Jugular vein wall repair after intravenous injection in equids.

The evolution of the healing process of venous puncture wounds was studied macroscopically and light-microscopically in order to determine the time of venipuncture. Seven small equids of various ages, all in normal healthy condition, were experimentally injected in the external jugular vein with a physiological Hartmann solution at different times before euthanasia. Two types of needle diameters i.e. 16.5 G and 19 G, were used. A fairly good uniformity in the healing process was seen in the 7 animals. In most cases the lesions induced within 5 weeks before death were macroscopically visible, whereas older perforation sites became indistinct. Light-microscopic study enabled determination of the time lapse after intravenous injection. The needle diameter seemed hereby relatively unimportant. Points of reference were endothelium repair, presence of a fibrin plug containing red and white blood cells, neovascularization and healing of the connective tissue fibers.