Depth of sedation in children undergoing computed tomography: validity and reliability of the University of Michigan Sedation Scale (UMSS)

Safe care of sedated children requires ongoing assessment of the depth of sedation to permit early recognition of progression to over-sedation. This study evaluated the validity and reliability of the University of Michigan Sedation Scale (UMSS) as a measure of sedation during procedures. The UMSS is a simple observational tool that assesses the level of alertness on a five-point scale ranging from 1 (wide awake) to 5 (unarousable with deep stimulation). Thirty-two children aged 4 months to 5 yr (mean 1.5 yr), sedated for computed tomography (CT), were studied prospectively. The CT nurse assessed sedation using the UMSS before sedative administration and every 10 min thereafter. The child was videotaped during each assessment, and segments were edited and their order was randomized. Four nurses blinded to sedative administration viewed the segments and scored sedation using the UMSS. One of these nurses also scored sedation using a visual analogue scale (VAS) and another using the Observer's Assessment of Alertness/Sedation Scale (OAAS). To examine the test–retest reliability, 75 randomly selected video segments were viewed and scored on a second occasion. Changes in scores from baseline to discharge supported construct validity (P