What is the correct positioning for a single-orifice catheter to withdraw air during a craniotomy?

When positioning a single-orifice catheter for the withdrawal of air during a craniotomy, it is important to consider the anatomical location of the superior vena cava (SVC) and right atrium (RA) junction. Positioning the catheter too high might not effectively reach the venous circulation where the air embolism can accumulate, while positioning it too low could risk complications related to catheter placement or ineffective air removal.

Placing the catheter 3 cm above the SVC and RA junction is optimal as it allows for access to the area where air might collect without being too far from the heart, ensuring the safe aspiration of air. This positioning helps ensure that any air that enters the venous circulation during the craniotomy can be efficiently removed, minimizing the risk of embolism and its associated complications. Thus, this specific length provides a balance of safety and efficacy in intervention during surgical procedures.