[Unknown danger in phlebotomy with vacuum flasks: air embolism (author's transl)].

A case of nonfatal air embolism during a phlebotomy is reported. It was due to an incorrect procedure and a negligently nonevacuated vacuum flask. The underlying mechanism is theoretically derived and experimentally confirmed. The experiments show that by this mode of phlebotomy hyperbaric pressure occurs in the withdrawal flask which cause the escape of air into the venous system. This inflow of air may be enough to cause fatal air embolism.