title: Unaltered blood coagulation and platelet function in healthy subjects exposed to acute hypoxia.
abstract: BACKGROUND
  Acute hypoxia has been suspected to cause blood coagulation and platelet activation. Our aim was to study blood coagulation and platelet function during a short hypoxic exposure.
  
  
  METHODS
  Healthy nonsmoking men (N = 10) inhaled a normobaric hypoxic gas mixture containing 8% of oxygen (92% nitrogen) for 7 min via a face mask. Venous blood was collected 5 min before and during the 5 to 7 min of hypoxia exposure (i.e., pretest and hypoxia samples, respectively) while monitoring arterial oxygen saturation (SaO2) with pulse oximetry. Blood sampling was completed in 2 min and the face mask was removed. Venous epinephrine and norepinephrine, complete blood counts, and a panel of coagulation markers were analyzed. Platelet aggregation induced by ristocetin, adenosine diphosphate (ADP), arachidonic acid, and thrombin receptor activating peptide was studied with Multiplate and shear force-dependent functions with PFA-100R (collagen/epinephrine and collagen/ADP cartridges), both assays in whole blood.
  
  
  RESULTS
  During hypoxia, SaO2 declined from 98 to 58% (ranges 97-99% vs. 42-85%), while heart rate increased from 69/min to 94/min (SD 11 vs. SD 13). Venous epinephrine and norepinephrine levels also increased. This short hypoxia induced minor but uniform increases in red cells, reticulocytes, and leukocytes and decreases in platelet counts. Plateletfunctions and prothrombin time, APTT, thrombin time, D-dimer, fibrinogen levels or von Willebrand factor (VWF), antithrombin, factor V (FV) or FVIII activities did not change.
  
  
  CONCLUSIONS
  Profound acute hypoxia failed to affect blood coagulation or platelet functions in healthy individuals.
authors: Aeromedical Centre and Diving Medical Centre, Centre for Military Medicine, Finnish Defence Forces, Helsinki, Finland. matti.mantysaari@mil.fi
authors: Matti
authors: M
authors: Mäntysaari
authors: Lotta
authors: L
authors: Joutsi-Korhonen
authors: Martti A
authors: MA
authors: Siimes
authors: Simo
authors: S
authors: Siitonen
authors: Kai
authors: K
authors: Parkkola
authors: Marja
authors: M
authors: Lemponen
authors: Riitta
authors: R
authors: Lassila
mesh_terms: D000328:Adult; D001777:Blood Coagulation / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010974:Platelet Aggregation / Q000502:physiology*; D055815:Young Adult