Measuring quality of sedation in adult mechanically ventilated critically ill patients:

Abstract 

There are no reliable, valid, and responsive scales to measure the quality of sedation in adult critically ill patients. Our objective was to develop a summated rating scale with these properties and to define the minimal clinically important difference (MCID). We developed and tested the scale in an 18-bed medical–surgical intensive care unit (ICU) (12-bed acute and 6-bed subacute unit). Following identification of relevant domains and item derivation, 116 observations were made on 38 patients; psychometric properties and interrater reliability were assessed to allow item reduction. The final scale consisted of two five-item subscales quantifying calmness and interaction along a continuum from 5 to 30 points. Interrater reliability was 0.89 and 0.90; internal consistency was 0.95 for both subscales. To test construct validity, MCID, and responsiveness 302 observations were made on 54 patients. Construct validity: calmness score vs. need for further intervention to make the patient calm (R = −0.82, P < 0.001); interaction score discriminated between acute vs. subacute units, mean scores 15.28 ± 8.26 vs. 23.54 ± 7.42, mean difference 8.27 (95% CI − 10.32 to −6.22); MCID - 2.2 and 2.5 for the calmness and interaction subscales; Guyatt's responsiveness statistics - 1.4 and 2.3. The Vancouver Interaction and Calmness Scale (VICS) is reliable, valid, and responsive.

Keywords:  Sedation scale, Reliability, Validity, Responsiveness, Critically ill, Sedation

• 1 Sedation Focus Group: Katherine Weglo, Denise Foster, Barbara Plumstead, Susan Biggs, Daile Robinson and Heather Bannerman.