January February 2010 Letter to the Editor

Abstract

Regarding the report of Gardner and Shirland1, I would like to clarify a few points. Firstly, our article (Kalyn, et al.2 [Ref 35]) was incorrectly categorized as a case controlled or cohort trial in Table 1 (Level IV evidence). It was actually a well designed, randomized controlled cross over trial (Level 2 evidence). An a priori sample size of 50 was calculated for a power of 0.8 and an alpha of 0.05 for a small effect size and an average correlation of 0.8 for 4 physiological variables. We utilized a cross over design with random allocation of infants to a suction procedure. After the initial suction and recovery each infant had a 90 minute washout followed by the alternate suction method. This minimized the change in respiratory status of the infant and more clearly delineated the response to the specific suction method. The final sample consisted of 200 infants who were stratified into three weight groups to account for varying endotracheal tube sizes and disease processes.