Background
Methods
Design and ethical approval
Inclusion and exclusion criteria
Medical Research Council score (the reference standard)
Neuromuscular ultrasound measurements (the index test)
Clinical data collection
Sample size estimation
Statistical analysis
Results
No ICU-AW
N = 30 | ICU-AW
N = 41 |
P value | |
---|---|---|---|
Male (%) | 22 (73) | 25 (61) | 0.41 |
Age (median years [IQR]) | 62 [49–69] | 60 [51–70] | 0.80 |
Body length (median cm [IQR]) | 175 [170–180] | 172 [168–183] | 0.46 |
Body weight (median kg [IQR]) | 75 [70–81] | 75 [65–90] | 0.66 |
History of myopathy (%) | 0 (0) | 1 (2) | 1.00 |
History of polyneuropathy (%) | 0 (0) | 0 (0) | 1.00 |
Any polyneuropathy risk factor in history (%) | 14 (47) | 22 (54) | 0.73 |
Diabetes mellitus (%) | 2 (7) | 5 (12) | 0.69 |
Alcohol abuse (%) | 5 (17) | 10 (24) | 0.56 |
Kidney failure (%) | 2 (7) | 1 (2) | 0.57 |
Chemotherapy (%) | 7 (23) | 9 (22) | 1.00 |
Admission reason (%) | 0.87 | ||
Medical (%) | 12 (40) | 18 (44) | |
Emergency surgical (%) | 9 (30) | 10 (24) | |
Elective surgical (%) | 9 (30) | 13 (32) | |
Dominant hand right (%) | 26 (90) | 34 (92) | 1.00 |
APACHE IV score (median [IQR]) | 58 [50–77] | 71 [61–85] | <0.01 |
Maximum total SOFA score before ultrasound (median [IQR]) | 8 [8–12] | 12 [10–14] | <0.01 |
Sepsis before ultrasound (%) | 18 (60) | 32 (78) | 0.17 |
Mean MRC (median [IQR]) | 4.4 [4.0–4.7] | 3.5 [2.8–3.7] | NA |
Day of MRC (median [IQR]) | 7 [4–11] | 9 [6–14] | 0.02 |
Day of NMUS (median [IQR]) | 7 [5–10] | 9 [6–14] | 0.02 |
Length of MV (median days [IQR]) | 6 [3–8] | 8 [5–17] | 0.01 |
Length of stay on ICU (median days [IQR]) | 9 [6–13] | 15 [9–23] | <0.01 |
Death in ICU (%) | 0 (0) | 2 (5) | 0.51 |
Muscle ultrasound
No ICU-AW | ICU-AW |
P value | ROC–AUC (95% CI) | |
---|---|---|---|---|
Thickness | ||||
BB thickness [mean cm (SD)] | 2.6 (0.6) | 2.2 (0.5) | 0.002* | 68.0 (55.4–80.7) |
FCR thickness [mean cm (SD)] | 1.1 (0.2) | 1.0 (0.2) | 0.035* | 64.5 (50.4–78.7) |
RF thickness [mean cm (SD)] | 3.1 (0.9) | 2.8 (0.8) | 0.258 | 55.6 (41.8–69.4) |
TA thickness [mean cm (SD)] | 2.2 (0.4) | 2.1 (0.4) | 0.558 | 54.3 (40.3–68.3) |
Z-score thickness | ||||
BB z-score thickness [mean (SD)] | 0.1 (0.6) | −0.3 (0.5) | 0.011* | 66.7 (53.7–79.6) |
FCR z-score thickness [mean (SD)] | −0.7 (1.2) | −1.3 (0.9) | 0.033* | 65.5 (51.3–79.7) |
RF z-score thickness [mean (SD)] | −0.5 (0.7) | −0.6 (0.8) | 0.656 | 53.2 (39.4–67.1) |
TA z-score thickness [mean (SD)] | −0.4 (0.7) | −0.4 (1.0) | 0.818 | 51.3 (37.5–65.1) |
Echo intensity | ||||
BB absolute echo intensity [mean gray scale level (SD)] | 76.2 (14.1) | 79.1 (16.4) | 0.434 | 57.6 (44.0–71.3) |
FCR absolute echo intensity [mean gray scale level (SD)] | 62.3 (12.6) | 67.7 (13.6) | 0.095 | 63.2 (49.6–76.9) |
