Risk Factors and Electromyographic Characteristics of Acquired Weakness in Critically Ill Patients: A Retrospective Study

Figures & data

Table 1 Demographic and Clinical Characteristics of the Patients at Baseline

	ICU-AW Group	Non-ICU-AW Group
	(N=47)	(N=50)
Characteristic
Age (mean value ±SD)	69.06±12.12	62.20±13.58
Sex no.(%)
Male	34 (72.34)	36 (72.00)
Female	13 (27.66)	14 (28.00)
BMI (mean value ±SD)	21.63±3.24	21.83±2.85
Chronic Diseases (no.)
Hypertension	21 (44.68)*	15 (30.00)*
Diabetes	14 (29.79)*	11 (22.00)*
COPD	12 (25.53)*	1 (2.00)*
Coronary heart disease	8 (17.02)*	4 (8.00)*
Chronic kidney disease	4 (8.51)*	6 (12.00)*
Tumor**	3 (6.38)*	13 (26.00)*
More than one chronic disease	20 (42.55)*	10 (20.00)*
No chronic disease	12 (25.53)*	14 (28.00)*

Notes: *Many patients suffer from two or more chronic diseases simultaneously. **There is no evidence of systemic metastasis or significant malnutrition. Sex was treated using the chi-square test. Age and BMI were processed using independent samples t test, mean value ±standard deviation.

Abbreviations: COPD, chronic obstructive pulmonary disease; BMI, body mass index; SD, standard deviation.

Figure 1 Reasons for admission to the ICU.

Note: Other diseases refers to other diseases that cause respiratory failure aside from those listed in the figure.

Abbreviation: AECOPD, acute exacerbation of chronic obstructive pulmonary disease.

Table 2 APACHE II and SOFA Scores, Limb Circumference, MRC-Scores, Laboratory Results and Prognosis

	ICU-AW Group	Non-ICU-AW Group	P-value
	(n=47) (Mean value ±SD)	(n=50) (Mean value ±SD)
APACHE II score*	19.94±9.11	13.20±5.58	0.000
SOFA score*	6.77±5.05	3.82±3.56	0.001
FC-L	190.85±11.70	209.58±6.40	0.000
UAC-L	234.23±14.18	246.26±11.91	0.000
FC-R	194.17±11.59	206.34±6.66	0.000
UAC-R	236.58±15.00	243.87±12.28	0.010
TC-L	369.04±33.07	406.14±12.61	0.000
CC-L	240.30±17.58	285.52±9.30	0.000
TC-R	366.41±32.82	403.10±13.86	0.000
CC-R	237.12±17.96	281.71±10.66	0.000
MRC scores	29.11±9.20	54.80±3.53
ALB (g/L)	27.11±3.31	37.36±5.18	0.000
PCT (ng/mL)	17.80±29.03	1.74±3.06	0.000
CRP (mg/L)	179.37±78.25	57.54±48.26	0.000
BUN (mmol/L)	19.37±10.98	8.64±5.02	0.000
Cr (μmol/L)	185.68±172.66	103.68±82.63	0.004
CK (U/L)	3426.40±11,663.37	1762.19±10,683.77	0.466
BNP (pg/mL)	1051.38±1596.16	151.75±191.97	0.000
MV (Hours)	595.49±561.71	87.26±36.51	0.000
ICU stay (Days)	27.02±17.78	5.56±2.21	0.000
Hospital stay (Days) **	36.06±25.47	23.20±18.23	0.006
Prognosis no.(%)			0.001
Cure	3 (14.3)	18 (85.7)
Improvement	35 (55.6)	28 (44.4)
Death	9 (69.2)	4 (30.8)

Notes: Patients enrolled in this study included those admitted to the ICU directly from the resuscitation unit, those transferred to the ICU following emergency surgery, those transferred to the ICU postoperatively after completing preoperative examinations in the outpatient clinic, and those transferred from other hospital departments with a duration of hospitalization before ICU admission of less than one week. *The APACHE II score and SOFA score were completed within the first 24 hours of ICU admission. Prognosis was processed using the chi-square test; other variables in the table were processed using the independent samples t test, mean value ± standard deviation.

Abbreviations: FC-L, left forearm circumference; UAC-L, left upper arm circumference; FC-R, right forearm circumference; UAC-R, right upper arm circumference; TC-L, left thigh circumference; CC-L, left calf circumference; TC-R, right thigh circumference; CC-R, right calf circumference; MV (hours), duration of mechanical ventilation (hours); ICU stay (days), length of ICU stay (days); **Hospital stay (days) = the sum of the time spent in ICU monitoring treatment plus the time spent in the general ward after leaving the ICU, MRC scores, Medical Research Council scores; APACHE II score, acute physiology and chronic health status II score; SOFA score, sequential organ failure score; SD, standard deviation.

