Table 1.
Characteristics of included studies assessing muscle wasting
| Author/References | Design/Country/Setting | No. of Population | Inclusion criteria | Tool | Body site | Timing | Muscle mass loss | Outcomes |
|---|---|---|---|---|---|---|---|---|
| 1. Lambell [45] |
RC single centre Australia ICU |
32 Trauma, medical, surgical |
> 18 yo, who had CT scans before admission with routine care and a second or multiple CT scan ≥ 7 days later. Patients included if both CT scans were appropriate for analysis of SMA and if the predominant nutrition route was enteral and/or parenteral (planned > 70% requirements), due to oral intake not being routinely recorded in a quantifiable manner | CT | Skeletal muscle CSA at L3 level | CT scan at week 1 (day 0–7) and second CT scan ≥ 7 days later |
SMA loss in 7 days MD: −21.9 [−29.9 to −13.9] cm2, (149.9 ± 38.8 vs. 127.9 ± 38.4 cm2), p < 0.001 %SMA change per day: −1.27 ± 0.88% cm2 |
Not reported |
| 2. Lee [15, 69] |
PC Single Centre Malaysia ICU |
86 Cardiovascular, respiratory, gastrointestinal, neurology, sepsis, trauma, metabolic, renal, immunocompromised |
Consecutive patients > 17 years old, expected to stay > 96 h on ICU. Patients with ‘normal’ baseline muscle status | USS | Quadriceps muscle layer thickness (QMLT), RF CSA, VI, pennation angle (PA) and fascicle length (FL) | Day 1 (within first 48 h), 7, 14, 22 of ICU admission |
%QMLT compared to baseline: at day 7: −8.61 ± 19.44 at day 14: −15.63 ± 23.75 %RF CSA compared to baseline: at day 7: −9.81 ± 19 at day 14: −22.73 ± 20 |
Every 1% loss of QMLT over the first week of critical illness was associated with 5% increase in 60-day mortality (Adjusted odds ratio [AdjOR] 0.950 for every 1% less QMLT loss, 95% CI 0.90,0.99; p = 0.023 |
| 3. Toledo [14] |
PC single centre Brazil ICU |
74 Sepsis, stroke, lung transplant, cardiac insufficiency |
Patients > 18 years old, needing mechanical ventilation for ≥ 48 h | USS | Quadriceps muscle thickness | Day 1, 3, 7 |
% Quadriceps muscle thickness decrease from day 1 to day 7 Right leg: 15% (± 19.5%) Left leg: 12.7% (± 16%) |
Predictor of survival: cut-off value in muscle thickness of ≤ 1.64 cm on day 7 (HR = 0.7, 95% CI, 0.582–0.801, sensitivity 81%, specificity 63%). Higher probability to remain on mechanical ventilation in patients with 1.64 cm loss of thigh muscle thickness on day 7, HR: 2.1 (95% CI, 1.1–3.8) higher than their counterparts (P = 0.017). Greater loss of thigh muscle thickness on day 7 for worst ICU survival (HR: 3.7; 95% CI, 1.2–11.5) and hospital survival (HR: 4.5; 95% CI, 1.5–13.7) |
| 4. Zhang [26] |
PC Single centre China ICU |
37 Sepsis, pneumonia, severe pancreatitis, liver failure, renal failure, cardiac dysfunction, surgical |
Patients aged ≥ 18 years with an anticipated ICU stay of at least 2 days | USS | RF thickness and CSA, VI and BB muscles | Day 1, 4, 7, 10 | % not reported | Not reported |
| 5. Borges [27] |
PC Single centre Brazil ICU |
45 Severe and septic shock |
Patients > 18 yo with sepsis or severe septic shock within 24 h of admission | USS | RF CSA | Day 2, 4, 6, at ICU discharge and hospital discharge |
RF CSA: day 2: 5.11 ± 0.85cm2 versus day 6: 4.49 ± 0.84cm2; P = 0.001 Daily RF CSA loss: 1.2% During ICU stay average muscle loss of 13.5% compared to baseline |
