Point-of-care ultrasound for detection of arteriovenous fistula prior to central venous catheterisation of the internal jugular vein

Dear Editor, Ultrasound guidance has become the standard of care for central venous catheter (CVC) insertion; however, most operators continue to rely predominantly on B-mode imaging and vessel compressibility. This approach may be inadequate in the presence of vascular anomalies such as an arteriovenous fistula (AVF), predisposing to inadvertent arterial injury and serious complications.[1] We highlight the role of point-of-care ultrasound (POCUS) using a multimodal approach—B-mode, colour Doppler, and spectral Doppler—in identifying an unsuspected AVF during pre-procedural scanning of the right internal jugular vein (IJV). A 57-year-old woman diagnosed with carcinoma of the gallbladder was scheduled for CVC insertion to start total parenteral nutrition. She had a history of previous intensive care unit (ICU) admission for the same illness, during which right IJV cannulation had been performed. On careful examination of the neck, no palpable thrill or audible bruit was detected at the proposed cannulation site. Written informed consent for publication was obtained from the patient. On B-mode ultrasound of the right IJV, two adjacent anechoic vascular structures of unequal size were identified in the expected anatomical location of the carotid artery and IJV. Notably, there was a loss of the normal intervening tissue plane between the carotid artery and IJV, with reduced compressibility of the vein, suggestive of an AVF [Figure 1a]. Colour Doppler imaging revealed a turbulent mosaic flow pattern with aliasing involving both vessels, consistent with abnormal arteriovenous communication [Figure 1b]. After switching to the spectral Doppler mode of ultrasound, a high-velocity, pulsatile, low-resistance waveform with persistent diastolic flow within the venous structure was detected, confirming arterialised venous flow and establishing the diagnosis of an AVF [Figure 1c]. In view of these findings, the right IJV was abandoned as a cannulation site. A CVC was successfully placed in the left IJV after confirming normal vascular anatomy on B-mode and spectral Doppler. The patient was then referred to the department of cardiovascular and thoracic surgery for further investigation and management of the AVF.Figure 1: Point-of-care ultrasound demonstrating arteriovenous fistula. (a) B-mode ultrasound showing two adjacent vascular structures of unequal size with loss of the normal intervening tissue plane between the two structures, suggestive of vascular communication. (b) Colour Doppler demonstrating turbulent mosaic flow with aliasing across both vessels. (c) Spectral Doppler showing arterialised venous flow with a high-velocity, pulsatile, low-resistance waveformIatrogenic AVFs are recognised complications of central venous catheterisation, especially after repeated attempts for vascular access.[2] Even with real-time ultrasound guidance, reliance on B-mode imaging alone may be insufficient to prevent misidentification of vessels, particularly when vascular anatomy is distorted.[3] International guidelines recommend ultrasound guidance for CVC insertion; however, routine Doppler interrogation during pre-procedural scanning is not universally practised.[1] As demonstrated in this case, careful B-mode assessment can provide early structural clues, while colour and spectral Doppler can confirm the diagnosis. Early recognition allows selection of an alternative cannulation site and prevents potentially catastrophic complications. Our case shows that ultrasound is now a tool that can be applied intelligently in advanced therapeutics including central venous and arterial cannulation to improve patient safety.[4,5] We emphasise multimodal systematic POCUS assessment of the target vein, incorporating B-mode, colour Doppler, and spectral Doppler before needling for CVC insertion. This is particularly helpful in patients with prior neck instrumentation or central venous access, thereby enhancing procedural safety. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given his consent for images and other clinical information to be reported in the journal. The guardian understands that names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed. Disclosure of use of artificial intelligence (AI)-assistive or generative tools No use of artificial intelligence or generative tools was done for writing or editing this paper. Author contributions VC was involved in conceptualization of the report, patient management, literature review, manuscript drafting, and final approval of the version to be published. AK was involved in patient management, data collection, and manuscript editing. CS was involved in literature review and preparation of the manuscript. SS was involved in supervision, manuscript drafting and critical revision of the manuscript. All the authors have participated in the review, drafting and final approval of the manuscript. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.