ACVNU common mistakes
ACVNU · Understand the traps and how to avoid them.
Choosing a catheter gauge or length by habit or by what is closest at hand instead of matching it to the vessel measured on ultrasound and the therapy planned.
Candidates memorize 'bigger is better' for flow and default to a familiar kit, forgetting that catheter-to-vein ratio and insertion depth determine both flow adequacy and thrombosis risk.
What to do instead
Before selecting the device, state the measured vessel diameter, the calculated catheter-to-vein ratio, the required flow rate, and the intended dwell time, then justify the chosen gauge and length against those numbers.
Treating the ultrasound image as a static picture: identifying a round anechoic structure as a vein without confirming compressibility, Doppler flow direction, or relationship to the artery.
Candidates anchor on the first plausible structure and stop interrogating it, especially under time pressure or when the vessel looks 'obvious'.
What to do instead
For every target, complete a fixed sequence: identify artery versus vein, compress the vein, confirm flow with color or pulsed Doppler, and trace the vessel proximally and distally before needle entry.
Advancing the needle while the tip is no longer visible on the ultrasound screen, then reporting the tip location from memory or assumption.
Tissue motion, probe drift, and the desire to reach the vessel quickly cause the operator to lose the tip and continue advancing blind.
What to do instead
Maintain the 'tip in view' rule: stop advancing whenever the tip is not visualized, re-find the tip by sliding the probe, and only then continue; angle the probe to keep the shaft and tip in plane.
Documenting a procedure with generic phrases such as 'line placed without complication' and omitting site, device specifications, number of attempts, tip location confirmation, and consent discussion.
Candidates treat documentation as an afterthought at the end of a long procedure and copy forward prior notes rather than recording what actually occurred.
What to do instead
Use a structured procedure note template that captures indication, consent, site, device type/size/length, ultrasound findings, number of attempts, blood loss, tip confirmation method, and patient tolerance, and complete it before leaving the bedside.
Skipping or abbreviating the pre-procedure assessment of coagulation status, prior access history, allergies, and alternative sites before cannulating a patient.
Candidates focus on the technical steps they are being tested on and regard the history as paperwork rather than as a determinant of site and device choice.
What to do instead
Perform and verbalize a checklist covering indication, coagulation and platelet status, anticoagulant timing, prior catheters and stenoses, allergies, and a documented site plan with a backup site.
Failing to recognize early catheter-related bloodstream infection signs because fever is attributed to the patient's underlying illness and the line is left in place.
Critically ill patients have many reasons for fever, and candidates anchor on the primary diagnosis rather than considering the catheter as a source.
What to do instead
For any febrile patient with a central catheter and no clear alternative source, assess the exit site, review line duration and lumens, obtain paired cultures before antibiotics, and escalate for prompt removal decisions.
Ignoring or minimizing a new limb swelling, pain, or ipsilateral collaterals in a patient with a central catheter, treating it as expected post-procedure discomfort.
Catheter-related thrombosis presents insidiously, and candidates attribute symptoms to the underlying condition or to the procedure itself.
What to do instead
Treat new ipsilateral swelling or arm pain as suspected thrombosis until excluded: obtain duplex ultrasound, notify the responsible clinician, and document the assessment and escalation.
Using a sterile technique that lapses during the procedure, such as contaminating the guidewire, reusing a dropped item, or breaking the sterile field to reposition equipment.
Candidates prepare the field correctly at the start but fail to maintain it once the procedure becomes technically demanding.
What to do instead
Apply maximal sterile barrier precautions, perform a spoken timeout before draping, and stop the procedure to re-establish sterility whenever contamination is suspected rather than continuing.
Misinterpreting a pressure waveform or transduced reading from a catheter, for example accepting a venous waveform from a catheter that is actually in an artery.
Candidates rely on color or resistance alone and do not systematically analyze the transduced waveform and pressure values before using the line.
What to do instead
Transduce and interpret the waveform and pressure before any infusion, compare with a contralateral or non-invasive reading, and confirm with imaging or a second method when the result is ambiguous.
Removing a catheter or making an access decision without confirming that the patient or surrogate understands the indication, alternatives, and risks, or proceeding when consent was never obtained.
Candidates view consent as a formality signed at admission and do not connect it to the specific procedure being performed.
What to do instead
Hold a procedure-specific consent discussion covering indication, alternatives, material risks, and the opportunity for questions, document who consented and how capacity was determined, and address language or surrogate needs before starting.