RF CSA in patients who underwent mechanical ventilation versus those without mechanical ventilation, P = 0.080. RF CSA during hospital stay in mechanically ventilated 17.25% versus patients without ventilation 10.76%, P = 0.001 |
| 6. Dimopoulos [13] |
PC Single centre Greece ICU |
165 Cardiac surgery |
Patients > 18 yo admitted to cardiac ICU within 24 h of cardiac surgery | USS | RF thickness | Day 1, 3, 5, 7 |
RF mass (cm): D1: 1.37 ± 0.25 D3: 1.2 ± 0.5 D5: 1.25 ± 0.52 RF + VI mass(cm): D1: 2.58 ± 0.34 D3: 2.41 ± 0.94 D5: 2.37 ± 0.8 In 5 days RF mass loss by 2.2% [(95%CI: −0.21 to 0.15), P = 0.729] and RF + VI mass loss by 3.5% [(95% CI: −0.4 to 0.22), P = 0.530] |
RF + VI mass < 2.5 cm on D1: longer ICU length of stay (47 ± 74 h vs 28 ± 46 h, P = 0.02) and ventilator time (17 ± 9 h vs 14 ± 9 h, P = 0.05). ICU-AW versus no ICU-AW on D3: longer ventilation (44 ± 14 h vs 19 ± 9 h, P = 0.006) and ECMO (159 ± 91 min vs 112 ± 71 min, P = 0.025) |
| 7. Kemp [12] |
PC Single centre UK ICU |
20 Cardiac surgery |
Adults > 18 yo with elective aortic operation requiring admission to the ICU as identified by the surgical team | USS | RF CSA | Day before surgery and day 1, 3, 7 after surgery |
RF CSA (cm2) at D0: 6.85 ± 1.45 (5.4–8.3) D7: 6.3 ± 1.45 (4.85–7.75) RF CSA mass loss: 8% (6.6–10.2) |
Muscle loss > 10% was associated with longer ICU length of stay (P = 0.038), hospital length of stay (P = 0.014), mechanical ventilation time (P = 0.05) |
| 8. Mayer [16] |
PC Single centre USA ICU |
41 Sepsis or acute respiratory failure |
Adults > 18 yo, diagnosis of acute respiratory failure or sepsis of any origin anticipated to survive and spend > 3 days on ICU, enrolled within 48 h of admission | USS | RF and TA CSA, muscle thickness (mT), echo intensity (EI) | Day 1, 3, 5, 7 |
RF mT: D1 0.98 ± 0.3 versus D7 0.81 ± 0.27, P = 0.0316 RF CSA: D1 2.99 ± 0.99 versus D7 2.47 ± 0.88; P = 0.0253 RF EI: D1 91 ± 24.9 versus D7 99.1 ± 27.6; P = 0.081 TA mT: D1 2.01 ± 0.36 versus D71.82 ± 0.31, P < 0.001 TA CSA: D1 5.3 ± 0.89 versus D7 4.71 ± 0.95, P < 0.001 TA EI: D1 82.7 ± 21.2 versus D7 96.7 ± 22.6; P = 0.002 Changes from D1 to 7 RF mT: 20.1% (12–26) RF CSA: 18.5% (11–23) RF EI: 10.5% (5–20) TA mT: 9.1% (5–12) TA CSA: 8.1% (5–15) TA EI: 15.4% (7–28) |
RF EI in first 7 days of ICU admission predictor of ICU-AW (area under curve = 0.912) |
| 9. McNelly [44] |
RCT Multi-centre UK ICU |
121 mechanically ventilated patients | Adult (> 18 years), expected to be intubated and ventilated for ≥ 48 h; requiring enteral nutrition via nasogastric tube; multi-organ failure (Sequential Organ Failure Assessment [SOFA] score > 2 in ≥ 2 domains at admission); likely ICU stay ≥ 7 days and likely survival ≥ 10 days | USS | RF CSA | At Day 1, 7, 10 in both groups |
Intermittent feed Day 7 −12.9%(95%CI −17.1 to –8.7) Day 10 −18.7% (95% CI −29.8 to −7.6) Continuous feed Day 7: −14.7% (95% CI −19.5 to 9.9) Day 10: −20.6% (95% CI −31.0 to 10.2) P value P = 0.431 P = 0.337 |
Safety profiles, gastric intolerance, physical function milestones, and discharge destinations did not differ between groups |
| 10. Nakamura [46] |
RCT Single centre Japan ICU |
117 Medical and surgical |
Patients admitted to ICU | CT | Femoral muscle volume | Day 1 and 10 | Femoral muscle volume loss was 12.9 ± 8.5% in the high-protein group and 16.9 ± 7.0% in the medium-protein group, with significant difference (p = 0.0059) | For critical care, high-protein delivery provided better muscle volume maintenance, but only with active early rehabilitation |
