Carpal tunnel syndrome is a common compression neuropathy of the median nerve. Acute carpal tunnel syndrome (aCTS) is rare, associated with a variety of conditions. In this case report we present a patient who developed aCTS and volar forearm compartment syndrome after a radial artery line placement, while receiving intravenous heparin. The patient underwent immediate forearm fasciotomy and surgical release for restoration of nerve function, which resulted in improved hand function and mild residual median nerve neuropathy. There is controversy whether to discontinue or not anticoagulation in a patient with aCTS. In our patient, heparin therapy was restarted on the second postoperative day.