A new vivo method to measure bleeding time, bleeding intensity and blood loss from
a standardized small skin wound was developed by Sutor, Bowie, and Owen at the Mayo
Clinic. At room temperature (24° C) bleeding time is prolonged in patients with quantitative and qualitative
platelet deficiencies. Patients with Morbus Willebrand show a prolonged bleeding time
and an abnormally high bleeding intensity. Patients with reduced capillary resistency
(M. Davis and allergic diathesis) have increased bleeding intensity but normal bleeding
time. Aspirin and Dipropyl-Acetate increase the blood loss, prednisone reduces the
bleeding intensity. When haemorrhagometry is performed at 17° C (cold tolerance test) bleeding time is pathologically increased in haemophiliacs and in most carriers of
haemophilia. If an already closed wound is heated to 43.5° C it starts bleeding again
in control subjects, the average heat lysis time is 1.03 min (SD : 0.16 min). In patients with thrombocytic haemorrhagic tendencies
the heat lysis time is shortened; a connection between prolonged heat lysis time and
hypercoagulaemia has been shown in some cases.
