Efficacy of belt-type EMS in preventing ICU-acquired weakness
Table I. Rehabilitation protocol in control group and electrical muscle stimulation (EMS) group. Each rehabilitation protocol is described.
Belt-electrode skeletal muscle electrical stimulation (B-SES) in the EMS group, or muscle loading with range of motion exercise, kicking
stability ball, standing exercise and ambulation exercise in the control group were introduced in 20 min sessions by physical therapists.
All other physical therapies were applied similarly by the nurses to each patient according to the patient´s condition
EMS group
Control group
Rehabilitation by physical therapists B-SES
707
Time per once, min
Times per day
Rehabilitation intensity adjustment
Rehabilitation by nurses
Time per session, min
Times per day
Rehabilitation intensity adjustment
Range of motion exercise, kicking stability ball, standing exercise
ambulation exercise
20
1
20
1
○
○
Range of motion exercise, mobilization and ambulation Range of motion exercise, mobilization and ambulation
5–20
5–20
3
3
×
×
○ : rehabilitation intensity can be adjusted; ×: rehabilitation intensity can not be adjusted.
CT scanning was performed with 64-line/128-slice CT (120-kV
tube voltage, 150–600-mA tube current (auto-exposure control),
0.35-s scan time, 0.625 × 64 collimation, 1.078 table pitch, and
2.5-mm slice) (Scenaria; Hitachi Ltd, Tokyo, Japan). Scanning
was performed between the femoral head and patella, avoiding
the pelvic organs as far as possible. Analysis was carried out
using a system volume analyser (VINCENT®, Fujifilm Corp.,
Tokyo, Japan). All femoral muscles were extracted with the CT
value of 0–100 in figures, reconstructed using 2.5-mm slices.
Femoral muscle volume (ml) was calculated using sagittal
direction integration of the cross-sectional area of the femoral
muscle (21). The estimated maximum exposure radiation dose
was calculated as 10–18 mGy by Waza-ari, a web-based CT
dose calculation, and was minimized further by avoiding the
pelvic organs. These analyses were performed by a radiology
technician who was blinded to the patient group.
Secondary outcomes were: length of ICU stay, 28-day survi-
val rate, hospital stay and mechanical ventilation, and Barthel
Index (23) at discharge from the hospital. The Barthel Index
at discharge was evaluated by nurses who were blinded to the
patient group.
Age, sex, Acute Physiology, and Chronic Health Evaluation
(APACHE II) score, Sequential Organ Failure Assessment
(SOFA) score and complicating diseases were analysed as
basic characteristics. The use of adjunctive therapy, such as
mechanical ventilation, renal replacement therapy, steroid
therapy, sedatives, vasopressive agents, and muscle relaxants,
were evaluated. The description of sedatives and analgesics,
administered when the first rehabilitation was introduced on
day 2, were also analysed. As nutrition therapy was generally
moved from the acute phase to the post-acute phase on day 7
in our ICU clinical practice (24), total calories per day, total
protein per day and enteral nutrition/total nutrition ratio on
day 7 were analysed for information regarding nutrition given
in both groups.
For intention-to-treat analysis, 28-day survival, lengths of ICU
stay, hospital stay, and mechanical ventilation were analysed
as outcomes.
Sample size estimation
A power analysis using G*Power 3 for Windows (Heinrich
Heine University, Dusseldorf, Germany) was performed during
the planning phase of this study. The effect size was estimated
by referring to our previous work (21), which reported that
mean femoral muscle volume loss for 2 weeks after intensive
care was 20.3% (standard deviation (SD) 10.3%). The detection
effect amount was set as SD × 1, level of significance 0.05, and
power 0.8, then a necessary sample size of 17 was calculated for
each group. Therefore, 20 patients, in whom day 1 and day 10
CT analysis could be performed, were targeted for each group.
Statistical analysis
Differences were assessed using Student’s t-tests, paired t-
tests, χ 2 tests, and one-way analysis of variance between the
control group and EMS group, when normality of distribution
of each parameter was not rejected by Shapiro–Wilk test. A
Mann–Whitney test was performed for ordinal data and when
the normal distribution was rejected. Survival analysis was
conducted using log-rank tests. All statistical analyses were
conducted using software (JMP 14; SAS Institute Inc. [https://
waza-ari.nirs.qst.go.jp/en/index.html]). The results are expres-
sed as means and standard deviations (SD). p-values < 0.05 were
inferred as significant.
RESULTS
The patient flowchart is shown in Fig. 2. During the
study period, 220 patients were admitted to the ICU. Of
these, 126 were excluded, and 94 were included in the
study. The patients were randomly assigned to control
(n = 47) and EMS (n = 47) groups, respectively. A final
total of 16 control group patients and 21 EMS group
patients were included in femoral muscle analysis on
day 10. Most of the drop-outs by day 10 were patients
who recovered and were discharged early. The intensity
and frequency of other rehabilitations were the same
in both groups (Table I).
The basic characteristics for which final muscle
volume analysis was conducted are shown in Table
II. Age, sex, severity score, adjunctive treatments, and
complicating diseases were not significantly different
between groups. Steroid use was almost 30% in both
groups. Muscle relaxants were rarely used. Vasopres-
sive agents and sedatives were administered to almost
all patients in both groups. The use of sedatives and
analgesics was not different between the groups (Table
II). The given nutrition on day 7 was almost 22 kcal/
kg/day, with protein 0.9 g/kg/day, in both groups, with
70% by enteral feeding. Both groups included many
patients with sepsis as a complication.
J Rehabil Med 51, 2019