It was called to my attention by a reader that the article by Nielsen et al.  1that was published in January 2005 issue of Anesthesiology was very similar in design and conclusions to another article, published by the same authors in the October 2004 issue of the Canadian Journal of Anesthesia .2The authors’ comments follow.

Editor-in-Chief, Anesthesiology, The University of Iowa, Iowa City, Iowa. anesthesiology@uiowa.edu

1.
Nielsen KC, Guller U, Steele SM, Klein SM, Greengrass RA, Pietrobon R: Influence of obesity on surgical regional anesthesia in the ambulatory setting: An analysis of 9,038 blocks. Anesthesiology 2005; 102:181–7
2.
Cotter JT, Nielsen KC, Guller U, Steele SM, Klein SM, Greengrass RA, Pietrobon R: Increased body mass index and ASA physical status IV are risk factors for block failure in ambulatory surgery: An analysis of 9,342 blocks. Can J Anesth 2004; 51:810–6