| 11. Nakanishi [28] |
PC Multi-centre Japan ICU |
56 Respiratory failure, heart failure, sepsis, cardiac arrest, trauma, neurologic |
Consecutive adult > 18 yo, expected to remain in ICU > 5 days. Patients were prospectively recruited within 12 h of ICU admission | USS | RF CSA | Day 1, 3, 5, 7 |
RF CSA loss: –8.6 ± 4.9% on D3, –13.8 ± 5.9% on D5, –18.2 ± 5.6% on D7, respectively (p < 0.01) |
Not reported |
| 12. Nakanishi [29] |
PC Multi-centre Japan ICU |
64 Respiratory failure, sepsis, post-cardiac surgery, heart failure, cardiac arrest, trauma, neurologic |
Expected mechanical ventilation > 48 h, stay in ICU > 5 days | USS | BB CSA, RF CSA | Day 1, 3, 5, 7 and ICU discharge |
BB CSA decreased by 6.0% (95% CI, 4.4–7.6%) D3, 11.0% (95% CI, 9.3–12.7%) D5, and 15.6% (95% CI, 13.5– 17.6%) D7 (p < 0.01) RF CSA decreased by 6.2% (95% CI, 3.3%–9.1%) D3, 12.9% (95% CI, 9.8–15.9%) D5, and 17.1% (95% CI, 13.4%– 20.7%) D7; (p < 0.01) BB CSA loss: 2.24% per day, BB CSA loss: 15.6% per week, RF CSA loss: 2.44% per day, RF CSA: 17.1% per week |
BB and RF muscle atrophy did not predict in-hospital mortality on day 3 (P = 0.70 and P = 0.53, respectively). BB muscle loss predicted mortality on days 5 (P = 0.02) and 7 (P = 0.01). RF muscle atrophy on days 5 and 7 predicted mortality (P = 0.02 and P = 0.01, respectively) |
| 13. Borges [30] |
PC Single centre Brazil ICU |
37 Severe sepsis or septic shock |
Patients > 18 yo diagnosed with severe sepsis or septic shock within 24 h of evolution | USS | RF CSA | Day 2, 4, 6, ICU discharge and hospital discharge |
RF CSA loss: −5.20 ± 0.47 on D2, −4.4 ± 0.45 on ICU discharge and 4.36 ± 0.42 on hospital discharge, (P < 0.05) RF CSA: −1.45% per day; −14.5% ± 7.6 in 10 days |
No difference in RF CSA between patients who underwent mechanical ventilation and in those without; P = 0.08 |
| 14. Dusseaux [47] |
RC Single centre France ICU |
25 Sepsis, septic shock, acute pancreatitis, cardiac arrest, pneumonia, endocarditis |
> 18yo, in ICU for at least 7 days, required mechanical ventilation during their ICU stay, and had abdominal CT scans within the first 48 h of admission to ICU (CT 1: initial assessment) and 7 to 14 days after (CT 2: late assessment CT 2) | CT | Skeletal muscle radiodensity, skeletal muscle mass CSA at L3 vertebra | CT 1: within the first 48 h of admission CT 2: 7 to 14 days later |
SMM (cm2/m2): CT 1 48.73 ± 12.57; CT 2 46.64 ± 10.64 SMD: CT 1 34.86 ± 10.46, CT 2 33.56 ± 7.67 SMM loss: −2.09 (± 6.96); p = 0.183 over 7–14 days SMD loss: −1.3 ± 8.53 over 7–14 days |
No significant correlation was observed between mortality outcome and SMM [P = 0.289; OR 95% CI: 0.93 (0.81–1.060)] or SMD [P = 0.091; OR 95% CI: 1.12 (0.98–1.28)] |
| 15. Haines [48] |
RC Single centre UK ICU |
10 7 Trauma |
All trauma admissions admitted to the adult ICU either directly or via the operating theatre |
Urea/creatinine ratio CT |
Total abdominal muscle CSA measured at the level of the third lumbar (L3) vertebrae, and psoas muscle CSA was calculated at the L4 level |
CT 1: on admission CT 2: within 1–9 days or after 10 days of ICU stay |
At the second CT urea/creatinine ratio negatively correlated with L4 psoas and L3 muscle cross-sectional areas (R2 0.39, p < 0.001) | |
| 16. Nakanishi [31] |
PC Single centre Japan ICU |
