Arterial line insertion or catheterization provides continuous blood pressure monitoring and facilitates arterial blood sampling in critical care practice. The most common insertion sites for arterial lines are the radial, femoral, brachial, and dorsalis pedis arteries. Each site has distinct advantages and disadvantages that must be carefully considered when choosing the optimal approach.
The radial artery is generally the preferred insertion site for an arterial line. Its superficial location and straightforward access make it suitable for both elective and emergency procedures. An important advantage is that the hand receives blood from both the radial and ulnar arteries, which reduces the risk of ischemia if thrombosis occurs. Additionally, compared with more proximal sites, radial artery catheterization carries a lower infection risk, supporting its position as the first choice in many operating rooms and intensive care units (1). However, radial access can be technically challenging in patients with peripheral vascular disease, weak pulses, severe hypotension, or multiple prior cannulations. Complications such as arterial spasm, hematoma formation, and rarely, ischemic injury, can occur; however, the overall risk profile is favorable compared to other sites.
The femoral artery is a valuable alternative site, especially when rapid access is necessary or radial cannulation fails. Its large diameter makes catheter placement easy, and its position in the femoral triangle allows for easy identification, even in critically ill patients with weak peripheral pulses. Femoral access is often preferred during emergent cardiopulmonary resuscitation, as chest compressions can make radial access challenging. However, catheter-related bloodstream infections occur more frequently with femoral placements, likely due to the proximity of the groin to perineal flora. Thrombotic complications and retroperitoneal hematomas are also recognized risks, especially in anticoagulated patients. These risks often restrict femoral access to urgent situations or cases where other sites are impractical (2).
The brachial artery is a less commonly chosen site for arterial line insertion. While the brachial artery’s relatively straight course makes cannulation technically simple, its deeper location and proximity to the median nerve increase the potential for complications, including nerve injury. Furthermore, because the brachial artery has limited collateral circulation, occlusion carries a significant risk of ischemia to the distal arm and hand. Although brachial access can provide stable pressure waveforms and is useful for certain patient populations (e.g., those undergoing bilateral radial artery harvest for coronary artery bypass grafting), its higher risk profile generally makes it an unfavorable choice compared to radial or femoral sites (3).
The dorsalis pedis artery is another peripheral option, though it is technically more challenging due to its small diameter and variable anatomy. This site may be useful when access to the upper extremities is contraindicated, such as in patients with arteriovenous fistulas or severe upper limb trauma. Although infection risk is lower than with femoral access, waveform fidelity can be problematic. Pressure tracings obtained from dorsalis pedis catheters may underrepresent central arterial pressures, especially in patients experiencing shock or severe peripheral vasoconstriction (4).
Beyond these commonly discussed insertion sites, alternative approaches, such as axillary arterial lines, have been described but are less frequently used in clinical practice. The axillary artery’s location allows for central pressure monitoring and has lower infection rates than femoral sites. However, its proximity to the brachial plexus and risk of hematoma limit widespread adoption. Similarly, posterior tibial artery cannulation may be considered in select cases, but it suffers from the same limitations as other distal sites, including waveform distortion and technical difficulty (1).
References
- Nuttall G, Burckhardt J, Hadley A, et al. Surgical and Patient Risk Factors for Severe Arterial Line Complications in Adults. Anesthesiology. 2016;124(3):590-597. doi:10.1097/ALN.0000000000000967
- Lorente L, Jiménez A, Jiménez JJ, et al. Higher arterial catheter-related infection rates in femoral than in dorsalis pedis access. J Hosp Infect. 2010;74(4):365-369. doi:10.1016/j.jhin.2009.08.019
- Handlogten KS, Wilson GA, Clifford L, Nuttall GA, Kor DJ. Brachial artery catheterization: an assessment of use patterns and associated complications. Anesth Analg. 2014;118(2):288-295. doi:10.1213/ANE.0000000000000082
- Martin C, Saux P, Papazian L, Gouin F. Long-term arterial cannulation in ICU patients using the radial artery or dorsalis pedis artery. Chest. 2001;119(3):901-906. doi:10.1378/chest.119.3.901