To the Editor:
Although we applaud the American Society of Anesthesiologists (ASA) in the development of evidence-based guidelines and the effort and expertise of esteemed leaders of our field in their preparation, we are concerned with several aspects of the guidance section in the recently published practice guidelines for central venous access.1
The prologue to the guidelines emphasize their application to “anesthesiologists or health care professionals under the direction/supervision of anesthesiologists” (in the Focus section) and intent “for use by anesthesiologists and individuals under the supervision of an anesthesiologist” (in the Application section). As such, the dearth of level 1 evidence presented by anesthesiologists is disconcerting.
For adults, only one of the three presented studies for static ultrasound use for internal jugular access, and only one of the eight presented for real-time ultrasound use, are from anesthesiologists, incongruent to the preceding admonition in the preamble. Examination of the referenced adult studies and their subsequent meta-analysis is disturbing for their heterogeneity, which does not necessarily reflect the practice of average ASA members, and is apparent as such in the ASA member survey responses.
The majority of the referenced studies (all fewer than 100 subjects) include hemodialysis and central line access by both nephrologists and interventional radiologists and multiple studies by nonanesthesia critical care physicians, including junior house staff. The largest of these (450 subjects) had incidences in the landmark group of carotid artery puncture (10.6%), hemothorax (1.7%), and pneumothorax (2.4%) greater than most anesthesiologists would accept. Thus it is not surprising that meta-analysis of these disparate studies (which have not been scored by traditional methods to assess for bias and scientific rigor) would find statistical significance only in success of line insertion.
Given this weak supportive evidence, it is further surprising to conclude that ASA members “agree” with the presented recommendation (table 5). In fact, only 48.2% agree in any form with the statement that real-time ultrasound should be used (table 3, item 35), which even by partisan estimation is not a majority. The vigorous discussion at the 2010 and 2011 ASA House of Delegates and reference committees, including more anecdotal comments than evidentiary discussion, is testimony to the discomfort that many ASA members have with the supportive level of evidence.
As users of ultrasound for central line insertion when indicated by prudent physician judgment and experience, we call for additional quality prospective, randomized investigations of ultrasound use for internal jugular placement by the anesthesia community before uniform adoption of guidelines based on data from nonanesthesiologists.