Regarding the article that appeared on page 75 of the July 2011 issue, the authors sincerely regret the typographical errors in the article and appreciate the readers allowing them the opportunity to clarify these discrepancies. The following corrections should be noted: The abstract and figure 1 legend should read PaO²rather than PaCO²; also, in figure 1 and table 1, PaOC should read PaO², and FIO²is expressed as a percentage.