Regional Techniques and Length of Hospital Stay after Abdominal Aortic Surgery
To the Editor:—
I would like to commend Norris et al . for performing an elegant and important study. 1The authors answered the primary question of the study and showed that length of hospital stay (LOS) did not differ among the four treatment arms. The rationale for using LOS as the primary outcome measure was that it is the “variable most directly proportional to an integrated final negative effect of all significant perioperative morbidity.” Although the authors explain in the discussion why they chose not to focus on “relatively rare events (death and myocardial infarction),” they go on to summarize the important findings of the study in the abstract reporting on LOS followed immediately by the statement:“Postoperative outcomes were similar among the four treatment groups with respect to death, myocardial infarction…”. The article lacks a clear statement in the abstract or in the limitations section explaining that the study was insufficiently powered to test differences in these outcomes. The message to the reader with respect to cardiovascular outcomes is contradictory, especially in view of two recent publications utilizing pooled analysis of thousands of patients showing that regional techniques reduced the incidence of postoperative myocardial infarction and mortality, respectively. 2,3The limitations of meta-analyses are well known, however, in the absence of large prospective trials designed to specifically answer questions on whether regional techniques have an impact on less frequent but more serious postoperative morbid events, anesthesiologists will be limited to using such data.