A recent trial evaluated the short-term efficacy of a suspension-based lower-limb rehabilitation device (SS) in patients with intensive care unit–acquired weakness (ICUAW). ICUAW is a frequent and serious complication of critical illness, characterised by symmetrical limb weakness, prolonged mechanical ventilation, functional impairment, and reduced quality of life. Despite widespread recommendations of early mobilisation, optimal rehabilitation strategies for ICUAW remain unclear.
In this study, the researchers investigated whether adding SS-assisted therapy to conventional rehabilitation could better preserve muscle mass and improve functional outcomes compared with conventional therapy alone.
The study was conducted over a two-year period at a large tertiary hospital ICU centre in Shanghai, China. A total of 60 patients with confirmed ICUAW, defined by a Medical Research Council (MRC) sum score below 48, were enrolled. Using a within-patient design, one lower limb of each participant was randomly assigned to receive SS-assisted rehabilitation in addition to standard physiotherapy (intervention limb), while the contralateral limb received standard physiotherapy alone (control limb). This design was chosen to minimise inter-individual confounding factors such as nutritional status and comorbidities. Both limbs received 40 minutes of therapy per day, five days per week, for two consecutive weeks. Outcomes were assessed at baseline, one week, and two weeks.
The primary outcome was lower-limb muscle thickness, assessed by musculoskeletal ultrasound. Measurements focused on key muscles commonly affected by ICUAW, including the rectus femoris, vastus intermedius, vastus medialis, vastus lateralis, and tibialis anterior. Secondary outcomes included muscle strength assessed using the MRC score, active range of motion (AROM) of the hip and knee, and lower-limb circumference. Safety, feasibility, and patient satisfaction were also evaluated.
Conventional rehabilitation consisted of stretching, passive and active range-of-motion exercises, muscle strengthening, breathing exercises, and sitting posture training, tailored to each patient’s tolerance and clinical stability. The SS intervention involved a suspension-based robotic device that supported the limb in a supine position, allowing passive and active-assisted multi-joint movements of the hip and knee. Training parameters such as speed and range of motion were individualised, and sessions were supervised by trained physiotherapists. The device was applied only to the intervention limb to minimise cross-over effects.
Of the 316 patients screened, 60 were enrolled, and 54 completed the full two-week intervention. Baseline characteristics and outcome measures were comparable between intervention and control limbs.
The results demonstrated a significant interaction between treatment group and time for muscle thickness. While both limbs exhibited some degree of muscle loss over the two-week period, the decline was substantially greater in the control limb. At two weeks, muscle thickness in the control limb was significantly lower than in the intervention limb. Within the control limb, muscle thickness was significantly reduced at both one and two weeks compared with baseline, whereas no significant change over time was observed in the intervention limb. These findings indicate that SS-assisted rehabilitation attenuated progressive muscle atrophy rather than reversing it.
Secondary outcomes supported these results. MRC scores showed a significant group-by-time interaction, with the control limb demonstrating lower muscle strength than the intervention limb at both one and two weeks. Similarly, AROM of the hip and knee declined more in the control limb, with significantly poorer values compared with the intervention limb at both follow-up points. In contrast, no significant differences were observed for lower-limb circumference, suggesting that circumference measurements may be insufficiently sensitive to detect short-term functional changes.
Exploratory subgroup analyses suggested that older patients and those with normal body mass index derived greater benefit from the intervention, whereas sex did not modify treatment effects. However, the authors caution that these findings are preliminary due to the limited sample size. Measurement reliability for ultrasound assessments was excellent, with very high intraclass correlation coefficients. Sensitivity analyses using per-protocol and last-observation-carried-forward approaches confirmed the consistency of the primary findings.
The intervention was well tolerated, with no adverse events attributed to the suspension device. Patient satisfaction was high, with over 90% of participants reporting satisfaction with SS-assisted rehabilitation. The authors highlight the practical advantages of the suspension-based system, including bedside feasibility, multi-planar movement capability, and reduced physical burden on therapists compared with manual mobilisation.
These findings show that SS-assisted rehabilitation can slow muscle wasting, preserve strength, and maintain joint mobility in patients with ICUAW. The device’s flexible, low-load, and controllable movements may enhance neuromuscular activation while remaining safe for critically ill patients.
Adding suspension-based lower-limb rehabilitation to standard care can mitigate muscle atrophy and improve short-term functional outcomes in patients with ICU-acquired weakness, supporting its potential as a novel and feasible rehabilitation strategy in the ICU setting.
Source: Critical Care
Image Credit: iStock
