critical care medicine
How To Do Femoral Vein Cannulation, Ultrasound Guided
Additional Considerations
The short-axis (cross-sectional, transverse) ultrasound view is easy to obtain and is the better view for identifying veins and arteries and their orientation to each other. Identifying a needle tip in cross section requires some skill, because the needle appears as an echogenic (ie, white) dot and the tip can be distinguished only by the dot's disappearance and reappearance as the needle tip traverses back and forth across the imaging plane.The short-axis view typically is used to determine a suitable venous impalement site and to guide steeply angled (eg, ≥ 45°) needle insertions. The long-axis (longitudinal, in-plane) ultrasound view is technically more difficult to obtain (must keep probe, vein, and needle in one plane), but it shows the needle longitudinally, so the entire needle—including the tip—can be imaged continuously as it approaches and enters the vein; this helps avoid aberrant placement.The long-axis view is helpful when the angle of needle insertion is shallow (eg, in axillary/subclavian cannulations) and to affirm proper longitudinal needle alignment during short-axis insertions. Cannulation attempts sometimes fail. Do not exceed 2 or 3 attempts (which increases the risk of complications), and use new equipment with each attempt (ie, do not re-use needles, catheters, or other equipment because they may have become blocked with tissue or blood). During cardiopulmonary arrest, or even low blood pressure and hypoxia, arterial blood may be dark and not pulsatile and may be mistaken for venous blood. If the femoral artery is errantly cannulated by either the tissue dilator or the CVC, leave the dilator or catheter in place and obtain surgical consultation for possible surgical removal. 