Association between acute hypobaric hypoxia and activation of coagulation in human beings

Bendz, Bjørn; Rostrup, Morten; Sevre, Knut; Andersen, Trine Opstad; Sandset, Per Morten

doi:10.1016/s0140-6736(00)03165-2

Cited by 220 publications

(156 citation statements)

References 5 publications

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“…There is an increase in ventilatory effort in response to hypoxic conditions and the cardiovascular system responds by elevation of the heart rate, with subsequent reduction of stroke volume and an increased risk of angina and dysrhythmias in coronary patients [2,13]. Acute hypobaric hypoxia is also known to induce a hypercoagulable state [14]. The cerebral effects are less clearly defined but include reduced night vision and a reduction in cognitive function [1,2].…”

Section: Discussionmentioning

confidence: 99%

The effect of high altitude commercial air travel on oxygen saturation

Humphreys

Deyermond²,

Bali³

et al. 2005

Anaesthesia

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SummaryAir travel has increased steadily over the last decade, and its effect on the health of passengers has been the subject of much debate. There is a paucity of evidence on the effects of air travel on oxygen saturation in general populations. The peripheral oxygen saturation and pulse rate of 84 passengers, aged 1-78 years, were measured by pulse oximetry at round level and altitude during air travel. There was a statistically significant reduction in oxygen saturation in all passengers travelling long haul and short haul flights (p < 0.05). The mean [range] (SD) SpO 2 for all flights at ground level was 97% [93-100] (1.33) and at cruising altitude 93% [85-98] (2.33). Fifty-four per cent of passengers had SpO 2 values of 94% or less at cruising altitude. This is a value which may prompt physicians to administer supplemental oxygen in hospital patients.

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Section: Discussionmentioning

confidence: 99%

The effect of high altitude commercial air travel on oxygen saturation

Humphreys

Deyermond²,

Bali³

et al. 2005

Anaesthesia

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“…Immobilisation for long periods could play a part, 7,8 as could flight specific factors-eg, hypobaric hypoxia, which might activate the clotting system. Bendz and colleagues 9 exposed volunteers to a hypoxic and hypobaric environment similar to that in an airplane. Markers of activated coagulation-ie, prothrombin fragment 1 and 2 (F1ϩ2) and thrombin-antithrombin complex (TAT)-were transiently increased, but these findings could have been the result of artificial activation.…”

Section: Introductionmentioning

confidence: 99%

Activation of coagulation system during air travel: a crossover study

et al. 2006

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SummaryBackground There is an increased risk of venous thrombosis after air travel, but the underlying mechanism is unclear. Our aim was to ascertain whether flying leads to a hypercoagulable state.Methods We did a crossover study in 71 healthy volunteers (15 men, 56 women), in whom we measured markers of activation of coagulation and fibrinolysis before, during, and after an 8-h flight. The same individuals participated in two control exposure situations (8-h movie marathon and daily life) to separate the effect of air travel on the coagulation system from those of immobilisation and circadian rhythm. To study the effect of risk factors for thrombosis, we included participants with the factor V Leiden mutation (n=11), those who took oral contraceptives (n=15), or both (n=15), as well as 30 individuals with no specific risk factors.Findings After the flight, median concentrations of thrombin-antithrombin (TAT) complex increased by 30·1% (95% CI 11·2-63·2), but decreased by 2·1% (Ϫ11·2 to 14) after the cinema and by 7·9% (Ϫ16·2 to Ϫ1·2) after the daily life situation. We recorded a high response in TAT levels in 17% (11 of 66) of individuals after air travel (3% [2 of 68] for movie marathon; 1% [1 of 70] in daily life). These findings were most evident in the group with the factor V Leiden mutation who used oral contraceptives. We noted a high response in all variables (prothrombin fragment 1 and 2, TAT, and D-dimer) in four of 63 (6·3%) volunteers after the flight, but in no-one after either of the control situations.Interpretation Activation of coagulation occurs in some individuals after an 8-h flight, indicating an additional mechanism to immobilisation underlying air travel related thrombosis. hypoxia controlled for effects of immobilisation at ground level and for circadian rhythm. We drew blood before, during, and after each exposure, at the same time of day. For the first exposure situation, we chartered a Boeing 757 for a non-stop day flight of 8 h from and to Schiphol airport, Amsterdam. We instructed volunteers not to smoke, use drugs, drink alcohol, or take any prophylactic measures to prevent thrombosis-eg, heparin or aspirin use, or wearing of elastic stockings during the flight-to remain seated as much as possible, and to keep a structured record of fluid intake. 2-3 weeks after the flight, all participants sat for 8 h (for practical reasons two sessions with half the participants in each) in a cinema. We imposed the same restrictions during this second exposure situation as in the first with respect to moving, drugs, smoking, and drinking, and again asked participants to keep a record of their fluid intake. For the final exposure situation, 2 weeks after the movie marathon, we asked participants to live their lives as they normally would for a day, recording fluid intake. We asked participants not to drink alcohol, take drugs, or smoke, but did not restrict movement. We asked participants to keep their food and fluid intake constant during the three exposures.Experienced technicians did the blood ...