21 surgical, non-surgical | Adults > 18yo expected mechanical ventilation > 48 h, stay in ICU > 5 days | USS, BIA | Combined BB and RF CSA | Day 1, 3, 5, 7, 10 |
Muscle mass: on D3 −9.2% (95% CI, 5.9–12.5%), on D5 −12.7% (95% CI, 9.3–16.1%), on D7 −18.2% (95% CI, 14.7–21.6%), on D10 −21.8% (95% CI, 17.9–25.7%) (P < 0.01) Muscle loss: −2.6% per day; −18.2% per week |
Not reported |
| 17. Trung [32] |
PC Single centre Vietnam ICU |
79 Tetanus |
Patients ≥ 16 y of age with a clinical diagnosis of generalized tetanus and within 48 h of ICU admission | USS | RF CSA | Day 1, 7, 14, at hospital discharge |
RF CSA loss: −7.43 ± 3.17 at D7, −11.59 ± 4.52 at D14, −13.2 ± 5.4 at discharge Muscle loss between admission and discharge P < 0.01 |
Not reported |
| 18. Wandrag [33] |
PC Multi-centre UK ICU |
43 Pneumonia, cardiology/cardiac surgery, neurology/neurosurgery, sepsis, septic shock, major trauma, traumatic brain injury, gastroenterology, gastrointestinal surgery, HIV, multi-organ failure, renal failure |
Patients > 18yo, anticipated to be ventilated > 48 h | USS | Combined muscle depth BB, forearm (flexor compartment of muscle) and thigh (rectus femoris and vastus intermedius) | Day 1, 3, 7 and 14 | Total muscle depth (cm): D1: 7.6 ± 3.7, D7: 6.5 ± 3.1; MD (cm): −1.1 (1.5–0.7), P < 0.0001 | |
| 19. Hadda [34] |
PC Single centre India ICU |
70 Sepsis |
Adults > 18 years old, diagnosis of sepsis (non-surgical) | USS | BB thickness and quadriceps muscles | Day 1, 3, 5, 7, 10, 14 and then weekly until discharge or death |
On day 7 percentage muscle thickness loss [median (IQR)] BB: 7.61 (− 1.51, 32.05) %; P < 0.001 Quadriceps: 10.62 (− 1.48, 32.06) %, p < 0.001); P < 0.001 |
Decline in muscle thickness was significantly higher among patients with worse outcome at 90 days |
| 20. Hayes [35] |
PC Single centre Australia ICU |
25 ARDS, bridge to transplant, pulmonary hypertension, cardiac failure/infarction, cardiac arrest |
Patients > 18 yo expected to be on ECMO > 24 h or > 5 days in ICU prior to recruitment | USS | RF CSA | At baseline, day 10, day 20 |
RF CSA loss: 4.2 ± 1.3 at D1, 3.4 ± 1.1 at D10 compared to baseline: RF CSA −19.2% [95% CI, − 13.7 to − 24.8%], P < 0.001 at day 10; −30.5% [95% CI, − 24.1 to − 36.9], P < 0.001 at day 20 |
Not reported |
| 21. Katari [36] |
PC Single centre India ICU |
100 Mixed medical and surgical |
Patients 18–90 years old, anticipated ICU stay > 7 days | USS | Total anterior thigh thickness, RF thickness, and combined thickness of VI and RF | Day 1, 3, 7 |
RF thickness: D1: 1.37 ± 0.41, (0.96) D3: 1.26 ± 0.41, D7: 1.22 ± 0.47; P < 0.001 respectively RF thickness: −11 (± 38.5)% at D7 compared to baseline |
Not reported |
| 22. Nakanishi [37] |
PC Single centre Japan ICU |
28 Mixed ICU patients |
Expected mechanical ventilation > 48 h, stay in ICU > 5 days | USS | BB and RF thickness and CSA | Day 1, 3, 5, 7 |
Loss compared to baseline: BB thickness at D7 −13.2%; P < 0.01 BB CSA at D7-16.9%; P < 0.01 RF thickness at D7: −18.8% RF CSA at D7: −20.7% |
Not reported |
| 23. Palakshappa [17] |
PC Single centre USA ICU |
29 Medical patients with sepsis and shock or respiratory failure |
Admitted to the medical ICU with a diagnosis of sepsis complicated by respiratory failure or shock requiring vasopressors for a minimum of 6 h, and an anticipated ICU length of stay > 48 h | USS |
RF CSA Quadricep muscle thickness |