Table 3 Electromyographic Features (n=29)

	Latency (ms) (Mean value ±SD)	Wave Amplitude (mv) (Mean value ±SD)	Conduction Speed (m/s) (Mean value ±SD)	Unleaded Potential (No.)*
Motor nerves
Peroneal L	11.98±3.15	1.47±0.99	39.49±5.00	11
Tibial L	12.01±2.38	3.65±3.02	42.50±2.49	2
Peroneal R	11.95±1.44	0.95±0.64	43.33±3.29	7
Tibial R	12.74±1.93	4.44±3.58	40.90±3.02	1
Median R	8.16±1.32	2.93±2.28	52.86±5.32	3
Ulnar R	9.80±0.80	2.35±1.55	38.45±1.85	3
Median L	3.73±0.73	4.00±3.03	41.3±26.45	3
Ulnar L	2.78±0.37	4.15±2.45	4.15±0.85	3
Phrenic L	7.64±0.98	0.29±0.09		3
Phrenic R	7.77±1.22	0.33±0.19		1
Sensory nerves
Sural L	2.08±0.49	7.14±5.92	46.69±7.62	7
Superficial peroneal L	2.04±0.32	6.42±5.70	48.44±6.90	9
Sural R	2.19±0.27	8.51±6.24	48.79±4.91	4
Superficial peroneal R	2.18±0.33	6.45±5.59	46.25±6.92	6
Superficial of ulnar L	2.18±0.31	7.23±5.94	55.22±5.92	2
Superficial of ulnar R	2.24±0.27	6.37±3.61	55.11±6.97	1
Median L	2.43±0.27	10.57±8.51	58.73±7.77	1
Median R	2.84±0.32	6.23±3.82	52.61±6.22	1

Notes: Unleaded potential (No.) *Because of the severity of peripheral nerve injury in some patients, motor or sensory potentials are not detected on EMG. Latency, wave amplitude and conduction speed results are expressed as the mean value ± standard deviation.

Abbreviations: EMG, electromyography; Peroneal L, left peroneal nerve; Peroneal R, right peroneal nerve; Tibial L, left tibial nerve; Tibial R, right tibial nerve; Median R, right median nerve; Median L, left median nerve; Ulnar R, right ulnar nerve; Ulnar L, left ulnar nerve; Sural L, left sural nerve; Sural R, right sural nerve; Superficial peroneal L, superficial of left peroneal nerve; Superficial peroneal R, superficial of right peroneal nerve; Superficial of ulnar L, superficial of left ulnar nerve; Superficial of ulnar R, superficial of right ulnar nerve; Median L, nerve of left median; Median R, nerve of right median; Phrenic L, left phrenic nerve; Phrenic R, right phrenic nerve; SD, Standard Deviation.

Table 4 Analysis of the Correlation Between ICU Acquired Weakness and Duration of Mechanical Ventilation, Duration of ICU Monitoring Treatment, Length of Stay and Prognosis

Variables	r	P-value
MV (Hours)	0.548**	0.000
ICU stay (Days)	0.656**	0.000
Hospital stay (Days) *	0.283**	0.005
Prognosis	0.306**	0.002

Notes: **At the 0.01 level (two-tailed), the correlation is significant. Statistical methods used were Pearson correlation analysis.

Abbreviations: *Hospital stay (Days), The sum of the time spent in ICU monitoring treatment plus the time spent in the general ward after leaving the ICU; ICU stay (days), length of ICU stay (days).

Table 5 Logistic Regression Analysis of Risk Factors for ICU-Acquired Weakness

Variables	B	SE	Wald	Beta	P	OR	95%CI
(Constants)	0.57	0.247	2.305		0.024	1.768	(1.089, 2.870)
Age	−0.003	0.002	−1.619	−0.068	0.109	0.997	(0.994, 1.001)
MRC score	0.019	0.002	9.036	0.558	0	1.019	(1.015, 1.024)
APACHE II score	−0.003	0.004	−0.775	−0.048	0.44	0.997	(0.990, 1.005)
SOFA score	0.002	0.007	0.22	0.014	0.827	1.002	(0.988, 1.015)
ALB (g/L)	0.016	0.004	3.611	0.217	0.001	1.016	(1.007, 1.025)
PCT (ng/mL)	−0.001	0.001	−0.888	−0.05	0.377	0.999	(0.996, 1.001)
CRP (mg/L)	−0.001	0	−2.945	−0.161	0.004	0.999	(0.998, 1.000)
BUN (mmol/L)	−0.002	0.003	−0.836	−0.049	0.406	0.998	(0.992, 1.003)
Cr (μmol/L)	4.41E-05	0	0.19	0.012	0.85	1	(1.000, 1.000)
BNP (pg/mL)	2.28E-05	0	0.897	0.054	0.372	1	(1.000, 1.000)
MV (Hours)	−7.40E-05	0	−0.926	−0.069	0.357	1	(1.000, 1.000)
ICU stay (Days)	0	0.003	−0.154	−0.014	0.878	1	(0.994, 1.005)
Hospital stay (Days)	−0.001	0.001	−0.56	−0.027	0.577	0.999	(0.997, 1.001)

Abbreviations: Hospital stay (Days), The sum of the time spent in ICU monitoring treatment plus the time spent in the general ward after leaving the ICU; ICU stay (Days), length of ICU stay (Days); MRC-scores, Medical research council scores; APACHE II score, acute physiology and chronic health status II score; SOFA score, sequential organ failure score; SE, standard error. Statistical methods were analyzed using binary logistic regression.

Data Availability Statement

The authors confirm that the data supporting the findings of this study are available within the article.