Acute hypotension or hypertension (hypertensive crisis)

 Hemodynamic instability or circulatory collapse

 Cardiac arrest

 Hemorrhage

 Shock from any cause

 Continuous infusion of vasoactive medications

 Frequent arterial blood gas measurements

 Nonpulsatile blood flow (i.e., use of nonpulsatile ventricular assist devices or extracorporeal membrane oxygenation)

 Intraaortic balloon pump therapy

 Neurologic injury

 Coronary interventional procedures

 Major surgical procedures

 Multiple trauma

 Respiratory failure

 Sepsis

 Obstetric emergencies

 Use the radial artery as the first choice. Conduct a modified Allen’s test before performing an arterial puncture on the radial artery (see Fig. 80-3). Normal palmar blushing is complete before 7 seconds, indicating a positive result; 8 to 14 seconds is considered equivocal; and 15 or more seconds indicates a negative test result. Doppler flow studies or plethysmography can also be performed to ensure the presence of collateral flow. Research shows these studies to be more reliable than the modified Allen’s test.^1,20 Thrombosis of the arterial cannula is a common complication. Ensuring collateral flow distal to the puncture site is important for prevention of ischemia. Puncture of both the radial and ulnar arteries on the same hand is never recommended, to prevent compromising blood supply to the hand.^4,10,14,16

 Use the brachial artery as the second choice, except in the presence of poor pulsation caused by shock, obesity, or a sclerotic vessel (e.g., because of previous cardiac catheterization). The brachial artery is larger than the radial artery. Hemostasis after arterial cannulation is enhanced by its proximity to the bone if the entry point is approximately 1.5 inches above the antecubital fossa.

 Use the femoral artery in the case of cardiopulmonary arrest or altered perfusion to the upper extremities. The femoral artery is a large superficial artery located in the groin. It is easily palpated and punctured. Complications related to femoral artery puncture include hemorrhage and hematoma formation (because bleeding can be difficult to control), inadvertent puncture of the femoral vein (because of its close proximity to the artery), infection (because aseptic technique is difficult to maintain in the groin area), and limb ischemia (if the femoral artery is damaged).

• Obtain the patient’s medical history, including history of diabetes, hypertension, peripheral vascular disease, vascular grafts, arterial vasospasm, thrombosis, or embolism. Obtain the patient’s history of coronary artery bypass graft surgery in which radial arteries were removed for use as conduits or presence of arteriovenous (AV) fistulas or shunts. Rationale: Extremities with any of these problems should be avoided as sites for cannulation because of the potential for complications. Patients with diabetes mellitus or hypertension are at higher risk for arterial or venous insufficiency. Previously removed radial arteries are a contraindication for ulnar artery cannulation.

• Assess the patient’s medical history of coagulopathies, use of anticoagulant therapy, vascular abnormalities, or peripheral neuropathies. Rationale: This assessment assists in determining safety of the procedure and aids in site selection.

• Assess the patient’s allergy history (e.g., allergy to lidocaine, topical anesthetic cream, antiseptic solutions, or tape). Rationale: This assessment decreases the risk for allergic reactions.

• Assess the patient’s current anticoagulation therapy, known blood dyscrasias, and pertinent laboratory values (e.g., platelet levels, partial thromboplastin time [PTT], prothrombin time [PT], and International normalized ratio [INR]) before the procedure. Rationale: Anticoagulation therapy, blood dyscrasias, or alterations in coagulation studies could increase the risk for hematoma formation or hemorrhage.

• Assess the intended insertion site for the presence of a strong pulse. Rationale: Identification and localization of the pulse increases the chance of a successful arterial cannulation.

• Presence of collateral flow to the area distal to the arterial catheter should be evaluated before the artery is cannulated. For radial arterial lines, a modified Allen’s test should be performed. Rationale: This assessment determines the presence of collateral flow to the hand to reduce vascular complications.

• If available, assess the intended artery with a Doppler ultrasound scan. Rationale: This assessment aids in determination of the patency of the artery and blood flow.1,2,16 Identification and localization of the artery to be cannulated increases the chance of a successful cannulization and reduces the complication rate and need for multiple attempts at placement.¹⁹

• Verify correct patient with two identifiers. Rationale: Prior to performing a procedure, the nurse should ensure the correct identification of the patient for the intended intervention.

• Perform a pre-procedure verification and time out, if non-emergent. Rationale: Ensures patient safety.

• Ensure that the patient and family understand preprocedural teaching. Answer questions as they arise and reinforce information as needed. Rationale: Understanding of previously taught information is evaluated and reinforced.

• Obtain informed consent. Rationale: Informed consent protects the rights of the patient and makes a competent decision possible for the patient; however, in emergency circumstances, time may not allow the form to be signed.

• Place the patient supine with the head of the bed at a comfortable position. The limb into which the arterial catheter will be inserted should be resting comfortably on the bed. Rationale: This placement provides patient comfort and facilitates insertion.

• Place a towel under the back of the wrist to hyperextend the wrist and tape it in place or have someone hold it (if the radial artery is being used). Rationale: This placement positions the arm and brings the artery closer to the surface.

• Elevate and hyperextend the patient’s arm. Support the arm with a pillow (when using the brachial artery). Rationale: This action increases accessibility of the artery.

• When the femoral artery is used, position the patient supine with the head of the bed at a comfortable angle. The patient’s leg should be straight with the femoral area easily accessible. Rationale: This position is the best for localizing the femoral artery pulse.