On Day 0 and Day 7 |
RF CSA decreased by 23.2% Quadriceps thickness decreased by 17.9% |
Quadriceps muscle thickness shows a weak correlation with the strength RF CSA depicts a moderate correlation with the strength |
| 24. Pardo [24] |
PC Single centre France ICU |
29 Mixed ICU patients |
> 18 years old, expected ICU stay > 7 days, patients to receive muscle US as part of usual care | USS | Quadriceps femori muscle thickness | Day 1, 3, 5, 7, 21 |
Quadriceps femori at admission: 1.72 [95% CI, 1.62; 2.13], D7: 1.45 [95% CI, 1.24; 1.665] P < 0.01, D21: 1.30 [95% CI, 0.80; 1.48] P < 0.01 Quadriceps femori loss: 16% over a week |
Not reported |
| 25. Silva [38] |
PC Single centre Brazil ICU |
22 TBI |
Patients 18–60 yo and mechanically ventilated | USS | TA, BB and RF muscle thickness | Day 1, 7, 14 |
Muscle wasting at D14 compared to baseline: RF: −22% P = 0.0001, TA: −19% P = 0.0001, BB: −12% P = 0.0004 |
Not reported |
| 26. Annetta [39] |
PC Single centre Italy ICU |
38 Trauma |
Trauma patients with an injury severity score (ISS) exceeding 25, admitted to ICU within few hours after the injury. Only well-nourished, previously healthy subjects, aged 18–59 yo | USS | RF and TA CSA | Admission day, 5, 10, 15, 20 |
RF CSA (cm2): D0: 6.1 [5.1–7.3], D5: 5.9 [4.8–6.3], D10: 5.1 [4.3–6.2], D15: 4.6 [3.8–5.3], D20: 3.5 [3.2–4.7] AT CSA (cm2): D0: 5.6 [4.5–6.4], D5: 4.8 [3.7–5.6], D10: 4.0 [3.7–5.2], D15: 4.0 [3.3–4.8], D20: 4.2 [3.4–4.7] Overall 45% reduction in RF CSA during the first 20 days of ICU stay; 15% loss from day 5 to 10, 12% from day 10 to 15, 21% from day 15 to 20 TA CSA 22% loss during the overall ICU stay, P = 0.30 |
Not reported |
| 27. Puthucheary [40] |
PC Multi-centre UK ICU |
43 Surgical and medical |
All patients were recruited within 24 h of admission to a university hospital and a community hospital and were expected to survive intensive care unit (ICU) admission after being invasively ventilated for over 48 h and in the ICU longer than 7 days | USS | RF thickness and RF CSA | Day 1, 7, 10 |
RF thickness Day 7: −5.88 (−11.69, −0.06) Day 10: −9.65 (−15.43, −3.84 (P = 0.031) RF CSA Day 7: −13 (−16.5, −9.48) Day 10: −17.72 (−21.15; −14.29) (P = 0.004 |
ΔRFCSA was greater in those with knee extensor weakness than those without (20.7% [95% CI, 13.7–27.7] vs. 8.4% [95% CI, 2.5–14.3], respectively; P = 0.012). ΔThickness did not differ between these groups (12.6% [95% CI, 0.94–24.2] vs. 12.1 [95% CI, 2.7–21.5], respectively; P = 0.95). In a bivariable logistical regression, ΔRFCSA was associated with knee extensor weakness (odds ratio, 1.101 [95% CI, 1.011–1.199]; P = 0.027), but Δthickness was not (odds ratio, 1.001 [95% CI, 0.960–1.044]; P = 0.947) |
| 28. Segaran [41] |
PC Single centre UK ICU |
39 Surgical, medical, trauma |
Patients > 18 yo, BMI > 19 kgm−2, expected to be mechanically ventilated > 48 h, and artificially fed | USS | Muscle depth of BB, forearm and thigh | Day 1, 3, 5, 7, 12, 14 | Muscle loss per day:2.93%, at D7: 20.53% | Not reported |
| 29. Turton [42] |
PC Single centre UK ICU |
22 Mechanically ventilated critically ill patients |
Patients who > 18 years of age who were assented within 24 h of being intubated and admitted to the participating intensive care units were included in the study | USS |
Pennation Angle and Fascicle Length and Muscle thickness Upper Limb: Right Elbow Flexor Compartment Lower Limb: Right Vastus Lateralis The right medial head of the gastrocnemius |
