lake City, Utah. Vital signs and subjective symptoms were recorded during the "flight." After 2 hours, while still at simulated altitude, a portable chest radiograph (CXR) was obtained. tPTX sizes on preflight, inflight, and postflight CXR were compared.

RESULTS

Sixteen subjects (80%) were male. Mean (SD) age and ISS were 49 (5) years and 10.5 (4.6), respectively. Fourteen (70%) had a CT to treat tPTX, which had been removed 19 hours (range, 4-43 hours) before the study. No subject complained of any cardiorespiratory symptoms while at altitude. Radiographic increase in tPTX size at altitude was 5.6 (0.61) mm from preflight CXR. No subject developed a tension tPTX. No subject required procedural intervention during the flight. Four hours after the study, all tPTX had returned to baseline size.

CONCLUSION

Patients with recently treated tPTX have a small increase in the size of tPTX when subjected to simulated altitude. This is clinically well tolerated. Current prohibitions regarding air travel following traumatic tPTX should be reconsidered and further studied.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

Syncope at altitude: an enigmatic case

We report a case of a young boy with recurrent episodes of syncope at elevated altitude. While not conforming to common presentations of altitude sickness, the differential diagnoses and possible etiologies are discussed.

International guidelines for the management and treatment of Morquio A syndrome

Morquio A syndrome (mucopolysaccharidosis IVA) is a lysosomal storage disorder associated with skeletal and joint abnormalities and significant non-skeletal manifestations including respiratory disease, spinal cord compression, cardiac disease, impaired vision, hearing loss, and dental problems. The clinical presentation, onset, severity and progression rate of clinical manifestations of Morquio A syndrome vary widely between patients. Because of the heterogeneous and progressive nature of the disease, the management of patients with Morquio A syndrome is challenging and requires a multidisciplinary approach, involving an array of specialists. The current paper presents international guidelines for the evaluation, treatment and symptom-based management of Morquio A syndrome. These guidelines were developed during two expert meetings by an international panel of specialists in pediatrics, genetics, orthopedics, pulmonology, cardiology, and anesthesia with extensive experience in managing Morquio A syndrome. © 2014 The Authors. American Journal of Medical Genetics Part A published by Wiley Periodicals, Inc.

Current legal framework and practical aspects of oxygen therapy during air travel

It is unusual for pulmonologists to be familiar with the European and US regulations governing the administration of oxygen during air travel and each airline's policy in this respect. This lack of knowledge is in large part due to the scarcity of articles addressing this matter in specialized journals and the noticeably limited information provided by airlines on their websites. In this article we examine the regulations, the policies of some airlines and practical aspects that must be taken into account, so that the questions of a patient who may need to use oxygen during a flight may be answered satisfactorily.

In-flight Medical Emergencies

Introduction:

Research and data regarding in-flight medical emergencies during commercial air travel are lacking. Although volunteer medical professionals are often called upon to assist, there are no guidelines or best practices to guide their actions. This paper reviews the literature quantifying and categorizing in-flight medical incidents, discusses the unique challenges posed by the in-flight environment, evaluates the legal aspects of volunteering to provide care, and suggests an approach to managing specific conditions at 30,000 feet.

Methods:

We conducted a MEDLINE search using search terms relevant to aviation medical emergencies and flight physiology. The reference lists of selected articles were reviewed to identify additional studies.

Results:

While incidence studies were limited by data availability, syncope, gastrointestinal upset, and respiratory complaints were among the most common medical events reported. Chest pain and cardiovascular events were commonly associated with flight diversion.

Conclusion:

When in-flight medical emergencies occur, volunteer physicians should have knowledge about the most common in-flight medical incidents, know what is available in on-board emergency medical kits, coordinate their therapy with the flight crew and remote resources, and provide care within their scope of practice.

Air travel considerations for the patients with heart failure

Context:

Prevalence of patients with heart failure (HF) is increasing in worldwide, and also the number of people with HF traveling long distances is increasing. These patients are more prone to experience problems contributed air travel and needs more attention during flight. However, observational studies about problems of HF patients during flight and appropriated considerations for them are limited.

Evidence Acquisition:

We evaluated the conditions that may be encountered in a HF patient and provide the recommendations to prevent the exacerbation of cardiac failure during air travel. For this review article, a comprehensive search was undertaken for the studies that evaluated the complications and considerations of HF patients during flight. Data bases searched were: MEDLINE, EMBASE, Science Direct, and Google Scholar.

Results:

HF patients are more prone to experience respiratory distress, anxiety, stress, cardiac decompensation, and venous thromboembolism (VTE) during air travel. Although stable HF patients can tolerate air travel, but those with acute heart failure syndrome should not fly until complete improvement is achieved.

