Dr. Shrestha’s letter1 highlights the value of real-time or dynamic ultrasound needle guidance during central venous catheterization. Our literature and survey findings both strongly support this intervention.2
Our evidence model did not include head position/rotation as an intervention to evaluate for a recommendation. However, if a sufficient evidence base exists (preferably randomized, controlled trials), we agree that the issue may be relevant to future updates of the Practice Guidelines for Central Venous Access. The evidence linkage would need to support the premise that an optimal degree of head rotation will minimize the chance of inadvertent carotid artery puncture.
We agree with several of Dr. Shrestha’s points and have some comments:
Current evidence indicates that the relationship of the internal jugular to the carotid artery is highly variable. This anatomic variability may be one of the strongest arguments supporting our recommendation to use real-time or dynamic ultrasound guidance during line insertion.
The literature reports that the overlap between the internal jugular vein and carotid artery increases as one progressively rotates the head to the contralateral side. However, no consensus optimal degree of rotation has yet been identified.
Dr. Shrestha’s letter raises a potential safety implication: Targeting a segment of the internal jugular vein that overlaps the carotid artery may increase the risk of carotid puncture. Although this implication seems self-evident, it deserves empiric testing because targeting other segments of the internal jugular may increase the risk of pneumothorax or other complications.
Importantly, our current Guideline has this recommendation: “Use static ultrasound imaging before prepping and draping for prepuncture identification of anatomy to determine vessel localization and patency when the internal jugular vein is selected for cannulation.” If supported by our rigorous guideline process, Dr. Shrestha’s comments regarding head position may modify this recommendation in future revisions.
On behalf of the American Society of Anesthesiologists (ASA) Task Force on Central Venous Access and the ASA Committee on Standards and Practice Parameters, we thank Dr. Shrestha for the thoughtful letter. Such letters illustrate the importance of practitioner input for developing and periodically updating ASA Practice Parameters. These concerns will assist the Committee on Standards and Practice Parameters in the identification of new topics as well as in the selection of new practice parameters.
Dr. Tung receives salary support from the International Anesthesia Research Society as section editor for the section on critical care. The other authors declare no competing interests.