Neuromuscular dysfunction associated with delayed weaning from mechanical ventilation in patients with respiratory failure

Peer review under responsibility of Alexandria University Faculty of Medicine.

Available online 21 March 2012

Figures & data

Table 1 Age, sex, BMI and smoking of the studied patients.

Age (mean ± SD)	57.7 ± 15
Sex (No. and %)
Male	10 (52%)
Female	9 (48%)
BMI (mean ± SD)	30 ± 7.9
Smoking (No. and %)
Smokers	10 (48%)
Non-smokers	9 (52%)

SD: standard deviation, BMI: body mass index (kg/m²).

Table 2 Relation between electromyography (EMG) and nerve conduction study findings and the outcome and duration of mechanical ventilation (MV).

EMG and nerve conduction	Outcome of mechanical ventilation			Monte-Carlo-Chi-square (P)	Duration of mechanical ventilation			Monte-Carlo-Chi-square (P)	Total
	Final weaning	Failed weaning and Death	Total		⩾14 days	<14 days	Total
Normal	4 (22%)	1 (5%)	5 (27%)	0.798	2 (10%)	3 (17%)	5 (27%)	0.184	5 (27%)
Myopathy	2 (10%)	0 (0%)	2 (10%)		1 (5%)	1 (5%)	2 (10%)		2 (10%)
Sensory–motor peripheral neuropathy	8 (42%)	4 (21%)	12 (63%)		10 (55%)	2 (10%)	12 (63%)		12 (63%)
Total	14 (73%)	5 (27%)	19 (100%)		13 (6%)	6 (31%)	19 (100%)		19 (100%)

By Monte Carlo-Chi-square test (P < 0.05 = significance).

Table 3 Relation between corticosteroids intake and neuromuscular dysfunction.

EMG and nerve conduction	Corticosteroid intake			Monte Carlo-Chi-Square (P value)	Total
	No steroids	⩾14 days duration of steroids intake	<14 days duration of steroids intake
Normal study	0 (0%)	2 (10%)	3 (17%)	1.000	5 (27%)
Positive findings	2 (10%)	6 (32%)	7 (37%)		14 (73%)
Total	2 (10%)	8 (42%)	9 (48%)		19 (100%)

By Monte Carlo-Chi-Square test, P value < 0.05 represents significant difference.

Table 4 Relation between the mean values of albumin, Mg, Ca, and Ph and neuromuscular dysfunctions.

		Electromyography and nerve conduction findings		Mann–Whitney Z (P)
		Normal study (n:5)	Myopathy or peripheral neuropathy (n:14)
Mean albumin g/dl	Mean ± SD	2.6 ± 0.1	2.4 ± 0.3	0.037^*
	Median	2.6	2.3
	Range	2.5–2.8	2–3.4
Mg (mg/dl)	Mean ± SD	1.6 ± 0.4	1.4 ± 0.3	0.671
	Median	1.7	1.4
	Range	1.1–1.9	1.1–2
Ca (mg/dl)	Mean ± SD	7.6 ± 0.4	7.7 ± 0.5	0.963
	Median	7.6	7.7
	Range	7–8.1	7–9
Ph (mg/dl)	Mean ± SD	3.4 ± 0.2	3.4 ± 0.5	0.607
	Median	3.4	3.5
	Range	3–3.6	2.2–4.1

By Mann–Whitney-U test, P value < 0.05 represents significant difference. Mg: magnesium, Ph: phosphorus, Ca: calcium.

* Denotes significance.

Table 5 Showing relation between PImax and neuromuscular dysfunctions.

Mean PImax cm H2O	EMG and nerve conduction findings		Mann–Whitney Z (P)
	Normal study (n:5)	Myopathy or Peripheral neuropathy (n:14)
Mean ± SD	−18 ± 4	−15 ± 4.4	21 (0.192)
Median	−16	−14.5
Range	−24 to −14	−24 to −10

By Mann–Whitney-U test, P value < 0.05 represents significant difference.