One-year trajectories of peripheral and inspiratory muscle strength in critical illness survivors: The impact of ICU-acquired weakness.

OBJECTIVE

This prospective cohort study evaluated one-year trajectories of age- and sex-normalized handgrip strength and maximal inspiratory pressure in intensive care unit (ICU) survivors and examined the impact of ICU-acquired weakness (ICUAW) on recovery.

METHODS

ICU survivors from six medical ICUs in Taiwan were enrolled. ICUAW was identified at ICU discharge using the Medical Research Council sum score (MRC-SS). Peripheral and inspiratory muscle strength were assessed by handgrip strength (HGS) and maximal inspiratory pressure (MIP) at ICU discharge and 1, 3, 6, and 12 months, and expressed as age- and sex-specific normative values. Trajectories were analyzed using Generalized Estimating Equations.

RESULTS

275 ICU survivors completed the MRC-SS assessment at ICU discharge; 166 (60.4%) required mechanical ventilation, and 62 (22.5%) screened positive for ICUAW. In the ICUAW group, mean HGS improved from 30.0% to 56.1% and MIP from 15.4% to 36.5% of normative values over one year. In contrast, non-ICUAW survivors improved from 70.2% to 97.5% for HGS and from 35.4% to 63.1% for MIP. Both groups showed significant improvements in HGS and MIP (p < .001), while ICUAW survivors exhibited lower muscle strength than those without ICUAW (HGS: β = -36.8; MIP: β = -23.1; p < .001). Group-by-time interactions were non-significant, indicating parallel improvements with a persistent deficit in the ICUAW group.

CONCLUSIONS

Survivors with ICUAW improved over time but remained consistently below non-ICUAW peers, particularly because of early respiratory weakness. Early screening, reassessment, and targeted peripheral and inspiratory muscle strengthening may help optimize recovery after ICU discharge.