Effects of high-dose L-carnitine supplementation on diaphragmatic function in patients with respiratory failure: A randomized clinical trial

Figures & data

Figure 1. M-mode and 2D-mode ultrasonographic images of diaphragmatic function.

A, B: Diaphragmatic excursions (D) Ein 2D, and M-ModesC, D: Diaphragmatic thickness (DT), and thickening fraction in 2D -Mode

Table 1. Clinical and demographic variables of the patients.

Variable	Total (N = 60)		Low-dose L-carnitine (N = 30)		High-dose L-carnitine (N = 30)		p-value
	Mean or N	SD or %	Mean or N	SD or %	Mean or N	SD or %
Age (yrs.)	55.05	15.35	56.3	15	53.8	15.9	0.52*
Height (cm)	163.50	8.88	163.8	8.14	163.2	9.69	0.79*
Weight (kg)	77.77	13.48	77.4	12.2	78.1	14.9	0.83*
Sex
female	23	38.33	11	36.67	12	40	0.79†
Male	37	61.67	19	63.33	18	60
L-carnitine level (nmol/ml)	44.85	11.62	43.7	11.1	46	12.2	0.87*
L-carnitine status
Deficient	14	23.33	7	23.33	7	23.33	1†
Normal	46	76.67	23	76.67	23	76.67
Diaphragmatic excursion (mm)	13.35	4.01	12.97	3.25	13.73	4.67	0.46*
Diaphragmatic thickening fraction (%)	35.97	4.71	36.07	4.97	35.87	4.52	0.87*

*Independent t-test. † chi-square test. p-value < 0.05 was considered statistically significant.

Figure 2. Serum L-carnitine levels in patients with RF after high or low-dose L-carnitine supplementation.

A. Serum L-carnitine levels in both groups at 0, 3, and 7 days. B. Changes in serum L-carnitine levels from day 0 to day 7 in the two groups. The significance of differences in L-carnitine levels between the two groups at each time point was determined by one-way ANOVA and Tukey’s test. A p-value < 0.05 was considered statistically significant.

Figure 3. Changes in diaphragmatic function parameters.

A: Differences between diaphragmatic excursion (DE) in each group at days 0, 3, and 7. B: Each group changes in DE from day 0 to day 7. C: Differences in diaphragmatic thickening fraction (DTF) in each group from days 0,3, and 7. D: Changes in DTf from days 0,3, and 7 in each group. Significance was determined by one-way ANOVA with Tukey’s post-hoc test. Significance was determined by independent t-tests. A p-value < 0.05 was considered statistically significant.

Figure 4. Correlations between serum L-carnitine levels and diaphragmatic parameters.

A. Correlations between L-carnitine and diaphragmatic excursion (DE). B. Correlations between Lcarnitine and diaphragmatic thickening fraction (DTf). The sign before “r” denotes the direction of the relationship. Correlations between L-carnitine and the two diaphragmatic parameters were identified using Pearson’s correlation coefficient

Table 2. Effects of L-carnitine on parameters of the diaphragmatic function.

	diaphragmatic excursion		diaphragmatic thickening fraction
	Coefficient	p-value*	Coefficient	p-value*
Unadjusted
L-carnitine level	0.17	< 0.001	0.25	< 0.001
L-carnitine dose (high)	2.1	0.04	1.29	0.25
Adjusted for age and sex
Age	0.003	0.913	0.015	0.655
Sex (male)	2.718	0.008	2.94	0.01
L-carnitine level	0.155	0.001	0.23	< 0.001
L-carnitine dose (high)	2.208	0.025	1.46	0.175

*Linear regression analysis. p-value < 0.05 was considered statistically significant.

The sign before each coefficient value denotes the direction of the relationship.