Artery cannulation is a procedure in which an artery is cannulated or a tube of some sort is placed inside it. Unlike veins, arteries have thicker walls with much more smooth muscle surrounding them. This thickness and muscularity allows arteries to maintain blood pressure as the blood courses through the vasculature (circulatory system). These properties also mean that artery cannulation must be done with care since aneurysm or serious hemorrhage could occur in the event of an artery cannulation complication. There are three main situations in which artery cannulation occurs in medicine: For artery cannulation or arterial intervention, radial artery cannulation, and umbilical artery cannulation.
Arteriography is a technique that allows doctors to visualize the inside of arteries and identify any blockages. The procedure begins with artery cannulation, usually in the femoral artery in the groin. The arterial cannula is directed to the arteries of interest and a radioopaque (reflects X-ray radiation) dye is injected into the artery and a special X-ray is taken with a device called a fluoroscope. Blocked or constricted arteries will appear abnormal. This form of artery cannulation also allows certain devices to be deployed in the affected artery. Coronary artery angioplasty and stent placement begins with artery cannulation as do interventions requiring arterial stabilization (such as aneurysms), ablation (arteriovenous malformation), or the administration of clot busting drugs (like t-PA).
Radial artery cannulation
When patients are in the intensive care unit it generally means they are not hemodynamically stable. Hemodynamic stability requires that the heart can generate adequate and consistent blood pressure. In order to assess blood pressure more accurately and rapidly (actually constantly), a pressure transducer in placed in an artery. Since most arteries run quite deep in the body or limbs, there are few places amenable to artery cannulation for blood pressure monitoring. One exception is the radial artery. At the wrist, the radial artery runs very close to the skin and is ripe for artery cannulation. In fact, place your finger on the palm side of your wrist on the thumb side of the hand and you will feel a pulse in the radial artery. Artery cannulation in the radial artery of the wrist is virtually standard for most people in the intensive care unit.
Umbilical artery cannulation
In newborn infants, umbilical artery cannulation serves the same purpose as radial artery cannulation serves in adult in intensive care. The umbilicus or belly button serves as the entry portal for blood in the unborn fetus and the umbilical cord is cut upon delivery. In neonates that must spend time in the neonatal intensive care unit (NICU), cannulation of the umbilical artery is fairly standard practice. Umbilical artery cannulation allows physicians to measure blood pressure continuously, sample arterial blood without breaking the skin, transfuse blood and other products into the bloodstream when necessary, and perform arteriography.
Artery cannulation is associated with more risk than venous (vein) cannulation and is considered a medical procedure. In most states, artery cannulation is performed by physicians and requires the patient or their proxy to sign an acknowledgement of informed consent.