Conclusions:

Thus, identifying the HF patients before the flight and providing them proper education about the events that may occur during flight is necessary.

The effect of altitude on inhaler performance

The purpose of the study is to understand the effect of altitude on the performance of selected pressurized metered dose inhalers (pMDIs) and dry powder inhalers (DPIs). A testing apparatus that created consistent breath profiles through the Alberta Idealized Throat was designed to test five pMDIs and two DPIs at altitudes of 670, 2450, 3260, and 4300 m. Both gravimetric and chemical assays were conducted to determine the in vitro lung dose. Additionally, spray duration and shot weight for pMDIs and device resistance for DPI were measured. There was no significant change in in vitro lung dose for any of the pMDIs tested. Shot weight and spray duration were unaffected. The device resistance of the DPIs decreased with increasing altitude and was successfully modeled as a function of ambient pressure. The in vitro lung dose of both DPIs showed no significant change when operated with an inhaler pressure drop of 4 kPa, but for the Bricanyl(®) Turbuhaler(®), a significant decrease occurred when matching the volumetric inspiratory flow rate to that of the baseline altitude.

Air travel and pneumothorax

The number of medical emergencies onboard aircraft is increasing as commercial air traffic increases and the general population ages, becomes more mobile, and includes individuals with serious medical conditions. Travelers with respiratory diseases are at particular risk for in-flight events because exposure to lower atmospheric pressure in a pressurized cabin at cruising altitude may result in not only hypoxemia but also pneumothorax due to gas expansion within enclosed pulmonary parenchymal spaces based on Boyle's law. Risks of pneumothorax during air travel pertain particularly to those patients with cystic lung diseases, recent pneumothorax or thoracic surgery, and chronic pneumothorax. Currently available guidelines are admittedly based on sparse data and include recommendations to delay air travel for 1 to 3 weeks after thoracic surgery or resolution of the pneumothorax. One of these guidelines declares existing pneumothorax to be an absolute contraindication to air travel although there are reports of uneventful air travel for those with chronic stable pneumothorax. In this article, we review the available data regarding pneumothorax and air travel that consist mostly of case reports and retrospective surveys. There is clearly a need for additional data that will inform decisions regarding air travel for patients at risk for pneumothorax, including those with recent thoracic surgery and transthoracic needle biopsy.

Physiology in Medicine: Acute altitude exposure in patients with pulmonary and cardiovascular disease

Travel is more affordable and improved high-altitude airports, railways, and roads allow rapid access to altitude destinations without acclimatization. The physiology of exposure to altitude has been extensively described in healthy individuals; however, there is a paucity of data pertaining to those who have reduced reserve. This Physiology in Medicine article discusses the physiological considerations relevant to the safe travel to altitude and by commercial aircraft in patients with pulmonary and/or cardiac disease.

Managing patients with stable respiratory disease planning air travel: a primary care summary of the British Thoracic Society recommendations

Air travel poses medical challenges to passengers with respiratory disease, principally because of exposure to a hypobaric environment. In 2002 the British Thoracic Society published recommendations for adults and children with respiratory disease planning air travel, with a web update in 2004. New full recommendations and a summary were published in 2011, containing key recommendations for the assessment of high-risk patients and identification of those likely to require in-flight supplemental oxygen. This paper highlights the aspects of particular relevance to primary care practitioners with the following key points: (1) At cabin altitudes of 8000 feet (the usual upper limit of in-flight cabin pressure, equivalent to 0.75 atmospheres) the partial pressure of oxygen falls to the equivalent of breathing 15.1% oxygen at sea level. Arterial oxygen tension falls in all passengers; in patients with respiratory disease, altitude may worsen preexisting hypoxaemia. (2) Altitude exposure also influences the volume of any air in cavities, where pressure x volume remain constant (Boyle's law), so that a pneumothorax or closed lung bulla will expand and may cause respiratory distress. Similarly, barotrauma may affect the middle ear or sinuses if these cavities fail to equilibrate. (3) Patients with respiratory disease require clinical assessment and advice before air travel to: (a) optimise usual care; (b) consider contraindications to travel and possible need for in-flight oxygen; (c) consider the need for secondary care referral for further assessment; (d) discuss the risk of venous thromboembolism; and (e) discuss forward planning for the journey.

Pregnancy and travel-related thromboembolism

Air travel is associated with an increased risk of venous thrombosis. The average risk in all travellers is not particularly high, but high-risk groups have been identified. One such high risk group could be pregnant women but no data are available on the exact magnitude of their risk. In this review we use results from studies performed in air travellers and pregnant women separately to estimate the risk of the combination, which leads to an estimated risk of 0.03-0.1%. Until real data are available, physicians will need to decide on a case-to-case basis how to prevent thrombosis in these women. In most passengers, prevention can be limited to encouraging exercise, and avoid prolonged immobilization through sleeping or taking a window seat. Women perceived to be at high risk (history of venous thrombosis, known thrombophilia or other risk factors for thrombosis) may benefit from a short period of LMWH therapy.

