Muscle Strength in ICU Patients Measured by Handgrip Dynamometer and ICU-Acquired Weakness: A Prospective, Single-Center Observational Study

BACKGROUND ICU-acquired weakness (ICU-AW) is a severe neuromuscular complication in critically ill patients, causing significant muscle function impairment. Inconsistent findings on recovery time and factors influencing rehabilitation hinder the development of optimal strategies. This study aimed to evaluate the time needed to achieve muscle strength above the ICU-AW diagnostic cutoff, as well as the 10th (P10) and 50th percentiles (P50), and to identify associated factors. MATERIAL AND METHODS A prospective, single-center observational study was conducted in the ICU at the Medical University of Lublin. Data from 178 patients in an early physiotherapy program were analyzed. Muscle strength was measured using a handgrip dynamometer. The primary outcome was the time to achieve strength above the ICU-AW diagnostic threshold (≥11 kg for men, ≥7 kg for women). Secondary outcomes included factors influencing recovery time and reaching the P10 and P50 of strength. RESULTS The mean time to regain strength above the threshold was 26.84 days. Quartile analysis showed 25% of patients achieved this strength within 5 days, 50% within 13 days, and 75% within 41 days. Duration of ICU stay (HR=0.746, P<0.001), duration of sedation (HR=0.805, P<0.001), duration of mechanical ventilation (HR=0.860, P<0.001), time to regain consciousness (HR=0.942, P=0.016), muscle strength at first measurement (HR=1.045, P=0.007), and weight (HR=1.041, P=0.018) significantly influenced recovery speed. Probability analysis estimated that 32% of patients would reach strength at the P10, and 9% at the P50 during their ICU stay. CONCLUSIONS Variability in muscle strength recovery among ICU patients emphasizes the need for individualized rehabilitation. Future research should optimize identified factors and tailor rehabilitation programs to enhance treatment outcomes.