Table 2.

Clinical, echocardiographic and respiratory ultrasound variables

Variable	Failed extubation (n = 11)	Successful extubation (n = 42)	Unadjusted OR (95% CI)	p value
RSBI (breath/min/l) median (IQR)	48.0 (35.1–72.0)	33.5 (25.6–55.4)	1.03 (1.00–1.06)	0.03
BNP (pmole/l) median (IQR)	372 (152–1620)	233 (95–475)	1.0 (0.99–1.00)	0.72
Echocardiographic variables
LVEF (%) median (IQR)	50 (45–55)	65 (53–65)	0.96 (0.91–1.0)	0.1
E median (IQR)	0.87 (0.68–1.04)	0.83 (0.68–0.99)	5.43 (0.35–85.2)	0.22
E/A median (IQR)	1.20 (0.60–1.64)	1.13 (0.85–1.36)	0.99 (0.38–2.59)	0.99
EDT median (IQR)	175 (125–259)	180 (155–217)	0.99 (0.98–1.01)	0.87
E′ median (IQR)	0.07 (0.05–0.11)	0.10 (0.08–0.12)	0.00 (0.00–1.36)	0.052
E/E′ median (IQR)	10.9 (8.7–18.0)	7.7 (6.4–10.6)	1.27 (1.05–1.54)	0.01
LAA median (IQR)	25.0 (19.3–32.0)	20.0 (18.0–23.7)	1.14 (1.02–1.28)	0.02
IAS fixed curvature n (%)	7 (72.7)	8 (17.1)	12.95 (2.73–61.41)	0.001
Lung ultrasound
Aeration score of left and right anterior and lateral region (upper and lower zones) median (IQR)	17 (8–20)	11 (8–13)	1.41 (1.01–1.82)	0.007
Aeration score of left and right lungs total median (IQR)	22 (13–28)	18 (13–21)	1.12 (0.99–1.27)	0.06
Diaphragmatic dysfunction n (%)
No diaphragmatic dysfunction	5 (45.5)	24 (57.1)		0.53
Hemidiaphragm dysfunction	4 (36.4)	15 (35.7)	1.28 (0.29–5.53)	0.26
Diaphragm dysfunction	2 (18.2)	3 (7.1)	3.2 (0.41–24.41)	0.49

Normal values of the parameters listed in the table are as follows: RSBI: < 105, BNP < 29 pmol/l, LVEF < 50%, E 73 ± 19 cm/s, A 69 ± 17 cm/s, E/A 1.20 ± 0.20, DT 192 ± 40 ms, E′ 12 ± 4 cm/s, E/E′ 10 ± 2, hemidiaphragm excursion ≥ 1.0 cm

IAS: interatrial septum; IQR: interquartile range; LAA: left atrial area; LVE/E: left ventricular early diastolic trans-mitral flow velocity; E wave: early diastolic mitral annulus velocity E′ ratio; LVEF: left ventricular ejection fraction; OR: odds ratio, RSBI: rapid shallow breathing index