Introduction
Pain is defined as an unpleasant sensory and emotional
experience associated with actual or potential tissue damage
and is a concern after surgical and invasive medical procedures
in the critical care setting (Savins 2002, Walker &
Wagner 2003). Many children experience moderate to severe
pain after major surgeries (Hammer et al. 2005, Ren 2006,
Li et al. 2009). Repeated or long-term unrelieved pain may
result in negative consequences for children, including altered
pain sensitivity, permanent neuroanatomic abnormalities, as
well as emotional, behavioural and learning disabilities