“…HOB elevation is a widely accepted aspiration reduction method achieved through keeping backrest elevated at least 30-45 • (Stroud et al, 2003, Williams and Leslie, 2005, Bourgault et al, 2007, McClave et al, 2009, Albertos et al, 2011. The mean of back rest elevation in the three sectors was approximately 42 • which is absolutely optimal, Miller et al (2008) found that only 4·9% of patients met the recommendation of maintaining HOB at 45 • . The discrepancy in nursing practice towards HOB elevation was referred to insufficiency of nursing knowledge about the relationship between HOB elevation and the risk for VAP (Miller et al, 2008, Reignier et al, 2010, Mueller et al, 2011.…”