Safety and Sustainability of Axillary Versus Radial Arterial Catheters in Critically Ill Children
A Retrospective Comparative Study
Pediatric Anesthesia
Submitted August 2025 by Dr Eamonn Upperton
Read by 108 Journal Watch subscribers
This retrospective cohort study examines axillary arterial lines placed in PICU patients to compare their safety profile with radial arterial lines, and provides some baseline data to support their use as a second line option.
Methods
The authors performed an EMR review of all documented axillary arterial lines placed on PICU patients under age 18 between 2007 and 2023 at a tertiary hospital, yielding 306 patients.
These patients were age-matched with patients who received a radial arterial line during the same time period, for 306 controls.
The electronic notes were reviewed for demographic information, data relating to the line and its complications, and PICU mortality.
Analysis
The limitations imposed by the retrospective cohort study design make it challenging to directly compare the two techniques:
- The axillary arterial line is described as an 'alternative access site' chosen by the clinician when catheterisation of the radial artery was not possible.
- The axillary artery cohort was therefore not randomly chosen, and consists of sicker patients with more difficult arterial access
- The radial artery cohort was matched by similar age but otherwise randomly selected from the electronic record
The cohorts were clearly quite different at baseline, as demonstrated by the 12% mortality rate in the axillary group compared with 2% in the radial group. It is therefore difficult to make conclusions about the safety of one technique compared with the other, except to say that one might expect a higher rate of complications in the axillary artery cohort commensurate with their higher severity of illness.
The primary outcome was the rate of vascular complications in each cohort, which the authors defined as treatment or consult for vascular injury or thrombosis.
- One patient in the axillary artery group experienced a documented vascular complication (0.33%). This was described as an ischaemic upper limb, and was treated sucessfully with a brachial plexus nerve block, systemic tPA, and heparin infusion.
- No patients in the radial artery group experienced a vascular complication
Secondary outcomes included duration of catheter use, reasons for catheter removal and catheter replacement.
Axillary catheters were retained longer than radial (presumably relating to the difficulty in siting them in the first place!), and otherwise had similar removal and replacement rates.
Discussion
This paper has a somewhat narrow definition of a 'vascular complication', requiring that a patient underwent treatment or surgical assessment for thrombosis or arterial injury. These events are rare but clinically significant, and would be at the forefront of a clinician's mind when choosing their approach.
It is possible that other studies with a broader view of what constitutes a 'vascular complication' may uncover more subtle or transient differences between axillary and radial artery techniques, but a focus on the more devastating outcome seems reasonable given the axillary approach's second-line status.
Given the higher severity of illness in the axillary catheter group, the absence of an excess of severe vascular complications should reassure a clinician considering the axillary artery approach as a second-line option.
Take home message
The purpose of this paper is to help the clinician faced with an unwell paediatric patient with difficult arterial access, and provides some reassurance that an axillary arterial line is a feasible option in those challenging circumstances.
A key decision point for clinicians faced with impossible distal artery access in paediatrics might be to choose between upper and lower limb - with femoral being the more traditional choice. The comparative safety of femoral versus axillary arterial access is not examined by this paper, though a referenced single-centre study does show a lower incidence of vascular compromise (defined as 'any perfusion abnormality') for axillary versus femoral arterial lines in paediatric cardiac patients (6.2% vs 19.9%, respectively); the same paper described 4 major arterial injuries in the femoral group (0.37%, n=1068) and 0 in the axillary group (n=195).
While the findings are largely reassuring, this paper's description of management for the single ischaemic limb complication in the axillary group (and brief mention of retrograde cerebral embolism) serves to temper enthusiasm for more routine use of proximal artery techniques.
