What is an Arterial Line?

An arterial line is a catheter that is inserted into an artery. It is used in intensive care medicine to obtain direct and continuous blood pressures in critically ill patients. These lines can also be used to obtain blood for labs and for arterial blood gases.

In most cases, an arterial line is connected to a transducer and pressurized flush bag by stiff intravenous tubing. The transducer is connected to a bedside monitor. The transducer is able to read fluctuations in the arterial blood pressure and turns this reading into an electrical signal that is picked up by the monitor. This signal is manifested in a wave form, much like an EKG tracing.

The flush bag connected to the transducer setup is encased in a pressure cuff that constantly squeezes the bag. This allows the fluid from the flush bag to flow into the artery. This is important because without pressure from the flush, the arterial line tubing would fill with blood.

The most common arteries used for arterial line placement are the radial arteries of the wrist. The brachial artery, located in the bend of the elbow, is another common site for line placement. On occasion, a doctor or anesthesiologist will place an arterial line in the femoral artery located in the groin area. The dorsalis pedis artery, located on the top of the foot, can also be used.

There are complications that can occur when this type of line is placed. One such complication could be the development of a hematoma. This buildup of blood could become so large it could compromise blood flow to the extremity where the arterial line is placed.

Another complication associated with arterial lines is the risk for bleeding. If the line becomes disconnected, a patient will bleed profusely. If the bleeding is not stopped, it is possible for a patient to bleed to death. A monitor is used to alert hospital staff if there is a disconnection anywhere in the line, however.

Arterial lines should only be used in critical care settings where they can be closely monitored by properly trained staff. They are an important diagnostic tool for monitoring a patient who is having trouble with blood pressure that is too low or too high. When a patient is on an intravenous drip that profoundly affects the blood pressure, the placement of an arterial line can be critical to the outcome of the patient.