Arterial blood sampling is used to determine the blood gas status and the acid-base of any animal. When the animal is conscious it’s femoral or dorsal metatarsal artery may be used to collect the sample needed. If the animal that this procedure is being performed on is under anesthesia the technician may also use its radial, brachial, or lingual arteries. During collection of arterial samples it is not necessary to occlude the artery of choice. When collecting these samples a technician will use a heparinized 1-ml syringe fitted with a 25-gauge needle. These samples are collected used to determine capacity of acid-base (pH), and oxygenation status (oxygen carry capacity of blood). Another use for these samples is to diagnose a disease, track their response to a certain drug, or to monitor the progression of their disease.
The femoral artery is located in the animal’s right leg and during collection the animal is placed in right lateral recumbency. The prepuce (mammary gland) is moved up out of the way to view and access the femoral artery. Before collection the area is wiped down with 70% isopropyl alcohol. After the initial wipe the technician palpates the artery with their fingertips to find the pulse and then the needle is introduced at a 60-degree angle into the artery. When the needle is introduced to the artery if successful the syringe should rapidly fill with blood (only 0.25 to 0.5ml of blood is needed). Immediately after collection firm pressure is applied to the puncture site for several minutes to stop bleeding and prevent hematoma formation.
If the femoral artery is difficult to palpate or is inaccessible blood may be taken from the dorsal metatarsal artery. The skin over the dorsal metatarsal artery is a little thicker and thus harder to penetrate than that of the femoral artery. If the dorsal metatarsal artery must be used the animal is placed in lateral recumbency, with its hock extended for use. Before the procedure the area is shaved and...