The conversation between human and AI assistant.
[|Human|] Given a reference text about the blood hammer phenomenon, tell me the background of the term "blood-hammer".
[|AI|] The term "blood-hammer" was introduced by analogy with the hydraulic expression "water hammer" that was already used in vascular physiology.
[|Human|] 
Given a reference text about the blood hammer phenomenon, tell me the background of the term "blood-hammer".