The venous needle must be placed in which direction relative to blood flow?

The venous needle must be placed in the direction of blood flow to facilitate smooth access to the circulation during hemodialysis. When the needle is positioned with the blood flow, it allows for an easier entry into the vein and reduces turbulence, making it more efficient for the blood to flow through the needle and into the dialysis machine. This orientation also helps to minimize the risk of trauma to the vein and ensures optimal blood flow, which is crucial for effective dialysis treatment.

In contrast, positioning the needle against the blood flow could lead to difficulties in drawing blood from the site, increased resistance, and potential injury to the vessel. Placing the needle perpendicular or at an angle may not provide the optimal access or flow rate needed for the procedure. Thus, the direction that aligns with blood flow is the most suitable for achieving successful venous access during dialysis.