RF absolute echo intensity [mean gray scale level (SD)] | 77.2 (17.0) | 83.9 (14.8) | 0.094 | 60.2 (46.4–74.0) |
TA absolute echo intensity [mean gray scale level (SD)] | 88.6 (12.4) | 94.6 (12.1) | 0.046* | 60.8 (47.4–74.1) |
Z-score echo intensity | ||||
BB z-score echo intensity [mean (SD)] | 0.5 (1.4) | 0.7 (1.9) | 0.519 | 56.3 (42.8–69.9) |
FCR z-score echo intensity [mean (SD)] | 1.4 (1.6) | 1.9 (2.0) | 0.207 | 59.2 (45.2–73.2) |
RF z-score echo intensity [mean (SD)] | 1.0 (1.6) | 1.6 (1.8) | 0.137 | 58.7 (45.0–72.4) |
TA z-score echo intensity [mean (SD)] | 1.0 (1.2) | 1.5 (1.4) | 0.118 | 59.4 (45.9–72.9) |
Echo intensity SD | ||||
BB echo intensity SD [mean gray scale level(SD)] | 29.0 (4.0) | 28.5 (4.4) | 0.585 | 53.3 (39.6–67.0) |
FCR echo intensity SD [mean gray scale level(SD)] | 21.3 (3.1) | 20.8 (3.9) | 0.573 | 56.2 (42.2–70.2) |
RF echo intensity SD [mean gray scale level(SD)] | 24.2 (3.3) | 23.5 (3.5) | 0.398 | 55.9 (42.0–69.8) |
TA echo intensity SD [mean gray scale level (SD)] | 25.8 (3.6) | 26.2 (3.9) | 0.698 | 54.4 (40.5–68.3) |
Z-score echo intensity SD | ||||
BB z-score echo intensity SD [mean (SD)] | 0.3 (1.5) | 0.1 (1.5) | 0.746 | 53.3 (39.6–67.0) |
FCR z-score echo intensity SD [mean (SD)] | 0.8 (1.4) | 0.6 (1.7) | 0.716 | 55.0 (41.0–69.1) |
RF z-score echo intensity SD [mean (SD)] | 0.1 (1.6) | 0.04 (1.4) | 0.890 | 54.2 (36.9–65.5) |
TA z-score echo intensity SD [mean (SD)] | −0.3 (1.1) | −0.2 (1.4) | 0.777 | 55.0 (41.1–68.9) |
Cutoff | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | |
---|---|---|---|---|---|
BB thickness |
Z-score < −2 | 3 | 97 | 50 | 43 |
FCR thickness |
Z-score < −2 | 27 | 83 | 67 | 48 |
RF thickness |
Z-score < −2 | 3 | 97 | 50 | 43 |
TA thickness |
Z-score < −2 | 8 | 93 | 60 | 43 |
BB echo intensity |
Z-score > 2 | 36 | 67 | 58 | 44 |
FCR echo intensity |
Z-score > 2 | 46 | 73 | 68 | 52 |
RF echo intensity |
Z-score > 2 | 36 | 67 | 58 | 44 |
TA echo intensity |
Z-score > 2 | 38 | 80 | 71 | 49 |
Nerve ultrasound
No ICU-AW | ICU-AW |
P value | ROC–AUC (95% CI) | |
---|---|---|---|---|
Median nerve | ||||
CSA wrist [mean mm2 (SD)] | 10.7 (3.5) | 8.9 (2.1) | 0.020* | 66.7 (53.6–79.9) |
CSA proximal [mean mm2 (SD)] | 7.3 (1.8) | 7.6 (1.7) | 0.445 | 52.5 (38.6–66.4) |
Thickness proximal [mean mm (SD)] | 2.4 (0.4) | 2.4 (0.4) | 0.977 | 51.0 (37.2–65.2) |
Intraneural vascularization proximal (%)a
| 6 (20.0) | 10 (25.6) | 0.793 | |
Peroneal nerve | ||||
CSA fibular head [mean mm2 (SD)] | 10.8 (3.5) | 11.7 (5.0) | 0.504 | 53.1 (35.6–70.7) |
CSA knee fold [mean mm2(SD)] | 8.2 (3.3) | 8.2 (3.0) | 0.999 | 52.4 (36.9–67.9) |
Thickness knee fold [mean mm (SD)] | 2.2 (0.4) | 2.3 (0.4) | 0.505 | 54.6 (38.9–70.2) |
Intraneural vascularization proximal (%)a
| 3 (12.0) | 4 (14.3) | 1.000 |