On days 1, 5 and 10 |
Elbow flexor compartment and gastrocnemius muscle thickness did not significantly change Vastus Lateralis pennation angle and muscle thickness significantly reduced by day 5 Fascicle length did not significantly change for all three muscle groups |
Muscle thickness and architecture of vastus lateralis undergo rapid changes during the early phase of admission to a critical care environment |
| 30. Parry [25] |
PC Single centre Australia ICU |
22 Mixed medical and surgical |
Adults ventilated > 48 h, remain at least 4 days in ICU | USS | RF thickness, vastus lateralis thickness, VI thickness, RF CSA | Baseline (day 1), day 3, day 5, day 7, day 10 |
Compared to baseline: RF Thickness: D3: −8.7%, D5: −16.6%, D7: −24.9%, D10: −30.4%.; VI Thickness D3: −1.3%, D5: −18.1%, D7: −20.0%, D10: −29.7% VL thickness D3: −0.2%, D5: −5.7%, D7: −6.0%, D10: −14.1% RF CSA D3: −1.0%, D5: −11.8%, D7: −16.8%, D10: −29.9% |
Correlation between ICU discharge and RF, VI, VL thickness (P < 0.05) |
| 31. Jung [49] |
RC Single centre France ICU |
23 Mixed ICU patients |
Admitted to ICU and had CT scan before admission, CT scan during ICU, at least one measure of diaphragmatic contractility | CT scan | Psoas volume, CSA of skeletal muscles at L3 vertebra examination with 64-section spiral CT | Baseline and 25 days after ICU admission |
Psoas volume baseline:272 ± 116, D25: 233 ± 108; P < 0.01 Skeletal muscle CSA cm2/m2 baseline: 17.1 ± 5.4, D25: 16.1 ± 5.2 Psoas loss: 14.34% skeletal muscle CSA loss: 5.85% |
Not reported |
| 32. Puthucheary [11] |
PC Single centre UK ICU |
63 Sepsis, trauma, intracranial bleeding, acute liver failure, cardiogenic shock |
Patients > 18 yo, anticipated to be intubated > 48 h, spend > 7 days in critical care, and to survive ICU stay | USS; 28 patients were assessed by USS, ration protein DNA, histopathological analysis | RF CSA, biopsy, histological samples | Day 1, 3, 7, 10 |
RF CSA mm2 at D1: 514 (464–566), D3: 495 (442–549), D7: 450 (402–498), D10: 423 (378–469) From days 1 to 7 (− 12.5% [95% CI, − 15.8% to − 9.1%]; P = 0.002), and to day 10 (− 17.7% [95% CI, − 20.9% to − 4.8%]; P < 0.001) In 28 patients assessed by all 3 methods on days 1 and 7, the rectus femoris cross-sectional area decreased by 10.3% (95% CI, 6.1% to 14.5%), the fibre cross-sectional area by 17.5% (95 CI%, 5.8% to 29.3%), and the ratio of protein to DNA by 29.5% (95% CI, 13.4% to 45.6%) |
Not reported |
| 33. Reid [43] |
PC Single centre UK ICU |
50 Sepsis, cardiac, respiratory failure, multiple trauma, head injury, head injury, medical |
Patients > 18yo admitted to the ICU for ventilatory support > for 5 days or longer | USS | Mid-upper arm circumference and muscle thickness | 1–3-day intervals between 5 and 39 days (median 7 days) |
Muscle thickness at baseline: 4.5(2.6–6.8); change at D7: −0.57(0.2–2.3) Muscle loss: 1.6%(0.2–5.7) per day, 12.05%(0–46.7) |
Not reported |
PC prospective cohort, RC retrospective cohort, RCT randomised controlled trial, ICU intensive care unit, CT computed tomography, USS ultrasound sonography, CSA cross-sectional area, SMA skeletal muscle area, MD median difference, RF rectus femoris, VI vastus intermedius, BB bicep brachii, TA tibia anterior, mT muscle thickness, D day, ICU-AW intensive care unit acquired weakness