Adaptation and validation of the ICU Mobility Scale in Spain

Abstract

Objective: To adapt the ICU Mobility Scale (IMS) to the area of intensive care units (ICU) in Spain and to evaluate the metric properties of the Spanish version of the IMS (IMS-Es).

Method: Descriptive metric study developed in two phases. Phase 1, adaptation to Spanish of the IMS by a team of nurses and physiotherapists (translation, pilot, backtranslation and agreement). Phase 2, analysis of metric properties (convergent, divergent and predictive validity, interobserver reliability, sensitivity and minimum important difference) of the IMS-Es. Patient characteristics (Barthel, Charlson, BMI, sex), sedation/agitation level (RASS), ICU and hospital stays, survival, quality of life (SF-12), muscle weakness (MRC-SS) and mobility (IMS-Es) were recorded in the patients of the MOviPre national multicentre study.

Results: After obtaining the IMS-Es, it was implemented in 645 patients from 80 Spanish ICUs between April and June 2017. Convergent validity: moderate correlation between IMS-Es and MRC-SS (r=.389; P<.001) and significant comparison between groups with and without ICU-acquired weakness (P<.001). Divergent validity: no correlation between IMS-Es and BMI [r (95%CI): -.112 (-.232 to .011)], weight [r (95%CI): -.098 (-.219 to .026)], Charlson [r (95%CI): -.122 (-.242 to .001)] and Barthel [r(95%CI): -.037 (-.160 to .087)] and no differences between sexes (P=.587) or BMI categories (P=.412). Predictive validity: moderate and significant correlations with post-ICU hospital stay [r (95%CI): -.442 (-.502 to -.377)] and physical component of SF-12 (PCS) [r (95%CI): .318 (.063 to .534)]; patients without active mobilisation in ICU increased risk of hospital mortality [OR (95%CI): 3.769 (1.428 to 9.947)]. Interobserver reliability: very good concordance between nurses [CCI (95%CI): .987 (.983 to .990)] and nurse-physiotherapist [CCI (95%CI): .963 (.948 to .974)]. Sensitivity to change: small effect on discharge from ICU (d=.273) and moderate effect at 3months after hospital discharge (d=.709). Minimal important difference: 2-point difference cut-off point, 91.1% sensitivity and 100.0% specificity.

Conclusions: The IMS-Es is useful, valid and reliable for implementation by ICU nurses and physiotherapists in assessing the mobility of critical patients.

Keywords: Critical care; Cuidados intensivos; Debilidad muscular; Early mobilization; Estudio de validación; Fiabilidad; Movilización precoz; Muscle weakness; Reliability; Responsiveness; Sensibilidad; Validation studies; Validez; Validity.