Can handgrip strength reflect muscle dysfunction in individuals in intensive care units? A prospective observational study.

BACKGROUND

Handgrip strength (HGS) is a tool for diagnosing intensive care unit (ICU)-acquired weakness. However, the influence of consciousness on HGS and its relationship with muscle dysfunction in the ICU remain unclear.

OBJECTIVES

This prospective observational study evaluated the feasibility, reliability, and performance of HGS in patients in the ICU with varying levels of consciousness and compared changes in muscle mass and HGS between patients with improved or worsened consciousness during their ICU stay.

METHODS

Critically ill patients in surgical ICUs were assessed daily for HGS, quadriceps muscle thickness, and diaphragm thickness, along with consciousness evaluations using the Richmond Agitation-Sedation Scale (RASS). Muscle thickness was assessed by ultrasound. Patients were categorised into worsened, stable, or improved groups based on RASS score changes. The intraclass correlation coefficient assessed the HGS reliability across consciousness levels. Independent t-tests compared HGS and muscle thickness between patients with better consciousness (RASS -1 to 1) and poorer consciousness (RASS outside -1 to 1). Generalised estimating equations explored HGS and muscle thickness trends between the worsened and improved groups during the ICU stay.

RESULTS

A total of 318 patients (mean age: 66.1 years; 32.4% female) were included in the study. HGS reliability was good in patients with RASS scores of 0 (intraclass correlation coefficient = 0.869). Patients with better consciousness displayed significantly higher HGS and quadriceps thickness than those with poorer consciousness. During ICU stay, HGS increased by 50% in the improved group; it decreased by 22% in the worsened group, showing a significantly opposite trend (p < 0.001). The quadriceps and diaphragm thicknesses decreased in both groups, with no significant differences in the trends between them.

CONCLUSIONS

HGS assessment is feasible and reliable in ICU patients with a RASS score of 0. Improvements in HGS in critically ill patients are associated with improved consciousness rather than muscle mass gain.