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“…Interestingly, 85-100% of VTE cases have been found to occur in passengers in non-aisle seats [4,11]. Factors such as chair position and, in the case of air travel, cabin-related factors such as low humidity, reduced air pressure and relative hypoxia, may be important [12].…”

Section: Introductionmentioning

confidence: 99%

Effect of leg exercises on popliteal venous blood flow during prolonged immobility of seated subjects: implications for prevention of travel‐related deep vein thrombosis

Hitos

Cannon²,

Cannon³

et al. 2007

Journal of Thrombosis and Haemostasis

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To cite this article: Hitos K, Cannon M, Cannon S, Garth S, Fletcher JP. Effect of leg exercises on popliteal venous blood flow during prolonged immobility of seated subjects: implications for prevention of travel-related deep vein thrombosis. J Thromb Haemost 2007; 5: 1890-5.Summary. Background: Venous stasis is an important contributing factor in the development of travel-related deep vein thrombosis. This study examined factors affecting popliteal venous blood flow in order to determine the most effective exercise regimen to prevent venous stasis. Methods: Twentyone healthy subjects were randomly assigned to various activities over a 9-week period. Subjects remained seated throughout the investigation and 3660 duplex ultrasound examinations were performed by a single examiner using a SonoSite 180 Plus handheld ultrasound. Baseline popliteal vein blood flow velocity, cross-sectional area and volume flow in subjects sitting motionless were assessed in the first 3 weeks.The remaining 6 weeks involved subjects performing airline-recommended activities, foot exercises, foot exercises against moderate resistance and foot exercises against increased resistance in order to determine the most beneficial method for enhancing popliteal venous flow. Sitting with feet not touching the floor and the effect of sleeping were also assessed. Results: The median age of the subjects was 22 years (range: 18-25.5 years), height 171 cm (162.5-180.5 cm) and body mass index 25.3 kg m -2 (23.2-26.3 kg m -2). Blood volume flow in the popliteal vein was reduced by almost 40% with immobility of seated subjects and by almost 2-fold when sitting motionless with feet not touching the floor. Foot exercises against increased resistance positively enhanced volume flow (P < 0.0001). Conclusion: Leg exercise regimens enhanced popliteal venous flow during prolonged immobility of seated subjects, reinforcing the importance of regular leg movement to prevent venous stasis during prolonged sitting, such as in longdistance travel.

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Association between acute hypobaric hypoxia and activation of coagulation in human beings

Cited by 220 publications

References 5 publications

The effect of high altitude commercial air travel on oxygen saturation

The effect of high altitude commercial air travel on oxygen saturation

Activation of coagulation system during air travel: a crossover study

Effect of leg exercises on popliteal venous blood flow during prolonged immobility of seated subjects: implications for prevention of travel‐related deep vein thrombosis

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