Arterial Line Complications

Introduction

• Intra-arterial catheterization is a commonly utilized technique when continuous blood pressure measurement or frequent arterial blood sampling is expected.
• Complications related to arterial line placement are uncommon but can be clinically significant.
• These complications can generally be classified into infectious, vascular, and mechanical/use-related categories.
• Various risk factors and preventative techniques to mitigate complications have been described in the literature.

Infectious Complications

• Most arterial catheter-related infections occur due to local site infection and catheter colonization, but bloodstream infections can also occur.¹
• While focus is placed more on central line-associated bloodstream infections, evidence suggests that indwelling arterial catheters are an under-recognized source of bloodstream infections.
  • The incidence of arterial catheter-related bloodstream infection (CRBI) was approximately 1.7 per 1,000 catheter days, compared with 2.7 per 1,000 catheter days for central venous catheters.
  • A large-scale survey showed that clinicians underestimated arterial CRBI risk by a factor of three, and only 44% of clinicians followed Centers for Disease Control and Prevention (CDC)-recommended practices during insertion of arterial catheters.²
• Gram-positive microorganisms are most often cause of infection, though the femoral site has been associated with a greater incidence of gram-negative bacilli infections compared to other sites.³
• The influence of the insertion site on infection risk is inconclusive: some studies show a higher risk at the femoral site, while others indicate similar bloodstream infection risk at both the radial and femoral sites.
• The CDC recommends limited sterile barrier precautions (cap, mask, sterile gloves, sterile fenestrated drape) for peripheral (radial, brachial, dorsalis pedis) arterial catheter insertion and maximal precautions (use of a sterile gown and a full body sterile drape in addition to limited precautions) for central (axillary and femoral) arterial catheter sites.
  • Studies have not found a difference in colonization or CRBI rates between limited and maximal barrier precautions during peripheral arterial line placement, suggesting that limited precautions are adequate for preventing infection.
• Replacement of catheters through placement at a new site or guidewire exchange every 7 days has not demonstrated a significant difference in arterial catheter-related infections.
• Use of chlorhexidine-based antiseptic preparation and chlorhexidine gluconate-impregnated sponge dressings has been shown to have significant reductions in infection related to arterial catheters.²

Vascular Complications

• Vasospasm is a common complication that can occur following arterial catheterization, which has been cited to occur in 57% of patients.
  • It is associated with blanching distal to the site of spasm, pain in the extremity, decrease in arterial blood pressure, damping of the waveform, or loss of the arterial pulse or pulse oximetry signal.
  • It can be an initial sign of developing thrombosis.
  • Arterial spasm is typically self-limited, but in severe cases, intra-arterial injection (nitroglycerin or verapamil) or regional nerve block (axillary nerve block) can be considered.
  • Risk factors include female sex, history of diabetes mellitus, and large catheter-to-radial artery size.^1,4
• Thrombosis typically presents with diminished distal pulses, a diminished or absent arterial waveform, and cyanotic digits.
  • It can appear several days after removal of the arterial catheter.
  • Risk factors include prolonged cannulation, larger catheter size (18 gauge or larger), small arterial diameter, low-flow states (decreased cardiac output, peripheral arterial disease), and vasospasm (Raynaud phenomenon).
  • Management is conservative when collateral flow is adequate, but fibrinolytic agents, stellate ganglion blockade, or surgical interventions can be considered in severe cases.
  • Use of heparin or sodium citrate for maintenance/flushing has not demonstrated differences in catheter patency compared with saline.^1,4
• Embolized particulate matter or air flushed into an arterial catheter can travel proximally (causing ischemic changes of the brain, spinal cord, and heart) or distally (causing ischemia of the extremities).
  • In primate models, 2 mL of air injected into the radial artery via a standard pressure infusion apparatus resulted in clinically significant cerebral air emboli.
  • Risk factors for cerebral embolization include volume of flush solution, speed of injection, placement in the proximal right upper extremity (due to aortic arch anatomy), and proximity of the catheter lumen to central circulation (i.e., higher risk in axillary lines compared to brachial and radial catheters).
• Dissection occurs when a wire or catheter enters the subintimal layer, creating a space between the media and intimal walls of the artery.
  • Blood flow through the false lumen can lead to aneurysm or thrombus formation.
  • In patients undergoing radial artery catheterization for coronary angiography, the dissection rate is approximately 1%.
• Pseudoaneurysm formation is rare, occurring in fewer than 0.1% of patients who undergo radial artery cannulation for coronary angiography.
  • Typically, this is a late complication and rarely progresses into an arteriovenous fistula.
  • It presents as a painful pulsatile mass after local site bleeding or hematoma formation.
  • Risk factors include multiple cannulation attempts, larger sheath size, anticoagulation use, and catheter infection.^1,5
• Site selection has been thought to influence the risk of vascular complications.
  • Studies have demonstrated safety at other sites with a large cohort study of patients undergoing cardiac surgery demonstrating the rate of vascular complications at the brachial site to be approximately 0.15%.⁶
• Technique has also been shown to influence the risk of complications, as ultrasound-guided dynamic needle-tip positioning was associated with a decreased risk of hematoma, vasospasm, and posterior wall punctures compared to other techniques (palpation or traditional ultrasound methods).⁷
• Assessment of collateral flow prior to radial artery catheterization with the Allen test can be performed to identify patients who may be at risk for ischemic complications.
  • The Allen test has significant interobserver variability, and studies have shown that it lacks predictive accuracy for subsequent hand ischemia.
  • Use of color Doppler ultrasonography has been suggested to be a more reliable alternative to the Allen test.¹

Mechanical/Use-Related Complications

• Nerve injury due to direct trauma is a rare complication of arterial line placement.
  • The proximity of the brachial artery to the median nerve and the axillary artery to the brachial plexus poses an increased risk of nerve injury.
  • Despite the anatomic proximity, nerve injury related to brachial artery cannulation is extremely rare, with no directly attributable neurologic complications cited in a large cohort study of cardiac surgery patients.⁶
  • Nerve damage related to axillary arterial line placement is not well studied, but it has been reported as 3.2% in a small retrospective analysis.⁸
• Hematoma formation occurs more frequently in patients on anticoagulation and is typically controlled with application of direct pressure.
  • Ultrasound-guided techniques have been found to decrease the risk of hematoma formation compared to traditional palpation techniques.⁷
• Iatrogenic blood loss or hemorrhage can be a use-related complication of intra-arterial catheterization.
  • Sampling for laboratory testing, as well as withdrawal of waste, can result in notable amounts of blood loss with frequent testing.
  • Use of a closed blood draw system for re-infusion of unused blood or sampling from a proximal port can minimize blood loss.
  • Disconnection of the catheter-tubing assembly carries the risk of major blood loss or exsanguination.^1,4
• Accidental intra-arterial injection of medications can lead to limb or other organ ischemia and damage.
  • This can result due to cytotoxicity of the medication, obstruction of blood flow through the formation of drug crystals, hemolysis/platelet aggregation due to vessel damage, or vasoconstriction from vasopressor use.¹
• Failure/malfunction of arterial catheters is a common use-related complication.
  • A multicenter randomized controlled trial of adult patients in the intensive care unit demonstrated a failure rate of 26%.
  • The risk of arterial catheter failure was reduced with ultrasound-assisted insertion.
  • Risk factors for arterial line failure included younger age and female sex.⁹