Arterial Line Awareness

An arterial line is a catheter positioned in an artery to display blood pressure continuously and to allow repeated arterial blood sampling without repeated needle punctures. It is most useful when blood pressure may change from minute to minute, when vasoactive therapy is being titrated, when arterial blood gases are needed frequently, or when non-invasive measurements are unreliable in a critically ill or high-risk surgical patient. The line provides invasive data, not automatically accurate data. Accuracy depends on the catheter, pressure tubing, stopcocks, flush solution, transducer position, and waveform quality. A number that looks precise can still be wrong if the transducer is mislevelled or the tubing is kinked. The radial artery is a common site because the hand usually has collateral supply through the ulnar artery. The line is not an intravenous route. Never administer medications, blood products, or routine fluid boluses through it; direct arterial injection can cause severe vasospasm, thrombosis, tissue necrosis, and limb loss.