Human coagulation abnormalities during acute exposure to hypobaric hypoxia

Abstract

Multiple coagulation studies were carried out in eight healthy young men at sea level (SL) and after 1, 24, and 48 h at a simulated altitude of 4,400 m. Platelet aggregation, as induced by ADP, epinephrine, and collagen, was not significantly altered by high-altitude (HA) exposure. Mean 2,3-diphosphoglycerate, a physiological inhibitor of platelet aggregation, rose (P less than 0.001) after 24 h at HA and remained elevated while no changes in circulating catecholamines were observed. Platelet count, factor 3 availability, and membrane lipid peroxide formation were likewise unaltered at HA, as were prothrombin and thrombin times and protamine paracoagulation test. However, mean partial thromboplastin time was significantly shortened (P less than 0.01) after 1 and 24 h at HA, recovering to SL control by 48 h. Fibrinogen and factor VIII levels also fell (P less than 0.01 and P less than 0.02) after 1 h at HA but returned to the preexposure values by 24 h. Fibrin degradation products were transiently detectable in three subjects at HA. Thus, although normal platelet function did not appear to be modified by short-term exposure to simulated high altitude, evidence for a coagulopathy was obtained.

Travel to high altitude with pre-existing lung disease

“…Similar conflicting results have been demonstrated for bleeding times [177,178]. Regarding other components of the coagulation system, studies consistently show that the activated partial thromboplastin time is shorter during acute hypoxic exposures [176,179,180] but reveal conflicting data with regard to other biochemical markers of coagulation activity. For example, MANNUCCI et al [181] report an increase in inhibitors of the fibrinolytic pathway while BARTSCH et al [180] provide evidence of activation of the fibrinolytic system.…”

“…The literature contains conflicting results about the effects of acute hypoxic exposure on platelet function. SHARMA [172] reported increased platelet counts following ascent above 3,000 m while other studies reported either a decrease [173][174][175] or no change in these levels [176]. Similar conflicting results have been demonstrated for bleeding times [177,178].…”

Increased Risk of Thromboembolism as a Result of High Thrombin Production Is Associated With Short Activated Partial Thromboplastin Time in Cancer Patients on and After Chemotherapy: A Prospective Study in a Tertiary Care Hospital

“…Maher et al (13) reported evidence that decreases in the aPTT after simulated high altitude exposure to 4, 000 m correlated with some rather mild and inconsistent elevation in fibrin degradation products. Finally, Vogt et al (14) found a significant shortening of the aPTT in healthy volunteers after strenuous exercise, but with no apparent clinical sequelae.…”

Interaction of hypoxia and haemostasis

“…Die ersten Analysen zu dieser Fragestellung liegen bereits mehr als 30 Jahre zurück. Maher et al [3] beschrieben während eines 2-tägigen Höhenaufent-haltes in 4.400 m eine signifikante Verkürzung der partiellen Thromboplastinzeit (aPTT) sowie eine passagere Reduktion von Fibrinogen und Faktor VIII und sahen darin einen Hinweis für eine "Koagulopathie" in der Höhe.…”