Commercial air travel after pneumothorax: a review of the literature

Because of the physiological stresses of commercial air travel, the presence of a pneumothorax has long been felt to be an absolute contraindication to flight. Additionally, most medical societies recommend that patients wait at least 2 weeks after radiographic resolution of the pneumothorax before they attempt to travel in a nonurgent fashion via commercial air transport. This review sought to survey the current body of literature on this topic to determine if a medical consensus exists; furthermore, this review considered the scientific support, if any, supporting these recommendations. In this review, we found a paucity of data on the issue and noted only a handful of prospective and retrospective studies; thus, true evidence-based recommendations are difficult to develop at this time. We have made recommendations, when possible, addressing the nonurgent commercial air travel for the patient with a recent pneumothorax. However, more scientific research is necessary in order to reach an evidence-based conclusion on pneumothoraces and flying.

Hypoxic challenge test applied to healthy children: influence of body positions and exertion on pulse oximetric saturation

BACKGROUND

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%.

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

[Preparing patients with chronic pulmonary disease for air travel]

Flying is the most important way of travelling in the continually growing international tourism. Number of passengers and those with preexisting diseases, mainly with cardiopulmonary problems, is increasing over years. One of the main tasks of the pre-travel advice is to assess tolerance to hypoxia of the traveler, and specify the necessity, as well as the type and volume of supplementary oxygen therapy. It is indispensable to know the cabin-environment and impact of that on the travelers' health. Travel medicine specialist has to be aware of the examinations which provide information for the appropriate decision on the fit-to-fly condition of the patient. The physician who prepares the patient with chronic obstructive pulmonary disease for repatriation by regular flight and the escorting doctor have to be fully aware of the possibilities, modalities, advantages and contraindications of the on-board oxygen supply and therapy. In this review, the authors give a summary of literature data, outline the tools of in-flight oxygen therapy as well as discuss possibilities for the preflight assessment of patients' condition including blood gas parameters required for safe air travel, as recommended in international medical literature. The preparation process for repatriation of patients with chronic obstructive pulmonary disease is also discussed.

[Children and air travel: national survey results]

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.

Comparison of portable oxygen concentrators in a simulated airplane environment

Portable oxygen concentrators (POC) are highly desirable for patients with lung disease traveling by airplane, as these devices allow theoretically much higher travel times if additional batteries can be used. However, it is unclear whether POCs produce enough oxygen in airplanes at cruising altitude, even if complying with aviation regulations. We evaluated five frequently used POCs (XPO2 (Invacare, USA), Freestyle (AirSep C., USA), Evergo (Philipps Healthcare, Germany), Inogen One (Inogen, USA), Eclipse 3 (Sequal, USA)) at an altitude of 2650 m (as simulated airplane environment) in 11 patients with chronic obstructive lung disease (COPD) and compared theses POCs with the standard oxygen system (WS120, EMS Ltd., Germany) used by Lufthansa. Oxygen was delivered by each POC for 30 min to each patient at rest, blood gases were then drawn from the arterialized ear lobe. All POCs were able to deliver enough oxygen to increase the PaO(2) of our subjects by at least 1.40 kPa (10 mmHg). However, to achieve this increase, the two most lightweight POCs (Freestyle and Invacare XPO2) had to be run at their maximum level. This causes a significant reduction of battery life. The three other POCs (EverGo, Inogen One, Eclipse 3) and the WS120 were able to increase the PaO(2) by more than 2.55 kPa (20 mmHg), which provides extra safety for patients with more severe basal hypoxemia. When choosing the right oxygen system for air travel in patients in COPD, not only weight, but also battery life and maximum possible oxygen output must be considered carefully.

Travel-related thrombosis

Travel-related thrombosis is a serious public health concern considering the large and increasing number of travellers. Due to a lack of evidence, counselling air travellers on their venous thrombosis risk is not immediately straightforward, and advice will have to be based mostly on theoretical grounds. In this review a basis for these considerations is given. First of all it needs to be recognized that venous thrombosis is a multicausal disease, i.e. several risk factors have to be present before an event occurs. This is reflected in the literature where clearly increased risks have been described for certain groups, such as subjects with factor V Leiden, those who use oral contraceptives or are obese. Also, an increased risk for tall and short people has been reported. So, for subjects with a known risk factor who plan to travel, benefits and risks of thrombosis prophylaxis, (pharmacological or other), need to be weighed. This review provides some theoretical examples. For all other travellers, the advice to move and exercise as much as possible is likely to be sufficient.