Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. An arterial line, or art-line, or a-line, is a thin catheter inserted into an artery. It is most commonly used in intensive care medicine and anesthesia to monitor the blood pressure real-time (rather than by intermittent measurement), and to obtain samples for arterial blood gas measurements. It is not generally used to administer medication. Since many injectable drugs used in intensive care and anesthesia, such as sodium pentothal, may lead to serious tissue damage and even amputation if given in an artery the arterial line must be clearly marked to avoid accidental intraarterial injection of intravenous drugs.An arterial line is usually inserted in the wrist (radial artery); but can also be inserted into the elbow (brachial artery), groin (femoral artery), foot (dorsalis pedis artery).