LETTERS TO EDITOR
Year : 2020 | Volume
| Issue : 4 | Page : 552-554
Assessing adequacy of collateral foot circulation: A simple bedside test prior to lower extremity arterial cannulation
Ashutosh Kaushal1, Shipra Verma1, Rudrashish Haldar2, Praveen Talawar1
1 Department of Anaesthesia, 6th Level, Medical College Building, All India Institute of Medical Sciences (A.I.I.M.S), Rishikesh, Uttarakhand, India
2 Department of Anaesthesia, SGPGIMS, Lucknow, Uttar Pradesh, India
Dr. Ashutosh Kaushal
Department of Aanaesthesia, All India Institute of Medical Sciences (A.I.I.M.S), Rishikesh - 249 201, Uttarakhand
Source of Support: None, Conflict of Interest: None
|Date of Submission||25-Jan-2020|
|Date of Acceptance||27-Jan-2020|
|Date of Web Publication||24-Sep-2020|
|How to cite this article:|
Kaushal A, Verma S, Haldar R, Talawar P. Assessing adequacy of collateral foot circulation: A simple bedside test prior to lower extremity arterial cannulation. Saudi J Anaesth 2020;14:552-4
|How to cite this URL:|
Kaushal A, Verma S, Haldar R, Talawar P. Assessing adequacy of collateral foot circulation: A simple bedside test prior to lower extremity arterial cannulation. Saudi J Anaesth [serial online] 2020 [cited 2020 Nov 28];14:552-4. Available from: https://www.saudija.org/text.asp?2020/14/4/552/296025
Arterial cannulation for invasive blood pressure monitoring and sequential arterial blood gas analysis is routinely used in the Operating Theatres (OTs) and Intensive Care Units (ICUs). Known complications of this procedure include temporary vascular occlusion, thrombosis, ischemia, hematoma formation, and local catheter-related infection and sepsis. Usually the radial artery of the hand is frequently employed owing to its close proximity to the skin, collateral circulation with the ulnar artery and low rate of complication. Before performing radial artery cannulation or blood sampling, palmar arches should be evaluated by Modified Allen's Test (MAT) which is a simple bedside test to assess adequate collateral circulation and the patency of hand collateral arteries (radial and ulnar). Quite often, lower extremity arterial cannulation is performed (failed radial artery cannulation, injured/burned upper limb, surgical procedures involving arms or where upper part of the body is not easily accessible) employing the dorsalis pedis or posterior tibial artery. A variation of MAT known as Lower Extremity Allen's Test (LEAT) has been previously described, which utilizes a hand held doppler probe. However, Doppler probes may not be universally available. Thus, there exists paucity of simple bedside tests which can be performed prior to arterial cannulation of lower extremities which can evaluate the adequacy of arterial collateral flow.
We propose a simple amendment of MAT which can be performed at the bedside test to assess distal lower extremity collateral circulation by supplementing sequential arterial compression and release with pulse oximetry.
With the patient lying supine, the pulse oximeter is attached to any of the toe for recording of baseline oxygen saturation and waveform [Figure 1]a. Both dorsalis pedis artery and posterior tibial artery are identified superficially by the pulsations and simultaneously compressed till pulse oximetry waveform flattens [Figure 1]b. Pressure on the posterior tibial artery is then released. Return of waveform indicates adequate posterior tibial artery flow to maintain perfusion of distal foot [Figure 1]c provided the dorsalis pedis is cannulated. Non-return of waveform after release of posterior tibial artery is indicative of inadequate patency of posterior tibial artery. If it occurs, pressure on dorsalis pedis artery is released. Return of waveform indicates dorsalis pedis artery dependent distal foot perfusion.
|Figure 1: Assessing adequacy of collateral foot circulation with use of pulse oxymeter|
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The entire procedure is repeated, beginning from simultaneous compression of both dorsalis pedis artery and posterior tibial artery till waveform flattens. Pressure on the dorsalis pedis artery is then released. Return of waveform indicates adequate dorsalis pedis artery flow to maintain perfusion of distal foot [Figure 1]c provided the posterior tibial artery is cannulated. Non-return of waveform after release of dorsalis pedis artery is indicative of inadequate patency of dorsalis pedis artery. In that case, pressure on posterior tibialis artery is released. Return of waveform is indicative of posterior tibialis artery dependent distal foot perfusion [Figure 1]d.
Amplitude of the waveform may vary depending on which toe the probe, local temperature and probe proximity with the arterial source.
Vascular complications following dorsalis pedis artery cannulation are quite uncommon, because the three major arteries feeding the foot have multiple inter arterial connections, which protect the foot from limb ischemia. Despite it, few reports of distal limb ischemia after dorsalis pedis artery cannulation have been reported previously.
Although recommended tests for evaluation of lower extremity circulation include directional Doppler flow studies, transcutaneous oxygen tension, and angiography (gold standard), they may not be ubiquitously available in the OT or ICU settings. This limits their extensive application. The described modification is safe, easy to perform and cost effective. Pulse oximeter being universally available in the OTs' and ICUs' can be used in the pre-procedural period to assess the collateral perfusion of the foot. If any uncertainty is revealed after the performance of this test, alternative sites for arterial cannulation should be considered. Compared to MAT for the upper limb which relies on subjective visual assessment of the palmer colour, the addition of an objective component like pulse oximetry adds to the reliability and unambiguity of the information obtained.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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Tutar O, Yildirim D, Samanci C, Rafiee B, Inan K, Dikici S, et al
. Defining the collateral flow of posterior tibial artery and dorsalis pedis artery in ischemic foot disease: Is it a preventing factor for ischemia? Iran J Radiol 2015;13:1-4.
Panda R, Mohanty C. Foot gangrene following dorsalis pedis artery cannulation: Risk versus benefit of arterial cannulation in polytrauma patient. Indian J Community Fam Med 2018;4:72. [Full text]
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