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Examining the role of ultrasound in the placement of radial artery catheters

Three Part Question

[In adult patients requiring radial artery catheterisation] does
[ultrasound guided technique] compared with [direct palpation technique] result in [improved first pass success rate]

Clinical Scenario

In the ED this intervention is usually required in the critically unwell patients who may well be
hypotensive, tachycardic and distressed. Such physiology often results in poor peripheral perfusion
and, in conjunction with an often pressured environment, can only increase the level of difficulty
associated with an already challenging procedure.
Dr Ian Sexton-Examining The Role of Ultrasound in The Placement of Radial Artery Catheters
Ultrasound (US) is becoming increasingly entwined in the delivery of critical care in the ED and
has been incorporated in EM training for a number of years. The use of US in establishing central
venous access is established best practice
in the UK, improving both
performance and safety. Perhaps the same applies to US in the placement of arterial catheters?

Search Strategy

Electronic bibliographic database search was of Medline and Embase conducted using the
OVIDTM Online interface. (Full search strategies outlined in Appendix B)
Medline 1946 to Jan 2017 (May 2017)
Embase 1974 to Jan 2017 (May2017)
1. exp ultrasonography 141757
2 174536
3. 1 or 2 265424
4. or exp catheterization 111863
5. or exp catheters 36323
6. 4 or 5 138227
7. 3 and 6 7407
8. radial or exp radial artery 8085
9. or exp palpation 15599
10. 8 and 9 77
11. 7 and 10 27
12. limit 11 to (English and randomised control trials) 13
1. or exp echography 290219
2. 385153
3. 1 or 2 569538
4. or exp catheterization 61224
5. cannula or 23515
6. 4 or 5 83885
7. 3 and 6 6149
8. radial or exp radial artery 12842
9., or exp palpation 22399
10. 8 and 9 178
11. 7 and 10 54
12. limit 11 to (randomised control trials and English) 20

Search Outcome

Limited to studies populated by patients from acute admissions

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Xiuyan Li, Guizhen Fang, Danhua Yang, et al
Adult ICU patients, 16 to 85 yo, with a diagnosis of shock. May 2014 to Dec 2014. Eligible patients 88, randomised to radial artery catheterisation by direct palpation (DP) method group or ultrasound (US)method ( experimental) group. Post exclusion 40/40 patients were analysed Successful catheterisation at first attemptUS 80%, DP 42% p=0.01Non blinded. Convenience sampling with small sample size. No detail for clinically significant difference or associated power calculation. Minor calculation error in CONSORT18 diagram, US group 44 4 withdrawals =40
S. Shiver, M Blaivas, M. Lyon.
Patients presenting to the ED of an Augusta(USA) urban level 1 trauma centre. Patient >= 18yo who were deemed to require an arterial line by the treating physician. Study period 6 months60 pts were enrolled randomised 30 /30 to direct palpation group (DP) and Ultrasound group(US).first pass success rateUS 87% [95% CI] 74% -99%, DP 50% [95% CI] 31% - 69%Convenience sampling. NO power calculation for clinically significant difference although Small sample size. No CONNSORT diagram. No patient demographics. All operators had extensive US experience beyond study. 3 from 4 data collectors are authors of the article introducing risk of confirmation bias.


2 studies with a patient population which is generalisable to other ED/critical care facilities. Clearly defined primary outcomes both found to support improved first pass success rate with US technique. Statistically significant in both studies and clinically significant in Shiver et al as demonstrated by results with 95% Confidence Intervals. Xiuyan et al also highlightd reduced complication rates on follow up with the US group. It is a logical assumption that a no touch technique for catheter placement and also for routine ABG sampling reduces the risk of self inflicted needlestick injury

Clinical Bottom Line

In an adult patient presenting to the Emergency Department who requires radial artery catheterisation, an ultrasound guided approach in the hands of a technically competent operator will improve first pass success rate over direct palpation.


  1. Xiuyan Li, Guizhen Fang, Danhua Yang, et al Ultrasonic technology improves radial artery puncture and cannulation in ICU shock patients. Medical Science Monitor 2016; 22: 2409-2416.
  2. S. Shiver, M Blaivas, M. Lyon. A prospective comparison of Ultrasound-guided and blindly placed radial artery catheters: Acad Emerg Med. 2006 Dec;13(12):1275-9.