Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

No link between low air-pressure on long-haul flights and DVT says new study

17.05.2006


Researchers simulating conditions of reduced cabin pressure and reduced oxygen levels, such as may be encountered during an 8-hour aeroplane flight, found no increase in the activation of the blood clotting system among healthy individuals, according to a study in the May 17 issue of JAMA. (Journal of the American Association).



Venous thromboembolism, a term used to describe deep vein thrombosis (DVT; blood clots forming in the veins) and pulmonary embolism (clots passing to the lungs where they may obstruct the blood flow), has been associated with long-haul air travel, but it has been unclear whether this is due to the effects of sitting for a long time, or whether there is a relationship with some other specific factor in the aeroplane environment, according to background information in the article. One hypothesis has been that hypoxia (reduced oxygen in the blood), associated with the decreased cabin pressure that occurs at altitude, produces changes in the blood that increase the risk for blood clots.

Dr William D. Toff, from the University of Leicester’s Department of Cardiovascular Sciences and colleagues –including in the UK Professor Mike Greaves, Head of the University of Aberdeen’s School of Medicine -conducted a study, from September 2003 to November 2005, to assess the effects of hypobaric (reduced air pressure) and hypoxia, similar to that which might be encountered during commercial air travel, on a variety of markers of activation of the haemostatic (blood clotting) system. The study included 73 healthy volunteers who spent 8 hours seated in a hypobaria chamber and were exposed to hypobaric hypoxia, similar to the conditions of reduced aeroplane cabin pressure that might occur during a long-haul flight (cabin pressure may be reduced to the equivalent of that at an altitude of about 8,000 feet). Blood was drawn before and after exposure to assess activation of factors associated with haemostasis (blood clotting). Similar measurements were taken of the same volunteers, on a separate occasion, before and after they spent 8 hours seated in a controlled environment, equivalent to atmospheric conditions at ground level (normobaric exposure).


The study was a collaboration between the Universities of Leicester and Aberdeen. The chamber studies were performed at the RAF Centre of Aviation Medicine at Henlow in Bedfordshire and Aberdeen. Analysis of blood samples was performed at Leicester and Aberdeen, and also by colleagues at the Academic Medical Center at the University of Amsterdam.

The researchers found that when comparing the results between the normobaric and the hypobaric exposures, there was no significant difference in the overall change for markers of coagulation activation (clot formation), fibrinolysis (the normal breakdown of small, naturally occurring blood clots), activation of platelets (small cells in the blood that clump together when stimulated to promote clot formation), and activation of endothelial cells (the cells that line the interior surface of blood vessels).

Dr Toff said: “Our study provides, for the first time, a carefully controlled assessment of the effects on blood clotting of the low air pressure and low oxygen level that might be found during a long-haul flight. We found no evidence that these conditions cause activation of the blood clotting mechanism.

“In our study we predominantly used healthy young people without known risk factors for thrombosis. We included some users of the combined oral contraceptive pill and some older subjects (aged over 50 years), both of which are factors that increase the risk of thrombosis. Although we found no difference in the results in these groups, the numbers of each were relatively small. We plan to extend the study to look at more people with these and other risk factors to see if they respond differently.

“Our volunteers abstained from alcohol during the study, to avoid any possible confounding of results. Air travellers are often advised to moderate their alcohol consumption in-flight, as excessive alcohol may induce somnolence and decrease mobility. Prolonged seated immobility is probably the most significant factor predisposing to thrombosis during long-haul travel. For the same reason, hypnotics (sleeping tablets) are sometimes also discouraged.”

“In conclusion, our findings do not support the hypothesis that hypobaric hypoxia of the degree that might be encountered during long-haul air travel is associated with prothrombotic alterations in the haemostatic system in healthy individuals at low risk of venous thromboembolism,” the authors write.

Alex Jelley | alfa
Further information:
http://www.le.ac.uk

More articles from Health and Medicine:

nachricht Millions through license revenues
27.04.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht New High-Performance Center Translational Medical Engineering
26.04.2017 | Fraunhofer ITEM

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>