<unk>  is the contraction of a vein as a protective mechanism. It may follow infusion of a cold or irritating substance into the vein. If a vein spasms while an intravenous catheter such as PICC line is being removed the catheter can become torn and require retrieval by interventional radiology.
Venospasm
Vasospasm
Cyclospasm
Allostasis
Leukostasis
Proarrhythmia
Myxedema
Cardiovascular drift